@article {354, title = {Phytophthora alni subsp. uniformis found in Alaska beneath thinleaf alders}, journal = {Plant Health Progress}, year = {2008}, abstract = {

Phytophthora alni Brasier \& S. A. Kirk 2004 is an emergent pathogen causing a lethal root and collar disease of alder species in Europe. The species has not been previously found in North America, although an isolate tentatively referred to as P. alni was reported in a survey of nurseries in Minnesota. The potential establishment and spread of this complex of pathogens is perceived to represent a threat to all species of Alnus in the western hemisphere.

}, doi = {doi:10.1094/PHP-2008-1212-02-BR}, url = {http://www.plantmanagementnetwork.org/php/elements/sum2.aspx?id=7094}, author = {G. C. Adams and M. Catal and L. Trummer and Hansen, E.M. and P. Reeser and J. J. Worrall} } @article {1289, title = {Strong genetic differentiation between North American and European populations of Phytophthora alni subsp. uniformis}, journal = {Phytopathology}, year = {2012}, abstract = {

Alder decline caused by Phytophthora alni has been one of the most important diseases of natural ecosystems in Europe during the last 20 years. The emergence of Phytophthora alni subsp. alni (Paa){\textemdash}the pathogen responsible for the epidemic{\textemdash}is linked to an interspecific hybridization event between two parental species: Phytophthora alni subsp. multiformis (Pam) and Phytophthora alni subsp. uniformis (Pau). One of the parental species, Pau, has been isolated in several European countries and recently in North America. The objective of this work was to assess the level of genetic diversity, the population genetic structure, and the putative reproduction mode and mating system of Pau. Five new polymorphic microsatellite markers were used to contrast both geographical populations. The study comprised 71 isolates of Pau collected from 8 European countries and 10 locations in North America. Our results revealed strong differences between continental populations (Fst=0.88; Rst=0.74), with no evidence for gene flow. European isolates showed extremely low genetic diversity compared to the North American collection. Selfing appears to be the predominant mating system in both continental collections. The results suggest that the European Pau population is most likely alien and derives from the introduction of a few individuals, while the North American population probably is an indigenous population.

}, issn = {0031-949X}, doi = {10.1094/PHYTO-05-12-0116-R}, url = {http://dx.doi.org/10.1094/PHYTO-05-12-0116-R}, author = {Aguayo, Jaime and Adams, Gerard C. and Halkett, Fabien and Catal, Mursel and Husson, Claude and Nagy, Zolt{\'a}n A. and Hansen, Everett M. and Beno{\^\i}t Mar{\c c}ais and Pascal Frey} } @article {doi:10.2989/20702620.2012.717381, title = {Potential of Phytophthora pinifolia to spread via sawn green lumber: a preliminary investigation}, journal = {Southern Forests: a Journal of Forest Science}, volume = {74}, number = {4}, year = {2012}, pages = {211-216}, abstract = {

Phytophthora pinifolia causes the needle and shoot disease of Pinus radiata in Chile known as Da{\~n}o Foliar del Pino. Although P. pinifolia is primarily a needle pathogen, there are concerns that it might be spread to new environments via the export of contaminated timber. In order to determine whether P. pinifolia can enter or persist in green sawn lumber, its presence in lumber produced from trees exposed to the pathogen for at least four years was examined. Green lumber produced from the infected trees, and green wood samples artificially exposed to P. pinifolia inoculum, were analysed by making extensive isolations on Phytophthora selective media. In addition, PCR was conducted using species-specific primers developed for P. pinifolia. Results of the study showed that the green sawn lumber taken from trees infected by P. pinifolia, or green lumber exposed in infected pine plantations, displayed no evidence of the pathogen surviving in this material.

}, doi = {10.2989/20702620.2012.717381}, url = {http://www.tandfonline.com/doi/abs/10.2989/20702620.2012.717381}, author = {Ahumada, R. and Rotella, A. and Slippers, B. and Wingfield, M. J.} } @article {EFP:EFP770, title = {Involvement of Phytophthora spp. in chestnut decline in the Black Sea region of Turkey}, journal = {Forest Pathology}, volume = {42}, number = {5}, year = {2012}, pages = {377{\textendash}386}, publisher = {Blackwell Publishing Ltd}, abstract = {

Chestnut blight caused by Cryphonectria parasitica is a serious disease of Castanea sativa in the Black Sea region of Turkey. During disease surveys, dieback and decline symptoms were observed on trees without apparent blight and ink disease symptoms. Black necroses, similar to those caused by Phytophthora infections, were noted on some of the chestnut coppices and saplings in one nursery in Ordu and led to an investigation into this disease complex. Only symptomatic plants showing dieback symptoms were investigated. Soil samples together with fine roots were collected from two directions, north and north-east, approximately 150\ cm away from the main stems. Phytophthora spp. were baited with young chestnut leaves. Three Phytophthora spp., P.\ cambivora, P.\ cinnamomi and P.\ plurivora, were identified from 12 soil samples collected from 73 locations, while from the nurseries, only P.\ cinnamomi was obtained. Phytophthora cinnamomi was the most common species, obtained from seven locations in five provinces and from four nurseries having similar symptoms mentioned above in different locations. Phytophthora cambivora and P.\ plurivora were less frequently obtained, from three to two stands, respectively. Phytophthora cinnamomi and P.\ cambivora were the most aggressive species when inoculated at the stem base on 3-year-old chestnut saplings, killing six saplings of eight inoculated in 2\ months. The three Phytophthora species were first recorded on chestnut in Black sea region of Turkey with the limited samples investigated in a large area about 150\ 000 ha chestnut forest.

}, issn = {1439-0329}, doi = {10.1111/j.1439-0329.2012.00770.x}, url = {http://dx.doi.org/10.1111/j.1439-0329.2012.00770.x}, author = {Ak{\i}ll{\i}, S. and Ser{\c c}e, U. and Kat{\i}rc{\i}o{\u g}lu, Y. Z. and Maden, S.} } @article {4122, title = {Management of Phytophthora pod rot disease on cocoa farms in Ghana}, journal = {Crop Protection}, volume = {22}, year = {2003}, month = {4/2003}, pages = {469 - 477}, abstract = {

From 1991 to 1997, field observations on trials involving the use of metalaxyl and copper-based fungicides were made on farmers{\textquoteright} farms in four Phytophthora megakarya affected cocoa growing regions of Ghana to control Phytophthora pod rot disease. Data on farm management practices, cocoa and shade tree types and densities, plot sizes, yield, land tenure and labour arrangements for farm operations, disease incidence and profitability of disease control were collected. Lower disease incidence and higher yields were recorded on fungicide-treated plots than on the untreated plots. The profitability of fungicide application depended on the level of farm management, nature of land tenure and labour arrangements for farm operations. The challenges involved in conducting trials with active participation by farmers are discussed. The involvement of farmers in the development of disease control programmes is crucial for subsequent adoption of the technology.

}, issn = {02612194}, doi = {10.1016/S0261-2194(02)00193-X}, url = {http://www.sciencedirect.com/science/article/pii/S026121940200193X}, author = {AY Akrofi and AA Appiah and IY Opoku} } @proceedings {4041, title = {On-farm farmer managed trials to control black pod disease caused by Phytophthora megakarya in Ghana}, year = {1995}, month = {1997}, pages = {pp. 109{\textendash}118}, publisher = {Owusu, G.K., Padi, B., Ollennu, L.A.A., Owusu Manu, E. (Eds.)}, address = {Accra, Ghana}, doi = {10.4314/gjas.v33i2.1876}, url = {http://dx.doi.org/10.4314/gjas.v33i2.1876}, author = {AY Akrofi and IY Opoku and AA Appiah} } @article {4261, title = {Phytophthora foot rot of black pepper in Brazil and Puerto Rico}, journal = {Phytopathology}, volume = {62}, year = {1972}, pages = {144-148}, doi = {10.1094/Phyto-62-144}, url = {http://www.apsnet.org/publications/phytopathology/backissues/Documents/1972Articles/Phyto62n01_144.PDF}, author = {Alconero, R and Albuquerque, F and Almeyda, N and Santiago, AG} } @article {springerlink:10.1007/s00267-010-9512-4, title = {Lessons learned from a decade of sudden oak death in California: evaluating local management}, journal = {Environmental Management}, volume = {46}, year = {2010}, note = {10.1007/s00267-010-9512-4}, pages = {315-328}, publisher = {Springer New York}, abstract = {Sudden Oak Death has been impacting California{\textquoteright}s coastal forests for more than a decade. In that time, and in the absence of a centrally organized and coordinated set of mandatory management actions for this disease in California{\textquoteright}s wildlands and open spaces, many local communities have initiated their own management programs. We present five case studies to explore how local-level management has attempted to control this disease. From these case studies, we glean three lessons: connections count, scale matters, and building capacity is crucial. These lessons may help management, research, and education planning for future pest and disease outbreaks.}, issn = {0364-152X}, doi = {10.1007/s00267-010-9512-4}, url = {http://dx.doi.org/10.1007/s00267-010-9512-4}, author = {Alexander, Janice and Lee, Christopher} } @article {JPH:JPH1895, title = {Defining plant resistance to Phytophthora cinnamomi: a standardized approach to assessment}, journal = {Journal of Phytopathology}, volume = {160}, year = {2012}, pages = {269{\textendash}276}, publisher = {Blackwell Publishing Ltd}, abstract = {

Phytophthora cinnamomi is a soil-borne plant pathogen that causes devastating disease in agricultural and natural systems worldwide. While a small number of species survive infection by the pathogen without producing disease symptoms, the nature of resistance, especially under controlled conditions, remains poorly understood. At present, there are no standardized criteria by which resistance or susceptibility to P.\ cinnamomi can be assessed, and we have used five parameters consisting of plant fresh weight, root growth, lesion length, relative chlorophyll content of leaves and pathogen colonization of roots to analyse responses to the pathogen. The parameters were tested using two plant species, Zea mays and Lupinus angustifolius, through a time course study of the interactions and resistance and susceptibility defined 7\ days after inoculation. A scoring system was devised to enable differentiation of these responses. In the resistant interaction with Z.\ mays, there was no significant difference in fresh weight, root length and relative chlorophyll content in inoculated compared with control plants. Both lesion size and pathogen colonization of root tissues were limited to the site of inoculation. Following inoculation L.\ angustifolius showed a significant reduction in plant fresh weight and relative leaf chlorophyll content, cessation of root growth and increased lesion lengths and pathogen colonization. We propose that this technique provides a standardized method for plant{\textendash}P.\ cinnamomi interactions that could be widely used to differentiate resistant from susceptible species.

}, keywords = {Phytophthora cinnamomi, resistance, root pathogen, Zea mays, zoospores}, issn = {1439-0434}, doi = {10.1111/j.1439-0434.2012.01895.x}, url = {http://dx.doi.org/10.1111/j.1439-0434.2012.01895.x}, author = {Allardyce, Jane A. and Rookes, James E. and Cahill, David M.} } @article {4373, title = {Lavender Cotton Root Rot: A New Host of Phytophthora tentaculata Found in Spain}, journal = {Plant Disease}, volume = {90}, year = {2006}, month = {Jan-04-2006}, pages = {523 - 523}, abstract = {

Lavender cotton, Santolina chamaecyparissus, is an evergreen shrub growing primarily in dry, calcareous habitats and is grown in rock gardens and mixed borders mainly for its ornamental and aromatic foliage. During 2004, several commercial nurseries in Valencia Province (eastern Spain) reported high mortality of lavender cotton. The foliage of the diseased plants turned brown, wilted, and died. A Phytophthora sp. was isolated consistently from the soil and roots of infected plants using apple baits and the selective medium PARBH (1), respectively. Four pure cultures (PS-31, PS-32, PS-33, and PS-34) were established from hyphal tips and characterized. Colony morphology on potato dextrose agar (PDA) at 24{\textdegree}C was stoloniferous (short stubby branches) with a growth rate of 2.2 mm per day. Sporangia, chlamydospores, and oospores were produced on V8 agar. The sporangia were ovoid to obpyriform, 27.5 to 64.8 (48.3) {\texttimes} 25 to 52.5 (37.5) μm, length/breadth ratio of 1.3:1, and papillate, from which 20\% were caducous with a short pedicel (\<5 μm). Hyphal swellings and chlamydospores (22 to 38 μm in diameter) were present. Isolates were homothallic, oogonia were globose, mostly terminal 27.5 to 40 (36.2) μm in diameter, 88\% of the antheridia were paragynous, monoclinous, or diclinous, and occasionally with two paragynous antheridia per oogonium. Amphigynous antheridia (12\%) were also observed. Oospores were aplerotic, 25 to 35 (32.3) μm in diameter, and thin walled. These characteristics and measurements conformed to the description of P. tentaculata described by Kr{\"o}ber and Marwitz (2). Sequencing the internal transcribed spacer region of Santolina isolates PS-32 and PS-34 and comparison of these sequences with other sequences available in GenBank revealed that they were identical to P. tentaculata (AF266775). Pathogenicity tests used 10 4-to-5-month-old potted lavender cotton and two methods. In the first method, inoculum was prepared on a media of 200 g of oats and 120 ml of V8 juice to 1 liter of distilled water. The medium was inoculated with P. tentaculata grown on PDA and incubated in the dark at 20{\textdegree}C for 4 weeks. Inoculum was buried into the compost mixture around the roots at a rate of 3\% (w/v). The second method applied a zoospore drench of 50 ml per plant (1 {\texttimes} 104 zoospores per ml) obtained by inducing zoospores in sterile soil extract from cultures of V8 juice agar. The control plants were inoculated with sterile media and sterile distilled water. The following day, the pots were flooded for 2 days, plants were maintained in a glasshouse at 24 {\textpm} 5{\textdegree}C, and watered twice a week. All plants inoculated with the first method had wilted foliage and died within 2 months after inoculation, while plants inoculated with zoospores died after 3 months. P. tentaculata was reisolated and the test was repeated twice. The control plants did not show any symptoms of the disease. P. tentaculata was first reported causing root and stalk rot on Chrysanthemum frutescens hybrids, C. leucanthemum, Delphinium ajacis, and Verbena hybrids in Germany (2). It has also been reported on Verbena hybrids in Spain (3). To our knowledge, this is the first report of P. tentaculata causing root rot on lavender cotton.

}, issn = {0191-2917}, doi = {10.1094/PD-90-0523A}, url = {http://apsjournals.apsnet.org/doi/abs/10.1094/PD-90-0523A}, author = {{\'A}lvarez, L. A. and P{\'e}rez-Sierra, A. and Le{\'o}n, M. and Armengol, J. and {\'\i}a-Jim{\'e}nez, J.} } @article {4513, title = {First Report of Gummosis Caused by Phytophthora frigida on Black Wattle in Brazil}, journal = {Plant Disease}, volume = {100}, year = {2016}, month = {Jan-11-2016}, pages = {2336 - 2336}, abstract = {

Black wattle (Acacia mearnsii), a tree species native to Australia, is considered the main source of bark for the tannin industry worldwide. It is the third most cultivated forest species in Brazil. Gummosis, caused by Phytophthora spp., is a major disease affecting black wattle plantations in that country, where the disease incidence can reach 43\%. The most common disease symptoms are lesions on the trunk, which may or may not be accompanied by gum exudation. Severe infection can lead to plant death. Phytophthora nicotianiae and P. bohemeriae were reported as causative agents of black wattle gummosis in Brazil (Santos et al. 2006). In South Africa, besides these species, P. meadii was also recorded on black wattle (Roux and Wingfield 1997), and P. frigida on green wattle (A. decurrens) (Maseko et al. 2007). A survey in 6-year-old black wattle plantations located in the Piratini and Cristal counties in the state of Rio Grande do Sul in 2008 revealed the occurrence of a third Phytophthora species causing gummosis on black wattle in Brazil, P. frigida. Twenty-four isolates were obtained, and all were identified as P. frigida based on morphological characteristics and the sequence of portions of the ITS-5.8S rDNA, and cox I and cox II genes. Morphological characterization of colonies on carrot agar medium (CA) revealed colonies of all isolates with dense aerial mycelium, and five different colony patterns were observed: stellate, cottony, petaloid-to-cottony, slightly stellated, and slightly rosaceous. The colony growth rate was 12 mm/day at 24 to 30{\textdegree}C. All isolates produced sporangia abundantly in 10\% nonsterile soil extract when grown under constant light. Most of the sporangia had prominent papilla. Most isolates had persistent sporangia formed singly or in a loose sympodium. The sporangial shape was predominantly ovoid, though there were other shapes such as globose, ellipsoid, and obpyriform found in some isolates, including some distorted shapes. The dimensions of 50 sporangia ranged from 29 to 71 {\texttimes} 20 to 53 {\textmu}m (avg. 46 {\texttimes} 33 {\textmu}m), with length-to-breadth ratios of 1.3 to 1.5 (avg. 1.4). The isolates produced globose chlamydospores, terminal or intercalary, and measured 21 to 55 {\textmu}m diameter (avg. 32 {\textmu}m). Oogonium diameter ranged from 22 to 37 {\textmu}m (avg. 30 {\textmu}m). Antheridia were amphigynous and oospores were globose, aplerotic, and 18 to 31 {\textmu}m (avg. 24 {\textmu}m) in diameter. Portions of the ITS-5.8 gene rDNA (730 bp) and the cox I (650 bp) and cox II (650 bp) genes were amplified by PCR. BLAST search of the GenBank database revealed that the fragments for ITS-5.8S gene rDNA (KU570067), and cox I (KU570065), and cox II (KU570066) sequence fragments from isolate P92 were 99 to 100\% similar with the accessions of P. frigida (Robideau et al. 2011). To confirm pathogenicity, the 24 isolates of P. frigida was used to inoculate 10 one-year-old black wattle plants. For inoculation, an agar mycelial plug from a 1-week-old colony on CA was put on the stem wound done with a cork borer (6 mm diam.). Necroses of stems were observed 4 weeks after inoculation with the presence, or absence, of gum exudation, as observed initially in the field. P. frigida was reisolated from each infected stem. This is the first report of P. frigida occurring in A. mearnsii worldwide.

}, issn = {0191-2917}, doi = {10.1094/PDIS-01-16-0134-PDN}, url = {http://apsjournals.apsnet.org/doi/10.1094/PDIS-01-16-0134-PDN}, author = {Alves, T. C. A. and Tessmann, D. J. and Ivors, K. L. and Ristaino, J. B. and Santos, A. F. dos} } @article {4517, title = {Caracteriza{\c c}{\~a}o morfofisiol{\'o}gica e an{\'a}lise de PCR-SSCP de isolados de Phytophthora da ac{\'a}cia-negra na regi{\~a}o Sul do Brasil}, journal = {Summa Phytopathologica}, volume = {37}, year = {2011}, month = {Jan-01-2011}, pages = {92 - 97}, abstract = {

The aim of this study was to characterize Phytophthora isolates from black wattle (Acacia mearnsii) in Southern Brazil, based on phenotypic traits such as morphology, mycelial growth, cultural features, sexual compatibility and pathogenicity, as well as on single strand conformation polymorphism (PCR-SSCP) of\ rDNA ITS-gene 5.8S region. The isolates presented sporangia with prominent papilla, irregularly sympodial sporangia, heterothalic cultures with amphigynous antheridia, presence of chlamydospore and mycelial growth at temperature above 35{\textdegree}C, allowing the classification of all 12 isolates as P. nicotianae. All isolates were pathogenic to black wattle, causing necrosis on stems without gum formation, with significant differences on aggressiveness (P=0.05). Two populations\ of P. nicotianae from black wattle can be distinguished based on PCR-SSCP analysis of rDNA; however, this separation has no apparent correlation with phenotypic traits.

O objetivo do trabalho foi caracterizar isolados de Phytophthora da ac{\'a}cia-negra (Acacia mearnsii) provenientes do Sul do Brasil, com base em caracter{\'\i}sticas fenot{\'\i}picas tais como morfologia, crescimento micelial, caracter{\'\i}sticas das culturas, compatibilidade sexual e patogenicidade, e em perfis de polimorfismo de conforma{\c c}{\~a}o de fita simples (SSCP = Single Strand Conformation Polymorphism) da regi{\~a}o ITS-gene 5.8S do rDNA. Os isolados apresentaram espor{\^a}ngios com papilas proeminentes, arranjo dos espor{\^a}ngios irregularmente simpodial, culturas heterot{\'a}licas com presen{\c c}a de anter{\'\i}dios anf{\'\i}genos, presen{\c c}a de clamid{\'o}sporos e crescimento micelial em temperatura acima de 35{\textdegree}C, permitindo a classifica{\c c}{\~a}o dos 12 isolados como P. nicotianae. Todos os isolados foram patog{\^e}nicos, causando necrose em ramos de ac{\'a}cia-negra, sem forma{\c c}{\~a}o de goma, com diferen{\c c}as significativas de agressividade (p=0,05). Duas popula{\c c}{\~o}es podem ser distinguidas em P. nicotianae da ac{\'a}cia negra pela an{\'a}lise PCR-SSCP do rDNA; no entanto essa separa{\c c}{\~a}o n{\~a}o apresenta aparente correla{\c c}{\~a}o com caracter{\'\i}sticas fenot{\'\i}picas.

}, issn = {0100-5405}, doi = {10.1590/S0100-54052011000300002}, url = {http://www.scielo.br/pdf/sp/v37n3/a02v37n3.pdf}, author = {Alves, TCA and Santos, A. F. dos and Tessmann, DJ and Vida, JB and Harakava, Ricardo} } @article { ISI:000277760100013, title = {Stand development patterns as a consequence of the mortality in Austrocedrus chilensis forests}, journal = {Forest Ecology and Management}, volume = {259}, number = {{10}}, year = {2010}, month = {APR 30}, pages = {1981-1992}, publisher = {{ELSEVIER SCIENCE BV}}, address = {{PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}}, keywords = {Austrocedrus chilensis, mortality, Stand dynamics, Uneven-aged}, issn = {0378-1127}, doi = {10.1016/j.foreco.2010.02.009}, author = {Amoroso, Mariano M. and Larson, Bruce C.} } @article {4611, title = {Distinct Trophic Specializations Affect How Phytophthora ramorum and Clade 6 Phytophthora spp. Colonize and Persist on Umbellularia californica Leaves in Streams}, journal = {Phytopathology}, year = {2018}, month = {Jun-05-2018}, pages = {PHYTO-06-17-019}, abstract = {

Phytophthora spp. are regularly recovered from streams but their ecology in aquatic environments is not well understood. Phytophthora ramorum, invasive in California forests, persists in streams at times when sporulation in the canopy is absent, suggesting that it reproduces in the water. Streams are also inhabited by resident, clade 6 Phytophthora spp., believed to be primarily saprotrophic. We conducted experiments to determine whether differences of trophic specialization exist between these two taxa, and investigated how this may affect their survival and competition on stream leaf litter. P. ramorum effectively colonized fresh (live) rhododendron leaves but not those killed by freezing or drying, whereas clade 6 species colonized all leaf types. However, both taxa were recovered from naturally occurring California bay leaf litter in streams. In stream experiments, P. ramorum colonized bay leaves rapidly at the onset; however, colonization was quickly succeeded by clade 6 species. Nevertheless, both taxa persisted in leaves over 16 weeks. Our results confirm that clade 6 Phytophthora spp. are competent saprotrophs and, though P. ramorum could not colonize dead tissue, early colonization of suitable litter allowed it to survive at a low level in decomposing leaves.

}, issn = {0031-949X}, doi = {10.1094/PHYTO-06-17-0196-R}, url = {https://apsjournals.apsnet.org/doi/pdf/10.1094/PHYTO-06-17-0196-R}, author = {Aram, Kamyar and Rizzo, David M.} } @article {4572, title = {Phytophthora cinnamomi A1: An ancient resident of New Guinea and Australia of Gondwanan origin?}, journal = {Forest Pathology}, year = {2017}, month = {Jan-02-2017}, pages = {e12342}, abstract = {

This article re-examines the hypothesis, first proposed by Shepherd (Search, 6(11-12), 1975, 484), that Phytophthora cinnamomi is an ancient organism in Australia and New Guinea. It further evaluates data that suggest the A1 mating type is Gondwanan in origin and may have been present in New Guinea for up to 10\ million years. It is postulated that there has been a mating type change in P.\ cinnamomi from A1 to A2 in relatively recent times as a result of genetic transformation of the A1 mating type.

}, issn = {1439-0329}, doi = {10.1111/efp.12342}, url = {http://doi.wiley.com/10.1111/efp.12342}, author = {Arentz, F.}, editor = {Woodward, S.} } @article {4253, title = {Strains and taxonomy of Phytophthora palmivora Butler (P. Faberi Maubl.)}, journal = {Transactions of the British Mycological Society}, volume = {14}, year = {1929}, month = {Jan-03-1929}, pages = {18 - 38}, issn = {00071536}, doi = {10.1016/S0007-1536(29)80025-3}, url = {http://linkinghub.elsevier.com/retrieve/pii/S0007153629800253}, author = {Ashby, S.F.} } @article {1108, title = {Environment Protection and Biodiversity Conservation Act 1999}, year = {1999}, isbn = {0 642 24863 3}, url = {http://www.environment.gov.au/biodiversity/invasive/diseases/phytophthora-cinnamomi.html}, author = {Australian Department of the Environment} } @article {Baccal{\textperiodcentered}1998261, title = {Austrocedrus chilensis mortality in the Nahuel Huapi National Park (Argentina)}, journal = {Forest Ecology and Management}, volume = {109}, number = {1-3}, year = {1998}, pages = {261 - 269}, abstract = {

Decline and mortality of Austrocedrus chilensis occurs throughout its natural distribution in Argentina. The problem was noted several decades ago but its causes are unknown. The aim of this work is to investigate the association between the occurrence of the decline and site characteristics considered to be relevant from the ecological point of view. A multivariate analysis is carried out using topographic and climatic information, obtained from 32 sites, within the limits of the Nahuel Huapi National Park, showing a wide range of decline and mortality incidence. Results of this study suggest that an ecological pattern of tree decline and mortality exists. The A. chilensis forests seem more prone to developing symptoms when occurring at sites with higher precipitation and not very high altitudes. To the eastern limit of its distribution, where precipitation is substantially low, A. chilensis forests show no symptoms of decline. It is, thus, hypothesized that sites with relatively poor soil drainage are more prone to develop symptoms. However, it is not clear whether high soil moisture directly affects roots or it produces a more suitable environment for root pathogen proliferation and infection.

}, keywords = {Decline, incidence, Saturated soil, Slope gradient}, issn = {0378-1127}, doi = {DOI: 10.1016/S0378-1127(98)00250-3}, url = {http://www.sciencedirect.com/science/article/B6T6X-3TW94FH-V/2/a6dc0b47a09acf8d6091e66f27b29502}, author = {Nora B. Baccal{\'a} and Pablo H. Rosso and Mar{\`I}a Havrylenko} } @article {JPH:JPH1079, title = {PCR-based DNA Markers for identifying hybrids within Phytophthora alni}, journal = {Journal of Phytopathology}, volume = {154}, number = {3}, year = {2006}, pages = {168{\textendash}177}, publisher = {Blackwell Verlag GmbH}, abstract = {

Two pairs of oligonucleotide primers were designed for the polymerase chain reaction (PCR)-based detection and differential identification of naturally occurring interspecific hybrid types (subspecies) of Phytophthora alni, all of which cause collar rot of alder trees. Primer pairs were derived from randomly amplified polymorphic DNA (RAPD) fragments that were unique to various subspecies of this alder pathogen. The primer pair set, SAP1/SAP2 (SAP), was derived from a 0.93-kb RAPD fragment amplified from P. alni ssp. alni. The primer pair set, SWAP1/SWAP2 (SWAP), was derived from a 1.13-kb fragment amplified from P. alni ssp. uniformis. Patterns of SAP and SWAP amplification enabled distinction among the three subspecies. No PCR products were amplified from isolates of 31 other Phytophthora spp. examined, including P. cambivora and P. fragariae, the suspected progenitors of P. alni. The SAP and SWAP primer sets were able to detect a minimum of 10\ pg of DNA from pure cultures or DNA extracted from as few as 10 zoospores. Pathogen DNA could also be amplified directly from bark lesions of artificially inoculated and naturally infected common alders and from lesions developed on common cherry-laurel leaves used in baiting the pathogen from infested soil. Direct detection of pathogen DNA from alder tissue using SAP and SWAP primer sets should prove useful in developing measures for effective quarantine and management of P. alni.

}, keywords = {Alnus, oomycete, Phytophthora alni, polymerase chain reaction markers, species hybrids}, issn = {1439-0434}, doi = {10.1111/j.1439-0434.2006.01079.x}, url = {http://dx.doi.org/10.1111/j.1439-0434.2006.01079.x}, author = {Bakonyi, J. and Nagy, Z. {\'A}. and {\'E}rsek, T.} } @article {doi:10.1094/PDIS-91-6-0705, title = {Phytophthora spp. associated with forest soils in eastern and north-central U.S. oak ecosystems}, journal = {Plant Disease}, volume = {91}, number = {6}, year = {2007}, pages = {705-710}, doi = {10.1094/PDIS-91-6-0705}, url = {http://apsjournals.apsnet.org/doi/abs/10.1094/PDIS-91-6-0705}, author = {Balci, Y. and Balci, S. and Eggers, J. and MacDonald, W. L. and Juzwik, J. and Long, R. P. and Gottschalk, K. W.} } @article {EFP:EFP617, title = {Involvement of Phytophthora species in white oak (Quercus alba) decline in southern Ohio}, journal = {Forest Pathology}, volume = {40}, number = {5}, year = {2010}, pages = {430{\textendash}442}, publisher = {Blackwell Publishing Ltd}, abstract = {

This study was initiated to investigate the possible role of Phytophthora species in white oak decline (Quercus alba) in southern Ohio at Scioto Trail State Forest. Surveys demonstrated the presence of four species of Phytophthora including one novel species. By far, the most common species was P.\ cinnamomi; P.\ citricola and P.\ cambivora were isolated infrequently. In few instances, P.\ cinnamomi was isolated from fine roots and necroses on larger roots. No special pattern of incidence was found, but P.\ cinnamomi was more commonly isolated from greater Integrated Moisture Index values suggesting moist lower bottomlands favour this Phytophthora species. When tree crown condition was examined relative to the presence of Phytophthora, no significant association was found. However, roots of declining P.\ cinnamomi-infested trees had 2.5 times less fine roots than non-infested and healthy trees, which was significantly different. The population densities of P.\ cinnamomi from declining trees were significantly greater than from healthy trees, suggesting increased pathogen activity that has the potential to cause dieback and decline and possibly the cause of a reduced fine root amount found on declining trees.

}, issn = {1439-0329}, doi = {10.1111/j.1439-0329.2009.00617.x}, url = {http://dx.doi.org/10.1111/j.1439-0329.2009.00617.x}, author = {Balci, Y. and Long, R. P. and Mansfield, M. and Balser, D. and MacDonald, W. L.} } @article {4042, title = {Phytophthora quercetorum sp. nov., a novel species isolated from eastern and north-central USA oak forest soils}, journal = {Mycological Research}, volume = {112}, year = {2008}, month = {08/2008}, pages = {906 - 916}, abstract = {

Isolates belonging to an undescribed Phytophthora species were frequently recovered during an oak forest soil survey of Phytophthora species in eastern and north-central USA in 2004. The species was isolated using an oak leaf baiting method from rhizosphere soil samples collected from Quercus rubra, Q. macrocarpa, and Q. phellos. This species is formally described as P. quercetorum. It is homothallic and has aplerotic oogonia and paragynous antheridia. It produces papillate sporangia (occasionally bipapillate) of ovoid-elongated shapes. Its temperature optimum for growth is ca 22.5\ {\textdegree}C with the upper limit of ca 32.5\ {\textdegree}C. P. quercetorum differs from the morphologically related P. quercina in producing distinct submerged colony-patterns, different growth-temperature requirements, and oogonial shapes and sizes. Phylogenetic analyses using seven nuclear loci supported P. quercetorum as a novel species within clade 4, closely related to P. arecae, P. palmivora, P. megakarya, and P. quercina.

}, issn = {09537562}, doi = {10.1016/j.mycres.2008.02.008}, url = {http://www.sciencedirect.com/science/article/pii/S0953756208000841}, author = {Yilmaz Balci and Balci, Selin and Jaime E. Blair and Sook-Young Park and Seogchan Kang and Macdonald, William L.} } @article {4077, title = {A diverse range of Phytophthora species are associated with dying urban trees}, journal = {Urban Forestry \& Urban Greening}, year = {2013}, month = {9/2013}, abstract = {

Surveys of dying vegetation within remnant bushland, parks and gardens, and streetscapes throughout the urban forest of Perth and the South-west of Western Australia revealed symptoms typical of those produced by Phytophthora species. A total of nine Phytophthora species, including P. alticola, P. multivora, P. litoralis, P. inundata, P. nicotianae and P. palmivora were isolated. In addition, three previously undescribed species, Phytophthora aff. arenaria, Phytophthora aff. humicola and Phytophthora sp. ohioensis were isolated. Isolates were recovered from a wide range of native and non-native host genera, including Agonis, Allocasuarina, Brachychiton, Calothamnus, Casuarina, Corymbia, Dracaena, Eucalyptus, Ficus, Pyrus and Xanthorrhoea. Phytophthora multivora was the most commonly isolated species. Out of 230 samples collected 69 were found to be infected with Phytophthora. Of those 69, 54\% were located within parks and gardens, 36\% within remnant bushland, and 10\% within streetscapes. These pathogens may play a key role in the premature decline in health of the urban forest throughout Perth, and should be managed according to the precautionary principle and given high priority when considering future sustainable management strategies.

}, issn = {16188667}, doi = {10.1016/j.ufug.2013.07.009}, url = {http://dx.doi.org/10.1016/j.ufug.2013.07.009}, author = {P.A. Barber and Paap, T. and Burgess, T. I. and Dunstan, W. and G.E.St.J. Hardy} } @book {4254, title = {Phytophthora basal canker of red maple}, series = {Plant Pathology Circular}, volume = { No. 361}, year = {1993}, publisher = {Fla. Dept. Agric. \& Consumer Services. Division of Plant Industry}, organization = {Fla. Dept. Agric. \& Consumer Services. Division of Plant Industry}, address = {Gainseville, FL. }, url = {http://www.freshfromflorida.com/content/download/11368/144504/pp361.pdf}, author = {Barnard, E.L. and Mitchell, D.J.} } @article {436, title = {Hongos Aphyllophorales (Basidiomycetes) que causan pudriciones en Austrocedrus chilensis}, journal = {Boletiacuten de la Sociedad Argentina de Botaacutenica}, volume = {31}, year = {1996}, pages = {201-216}, author = {Barroetave{\~n}a, C. and Rajchenberg, M.} } @article {PPA:PPA1961, title = {A new threat to UK heathland from Phytophthora kernoviae on Vaccinium myrtillus in the wild}, journal = {Plant Pathology}, volume = {58}, number = {2}, year = {2009}, pages = {393{\textendash}393}, publisher = {Blackwell Publishing Ltd}, issn = {1365-3059}, doi = {10.1111/j.1365-3059.2008.01961.x}, url = {http://dx.doi.org/10.1111/j.1365-3059.2008.01961.x}, author = {Beales, P. A. and Giltrap, P. G. and Payne, A. and Ingram, N.} } @article {4569, title = {Genotypic diversity of Phytophthora cinnamomi and P. plurivora in Maryland{\textquoteright}s nurseries and Mid-Atlantic forests}, journal = {Phytopathology}, year = {2017}, month = {Jul-02-2017}, abstract = {

Genetic diversity of two Phytophthora species, P. cinnamomi (102 isolates) and P. plurivora (186), commonly encountered in Maryland nurseries and forests in the Mid-Atlantic United States was characterized using amplified fragment length polymorphism (AFLP). Expected heterozygosity and other indices suggested a lower level of diversity among P. cinnamomi than P. plurivora. Hierarchical clustering showed P. cinnamomi isolates separated into four clusters, and two of the largest clusters were closely related, containing 80\% of the isolates. In contrast, P. plurivora isolates separated into six clusters, one of which included approximately 40\% of the isolates. P. plurivora isolates recovered from the environment (e.g. soil, water) were genotypically more diverse than those found causing lesions. For both species, isolate origin (forest vs. nursery or among nurseries) was a significant factor of heterozygosity. Clonal groups existed within P. cinnamomi and P. plurivora and included isolates from both forest and nurseries, suggesting that a pathway from nurseries to forests or visa verse exists.

}, issn = {0031-949X}, doi = {10.1094/PHYTO-05-16-0215-R}, url = {http://apsjournals.apsnet.org/doi/10.1094/PHYTO-05-16-0215-R}, author = {Beaulieu, Justine and Ford, Blain B and Balci, Yilmaz} } @proceedings {4338, title = {Kauri (Agathis australis) Under Threat From Phytophthora?}, volume = {General Technical report PSW-GTR-221}, year = {2007}, month = {2009}, pages = {74{\textendash}85}, publisher = {U.S. Department of Agriculture, Forest Service Pacific Southwest Research Station}, address = {Monterey, California}, abstract = {

Five species of Phytophthora have been recorded from Agathis australis (kauri) or soil in kauri forests: P. cinnamomi, P. cryptogea, P. kernoviae, P. nicotianae and Phytophthora taxon Agathis (PTA) initially recorded as P. heveae. P. cinnamomi has been found widely in natural stands and has been linked with ill-thrift and occasional tree death, especially in regenerating stands on poorly drained sites. PTA, which is known from fewer natural stands, is associated with a collar rot, causing large bleeding lesions near the ground, yellowing foliage, and tree death. The other three species have only been reported once. ITS sequence studies of PTA show it belongs with, but is distinct from, P. heveae in ITS clade 5. Cultural and molecular studies indicate a close relationship with P. katsurae. It is proposed that PTA may be introduced to New Zealand, but too few isolates are available to determine whether genetic variability of this species provides support for this hypothesis. Recent surveys have found collar rot is widely distributed across the natural range of kauri. Typically, affected stands are relatively small in size. Size class distributions indicate trees of many ages are affected and a disease front can sometimes be detected. Pathogenicity tests show PTA is highly pathogenic to kauri. We propose that collar rot caused by PTA is an emerging disease caused by an introduced pathogen that is spreading slowly from widespread disease foci. It poses a threat to kauri, both at the individual icon level and at the population level, with flow-on effects to kauri ecosystems.

}, author = {Beever, JE and Coffey, MD and Ramsfield, TD and Dick, MA and Horner, IJ} } @article {4553, title = {Phytophthora gonapodyides Causes Decline and Death of English (Persian) Walnut ( Juglans regia) in Italy}, journal = {Plant Disease}, volume = {100}, year = {2016}, month = {Jan-12-2016}, pages = {2537 - 2537}, abstract = {

In late spring 2015, several commercially grown Persian walnut (Juglans regia L.) cv. Lara trees in northeastern Italy (Udine) exhibited extensive foliar wilt and canopy decline associated with collar and root rot. Sudden collapse was recorded in about 80\% of trees facing an irrigation canal. Symptomatic tissues excised from roots and collars of affected plants were surface disinfested for 1 min in a 1\% NaOCl solution, rinsed for 5 min in sterile distilled water, and placed onto P5ARPH selective medium. A Phytophthora-like organism was consistently isolated. Pure cultures, with a typical rosette pattern, were obtained by single-hyphal transfers onto potato dextrose agar (PDA). Mycelial disks of three isolates, AB260, AB261, and AB262, grown on carrot piece agar, were floated in petri plates with soil extract solution and incubated under continuous fluorescent light at room temperature. Within 48 to 72 h, sporangia were produced that were persistent, nonpapillate, tapered at the apex, and 40.0 to 102.8 {\texttimes} 22.8 to 45.7 {\textmu}m (average 56 {\texttimes} 33 {\textmu}m of 30 sporangia). Both internal and external proliferations were observed. Oospores and chlamydospores were absent. These morphological characteristics all corresponded to those reported for Phytophthora gonapodyides (Brasier et al. 1993; Erwin and Ribeiro 1996). Optimal growth for all three isolates was at 30{\textdegree}C (3.4 mm/day), with limited growth at 4{\textdegree}C (1.25 mm/day), and no growth at 35{\textdegree}C. The identity was confirmed by sequencing the internal transcribed spacer (ITS) using universal primers ITS4 and ITS6 (Cooke et al. 2000) and cytochrome c oxidase, subunit II (Cox II) (Martin and Tooley 2003). BLAST analysis of ITS 821-bp segment (GenBank accession nos. LN877760, LN901312, LN901313) showed 100\% identity with published P. gonapodyides sequences available in GenBank (i.e., HQ261570, AF541889, or AF541888), as well as with a Cox II 568-bp segment (LN877762, LN894191, LN894192) against AY129197. Greenhouse pathogenicity tests were conducted in controlled conditions. A total of six 1-year-old shoots cut from J. regia plants, about 2 cm in diameter, were used and three inoculation points each were made. Mycelial plugs (6 mm in diameter) cut from margins of actively growing 10-day-old cultures on PDA were inserted through the epidermis into phloem tissue. Controls were treated as described above except that sterile PDA plugs replaced the inoculum. Shoots were incubated in test tubes with sterile water in the dark at 24 {\textpm} 2{\textdegree}C. After 2 weeks, lesions were evident at all inoculation points, with an average length of 26 mm. Symptoms were similar to those caused by natural infection. P. gonapodyides was consistently reisolated from lesion margins. No colonies were isolated from control plants that remained symptomless. P. gonapodyides is ubiquitous in streams and ephemeral water pools, and is capable of saprophytic existence (Erwin and Ribeiro 1996). Although it is mainly known as a minor pathogen, there are reports indicating that some isolates can be highly virulent (Orlikowski et al. 2011) as in the present study where well developed 7-year-old walnut trees were killed by the pathogen. In the current study, P. gonapodyides aggressiveness was most likely sustained by the prolonged presence of flooding water at the root level, and a cool soil environment. To our knowledge, this is the first report of P. gonapodyides on Persian walnut in Italy or elsewhere.

}, issn = {0191-2917}, doi = {10.1094/PDIS-03-16-0394-PDN}, url = {http://apsjournals.apsnet.org/doi/10.1094/PDIS-03-16-0394-PDN}, author = {Belisario, A. and Luongo, L. and Vitale, S. and Galli, M. and Haegi, A.} } @article {doi:10.1094/PD-90-1362C, title = {First report of Phytophthora cambivora causing bleeding cankers and dieback on beech (Fagus sylvatica) in Italy}, journal = {Plant Disease}, volume = {90}, number = {10}, year = {2006}, pages = {1362-1362}, abstract = {

European beech (Fagus sylvatica) is an important forest tree species common in northern and central Europe. In Italy, this species is typical in mountain areas over 1,000 m above sea level. In the last decade, decline and death was reported on European beech caused by several Phytophthora species (2), and P. pseudosyringae was recently reported in Italy (3). During 2004 and 2005, seven declining and dying F. sylvatica trees, older than 20 years, were observed in the Veneto Region of Italy with symptoms of bleeding cankers at the base of trunks and on branches. Cankers on the collar showed tongue-shaped necroses of the inner bark and cambium tissues. Four trees were in a public park of Mestre and three were in a forest stand in the province of Belluno. Samples were taken from declining trees, one in the park and two in the forest. Inner bark and cambium tissue pieces were cut from the canker margins, cultured on CARPBHy-agar (corn meal agar amended with 250 μg ml-1 ampicillin, 10 μg ml-1 rifampicin, 10 μg ml-1 pimaricin, 15 μg ml-1 benomyl, 50 μg ml-1 hymexazol), and incubated at 20{\textdegree}C. Ten morphologically similar isolates were subcultured as single hyphal tips and characterized. These isolates produced nonpapillate sporangia that were ovoid, obpyriform or ellipsoid, and exhibited predominately internal proliferation in soil extract. Hyphal swellings with outgrowths were present under those conditions. The morphological characteristics were consistent with those of P. cambivora (1). Base sequences of the ITS region of rDNA were determined for six of the isolates, and an 832-bp fragment was amplified for each isolate and that sequence was 100\% homologous with sequences DQ396418 and AY880985 of P. cambivora in the NCBI database (http://www.ncbi.nlm.nih.gov/BLAST/). The sequence of one isolate, ISPaVe 1950, was deposited in GenBank (Accession No. AM269752). Pathogenicity tests were conducted with 2-year-old potted beech seedlings. Inoculum of representative isolates was grown for 4 weeks on sterilized millet seeds moistened with V8 broth and added to soil at 3\% (wt/vol). Control plants received sterilized inoculum only. The soil was flooded for 48 h. Inoculations were performed during May 2005 at 15 to 35{\textdegree}C with six replicates for the inoculated and control plants. The plants were maintained outdoors and assessed after 3 months. Wilt, root rot, and dark brown lesions at the collar developed on inoculated plants, but not on the controls. Symptoms were similar to those on naturally infected trees. The pathogen reisolated from the inoculated plants was morphologically identical to the original isolates, which confirmed P. cambivora as the causal agent. To our knowledge, this is the first report of P. cambivora on beech in Italy.

}, doi = {10.1094/PD-90-1362C}, url = {http://apsjournals.apsnet.org/doi/abs/10.1094/PD-90-1362C}, author = {Belisario, A. and Maccaroni, M. and Vettorazzo, M.} } @article {4466, title = {Visualizing the early infection of Agathis australis by Phytophthora agathidicida, using microscopy and fluorescent in~situ hybridization}, journal = {Forest Pathology}, year = {2016}, month = {Jan-03-2016}, pages = {n/a - n/a}, abstract = {

Phytophthora agathidicida (PTA) causes a root rot and collar rot of New Zealand kauri (Agathis australis). This study developed techniques to visualize early infection of kauri by PTA in deliberately inoculated seedlings. Conventional light microscopy was carried out on cleared and stained roots using trypan blue to observe PTA structures. Additionally, scanning electron microscopy (SEM) was used to study the PTA root structures at a higher resolution. A fluorescent in\ situ hybridization assay (FISH) was developed using a PTA-specific probe to label PTA structures in planta. Infection progression in roots of 2-year-old kauri inoculated with PTA at 5, 10, 16 and 20\ days post-inoculation (d.p.i.) was compared using these three approaches. Light microscopy identified no Phytophthora-like structures in the control treatments. In PTA-inoculated plants, lignitubers were produced 5\ d.p.i. in cortical cells. Infection was localized after 5\ days, but as the infection progressed (up to 20\ d.p.i.), the {\textquoteleft}degree{\textquoteright} of root infection increased, as did the number of replicates in which structures were observed. SEM provided higher resolution images; again, no PTA structures were observed in the negative control material examined. The slide-based FISH-specificity assay successfully hybridized with PTA hyphae. Fluorescence was observed using 330{\textendash}380\ nm excitation and an emission filter at 420\ nm (DAPI), with PTA nuclei fluorescing a bright greenish-yellow. Cross-reactivity was not observed when the assay was applied to six other non-target Phytophthora species. Successful hybridization reactions occurred between the primer and PTA structures in planta. Applying this FISH assay has allowed clear differentiation of the intracellular and intercellular structures of PTA. The technique can be applied to longer term studies or analysis of ex situ inoculation studies aiming to elucidate differential host-responses to the pathogen. Additionally, the technique could be applied to study the interactions with other fungal endophytes (e.g. mycorrhizal fungi), which could be assessed for biocontrol potential as part of the integrated management of the disease.

}, doi = {10.1111/efp.12280}, url = {http://doi.wiley.com/10.1111/efp.12280}, author = {Bellgard, S. E. and Padamsee, M. and Probst, C. M. and Lebel, T. and Williams, S. E.}, editor = {Jung, T.} } @article {doi:10.1094/PDIS.2000.84.6.661, title = {Incidence of Phytophthora root rot of Fraser fir in North Carolina and sensitivity of isolates of Phytophthora cinnamomi to metalaxyl}, journal = {Plant Disease}, volume = {84}, number = {6}, year = {2000}, pages = {661-664}, doi = {10.1094/PDIS.2000.84.6.661}, url = {http://apsjournals.apsnet.org/doi/abs/10.1094/PDIS.2000.84.6.661}, author = {Benson, D. M. and Grand, L. F.} } @book {3946, title = {A range-wide assessment of Port-Orford-Cedar (Chamaecyparis lawsoniana) on federal lands}, year = {2003}, pages = {182}, publisher = { U.S. Department of Agriculture, Forest Service, and U.S. Department of the Interior, Bureau of Land Management}, organization = { U.S. Department of Agriculture, Forest Service, and U.S. Department of the Interior, Bureau of Land Management}, address = {Portland, OR}, url = {http://www.fs.fed.us/r6/dorena/publications/in/poc-range-wide-assessment}, author = {Betlejewski, F. and Casavan, K. and Dawson, A. and Goheen, D.G. and Mastrofini, K. and Rose, D.L. and White, D.E.} } @article {4720, title = {Phytophthora spp. associated with Appalachian oak forests and waterways in Pennsylvania, with P. abietivora as a pathogen of five native woody plant species.}, journal = {Plant Disease}, year = {2021}, month = {11/2021}, abstract = {

To document the distribution of potentially harmful Phytophthora spp. within Pennsylvania (PA), the PA Department of Agriculture collected 89 plant, 137 soil, and 48 water samples at 64 forested sites from 2018 to 2020. In total, 231 Phytophthora strains were isolated using baiting assays and identified based on morphological characteristics and sequences of nuclear and mitochondrial loci. Twenty-one Phytophthora spp. in nine clades and one unidentified species were present. Phytophthora abietivora, a recently described clade 7a species, was recovered from diseased tissue of 10 native broadleaved plants and twice from soil from 12 locations. Phytophthora abietivora is most likely endemic to PA based on pathogenicity tests on six native plant species, intraspecific genetic diversity, wide distribution, and recoveries from Abies Mill. and Tsuga Carri{\`e}re plantations dating back to 1989. Cardinal temperatures and morphological traits are provided for this species. Other taxa, in decreasing order of frequency, include P. chlamydospora, P. plurivora, P. pini, P. cinnamomi, P. xcambivora, P. irrigata, P. gonapodyides, P. cactorum, P. pseudosyringae, P. hydropathica, P. stricta, P. xstagnum, P. caryae, P. intercalaris, Phytophthora {\textquoteleft}bitahaiensis{\textquoteright}, P. heveae, P. citrophthora, P. macilentosa, P. cryptogea, and P. riparia. Twelve species were associated with diseased plant tissues. This survey documented 53 new plant-Phytophthora associations and expanded the known distribution of some species.

}, issn = {0191-2917}, doi = {10.1094/PDIS-05-21-0976-RE}, url = {https://apsjournals.apsnet.org/doi/10.1094/PDIS-05-21-0976-RE}, author = {Bily, Devin and Nikolaeva, Ekaterina V. and Olson, Tracey and Kang, Seogchan} } @article {Blackwell194371, title = {The life history of Phytophthora cactorum (Leb. \& Cohn) Schroet}, journal = {Transactions of the British Mycological Society}, volume = {26}, number = {1-2}, year = {1943}, pages = {71 - 89}, abstract = {Summary An account is given of the life history of Phytophthora Cactorum (Leb. \& Cohn) Schroet., a paragynous, homothallic species. The mycelium and reproductive spores in their development and germination are described as under: The mycelium: its vegetative growth and form and its perennation. The sporangium, conidium, resting conidium, chlamydospore: their interrelationships, development and germination. The oogonium and antheridium: fertilization. The oospore: its dormancy and germination.}, issn = {0007-1536}, doi = {DOI: 10.1016/S0007-1536(43)80013-9}, url = {http://www.sciencedirect.com/science/article/B985G-4YW2HHM-D/2/d8cd209743ea7bb728b94dadd761bd5d}, author = {Elizabeth Blackwell} } @article {Blaha19941379, title = {Phytophthora isolates from coconut plantations in Indonesia and Ivory Coast: characterization and identification by morphology and isozyme analysis}, journal = {Mycological Research}, volume = {98}, number = {12}, year = {1994}, pages = {1379 - 1389}, abstract = {

Isolates of Phytophthora were obtained from coconut palms with bud rot and/or premature nut-fall disease in Indonesia (36 isolates) and Ivory Cost (15 isolates), and from coconut plantation soil in Indonesia (17 isolates). Their morphology and isozyme patterns for MDH and GPI were compared with those of seven known Phytophthora species. Isolates from Indonesia assigned to P. arecae or P. palmivora by morphology had identical isozyme patterns and could not be separated by cluster analysis. Isolates of P. palmivora had one single-banded, and three triple-banded GPI patterns, one of which was unique to isolates from coconut. Isolates from Ivory Coast were assigned by morphology and by a distinctive MDH isozyme pattern to P. katsurae. They showed some morphological similarities, and had an identical GPI isozyme pattern to reference cultures of P. heveae, previously reported as a pathogen on coconut. We conclude that P. palmivora is the main pathogen associated with bud rot and premature nut-fall in Indonesia, whereas P. katsurae is associated with premature nut-fall in Ivory Coast.

}, issn = {0953-7562}, doi = {DOI: 10.1016/S0953-7562(09)81067-8}, url = {http://www.sciencedirect.com/science/article/pii/S0953756209810678}, author = {Georges Blaha and Geoffrey Hall and Jeffry S. Warokka and Erlene Concibido and Carlos Ortiz-Garcia} } @article {Blair2008266, title = {A multi-locus phylogeny for Phytophthora utilizing markers derived from complete genome sequences}, journal = {Fungal Genetics and Biology}, volume = {45}, number = {3}, year = {2008}, pages = {266 - 277}, keywords = {Molecular markers}, issn = {1087-1845}, doi = {DOI: 10.1016/j.fgb.2007.10.010}, url = {http://www.sciencedirect.com/science/article/B6WFV-4PYP77J-1/2/ebf8754b49bc2fd36ab9e34941eeed43}, author = {Jaime E. Blair and Michael D. Coffey and Sook-Young Park and David M. Geiser and Seogchan Kang} } @article {4449, title = {Detection of Phytophthora ramorum in Nurseries and Forest Lands in California in 2004 to 2009}, journal = {Plant Disease}, volume = {100}, year = {2016}, month = {Jan-01-2016}, pages = {139 - 148}, abstract = {

From December 2004 through May 2009, samples were collected from California nurseries and wild lands to survey for Phytophthora ramorum and comply with federal regulations of nursery stock. Samples were prescreened by an enzyme-linked immunosorbent assay (ELISA) that detects Phytophthora spp. and tested by culture, P. ramorum-specific real-time polymerase chain reaction (PCR), and nested PCR. Yearly percentages of infected samples ranged from 0.6 to 2.3\%. Camellia spp., Rhododendron spp., Magnolia spp., Pieris spp., and Laurus nobilis tested positive the most frequently in the nurseries and Lithocarpus densiflorus, Umbellularia californica, and Quercus agrifolia tested positive most often from wild lands. Of the 118,410 samples isolated onto PARP media, 0.8\% was identified as P. ramorum. Of 115,056 samples tested by ELISA, 5.9\% tested positive for Phytophthora spp. Of the 6,520 samples tested by PCR, 12.4\% tested positive for P. ramorum. The false-negative, positive, and internal control failure rates of the assays are discussed. After removing the seasonal effect of sampling strategy, isolation of the pathogen into culture was found to be seasonally dependent whereas detectability by PCR and ELISA was not. To our knowledge, this is the first evaluation of a regulatory testing program for a plant pathogen on this scale using standardized assays.

}, issn = {0191-2917}, doi = {10.1094/PDIS-12-14-1302-RE}, url = {http://apsjournals.apsnet.org/doi/10.1094/PDIS-12-14-1302-RE}, author = {Blomquist, C. L. and Yakabe, L. E. and Rooney-Latham, S. and McRoberts, N. and Thomas, C.} } @article {4651, title = {First Report of Leaf Spot Caused by Phytophthora taxon Pgchlamydo on Evergreen Nursery Stock in California}, journal = {Plant Disease}, volume = {96}, year = {2012}, month = {Jan-11-2012}, pages = {1691 - 1691}, abstract = {

As part of the Phytophthora ramorum testing program from 2005 through 2007, a Phytophthora sp. was isolated on PARP-CMA medium (4) at the CDFA lab in Sacramento, CA, from the margin of necrotic spots and tissue suffering from dieback on Arctostaphylos sp. (manzanita), Camellia spp., Laurus nobilis (bay), Buxus sempervirens (boxwood), Rhododendron sp., Arbutus unedo (strawberry tree), and Sequoia sempervirens (coast redwood). Isolates were collected from Shasta, Contra Costa, San Diego, Solano, Santa Cruz, Alameda, Sacramento, San Joaquin, Monterey, and Los Angeles Counties. Isolates from A. unedo tissue on PARP medium produced apapillate, obovate sporangia 25 to 80 {\texttimes} 15 to 40 μm (48.0 {\texttimes} 26.9 μm average) and a few isolates produced intercalary and terminal chlamydospores at 22{\textdegree}C (30 to 46 μm diameter, 38.9 μm average). The internal transcribed spacer region (ITS) of rDNA was amplified from four isolates using ITS1 and ITS4 primers as described by White et al. (3) and the amplicons sequenced (GenBank Accession Nos. JQ307188 through JQ307191). BLAST analysis of the amplicons showed 99 to 100\% identity with the ITS sequence of Phytophthora taxon Pgchlamydo from forest streams in Oregon (GenBank Accession No. HM004224) (1). Pathogenicity tests were performed on B. sempervirens, C. sasanqua, L. nobilis, and A. unedo. Five plants of each species were inoculated with 6-mm plugs taken from the margin of a 7- to 10-day-old culture grown on V8 juice agar. Plant leaves were wounded with a sterile pushpin and two agar plugs were covered with a freezer tube cap filled with sterile dH2O and clipped to the underside of the leaves with a sterile pin-curl clip (4). Inoculated plants were sprayed with water, covered with plastic bags, and incubated for 2 days, when bags and plugs were removed. Five leaves of each isolate plus five control plugs using V8 juice agar alone were inoculated on each plant. Plants were incubated for 12 days at 18{\textdegree}C (16-h photoperiod). Lesions formed on all inoculated plants, ranging in size from approx. 1 mm on B. sempervirens to 9.2 {\texttimes} 10.9 mm average on A. unedo. The lesions on A. unedo grew into and caused the mid-vein to blacken. The lesion sizes on camellia and bay were larger than those formed on B. sempervirens and smaller than those formed on A. unedo, with most lesions surrounded by a dark ring. Phytophthora taxon Pgchlamydo is associated with leaf lesions on rhododendron and dieback of yew in Minnesota (2). To our knowledge, this is the first report of Phytophthora taxon Pgchlamydo causing disease in camellia, bay, strawberry tree, and boxwood in California. Phytophthora taxon Pgchlamydo causes damage that is indistinguishable from the quarantine pest, P. ramorum (4).

References: (1) P. W. Reeser et al. Mycologia 103:22, 2011. (2) B. W. Schwingle and R. A. Blanchette. Plant Dis. 92:642, 2008. (3) T. J. White et al. PCR Protocols: A Guide to Methods and Applications. M. A. Innis et al., eds., Academic Press, San Diego, 1990. (4) L. E. Yakabe et al. Plant Dis. 93:883, 2009.

}, issn = {0191-2917}, doi = {10.1094/PDIS-02-12-0221-PDN}, url = {http://apsjournals.apsnet.org/doi/10.1094/PDIS-02-12-0221-PDN}, author = {Blomquist, C. L. and Yakabe, L. E. and Soriano, M. C. and Negrete, M. A.} } @article {4123, title = {The impact of plant diseases on world chocolate production}, journal = {Plant Health Progress}, year = {2001}, abstract = {

Many factors contribute to a decline in production of cocoa beans worldwide. Plant diseases such as black pod, witches{\textquoteright} broom, and frosty pod rot are major components of the decline in production. Plant pathologists and microbiologists must discover and devise means to reduce disease losses and to save chocolate for the enthusiastic consumers of the world. This review discusses the major disease of cacao and their effect on world production.

}, doi = {10.1094/PHP-2001-0709-01-RV}, url = {http://www.plantmanagementnetwork.org/pub/php/review/cacao/}, author = {Bowers, J. H. and Bailey, B. A. and Hebbar, P. K. and Sanogo, S. and Lumsden, R. D.} } @article {4680, title = {Phytophthora agathidicida: research progress, cultural perspectives and knowledge gaps in the control and management of kauri dieback in New Zealand}, journal = {Plant Pathology}, volume = {69}, year = {2020}, month = {Feb-01-2021}, pages = {3 - 16}, abstract = {

Kauri (Agathis australis), which is one of the world{\textquoteright}s largest and longest-living conifer species, is under threat from a root and collar dieback disease caused by the oomycete pathogen Phytophthora agathidicida. The noted incidence of kauri dieback has increased in the past decade, and even trees \>1000\ years old are not immune. This disease has profound effects on both forest ecosystems and human society, particularly indigenous M{\={a}}ori, for whom kauri is a taonga or treasure of immense significance. This review brings together existing scientific knowledge about the pathogen and the devastating disease it causes, as well as highlighting important knowledge gaps and potential approaches for disease management. The life cycle of P.\ agathidicida is similar to those of other soilborne Phytophthora pathogens, with roles for vegetative hyphae, zoospores and oospores in the disease. However, there is comparatively little known about many aspects of the biology of P.\ agathidicida, such as its host range and disease latency, or about the impact on the disease of abiotic and biotic factors such as soil health and co-occurring Phytophthora species. This review discusses current and emerging tools and strategies for surveillance, diagnostics and management, including a consideration of genomic resources, and the role these play in understanding the pathogen and how it causes this deadly disease. Key aspects of indigenous M{\={a}}ori knowledge, which include rich ecological and historical knowledge of kauri forests and a holistic approach to forest health, are highlighted.

}, issn = {0032-0862}, doi = {10.1111/ppa.v69.110.1111/ppa.13104}, url = {https://bsppjournals.onlinelibrary.wiley.com/doi/full/10.1111/ppa.13104}, author = {Bradshaw, R. E. and Bellgard, S. E. and Black, A. and Burns, B. R. and Gerth, M. L. and McDougal, R. L. and Scott, P. M. and Waipara, N. W. and Weir, B. S. and Williams, N. M. and Winkworth, R. C. and Ashcroft, T. and Bradley, E. L. and Dijkwel, P. P. and Guo, Y. and Lacey, R. F. and Mesarich, C. H. and Panda, P. and Horner, I. J.} } @proceedings {607, title = {A disease survey of cherimoya orchards in Northland, New Zealand.}, year = {2007}, address = {Adelaide}, author = {Braithwaite, M. and Bullians, M.S. and Pay, J.M. and Gill, G.S.C. and Hill, C.F.} } @article {4612, title = {Genetic diversity of Phytophthora pluvialis, a pathogen of conifers, in New Zealand and the west coast of the United States of America}, journal = {Plant Pathology}, volume = {67}, year = {2018}, month = {Jan-06-2018}, pages = {1131 - 1139}, abstract = {

Phytophthora pluvialis is the causal agent of red needle cast on Pinus radiata in New Zealand. It was first isolated in 2008 but had previously been recovered from tanoak (Notholithocarpus densiflorus) and Douglas-fir (Pseudotsuga menziesii) trees in Oregon, USA in 2002. Phytophthora pluvialis was subsequently described as a new species in 2013 and classified as a clade III Phytophthora species. The aim of this study was to gain a better understanding of the genetic diversity, population structure and origin of this pathogen. A total of 360 P.\ pluvialis isolates were collected from the USA and New Zealand. The genome sequences of two P.\ pluvialis isolates were used to identify 27 single nucleotide polymorphism (SNP) markers that were then used to genotype the two populations. The genotypic data showed that the USA population of P.\ pluvialis had twice the genetic diversity and a greater number of multilocus genotypes (MLGs) compared to the New Zealand population, with 126 and 24 MLGs, respectively. The majority of the subpopulations within the USA and New Zealand showed linkage disequilibrium. All subpopulations had a negative fixation index, indicating that clonal reproduction is prevalent in both countries. A minimum spanning network (MSN) showed two unique clusters of isolates in the New Zealand population, suggesting two potential introductions of P.\ pluvialis into New Zealand from the USA. There was no significant structure within the New Zealand or USA populations. This study provides novel insight into the genetic structure of P.\ pluvialis in New Zealand and the USA.

}, doi = {https://doi.org/10.1111/ppa.12812}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/ppa.12812?campaign=wolacceptedarticle}, author = {Brar, S. and Tabima, J. F. and McDougal, R. L. and Dupont, P.-Y. and Feau, N. and Hamelin, R. C. and Panda, P. and LeBoldus, J. M. and Gr{\"u}nwald, N. J. and Hansen, E. M. and Bradshaw, R. E. and Williams, N. M.} } @article { refId, title = {Phytophthora cinnamomi and oak decline in southern Europe. Environmental constraints including climate change}, journal = {Ann. For. Sci.}, volume = {53}, year = {1996}, pages = {347-358}, doi = {10.1051/forest:19960217}, url = {http://dx.doi.org/10.1051/forest:19960217}, author = {C.M. Brasier} } @proceedings {brasier1999role, title = {The role of Phytophthora pathogens in forests and semi-natural communities in Europe and Africa}, year = {1999}, month = {2000}, pages = {6{\textendash}13}, publisher = {International Union of Forestry Research Organizations Working Party 7.02.09.}, address = {Forest Research Laboratory, Oregon State University, Corvallis, OR}, author = {C.M. Brasier}, editor = {Hansen, E.M. and Sutton, W.} } @conference {brasier2002pathogenicity, title = {Pathogenicity of Phytophthora ramorum isolates from North America and Europe to bark of European Fagaceae, American Quercus rubra and other forest trees}, booktitle = {Sudden oak death, a science symposium - the state of our knowledge, USDA Forest Service and University of California, Berkeley.}, year = {2002}, pages = {30{\textendash}31}, author = {C.M. Brasier and Rose, J. and Kirk, S.A. and Webber, JF} } @article {brasier2006recent, title = {Recent developments in Phytophthora diseases of trees and natural ecosystems in Europe}, journal = {Progress in Research on Phytophthora Diseases of Forest Trees. Proceedings, 3rd Int. IUFRO Working Party}, volume = {7}, number = {09}, year = {2006}, pages = {11{\textendash}17}, author = {C.M. Brasier and T. Jung} } @article {Brasier2005853, title = {Phytophthora kernoviae sp. nov., an invasive pathogen causing bleeding stem lesions on forest trees and foliar necrosis of ornamentals in the UK}, journal = {Mycological Research}, volume = {109}, number = {8}, year = {2005}, pages = {853 - 859}, abstract = {

A new Phytophthora pathogen of trees and shrubs, previously informally designated Phytophthora taxon C, is formally named here as P. kernoviae. P. kernoviae was discovered in late 2003 during surveys of woodlands in Cornwall, south-west England, for the presence of another invasive pathogen, P. ramorum. P. kernoviae is self-fertile (homothallic), having plerotic oogonia, often with distinctly tapered stalks and amphigynous antheridia. It produces papillate sporangia, sometimes markedly asymmetric with medium length pedicels. Its optimum temperature for growth is ca 18 ${\i}nfty$C and upper limit ca 26${\i}nfty$. Currently, P. kernoviae is especially noted for causing bleeding stem lesions on mature Fagus sylvatica and foliar and stem necrosis of Rhododendron ponticum. P. kernoviae is the latest of several invasive tree Phytophthoras recently identified in the UK. Its geographical origins and the possible plant health risk it poses are discussed.

}, issn = {0953-7562}, doi = {DOI: 10.1017/S0953756205003357}, url = {http://www.sciencedirect.com/science/article/B7XMR-4RS503Y-5/2/2264e8910ee36f4e72255d6160ebf9e4}, author = {Clive M. Brasier and Paul A. Beales and KIRK,Susan A. and Denman,Sandra and Joan Rose} } @article {4653, title = {Multiple new phenotypic taxa from trees and riparian ecosystems in Phytophthora gonapodyides-P. megasperma ITS Clade 6, which tend to be high-temperature tolerant and either inbreeding or sterile}, journal = {Mycological Research}, volume = {107}, year = {2003}, month = {Jan-03-2003}, pages = {277 - 290}, abstract = {

Phytophthora isolates associated with Phytophthora major ITS Clade 6 were grouped into 11 phenotypic taxa. These comprised the described morphospecies P. gonapodyides, P. megasperma s. str. and P. humicola; four previously identified but so far undescribed taxa, informally designated here P. sp. O-group, P. sp. Apple-cherry, P. taxon Pgchlamydo, and P. taxon Walnut; and four previously unknown taxa, designated P. taxon Oaksoil, P. taxon Raspberry, P. taxon Forestsoil, and P. taxon Riversoil. With the exception of P. gonapodyides each phenotypic taxon represented an unique ITS lineage. Two isolates morphologically identical to P. gonapodyides comprised a separate lineage and probably represent another taxon, designated here P. taxon Salixsoil. P. humicola, P. sp. O-group, P. sp. Apple-cherry and P. taxon Walnut grouped together as subclade I. Within subclade II, P. taxon Oaksoil, P. taxon Raspberry, P. taxon Forestsoil, P. taxon Riversoil and P. taxon Pgchlamydo formed a cluster of closely related but phenotypically distinct lineages basal to P. gonapodyides and P. megasperma, P. taxon Salixsoil being the most basal member. The taxonomy, adaptation and breeding systems of Clade 6 taxa are discussed. They show a strong association with forests and riparian ecosystems, only a limited association with agriculture and an ability to tolerate high temperatures. Also, in contrast to most other Phytophthora clades, Clade 6 taxa are predominantly sterile or inbreeding in culture. Only one taxon, P. sp. O-group, appears classically A1/A2 heterothallic.

}, issn = {09537562}, doi = {10.1017/S095375620300738X}, url = {http://linkinghub.elsevier.com/retrieve/pii/S0953756208611788}, author = {Brasier, Clive M. and Cooke, David E.L. and Duncan, James M. and Hansen, Everett M.} } @article {brasier_phytophthora_2010, title = {Phytophthora lateralis discovered in an old growth Chamaecyparis forest in Taiwan.}, journal = {Plant pathology}, volume = {59}, number = {4}, year = {2010}, pages = {595{\textendash}603}, keywords = {phylogeny}, issn = {00320862}, doi = {http://dx.doi.org/10.1111/j.1365-3059.2010.02278.x}, author = {C.M. Brasier and A. Vannini and T.T. Chang and A.M. Vettraino} } @article {PPA:PPA1886, title = {The biosecurity threat to the UK and global environment from international trade in plants}, journal = {Plant Pathology}, volume = {57}, number = {5}, year = {2008}, pages = {792{\textendash}808}, publisher = {Blackwell Publishing Ltd}, abstract = {Native plant communities, woodlands and landscapes in the UK and across the world are suffering from pathogens introduced by human activities. Many of these pathogens arrive on or with living plants. The potential for damage in the future may be large, but current international regulations aimed at reducing the risks take insufficient account of scientific evidence and, in practice, are often highly inadequate. In this Letter I outline the problems and discuss some possible approaches to reducing the threats.}, keywords = {biosecurity, forests, invasive pathogens, natural ecosystems, PLANT diseases, plant health}, issn = {1365-3059}, doi = {10.1111/j.1365-3059.2008.01886.x}, url = {http://dx.doi.org/10.1111/j.1365-3059.2008.01886.x}, author = {C.M. Brasier} } @article {588, title = {Plant pathology: Sudden larch death}, journal = {Nature}, volume = {466}, year = {2010}, pages = {824-825}, chapter = {824}, doi = {10.1038/466824a}, url = {http://dx.doi.org/10.1038/466824a}, author = {Brasier,Clive and Webber,Joan} } @article {268, title = {Oak mortality in Iberia}, journal = {Nature}, volume = {360}, year = {1992}, pages = {539-539}, issn = {0028-0836}, doi = {doi:10.1038/360539a0}, url = {http://www.nature.com/nature/journal/v360/n6404/abs/360539a0.html}, author = {C.M. Brasier} } @article {CambridgeJournals:150657, title = {Sudden Oak Death: Phytophthora ramorum exhibits transatlantic differences}, journal = {Mycological Research}, volume = {107}, number = {03}, year = {2003}, pages = {257-259}, doi = {10.1017/S0953756203227660}, url = {http://dx.doi.org/10.1017/S0953756203227660}, author = {Brasier,Clive} } @article {4652, title = {Cultural characters, protein patterns and unusual mating behaviour of Phytophthora gonapodyides isolates from Britain and North America}, journal = {Mycological Research}, volume = {97}, year = {1993}, month = {Jan-11-1993}, pages = {1287 - 1298}, abstract = {

Isolates of Phytophthora gonapodyides associated with roots of woody hosts or from aquatic habitats in Britain (10 isolates) and North America (Alaska to California, 12 isolates) were compared. They showed similar characteristics including similar sporangial dimensions, colonies with often distinctive petaloid patterns and a silvery appearance, slow growth rates at 20, 25 and 30 {\textdegree}C, and a maximum temperature for growth of about 35{\textdegree}. Most isolates exhibited a similar protein banding pattern distinct from that of P. cryptogea or P. drechsleri, and including a characteristic band designated the {\textquoteleft}PG band{\textquoteright}. Three isolates deviated from this pattern and two of these also produced chlamydospores and chains of swellings in culture. These isolates might be hybrids related to P. gonapodyides or a different taxon, in which case {\textquoteleft}P. gonapodyides{\textquoteright} is polyphyletic.

All the isolates were self-sterile. When paired directly or indirectly via polycarbonate membranes with A2 sexual compatibility types of heterothallic species such as P. cambivora, P. megakarya or P. meadii, gametangia were produced which were morphologically characteristic of these species. The range of heterothallic species responding was different from that responding sexually to Trichoderma volatiles. P. gonapodyides isolates may be sterile A1 compatibility types able to produce a compatibility substance which induces selfing in the heterothallic A2s.

Three other self-sterile Phytophthora isolates associated with woody hosts in Britain were a distinct group, with a different colony pattern, a distinct 30{\textdegree} growth optimum and an ability to grow at 37{\textdegree}. Their protein banding pattern was different from that of either P. gonapodyides or P. cryptogea/P. drechsleri, but showed similarities to these species. One isolate induced gametangial formation in P. drechsleri A1 types, the two others were sexually neutral. These three isolates might also be species hybrids, possibly with P. gonapodyides and P. cryptogea as parents.

}, issn = {09537562}, doi = {10.1016/S0953-7562(09)80160-3}, url = {https://linkinghub.elsevier.com/retrieve/pii/S0953756209801603}, author = {Brasier, C.M. and Hamm, P.B. and Hansen, E.M.} } @article {594531620010401, title = {Comparative aggressiveness of standard and variant hybrid alder phytophthoras, Phytophthora cambivora and other phytophthora species on bark of alnus, Quercus and other woody hosts.}, journal = {Plant Pathology}, volume = {50}, number = {2}, year = {2001}, pages = {218}, abstract = {

Analyzes results of pathogenicity tests on the bark of Alnus glutinosa with standard and variant hybrid alder phytophthoras. Aggressiveness on living alder logs; Levels of pathogenicity; Rates of lesion development.

}, keywords = {Alnus glutinosa, Disease, pest resistance, Phytophthora, plants}, issn = {00320862}, doi = {10.1046/j.1365-3059.2001.00553.x}, url = {http://onlinelibrary.wiley.com.proxy.library.oregonstate.edu/doi/10.1046/j.1365-3059.2001.00553.x/abstract}, author = {C.M. Brasier and Kirk, S.A.} } @article {PPA:PPA140, title = {Evidence for Phytophthora cinnamomi involvement in Iberian oak decline}, journal = {Plant Pathology}, volume = {42}, number = {1}, year = {1993}, pages = {140{\textendash}145}, publisher = {Blackwell Publishing Ltd}, abstract = {

Rapid and sometimes extensive mortality and decline of oak, principally Quercus suber and Q. ilex, has occurred in parts of southern Spain and Portugal in recent decades. We report here isolation of the aggressive root pathogen Phytophthora cinnamomi from roots of diseased oaks or from soil at eleven out of thirteen decline foci examined. It is proposed that the introduction and spread of P. cinnamomi may be a major factor in the Iberian oak decline, interacting with drought and other site factors, and leading to stress-related attacks by insects and other fungi. By analogy, it may also be involved in the similar oak declines occurring elsewhere on the Mediterranean.

}, issn = {1365-3059}, doi = {10.1111/j.1365-3059.1993.tb01482.x}, url = {http://dx.doi.org/10.1111/j.1365-3059.1993.tb01482.x}, author = {C.M. Brasier and Robredo, F. and Ferraz, J. F. P.} } @article {4135, title = {Taxonomy of Phytophthora palmivora on cocoa}, journal = {Transactions of the British Mycological Society}, volume = {72}, year = {1979}, month = {2/1979}, pages = {111 - 143}, abstract = {

Morphological and physiological studies-chromosome type, colony morphology and growth rate on carrot agar, cocoa pod lesion characteristics, morphology and size of sporangia, sporangial pedicels, chlamydospores and sex organs, compatibility type, growth on a synthetic medium, response to Trichoderma, and temperature relations-were made with c. 950 Phytophthora isolates from cocoa (Theobroma cacao L.) attributed to P. palmivora (Butl.) Butl. The survey covered isolates from all the major cocoa growing areas of the world, and included isolates studied by C. H. Gadd and S. F. Ashby in the 1920s.

The majority of the isolates could be assigned to one of three distinct forms, termed S, L and MF4. The S-type is attributed here to P. palmivora, which is redefined. Both L and MF4 are considered to be distinct species of Phytophthora. The L-type could not be identified with any known species and is described here as P. megakarya sp.nov. P. palmivora occurred world-wide on cocoa, whereas P. megakarya was obtained only from West Africa and MF4 only from Central and South America and the West Indies.

Isolates attributed to P. palmivora from other hosts were also examined. Some isolates from rubber, coconut and durian were P. palmivora (S-type). Isolates from pepper comprised a group closely resembling MF4. Isolates from coconut and rubber originally attributed to P. palmivora by S. F. Ashby, C. H. Gadd and E. M. Blackwell comprised a further group, and were also attributed here to P. palmivora, yet were somewhat different morphologically from the S-type on cocoa. It is not clear which of these two types is authentic P. palmivora.

The significance of these results, and the value of the various diagnostic criteria used, is discussed.

}, issn = {00071536}, doi = {10.1016/S0007-1536(79)80015-7}, url = {http://www.sciencedirect.com/science/article/pii/S0007153679800157}, author = {C.M. Brasier and Griffin, M.J.} } @article {Brasier2012, title = {Four phenotypically and phylogenetically distinct lineages in Phytophthora lateralis}, journal = {Fungal Biology}, year = {2012}, pages = {-}, abstract = {

Until recently Phytophthora lateralis was known only as the cause of dieback and mortality of Chamaecyparis lawsoniana in its native range in the Pacific Northwest. Since the 1990s however disease outbreaks have occurred increasingly on ornamental C. lawsoniana in Europe; and in 2007 the pathogen was discovered in soil around old growth C. obtusa in Taiwan, where it may be endemic. When the phenotypes of over 150 isolates of P. lateralis from Taiwan, across the Pacific Northwest (British Columbia to California) and from France, the Netherlands and the UK were compared three growth rate groups were resolved: one slow growing from Taiwan, one fast growing from the Pacific Northwest and Europe and one of intermediate growth from a small area of the UK. Within these growth groups distinct subtypes were identified based on colony patterns and spore metrics and further discriminated in a multivariate analysis. The assumption that the three main growth groups represented phylogenetic units was tested by comparative sequencing of two mitochondrial and three nuclear genes. This assumption was confirmed. In addition two phenotype clusters within the Taiwan growth group were also shown to be phylogenetically distinct. These four phenotypically and genotypically unique populations are informally designated as the Pacific Northwest lineage, the UK lineage, the Taiwan J lineage and the Taiwan K lineage. Their characteristics and distribution are described and their evolution, taxonomic and plant health significance is discussed.

}, keywords = {Colony pattern, evolution, Growth rate, Multigene phylogeny, Multivariate analysis, Sporangial morphology}, issn = {1878-6146}, doi = {10.1016/j.funbio.2012.10.002}, url = {http://www.sciencedirect.com/science/article/pii/S1878614612001717?v=s5}, author = {Clive M. Brasier and Selma Franceschini and Vettraino, Anna Maria and Hansen, Everett M. and Sarah Green and Cecile Robin and Joan F. Webber and Andrea Vannini} } @article {Brasier11051999, title = {Origin of a new Phytophthora pathogen through interspecific hybridization}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {96}, number = {10}, year = {1999}, pages = {5878-5883}, abstract = {Plant disease epidemics resulting from introductions of exotic fungal plant pathogens are a well known phenomenon. An associated risk that accelerated pathogen evolution may be occurring as a consequence of genetic exchange between introduced, or introduced and resident, fungal pathogens is largely unrecognized. This is, in part, because examples of natural, interspecific hybridization in fungi are very rare. Potential evolutionary developments range from the acquisition of new host specificities to emergence of entirely new pathogen taxa. We present evidence from cytological behavior, additive nucleotide bases in repetitive internal transcribed spacer regions of the rRNA-encoding DNA (rDNA), and amplified fragment length polymorphisms of total DNA that a new, aggressive Phytophthora pathogen of alder trees in Europe comprises a range of heteroploid-interspecific hybrids involving a Phytophthora cambivora-like species and an unknown taxon similar to Phytophthora fragariae. The hybrids marked developmental instabilities, unusual morphological variability, and evidence for recombination in their internal transcribed spacer profiles indicates that they are of recent origin and that their evolution is continuing. The likelihood of such evolutionary events may be increasing as world trade in plants intensifies. However, routine diagnostic procedures currently in use are insufficiently sensitive to allow their detection.}, doi = {doi: 10.1073/pnas.96.10.5878}, url = {http://www.pnas.org/content/96/10/5878.abstract}, author = {C.M. Brasier and Cooke, D. E. L. and Duncan, J. M.} } @article {Brasier19931287, title = {Cultural characters, protein patterns and unusual mating behaviour of Phytophthora gonapodyides isolates from Britain and North America}, journal = {Mycological Research}, volume = {97}, number = {11}, year = {1993}, pages = {1287 - 1298}, issn = {0953-7562}, doi = {DOI: 10.1016/S0953-7562(09)80160-3}, url = {http://www.sciencedirect.com/science/article/B7XMR-4VXMWBV-2/2/79f23cf89ac836528cb576d2f46f81b3}, author = {C.M. Brasier and P.B. Hamm and Hansen, E.M.} } @article {1261, title = {Natural stem infection of Lawson cypress (Chamaecyparis lawsoniana) caused by Phytophthora ramorum}, journal = {New Disease Reports}, volume = {25}, year = {2012}, pages = {26}, url = {http://dx.doi.org/10.5197/j.2044-0588.2012.025.026}, author = {C.M. Brasier and Webber, JF} } @article {1439572819951201, title = {An unusual Phytophthora associated with widespread alder mortality in Britain}, journal = {Plant Pathology}, volume = {44}, number = {6}, year = {1995}, pages = {999 - 1007}, abstract = {

During 1993 and 1994 an unusual Phytophthora was consistently isolated from bark lesions at the stem bases of dying alder in Southern Britain. The Phytophthora resembles P. cambivora in both its gametangial and sporangial morphology. However, it is distinct from this species in being homothallic rather than outcrossing; in producing a significant proportion of small and sometimes partially developed oogonia; in having a high frequency of oosphere abortion; in having an appressed felty colony type with little or no aerial mycelium; and in exhibiting a lower optimum temperature for growth (c.22.5{\textdegree}C) and lower growth temperature maximum (c.29{\textdegree}C) on carrot agar than P. cambivora (c.27.5{\textdegree} and 33.5{\textdegree}C respectively). An inoculation test confirmed its pathogenicity to Alnus. The status of the alder Phytophthora is discussed. On the basis of its unusual characteristics and unusual host it is suggested that it might be a new or recently introduced organism rather than a previously unrecorded indigenous variant of P. cambivora.

}, keywords = {AGRICULTURAL pests, ALDER, ALDER {\textendash} Diseases \& pests, GREAT Britain, Phytophthora, PLANT diseases}, issn = {00320862}, doi = {doi/10.1111/j.1365-3059.1995.tb02658.x}, url = {http://onlinelibrary.wiley.com/doi/10.1111/j.1365-3059.1995.tb02658.x/abstract}, author = {C.M. Brasier and Rose, J. and Gibbs, J. N.} } @article {CambridgeJournals:249527, title = {Sudden oak death (Phytophthora ramorum) discovered on trees in Europe}, journal = {Mycological Research}, volume = {108}, number = {10}, year = {2004}, pages = {1108-1110}, doi = {10.1017/S0953756204221244}, url = {http://dx.doi.org/10.1017/S0953756204221244}, author = {Brasier,Clive and Denman,Sandra and Brown,Anna and Webber,Joan} } @article {Brasier2004823, title = {Production of gametangia by Phytophthora ramorum in vitro}, journal = {Mycological Research}, volume = {108}, number = {7}, year = {2004}, pages = {823 - 827}, abstract = {

Until now gametangia have not been obtained between paired European A1 and American A2 isolates of Phytopthora ramorum in vitro. Their production in artificial culture relies on interspecific pairings. Using P. drechsleri and P. cambivora testers, 51 of 110 P. ramorum isolates from across Europe were all shown to be A1s; while 32 of 38 American isolates from across California and southwest Oregon were shown to be A2s. However, these interspecific pairings are complex, unusually slow and unpredictable. A range of culture media and conditions are described that were tested, unsuccessfully, with a view to enhancing the efficiency of the interspecific pairings. In further tests, gametangia were obtained between A1 and A2 isolates of P. ramorum when juvenile, pre-chlamydospore producing mycelia were mixed together on carrot agar. The gametangia formed in 3{\textendash}10 d, sparsely to frequently, initially only within the boundaries of the mixed inocula but subsequently in the extended mycelial growth. Chlamydospores were also produced. This inoculum-mixing method, though again sometimes unpredictable, should enhance efficiency of testing for compatibility types and facilitate further studies on whether the sexual outcrossing system of P. ramorum is functional. Differences between sexual reproduction of P. ramorum and that of other heterothallic Phytophthora species are discussed.

}, issn = {0953-7562}, doi = {10.1017/S0953756204000565}, url = {http://www.sciencedirect.com/science/article/pii/S0953756208603949}, author = {Brasier,Clive and Susan Kirk} } @article {CambridgeJournals:249519, title = {Phytophthora alni sp. nov. and its variants: designation of emerging heteroploid hybrid pathogens spreading on Alnus trees}, journal = {Mycological Research}, volume = {108}, number = {10}, year = {2004}, pages = {1172-1184}, abstract = {

In 1993 a destructive new Phytophthora pathogen of riparian Alnus trees was discovered in the UK and subsequently shown to be present in other parts of Europe. The new Phytophthora comprised a group of emergent heteroploid hybrids, probably between P. cambivora and a species related to P. fragariae. These included a common, near tetraploid standard hybrid, the presumptive allopolyploid; and four scarcer major variant types with chromosome numbers intermediate between diploid and tetraploid, named the Swedish, Dutch, German and UK variants. The standard hybrid type is formally designated here as Phytophthora alni subsp. alni. The Swedish variant is designated as P. alni subsp. uniformis; and the Dutch, German and UK variants collectively as P. alni subsp. multiformis. The properties of the Dutch, German and UK variants within subsp. multiformis are informally described. The problems of designating emergent species hybrids under the International Code of Botanical Nomenclature and the reasons for the taxonomic choices made are discussed.

}, doi = {10.1017/S0953756204001005}, url = {http://dx.doi.org/10.1017/S0953756204001005}, author = {Clive M. Brasier and Kirk, S.A. and Jose Delcan and David E.L. Cooke and Thomas Jung and Man In{\textquoteright}t Veld, W.A.} } @article {Brasier2003277, title = {Multiple new phenotypic taxa from trees and riparian ecosystems in Phytophthora gonapodyides-P. megasperma ITS Clade 6, which tend to be high-temperature tolerant and either inbreeding or sterile}, journal = {Mycological Research}, volume = {107}, number = {3}, year = {2003}, pages = {277 - 290}, issn = {0953-7562}, doi = {DOI: 10.1017/S095375620300738X}, url = {http://www.sciencedirect.com/science/article/B7XMR-4RT04VN-6/2/68f2582c518f07f52e7a0db891ca14dd}, author = {Clive M. Brasier and David E.L. Cooke and James M. Duncan and Hansen, Everett M.} } @article {4630, title = {Phytophthora species recovered from the Connecticut River Valley in Massachusetts, USA}, journal = {Mycologia}, volume = {108}, year = {2016}, month = {Aug-01-2017}, pages = {6 - 19}, abstract = {

Little is currently known about the assemblage of Phytophthora species in northeastern North America, representing a gap in our understanding of species incidence. Therefore, Phytophthora species were surveyed at 20 sites in Massachusetts, with 16 occurring in the Connecticut River Valley. Many of the sampled waterways were adjacent to active agricultural lands, yet were buffered by mature floodplain forests composed of Acer, Platanus, Populus and Ulmus. Isolates were recovered with three types of baits (rhododendron leaves, pear, green pepper) in 2013 and water filtration in 2014. Overall, 457 isolates of Phytophthora were recovered and based on morphological characters and rDNA internal transcribed spacer (ITS), β-tubulin (β-tub) and cytochrome oxidase c subunit I (cox1) sequences, 18 taxa were identified, including three new species: P. taxon intercalaris, P. taxon caryae and P. taxon pocumtuck. In addition, 49 isolates representing five species of Phytopythium also were identified. Water filtration captured a greater number of taxa (18) compared to leaf and fruit baits (12). Of the three bait types rhododendron leaves yielded the greatest number of isolates and taxa, followed by pear and green pepper, respectively. Despite the proximity to agricultural lands, none of the Phytophthora species baited are considered serious pathogens of vegetable crops in the region. However, many of the recovered species are known woody plant pathogens, including four species in the P. citricola s.l. complex that were identified: P. plurivora, P. citricola III, P. pini and a putative novel species, referred to here as P. taxon caryae. An additional novel species, P. taxon pocumtuck, is a close relative of P. borealis based on cox1 sequences. The results illustrate a high level of Phytophthora species richness in the Connecticut River Valley and that major rivers can serve as a source of inoculum for pathogenic Phytophthora species in the northeast.

}, issn = {0027-5514}, doi = {10.3852/15-038}, url = {https://www.tandfonline.com/doi/full/10.3852/15-038}, author = {Brazee, Nicholas J. and Wick, Robert L. and Hulvey, Jonathan P.} } @article {4703, title = {Diversity and Pathogenicity of Phytophthora Species Associated with Declining Alder Trees in Italy and Description of Phytophthora alpina sp. nov}, journal = {Forests}, volume = {11}, year = {2020}, month = {Aug-05-2020}, pages = {848}, abstract = {

Extensive decline and mortality events of alder trees have recently been observed in several riparian ecosystems in Italy. Since there is little information about the aetiology of this disease and given the high ecological relevance of riparian ecosystems, an in-depth study was conducted in three sites spanning from the Mediterranean to Alpine regions. From spring 2019 to spring 2020, 261 samples of bleeding cankers, rhizosphere soil and leaves used as baits along waterways were collected and used for Phytophthora isolation. Based on morphology, colony appearance and DNA sequence data, 10 species belonging to 6 clades were identified. These included P. plurivora (84 isolates), P. pseudocryptogea (50), P. hydropathica (18), P. gonapodyides (14), P. bilorbang (13), P. pseudosyringae (12), P. lacustris (11), P. acerina (7), P. cactorum (1) and one isolate of the hybrid Phytophthora {\texttimes}serendipita. In addition, two new Phytophthora species, one of which is described here as Phytophthora alpina sp. nov., were isolated. The pathogenicity of P. alpina and other species obtained from samples collected in the green alder stand was assessed on 3-year-old seedlings. All species proved to be pathogenic on green alder causing symptoms congruent with field observations. Results obtained have allowed us to expand knowledge about alder decline aetiology. The diversity of pathogenicity of Phytophthora species associated with symptomatic alder trees suggested that no single agent is responsible for the disease, but that it is the result of multiple infections of different Phytophthora species, variable in assemblages among sites.

}, doi = {10.3390/f11080848}, url = {https://www.mdpi.com/1999-4907/11/8/848/htm}, author = {Bregant, Carlo and Sanna, Gian Paolo and Bottos, Adriano and Maddau, Lucia and Montecchio, Lucio and Linaldeddu, Benedetto T.} } @article {4258, title = {Phytophthora palmivora}, volume = {Number 12}, year = {2005}, pages = {2 pp}, publisher = {American Samoa Community College Community \& Natural Resources Cooperative Research \& Extension }, abstract = {

The organism that caused the 1845-46 Irish Potato Famine was named Phytophthora, the {\textquotedblleft}plant destroyer{\textquotedblright}. Though initially considered a fungus, or water mold, this organism is more like certain algae and has been moved from the kingdom Fungi to Chromista. There are about 80 species of Phytophthora, all damaging to plants. One of the most common tropical species is P. palmivora, with more than 150 plant hosts. Some of the most important hosts are black pepper (Piper nigrum), rubber (Hevea brasilensis), durian (Durio zibethinus), coconut (Co- cos nucifera), cocoa (Theobroma cacao), breadfruit (Artocarpus altilis), and papaya (Carica papaya). In American Samoa, the last three hosts are attacked by P. palmivora.

}, url = {http://www2.ctahr.hawaii.edu/adap/ASCC_LandGrant/Dr_Brooks/BrochureNo12.pdf}, author = {Brooks, F} } @article {PPA:PPA1511, title = {Colonization of tree xylem by Phytophthora ramorum, P. kernoviae and other Phytophthora species}, journal = {Plant Pathology}, volume = {56}, number = {2}, year = {2007}, pages = {227{\textendash}241}, publisher = {Blackwell Publishing Ltd}, abstract = {

The aetiology and frequency of Phytophthora spp. in discoloured xylem tissue beneath phloem lesions was investigated in a range of broadleaved trees infected with P. ramorum, P. kernoviae, P. cambivora, P. citricola and other species. Isolation was attempted from the inner surface of 81 sterilized discoloured wood panels (6 {\texttimes} 4 cm) from 53 trees. Discolouration mostly extended 1{\textendash}5 mm into the xylem (75\%), but incursions of 6{\textendash}10 mm (10\%) and 10{\textendash}25 mm (15\%) were frequent. Of the wood panels, 81\% yielded Phytophthora spp. In 66 cases, both a wood panel and an overlying phloem panel were sampled. In 56\% of these, a Phytophthora, sp. was isolated from both the wood and the phloem panel. In 23\% the Phytophthora sp. was isolated from the wood panel only and in 8\% from the phloem panel only. Small {\textquoteleft}island{\textquoteright} phloem lesions, often in linear arrays adjacent to main lesions, were a common feature of Fagus sylvatica and Quercus spp. trees infected with P. ramorum or P. kernoviae. Island lesions were often connected by underlying strips or intermittent pits of discoloured xylem in line with the wood grain. Phytophthora ramorum, P. kernoviae and other Phytophthora spp. were successfully isolated from these connecting xylem features with P. ramorum and P. kernoviae also recovered from discoloured tissue 5{\textendash}25 mm below exposed xylem surfaces 24{\textendash}27 months after the overlying phloem was removed. These results show that these pathogens commonly occupy xylem beneath phloem lesions; that they can perennate in xylem tissue; that they can spread in xylem tissue ahead of phloem lesions; and indicate that they may initiate new phloem lesions in this way. Such colonization must lead to at least local xylem dysfunction. It is recommended that, if xylem discoloration is present, isolation of the Phytophthora sp. should be attempted from the xylem as well as the bark; also, that removal of infected outer sapwood should be undertaken during excision of bleeding lesions for disease control and in protocols aimed at preventing national or international spread of these tree stem pathogens.

}, keywords = {bark lesions, bleeding cankers, phloem, Phytophthora, tree stem diseases, wood}, issn = {1365-3059}, doi = {10.1111/j.1365-3059.2006.01511.x}, url = {http://dx.doi.org/10.1111/j.1365-3059.2006.01511.x}, author = {Brown, A. V. and C.M. Brasier} } @article {1306, title = {A leaf and twig disease of English holly caused by Phytophthora ilicis N. sp.}, journal = {Phytopathology}, volume = {47}, year = {1957}, pages = {95-101}, abstract = {

This is an expanded account from Oregon State College, Corvallis, of a disease of holly caused by Phytophthora sp. [34, p. 328], for which the name P. ilicis n.sp. is proposed. It was shown that the defoliation which accompanies the disease is due to the production of ethylene by infected leaf tissue. The disease develops from October to May, and is inactive in the summer. The pathogen is distinguishable from P. porri by its smaller oogonia, and from P. hibernalis and P. syringae by the consistent presence of amphigynous antheridia. On diseased holly tissues the sporangia have a shallow apical thickening and no papilla, and measure 18 to 30 by 30 to 50 (average 24 by 39) {\textmu}, with persistent pedicels, 5 to 15 {\textmu} long. Oogonia average 21 {\textmu} and oospores 18 {\textmu}, with a slightly yellow wall; antheridia average 13 by 1{\textmu}.

}, author = {Buddenhagen, I. W. and Young, R. A.} } @mastersthesis {1305, title = {A Phytophthora-induced disease of English holly, Ilex aquifolium L.}, volume = {MS}, year = {1954}, school = {Oregon State University}, type = {masters}, address = {Corvallis}, author = {Buddenhagen, I. W.} } @mastersthesis {1197, title = {Root rots caused by Phycomycetes}, year = {1927}, pages = {51 pp.}, school = {University of Utrecht, Meded. Phytopath. Lab. Willie Commelin Scholten Baarn 11: 4,7.}, type = {masters}, author = {Buisman, C.J.} } @article {4487, title = {Current and projected global distribution of Phytophthora cinnamomi, one of the world{\textquoteright}s worst plant pathogens}, journal = {Global Change Biology}, year = {2016}, month = {Jan-09-2016}, abstract = {

Globally, Phytophthora cinnamomi is listed as one of the 100 worst invasive alien species and active management is required to reduce impact and prevent spread in both horticulture and natural ecosystems. Conversely, there are regions thought to be suitable for the pathogen where no disease is observed. We developed a CLIMEX model for the global distribution of P. cinnamomi based on the pathogen{\textquoteright}s response to temperature and moisture and by incorporating extensive empirical evidence on the presence and absence of the pathogen. The CLIMEX model captured areas of climatic suitability where P. cinnamomi occurs that is congruent with all available records. The model was validated by the collection of soil samples from asymptomatic vegetation in areas projected to be suitable by the model for which there were few records. DNA was extracted and the presence or absence of P. cinnamomi determined by high throughput sequencing (HTS). While not detected using traditional isolation methods, HTS detected P. cinnamomi at higher elevations in eastern Australia and central Tasmania as projected by the CLIMEX model. Further support for the CLIMEX model was obtained by using the large dataset from southwest Australia where the proportion of positive records in an area is related to the Ecoclimatic Index value for the same area. We provide for the first time a comprehensive global map of the current P. cinnamomi distribution, an improved CLIMEX model of the distribution, and a projection to 2080 of the distribution with predicted climate change. This information provides the basis for more detailed regional scale modelling and supports risk assessment for governments to plan management of this important soil-borne plant pathogen.

}, doi = {http://dx.doi.org/10.1111/gcb.13492 }, url = { http://dx.doi.org/10.1111/gcb.13492 }, author = {Burgess, Treena I. and Scott, John K. and McDougall, Keith L. and Stukely, Michael J. C. and Crane, Colin and Dunstan, William A. and Brigg, Frances and Andjic, Vera and White, Diane and Rudman, Tim and Arentz, Frans and Ota, Noboru and Hardy, Giles E. St.J.} } @article {4078, title = {Re-evaluation of Phytophthora species isolated during 30 years of vegetation health surveys in western Australia using molecular techniques}, journal = {Plant Disease}, volume = {93}, year = {2009}, month = {03/2009}, pages = {215 - 223}, abstract = {

For 30 years, large-scale aerial photography has been used to map the extent of Phytophthora dieback disease in native forests in the southwest of Western Australia, with validation of the observations involving routine testing of soil and root samples for the presence of Phytophthora cinnamomi. In addition to P. cinnamomi, six morpho-species have been identified using this technique: P. citricola, P. megasperma, P. cryptogea, P. drechsleri, P. nicotianae, and P. boehmeriae. In recent years, many new Phytophthora species have been described worldwide, often with similar morphology to existing species; thus, as many of the isolates collected in Western Australia have been difficult to identify based on morphology, molecular identification of the morpho-species is required. Based on amplification of the internal transcribed spacer (ITS) region of the rDNA gene, sequence data of more than 230 isolates were compared with those of existing species and undescribed taxa. P. inundata, P. asparagi, P. taxon PgChlamydo, P. taxon personii, and P. taxon niederhauserii were identified based on sequence data. Phylogenetic analysis revealed that nine potentially new and undescribed taxa can be distinguished. Several of the new taxa are morphologically indistinguishable from species such as P. citricola, P. drechsleri, and P. megasperma. In some cases, the new taxa are closely related to species with similar morphology (e.g., P.sp.4 and P. citricola). However, the DNA sequences of other new taxa such as P.sp.3 and P.sp.9 show that they are not closely related to morphologically similar species P. drechsleri and P. megasperma, respectively. Most of the new taxa have been associated with dying Banksia spp., while P.sp.2 and P.sp.4 have also been isolated from dying Eucalyptus marginata (jarrah). Some taxa (P.sp.3, 6, and 7) appear to have limited distribution, while others like P.sp.4 are widespread.

}, issn = {0191-2917}, doi = {10.1094/PDIS-93-3-0215}, author = {Burgess, Treena I. and Webster, Janet L. and Ciampini, Juanita A. and White, Diane and Hardy, Giles E. StJ. and Stukely, Michael J. C.} } @article {4706, title = {Towards a best practice methodology for the detection of Phytophthora species in soils}, journal = {Plant Pathology}, volume = {Early view}, year = {2020}, month = {Nov-07-2020}, abstract = {

The genus Phytophthora contains species that are major pathogens worldwide, affecting a multitude of plant species across agriculture, horticulture, forestry, and natural ecosystems. Here, we concentrate on those species that are dispersed through soil and water, attacking the roots of the plants, causing them to rot and die. The intention of this study was to compare the soil baiting protocol developed by the Centre for Phytophthora Science and Management (CPSM) with two other baiting methods used in Australia. The aim was to demonstrate the effectiveness of each protocol for soil baiting Phytophthora species in different substrates. Three experiments were conducted: the first to test the sensitivity of each method to detect Phytophthora cinnamomi, the second to test the effect of substrate type (sand or loam), and the third to test the detection of species (P. cinnamomi, P. multivora, or P. pseudocryptogea). The specificity of different plant species baits was compared within and between the methods. Substrate type influenced isolation in all methods; however, the CPSM method was superior regardless of substrate, albeit slower than one of the other methods for one substrate. Comparing bait species between the three methods, Quercus ilex was the most attractive bait for P. cinnamomi, particularly in the CPSM method. The choice of protocol affected the isolation associated with each bait type. Overall, the multiple bait system used by CPSM was shown to provide the most sensitive and reliable detection of Phytophthora species from soil samples.

}, issn = {0032-0862}, doi = {10.1111/ppa.13312}, url = {https://bsppjournals.onlinelibrary.wiley.com/doi/abs/10.1111/ppa.13312?af=R}, author = {Burgess, Treena I. and L{\'o}pez-Villamor, {\'a}n and Paap, Trudy and Williams, Briony and Belhaj, Rajah and Crone, Michael and Dunstan, William and Howard, Kay and Hardy, Giles E. St. J.} } @proceedings {4218, title = {Bud rot of coconut and other palms}, year = {1924}, pages = {145-147}, author = {Butler, EJ} } @article {4257, title = {Report of the imperial mycologist, 1918{\textendash}1919}, journal = {Science Report Institute Pusa}, pages = {82 pp}, author = {Butler, EJ} } @article {486, title = {Phytophthora cinnamomi and Australia{\textquoteright}s biodiversity: impacts, predictions and progress towards control.}, journal = {Australian Journal of Botany}, volume = {56}, year = {2008}, pages = {279{\textendash}310}, doi = {10.1071/BT07159}, url = {http://dx.doi.org/10.1071/BT07159}, author = {Cahill, DM and Rookes, JE and Wilson, BA and Gibson, L and McDougall, KL} } @article {261, title = {The occurrence of Phytophthora cinnamomi in the soil under pine stands in the southeast.}, journal = {Phytopathology}, volume = {41}, year = {1951}, pages = {742-746}, author = {Campbell, W.A.} } @article {campbell1954littleleaf, title = {Littleleaf disease of shortleaf and loblolly pines}, number = {Circular no. 940.}, year = {1954}, pages = {41 pages}, publisher = {USDA Forest Service}, address = {Washington, DC}, author = {Campbell, W.A. and Copeland, O.L.} } @article {delCastilloM√∫nera2012, title = {Developing a taxonomic identification system of Phytophthora species based on microsatellites}, journal = {Revista Iberoamericana de Micologia}, volume = {In press}, year = {2012}, pages = {-}, abstract = {

Phytophthora spp. is the most important genus of the Oomycete plant pathogens. Nowadays, there are 117 described species in this genus, most of them being primary invaders of plant tissues. The different species are causal agents of diseases in a wide range of crops and plants in natural environments. In order to develop control strategies against Phytophthora spp., it is important to know the biology, ecology and evolutionary processes of these important pathogens.

}, issn = {1130-1406}, doi = {10.1016/j.riam.2012.11.002}, url = {http://www.sciencedirect.com/science/article/pii/S1130140612001106}, author = {J. del Castillo-M{\'u}nera and M. C{\'a}rdenas and A. Pinz{\'o}n and A. Casta{\~n}eda and A.J. Bernal and S. Restrepo} } @article {4472, title = {Metabarcoding and development of new Real-time specific assays reveal Phytophthora species diversity in Holm Oak forests in eastern Spain}, journal = {Plant Pathology}, volume = {66}, year = {2017}, month = {Jan-04-2016}, pages = {115{\textendash}123}, abstract = {

The evergreen holm oaks (Quercus ilex subsp. ilex and Q.\ ilex subsp. ballota) are the most representative tree species in the Iberian peninsula and the main tree species in oak-rangeland ecosystems (dehesas). Oak decline in western, central and southern parts of Spain has been associated with root rot caused by Phytophthora cinnamomi for decades. However, Phytophthora species such as P.\ quercina and P.\ psychrophila have recently been found associated with Quercus decline in eastern Spain where calcareous soils are predominant. Soil and root samples from two Quercus forests presenting decline symptoms in two different geographical areas in eastern Spain (Carrascar de la Font Roja and Vallivana) were analysed by amplicon pyrosequencing. Metabarcoding analysis showed Phytophthora species diversity, and revealed that an uncultured Phytophthora taxon, named provisionally Phytophthora taxon ballota, was the predominant species in both areas. In addition, a real-time PCR assay, based on the pyrosequencing results, was developed for the detection of this uncultured Phytophthora taxon, and also for the detection of P.\ quercina. TaqMan assays were tested on soil and root samples, and on Phytophthora pure cultures. The new assays showed high specificity and were consistent with metabarcoding results. A new real-time PCR protocol is proposed to evaluate the implication of different Phytophthora spp. in oak decline in eastern Spain.

}, doi = {10.1111/ppa.12541}, url = {http://doi.wiley.com/10.1111/ppa.12541}, author = {Catal{\`a}, S. and Berbegal, M. and P{\'e}rez-Sierra, A. and Abad-Campos, P.} } @article {{\v c}ern{\'y}2008phytophthora, title = {Phytophthora cambivora causing ink disease of sweet chestnut recorded in the Czech Republic}, journal = {Czech Mycol.}, volume = {60}, year = {2008}, pages = {265{\textendash}274}, abstract = {

Castanea sativa is a non-autochthonous but commonly planted ornamental tree in the Czech Republic. It is sensitive to some Phytophthora infections causing the so-called ink disease. The disease usually occurs in warmer regions in Europe. In the Czech Republic it had not been detected until the nineties of the 20th century. In 1997 extensive decline of a sweet chestnut ornamental orchard with typical symptoms of ink disease was found at one locality in eastern Bohemia. Later the causal organism of this disease, Phytophthora cambivora, was isolated from necrotised tissues of trunks of several declining chestnut trees. This is the first find of the pathogen causing ink disease of chestnut in the Czech Republic.

}, issn = {0009-0476}, url = {http://www.natur.cuni.cz/cvsm/CM60210.pdf}, author = {Cerny, K. and Gregorov{\'a}, B. and Strnadov{\'a}, V. and Tom{\v s}ovsky, M. and Holub, V. and Gabrielov{\'a}, {\v S}.} } @article {EFP:EFP735, title = {Phytophthora ramorum in England and Wales: which environmental variables predict county disease incidence?}, journal = {Forest Pathology}, year = {2011}, pages = {no{\textendash}no}, publisher = {Blackwell Publishing Ltd}, abstract = {

Phytophthora ramorum is the oomycete pathogen responsible for Sudden Oak Death on the West Coast of the USA and Sudden Larch Death in the British Isles. It also causes twig dieback and leaf blight on a series of ornamental hosts (e.g. Rhododendron, Viburnum, Pieris and Camellia) commonly grown in plant nurseries, traded by garden centres and cultivated in public and private gardens. The role of the plant trade in the dispersal of P. ramorum has been well documented, but there is a need for regional analyses of which environmental variables can predict disease expression in the trade and in the wild, so as to be able to better predict the further development of this worldwide plant health issue. In this study, we analyse data on the incidence of P. ramorum (2002{\textendash}2009, thus before the reports in Japanese larch plantations) in counties in England and Wales as a function of environmental variables such as temperature and rainfall, controlling for confounding factors such as county area, human population and spatial autocorrelation. While P. ramorum county incidence in nurseries and retail centres was positively related to county area and human population density, county incidence in gardens and the wild did not show such correlations, declined significantly towards the East and was positively correlated with disease incidence in the trade. The latter finding, although not conclusively proving causation, suggests a role of the trade in the dispersal of this pathogen across English and Welsh landscapes. Combined together, P. ramorum county incidence in the trade and in the semi-natural environment increased with increasing precipitation and with declining latitude. This study shows the importance of environmental variables in shaping regional plant epidemics, but also yields results that are suggestive of a role of people in spreading plant diseases across entire countries.

}, issn = {1439-0329}, doi = {10.1111/j.1439-0329.2011.00735.x}, url = {http://dx.doi.org/10.1111/j.1439-0329.2011.00735.x}, author = {Chadfield, V. and Pautasso, M.} } @article {4031, title = {Change of Mating Type in an EU1 Lineage Isolate of Phytophthora ramorum}, journal = {Journal of Phytopathology}, year = {2013}, month = {07/2013}, pages = {n/a - n/a}, abstract = {

All Phytophthora ramorum EU1 lineage isolates tested are of A1 mating type, except for three rare isolates from 2002 to 2003 from Belgium, which were originally assigned the A2 mating type. In one of these isolates (2338), a switch from A2 to A1 mating type was observed in 2006. This observation initiated a larger study in which all cultures and subcultures of the original three EU1 A2 isolates, maintained in three laboratories under different storage conditions, were checked for mating type change. The A2 to A1 mating type switch was observed in four of seven independently maintained isolates that were derived from isolate 2338 in two laboratories, using different transfer regimes and storage conditions. Following the mating type switch to A1 in these four derived isolates, no reversion back to A2 mating was observed, even after up to 5\ years of additional isolate maintenance and several more subculturing events. The three other isolates that were derived from isolate 2338 as well as the other EU1 A2 isolates collected in 2002 and 2003 and stored in the same conditions did not display such mating type change. The potential causes of the mating type conversions as well as their epidemiological implications are discussed.

}, doi = {10.1111/jph.12150}, url = {http://onlinelibrary.wiley.com/doi/10.1111/jph.12150/abstract}, author = {Chandelier, Anne and Heungens, Kurt and Werres, Sabine} } @article {375, title = {Effect of temperature and bacteria on sporulation of Phytophthora alni in river water}, journal = {Commun Agric Appl Biol Sci.}, volume = {71}, year = {2006}, pages = {873{\textendash}80}, url = {http://www.ncbi.nlm.nih.gov/pubmed/17390834}, author = {Chandelier, A. and Abras, S. and Laurent, F. and Debruxelles, N. and Cavelier, M.} } @article {4455, title = {Assessment of inoculation methods for screening black alder resistance to Phytophthora~{\texttimes} alni}, journal = {Plant Pathology}, volume = {65}, year = {2016}, month = {Jan-04-2016}, pages = {441 - 450}, abstract = {

Identification of resistance to Phytophthora\ {\texttimes}alni could provide the basis for a management strategy against alder decline in riparian ecosystems in Europe. This study aimed to test methods to evaluate the resistance of riparian alders to the disease, and to screen alder genotypes for resistance. Phytophthora\ {\texttimes}alni isolates were compared for their aggressiveness (lesion length on stem) and sporulation capacity (sporangia). While no difference in lesion lengths was found between isolates, sporangia production was dependent on isolate, highlighting the need for careful selection of isolates used for zoospore inoculation methods. Inoculation tests carried out at different periods of the year revealed a seasonal change in susceptibility to the disease, with the period from June to September being the most efficient for inoculation tests. Stem-wounded inoculations, carried out on excised shoots, were unreliable for evaluating the level of resistance of alder genotypes to P.\ {\texttimes}alni infection, with divergent results between two successive years or between two inoculation periods during the same year. In contrast, a method that mimics the natural conditions of infection, based on flooding of rooted cuttings in artificially infected river water, was found promising. Another method, based on the inoculation of foliated terminal shoots with zoospore suspensions, was found to be repeatable and could be used for high-throughput analyses. Altogether, the results show a continuous resistance response from highly susceptible to moderately resistant genotypes. This suggests that breeding might be a useful strategy to manage alder decline caused by P.\ {\texttimes}alni.

}, doi = {10.1111/ppa.2016.65.issue-310.1111/ppa.12418}, url = {http://doi.wiley.com/10.1111/ppa.2016.65.issue-3http://doi.wiley.com/10.1111/ppa.12418http://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111\%2Fppa.12418}, author = {Chandelier, A. and Husson, C. and Druart, P. and Mar{\c c}ais, B.} } @article {chastagner1995symptoms, title = {Symptoms and Phytophthora spp. associated with root rot and stem canker of noble fir Christmas trees in the Pacific Northwest}, journal = {Plant disease}, volume = {79}, number = {3}, year = {1995}, pages = {290{\textendash}293}, publisher = {American Phytopathological Society}, keywords = {Abies procera, America, Artificial forest stand, Coniferales, epidemiology, Field study, Fungi, Gymnospermae, Host agent relation, infection, Mycosis, North America, Oregon, Phycomycetes, Phytophthora, Plant pathogen, Root, Softwood forest tree, Spermatophyta, Stem, Symptomatology, Thallophyta, United States, Washington}, issn = {0191-2917}, doi = {DOI: 10.1094/PD-79-0290}, url = {http://www.apsnet.org/publications/PlantDisease/BackIssues/Documents/1995Abstracts/PD_79_290.htm}, author = {Chastagner, G.A. and P.B. Hamm and Riley, K.L.} } @article {4012, title = {Membrane-based oligonucleotide array developed from multiple markers for the detection of many Phytophthora species}, journal = {Phytopathology}, volume = {103}, year = {2013}, month = {01/2013}, pages = {43 - 54}, abstract = {

Most Phytophthora spp. are destructive plant pathogens; therefore, effective monitoring and accurate early detection are important means of preventing potential epidemics and outbreaks of diseases. In the current study, a membrane-based oligonucleotide array was developed that can detect Phytophthora spp. reliably using three DNA regions; namely, the internal transcribed spacer (ITS), the 5' end of cytochrome c oxidase 1 gene (cox1), and the intergenic region between cytochrome c oxidase 2 gene (cox2) and cox1 (cox2-1 spacer). Each sequence data set contained ≈250 sequences representing 98 described and 15 undescribed species of Phytophthora. The array was validated with 143 pure cultures and 35 field samples. Together, nonrejected oligonucleotides from all three markers have the ability to reliably detect 82 described and 8 undescribed Phytophthora spp., including several quarantine or regulated pathogens such as Phytophthora ramorum. Our results showed that a DNA array containing signature oligonucleotides designed from multiple genomic regions provided robustness and redundancy for the detection and differentiation of closely related taxon groups. This array has the potential to be used as a routine diagnostic tool for Phytophthora spp. from complex environmental samples without the need for extensive growth of cultures.

}, issn = {0031-949X}, doi = {10.1094/PHYTO-04-12-0092-R}, author = {Chen, Wen and Djama, Zeinab Robleh and Michael D. Coffey and Martin, Frank N. and Bilodeau, Guillaume J. and Radmer, Lorien and Denton, Geoff and L{\'e}vesque, C. Andr{\'e}} } @article {EFP:EFP717, title = {Detection of mRNA by reverse-transcription PCR as an indicator of viability in Phytophthora ramorum}, journal = {Forest Pathology}, volume = {42}, number = {1}, year = {2012}, pages = {14{\textendash}21}, publisher = {Blackwell Publishing Ltd}, abstract = {

In the last few decades, the use of molecular tools has greatly improved the efficiency of plant disease diagnosis. However, one of the major setbacks of most molecular diagnostic approaches is their inability to differentiate between dead and viable pathogens. We propose a new strategy for the detection of plant pathogens, based on the use of mRNA as a viability marker, on the basis that mRNA degradation in dead cells is significantly more rapid than that of DNA. A real-time reverse-transcription PCR (RT-PCR) assay targeting the mRNA of the subunit I of the cytochrome oxidase gene was designed for Phytophthora ramorum, the causal agent of sudden oak death and ramorum blight. In controlled laboratory tests, the developed RT-PCR assay did not detect the target mRNA a week after the pathogen had been killed by rapid lyophilization, while DNA of the pathogen could still be detected 3\ months after the pathogen had died. The RT-PCR assay was then compared with a traditional culturing approach using PARP selective medium and two nested real-time PCR techniques on symptomatic California bay laurel leaves. Samples were either collected in three different sites in July, or in the same site but in three different seasons. Overall, RT-PCR results showed less positive samples than DNA-based nested PCR techniques (p\ \<\ 0.0001), but more than culturing (p\ =\ 0.017). Nested PCR-positive but RT-PCR-negative samples may not be viable. On the other hand, RT-PCR-positive but culture-negative samples may be viable but dormant. A comparative analysis of the results indicated that RT-PCR and culturing provide comparable results when climatic conditions are optimal for the pathogen, but RT-PCR may be the most accurate approach to determine pathogen viability when climatic conditions are less than optimal for the pathogen.

}, issn = {1439-0329}, doi = {10.1111/j.1439-0329.2011.00717.x}, url = {http://dx.doi.org/10.1111/j.1439-0329.2011.00717.x}, author = {Chimento, A. and Cacciola, S. O. and Garbelotto, M.} } @article {4480, title = {First report of Phytophthora gonapodyides causing stem canker on European beech (Fagus sylvatica) in Southern Sweden}, journal = {Plant Disease}, year = {2016}, month = {Nov-05-2017}, abstract = {

Since 2010, extensive crown transparency of European beech (Fagus sylvatica) has been recorded in Southern Sweden, with P. cambivora, P. plurivora, and P. cactorum as well as associated climatic triggers believed to be the major factors involved. In 2015, a different Phytophthora species was isolated from three F. sylvatica trees showing characteristic bleeding canker symptoms in Pildammsparken in Malm{\"o}, Sweden. Small sections of inner phloem were dissected at the interface between necrotic and healthy tissue, directly plated onto PAR(PH)-V8 Selective medium containing 0.250 g/liter sodium ampicillin, 0.01 g/liter benomyl, 0.05 g/liter hymexazol, 0.1 g/liter PCNB, 0.05 g/liter pimaricin, and 0.01 g/liter rifamycin) and incubated at 20{\textdegree}C in darkness. Growing hyphae were later transferred to PDA media and incubated at 20{\textdegree}C in the dark. The colony pattern was stellate. The average radial growth rate at 20 {\textdegree}C was 0.6 cm/day. These morphological features are similar to that previously described for P. gonapodyides (Corcobado et al., 2010; Erwin \& Ribeiro, 1996; Jung et al., 1996). The isolates grown on PDA formed irregularly branched hyphae. Nonpapillate, elongated-ovoid to obpyriform sporangia (approximately 50 x 40 {\textmu}m) were produced after 7 days by incubating on V8 agar culture (non-sterile soil water). DNA was extracted from mycelia and the identity of P. gonapodyides was confirmed by sequencing the internal transcribed (ITS) spacer region of the rDNA with the primers ITS4/ITS6 [GenBank Accession Nos. KX055998, KX055999, KX056000]. Blast search showed 99-100\% identity with reference sequences of P. gonapodyides deposited in GenBank (NCBI). Pathogenicity on F. sylvatica was confirmed in a greenhouse experiment using two different isolates of P. gonapodyides. Mycelial plugs of 3-week-old cultures of each isolate grown on PDA were inoculated on the stems of 1-year-old seedlings at two locations, separated by 20 cm, by aseptically excising a small 5-mm flap of bark, inserting the mycelial plug along the cambium and adding a droplet of Milliq H2O before sealing the wound with Parafilm{\textregistered}. Ten seedlings were inoculated for each isolate. Controls consisted of stem-wound inoculation with a sterile plug of PDA, and no wounding at all. After 7 weeks, lesion length was measured. All seedlings inoculated with P. gonapodyides showed distinct necrotic lesions, whereas control treatments did not show any symptoms of disease. The average cumulative lesion length on seedlings inoculated with P. gonapodyides was significantly higher than on the wounded control treatment (25.4 mm, {\textpm}1.66 vs. 0.4 mm, {\textpm}0.01; P\<0.0001 for Isolate 1 and 28.9 mm, {\textpm}1.42 vs. 0.4 mm, {\textpm}0.01; P\<0.001 for Isolate 2). Koch{\textquoteright}s postulates were fulfilled by successfully reisolating the pathogen from infected seedlings. To our knowledge, this is the first report of P. gonapodyides causing disease on trees in Sweden. P. gonapodyides has been noted previously in Denmark (Erwin and Ribeiro, 1996), and has been traditionally regarded as a weak parasite with saprophytic abilities, usually associated with aquatic environments such as rivers, riparian areas and wetlands (Brasier et al., 2003). We cannot exclude that recent climatic triggers such as high summer precipitation coupled with mild winter temperatures have favored conditions to multicyclic spread of P. gonapodyides via zoospores, or that increased average age of beech stands has contributed to their higher susceptibility to weaker pathogens. Damage caused by P. gonapodyides however might be underestimated as it also can inhibit seed germination, and is known to cause root rot and stem lesions in Q. robur and Q. ilex (Jung et al. 1996; Corcobado et al. 2010). The newly reported damage caused by P. gonapodyides on F. sylvatica trees in Southern Sweden is alarming particularly since beech is a dominant and ecologically important hardwood species that is widely used in forestry and as a planted ornamental in urban and landscape settings. Furthermore, other hosts such as Alnus glutinosa, Quercus petraea, Q. robur (Jung et al., 1996), Picea abies, Betula spp., Acer spp., Tilia spp., (Jung et al., 2009) and Salix spp. (Brasier et al., 2003), also common in southern Sweden, may face an increased risk of damages caused by P. gonapodyides in the future.

}, issn = {0191-2917}, doi = {10.1094/PDIS-04-16-0468-PDN}, url = {http://apsjournals.apsnet.org/doi/10.1094/PDIS-04-16-0468-PDN}, author = {Cleary, Michelle and Ghasemkhani, Marjan and Blomquist, Mimmi and Witzell, Johanna} } @article {4664, title = {Promise and Pitfalls of Endemic Resistance for Cultural Resources Threatened by Phytophthora ramorum}, journal = {Phytopathology}, volume = {109}, year = {2019}, month = {Jan-05-2019}, pages = {760 - 769}, abstract = {

Invasive forest pathogens can harm cultural, economic, and ecological resources. Here, we demonstrate the potential of endemic tree pathogen resistance in forest disease management using Phytophthora ramorum, cause of sudden oak death, in the context of management of tanoak (Notholithocarpus densiflorus), an ecologically unique and highly valued tree within Native American communities of northern California and southern Oregon in the United States. We surveyed resistance to P. ramorum on the Hoopa Valley Indian Reservation and Yurok Indian Reservation in a set of study sites with variable management intensities. Variation in resistance was found at all sites with similar mean and variation across stands, and resistance tended to have a random spatial distribution within stands but was not associated with previous stand management (thinning or prescribed fire) or structural characteristics such as tree density, basal area, or pairwise relatedness among study trees. These results did not suggest host, genetic, management, or environment interactions that could be easily leveraged into treatments to increase the prevalence of resistant trees. We applied epidemiological models to assess the potential application of endemic resistance in this system and to examine our assumption that in planta differences in lesion size{\textemdash}our measure of resistance{\textemdash}reflect linkages between mortality and transmission (resistance) versus reduced mortality with no change in transmission (tolerance). This assumption strongly influenced infection dynamics but changes in host populations{\textemdash}our conservation focus{\textemdash}was dependent on community-level variation in transmission. For P. ramorum, slowing mortality rates (whether by resistance or tolerance) conserves host resources when a second source of inoculum is present; these results are likely generalizable to pathogens with a broader host range. However, when the focal host is the sole source of inoculum, increasing tolerant individuals led to the greatest stand-level pathogen accumulation in our model. When seeking to use variation in mortality rates to affect conservation strategies, it is important to understand how these traits are linked with transmission because tolerance will be more useful for management in mixed-host stands that are already invaded, compared with single-host stands with low or no pathogen presence, where resistance will have the greatest conservation benefits.

}, issn = {0031-949X}, doi = {10.1094/PHYTO-04-18-0142-R}, url = {https://apsjournals.apsnet.org/doi/pdf/10.1094/PHYTO-04-18-0142-R}, author = {Cobb, Richard C. and Ross, Noam and Hayden, Katherine J. and Eyre, Catherine A. and Dodd, Richard S. and Frankel, Susan J. and Garbelotto, Matteo and Rizzo, David M.} } @proceedings {369, title = {Phytophthora siskiyouensis on alders in southern California: an update.}, year = {2009}, pages = {pg 46-47}, publisher = {California Forest Pest Council. Meeting Abstracts}, address = {Heidrick Ag Center, Woodland, California}, author = {Coffey, M. D. and D. M. Mathews} } @article {EFP:EFP718, title = {The long-term survival of Phytophthora cinnamomi in mature Banksia grandis killed by the pathogen}, journal = {Forest Pathology}, volume = {42}, year = {2012}, month = {02/2012}, pages = {28{\textendash}36}, publisher = {Blackwell Publishing Ltd}, abstract = {

The ability of Phytophthora cinnamomi to survive long dry periods is the key to its persistence in the south-west of Western Australia. It has been proposed that dead Banksia grandis are a significant long-term reservoir for P.\ cinnamomi inoculum. To test this, 36 healthy B.\ grandis trees were inoculated in April 1999, and the presence of viable propagules in planta was determined between 2 and 34\ months after tree death. By 10\ months after inoculation, 75\% of the trees had died, with the remaining seven trees dying by 22\ months. The pathogen was more commonly recovered from bark than from wood, except from those trees that died at 22\ months, and more commonly from above-ground trunks than below-ground trunks and roots until 8\ months after plant death. In trees that died 12\ months after inoculation, P.\ cinnamomi was recovered from 60\% of trunk and root core samples at 3\ months, declining to 33\% at 10\ months, 5.5\% at 12\ months and 0.1\% at 34\ months after tree death. In trees that died at 22\ months, P.\ cinnamomi was recovered from 87\% of trunk and root samples 2\ months after tree death, decreasing to 0.5\% by 33\ months. This study suggests that the pathogen does not have a saprotrophic phase within dead B.\ grandis tissue, and B.\ grandis is unlikely to be a long-term reservoir for P.\ cinnamomi. However, the manipulation of the density of B.\ grandis and the use of fire to facilitate the breakdown of dead Banksia trunks in the Eucalyptus marginata (jarrah) forest may reduce the spread and impact of P.\ cinnamomi.

}, issn = {1439-0329}, doi = {10.1111/j.1439-0329.2011.00718.x}, url = {http://dx.doi.org/10.1111/j.1439-0329.2011.00718.x}, author = {Collins, S. and McComb, J. A. and Howard, K. and Shearer, B. L. and Colquhoun, I. J. and Hardy, G. E. St. J.} } @article {3969, title = {Genetic diversity of European populations of the oak fine-root pathogen Phytophthora quercina}, journal = {Forest Pathology}, volume = {35}, year = {2005}, month = {02/2005}, pages = {57 - 70}, abstract = {

The recently discovered oak-specific fine root plant pathogen Phytophthora quercina is a significant factor in the current phase of European oak decline but its origins and ecology are poorly understood. A genome-wide analysis of 260 amplified fragment length polymorphism (AFLP) markers was used to examine the genetic diversity of 72 isolates from five oak species at 28 sites in Germany (particularly Bavaria), Italy, France, Hungary and the UK. Within-site diversity was examined at 16 sites. The limited genetic diversity (within and between sites) and lack of genetic substructuring according to geographic origin or host species suggest the rapid spread of a relatively recently introduced species. Two subgroups were distinguished and these may reflect an initial introduction of isolates of two different genetic backgrounds. The relatively low genetic diversity is probably because of the predominantly inbreeding (homothallic) nature of P. quercina. However, evidence of limited intra-site diversity, temporal variation and the lack of clonality within the European population suggest that some diversity is being maintained by occasional outcrossing and turnover of a reservoir of long-lived soil-borne oospore (sexually derived) inoculum.

}, issn = {1437-4781}, doi = {10.1111/efp.2005.35.issue-110.1111/j.1439-0329.2004.00384.x}, author = {Cooke, D. E. L. and T. Jung and Williams, N. A. and Schubert, R. and W. O{\ss}wald and Duncan, J. M.} } @article {4251, title = {Phylogenetic analysis of Phytophthora species based on ITS1 and ITS2 sequences of the ribosomal RNA gene repeat}, journal = {Mycological Research}, volume = {101}, year = {1997}, month = {Jan-06-1997}, pages = {667 - 677}, abstract = {

The internal transcribed spacer regions (ITS1 and ITS2) of the ribosomal RNA gene repeat from Phytophthora species were amplified using the polymerase chain reaction and sequenced. Sequences from P. cambivora, P. cinnamomi, P. citricola, P. cryptogea, P. drechsleri, P. fragariae var. fragariae, P. fragariae var. rubi, P. megasperma var. megasperma and P. nicotianae were compared with published sequences and phylogenetic trees were produced. The resultant grouping of species generally agreed with groupings established using classical morphological criteria, primarily sporangial morphology. Amongst species with non-papillate sporangia two clades were evident, one consisting of P. fragariae, P. cambivora and P. cinnamomi and the other of P. megasperma, P. drechsleri and P. cryptogea. The latter three were placed in the tree between the non-papillate groups and the papillate and semi-papillate groups which formed three distinct clades. One group comprised P. citricola, P. citrophthora and P. capsici, another P. megakarya and P. palmivora and a third P. pseudotsugae, P. cactorum, P. idaei, P. nicotianae and P. infestans. More isolates of P. megasperma, P. drechsleri and P. cryptogea will need to be examined to settle more precisely the relationship of these species to the others. PCR amplification of ITS sequences using freeze-thawed mycelial scrapings from pure cultures growing on agar followed by digestion with restriction enzymes is a quick and easy way to compare and identify isolates without the need for laborious DNA extraction procedures. With improved technology, rapid automatic sequencing of PCR-amplified ITS regions is now possible and yields detailed information of relationships within the genus as well as allowing the design of species-specific PCR primers for diagnostic purposes.

}, issn = {09537562}, doi = {10.1017/S0953756296003218}, url = {http://linkinghub.elsevier.com/retrieve/pii/S0953756208604888}, author = {Cooke, David E.L. and Duncan, James M.} } @article {Cooke200017, title = {A molecular phylogeny of Phytophthora and related Oomycetes}, journal = {Fungal Genetics and Biology}, volume = {30}, number = {1}, year = {2000}, pages = {17-32}, abstract = {

Phylogenetic relationships among 50 Phytophthora species and between Phytophthora and other oomycetes were examined on the basis of the ITS sequences of genomic rDNA. Phytophthora grouped with Pythium, Peronospora, and Halophytophthora, distant from genera in the Saprolegniales. Albugo was intermediate between these two groups. Unlike Pythium, Phytophthora was essentially monophyletic, all but three species forming a cluster of eight clades. Two clades contained only species with nonpapillate sporangia. The other six clades included either papillate and semipapillate, or semipapillate and nonpapillate types, transcending traditional morphological groupings, which are evidently not natural assemblages. Peronospora was related to P. megakarya and P. palmivora and appears to be derived from a Phytophthora that has both lost the ability to produce zoospores and become an obligate biotroph. Three other Phytophthoras located some distance from the main Phytophthora-Peronospora cluster probably represent one or more additional genera.

}, keywords = {evolution, internal transcribed spacers, ITS, Peronospora., Pythium, rDNA}, issn = {1087-1845}, doi = {DOI: 10.1006/fgbi.2000.1202}, url = {http://www.sciencedirect.com/science/article/B6WFV-45FC03G-1G/2/1cb8ec25d08dae3a16f56e74cd92e99e}, author = {Cooke, D. E. L. and A. Drenth and Duncan, J. M. and G. Wagels and C.M. Brasier} } @article {3962, title = {First report of Phytophthora gonapodyides involved in the decline of Quercus ilex in xeric conditions in Spain}, journal = {New Disease Reports}, volume = {22}, year = {2010}, month = {12/2010}, pages = {33}, abstract = {

Over the last three decades an intense dieback of holm oak (Quercus ilex) has been recorded in southwest Spain, with Phytophthora cinnamomi and water stress believed to be the major factors involved (Romero et al., 2007; Solla et al., 2009). In 2009, P. cinnamomi and Pythium spiculum were recovered during all seasons from soil and roots from trees showing characteristic symptoms in five declining Q. ilex stands in the province of C{\'a}ceres, Extremadura, SW Spain. In October 2009, a different Phytophthora species was isolated from roots and from rhizosphere soil of a single tree located in Malpartida de Plasencia (39{\textdegree}58{\textquoteright}N 6{\textdegree}5{\textquoteright}W, 443 m above sea level), using young Q. robur and Q. ilex leaves as baits and V8-PARPH agar as a selective medium (Jung et al., 1996). The heterothallic isolates formed irregularly branched hyphae, but no chlamydospores or hyphal swellings were observed. Nonpapillate elongated-ovoid to obpyriform sporangia (28-58 x 25-40 {\textmu}m) with exit pores of 10-20 {\textmu}m were produced by flooding one cm squares from the growing margin of a V8-agar culture for 24 h in non-sterile soil-extract. The colony pattern on V8 agar was stellate, and the average radial growth rates at 20, 25 and 30{\textdegree}C were 2.5-2.7, 2.5-2.7 and 2.2-2.3 mm/day, respectively. All these features are typical of P. gonapodyides (Erwin \& Ribeiro, 1996; Jung et al., 1996). The identity was confirmed by sequencing the internal transcribed spacer region of the rDNA with the primers ITS4/ITS6 (GenBank Accession No. GU724194).

Because P. gonapodyides causes root rot and stem lesions in Q. robur (Jung et al., 1996; Balci \& Halmschlager, 2003), pathogenicity tests on one-year-old Q. ilex seedlings were performed. Thirty plants were grown on 250 ml pots containing a mixture of sand and peat (1:1). For inoculum preparation (Romero et al., 2007), the isolate was grown in petri dishes containing 20 ml of carrot broth at 20{\textdegree}C in darkness. After four weeks of incubation, the liquid medium was discarded, and the mycelium was washed, added to sterile water, shaken and mixed for three minutes. Each pot was inoculated with the mycelium harvested from one petri dish. Plants were kept at an average temperature of 25{\textdegree}C in natural daylight. Three months after inoculation, mortality of infected plants was 53\%, and mean survival time ({\textpm}SD) of infected plants was 71{\textpm}15 days. For comparison, additional plants were inoculated in the same way with P. cinnamomi. After three months, mortality of Q. ilex seedlings was 94\% and mean survival time 28{\textpm}7 days. The pathogens were consistently re-isolated from the roots of the dead plants. Control plants did not show any symptoms of disease. To our knowledge, this is the first report of P. gonapodyides in Spain. This pathogen has always been associated with moist sites (Hansen \& Delatour, 1999; Balci \& Halmschlager, 2003), in contrast to our findings, in which mean volumetric soil moisture values at 30 and at 100 cm depth (loam soil) were 11.4 and 22.1\% respectively, and the mean soil water table depth was 4.6 m. Under field conditions, further research about the involvement of this pathogen in Q. ilex decline will be undertaken

}, keywords = {Phytophthora cinnamomi, soil moisture, soil water table}, doi = {10.5197/j.2044-0588.2010.02210.5197/j.2044-0588.2010.022.033}, author = {Corcobado, T. and Cubera, E. and P{\'e}rez-Sierra, A. and T. Jung and Solla, A.} } @article {263, title = {Root disease of Castanea species and some coniferous and broadleaf nursery stocks, caused by Phytophthora cinnamomi}, journal = {Phytopathology}, volume = {35}, year = {1945}, pages = {162-180.}, abstract = {

The fungus, Phytophthora cinnamomi Rands, is responsible for a destructive root rot of Chestnut and Chinkapin trees (Castanea spp.) in the United States. The author gives an outline of the work leading to the identification of the fungus, and reports on inoculation and field tests that have proved its pathogenicity on Chestnut and other hosts. The fungus causes a similar root disease in forest-tree nursery stock. Infection has been observed in the nursery on twenty broadleaf and coniferous species. Field and greenhouse inoculation tests have demonstrated the susceptibility to the disease of European Chestnut (Castanea sativa). The Asiatic species, C. crenata, C. mollissima, C. henryi, and C. seguinii, however, show a high degree of resistance. It seems probable that root rot of this type has been responsible for the recession of the American Chestnut in some areas of the United States. No satisfactory control measures have been evolved. Hybrid varieties resistant to both blight and root rot are being developed by crossing American Chestnut and Chinkapins with Asiatic species.

}, issn = {0031-949X}, author = {Crandall, B.S. and G.F. Gravatt and M.M. Ryan} } @article {grandall1950distribution, title = {The distribution and significance of the chestnut root rot Phytophthoras, P. cinnamomi and P. cambivora.}, journal = {Plant Disease Reporter}, volume = {34}, number = {6}, year = {1950}, pages = {194{\textendash}6}, abstract = {

A review of literature, with special reference to some recent publications in Spain and Portugal [cf. For. Abstr. 11 (Nos. 1468, 2268)]. The author concludes that Phytophthora cinnamomi plays a great part in disease of Chestnut in Spain, Portugal, France and Italy, and elsewhere in southern Europe, and is probably the major cause of death in the more southerly regions. P. cinnamomi has a considerable range of hosts. It has been found to attack Castanea sativa, Juglans regia, Pseudotsuga taxifolia, Quercus robur, Q. suber, Betula alba, Cedrus atlantica, Abies nordmanniana, A. alba, A. sibirica and Castanea crenata var. tamba. A close watch on Douglas Fir in the U.S.A. seems advisable in case a strain of the fungus should encounter and attack it. In contrast P. cambivora has only been found on Castanea sativa and C. crenata var. tamba.

}, keywords = {Abies alba disease, Abies nordmanniana, Abies sibirica, Betula alba, Castanea crenata, Castanea sativa diseases, Cedrus atlantica, decay, Disease, fungal diseases, Ink disease, Juglans regia disease, Pseudotsuga laxifolia diseases, Quercus robur, Quercus suber disease, trees}, url = {http://www.cabdirect.org/abstracts/19500602345.html}, author = {Crandall, B.S.} } @article {4381, title = {Phytophthora tentaculata su gerbera in Italia}, journal = {Informatore Fitopatologico }, volume = {56}, year = {2006}, pages = {23-25}, abstract = {

During spring 2002, gerbera (Gerbera jamesonii) plants showing blighted leaves and crown and stem rot symptoms were observed in a commercial gerbera planting located at Torre del Greco, near Naples. A Phytophthora sp. was consistently isolated from stem and collar tissues of symptomatic plants. The isolated oomycete was later further investigate, using traditional and polymerase chain reaction (PCR)-based methods to determine species identity, as well as to test pathogenicity. On V8a-juice agar medium at 21{\textpm}1{\textdegree}C, the observed morphological characters were similar to those of P. tentaculata whereas colony growth ceased at 32-34{\textdegree}C. Sequence analysis of PCR-amplified nuclear ribosomal DNA (rDNA), which includes the internal transcribed spacer (ITS) regions, ITS1 and ITS2 and 5.8S, obtained in template DNA extracted from pure culture fresh mycelium, revealed that the Italian Phytophthora sp. infecting gerbera was most closely related to P. tentaculata infecting Chrysanthemum, which had been reported from Germany. Also, extensive restriction fragment length polymorphism (RFLP) analysis of the rDNA repeat (ITS1, 5.8S and ITS2), using several restriction endonucleases, showed that the gerbera-infecting oomycete differed from several other Phytophthora species used for comparison, and had restriction fragments identical to those known from the German P. tentaculata. Thus, on the basis of biological, morphological and molecular data obtained, the chromist infecting gerbera in Italy was identified as P. tentaculata. Also, it proved to be the causal agent of crown and stem rot of gerbera according to Koch{\textquoteright}s rule fulfilment. This is the first report of the presence of P. tentaculata in Italy and further extends knowledge on the natural host range of such chromist.

}, issn = {0020-0735}, url = {http://www.cabdirect.org/abstracts/20063066005.html;jsessionid=C23F9F14D93FF641EEE94948EFEB99D5}, author = {Cristinzio, G and Camele, I and Marcone, C} } @article {PPA:PPA12016, title = {Annual and herbaceous perennial native Australian plant species are symptomless hosts of Phytophthora cinnamomi in the Eucalyptus marginata (jarrah) forest of Western Australia}, journal = {Plant Pathology}, volume = {43}, year = {2012}, month = {11/2012}, pages = {245{\textendash}251}, abstract = {

Resistant annual and herbaceous perennial plant species were identified as key hosts which allow Phytophthora cinnamomi to persist on severely impacted black gravel sites within the Eucalyptus marginata (jarrah) forest of southwest Western Australia. Of the annual and herbaceous perennial plant species present on black gravel sites, 15 out of 19 species were found to be hosts of P.\ cinnamomi, and 10 of these were symptomless hosts. In particular, the native annual Trachymene pilosa and the two native herbaceous perennials Stylidium diuroides and Chamaescilla corymbosa were commonly found to be hosts of the pathogen. Species from 12 new genera including three from new families (Crassulaceae, Droseraceae and Primulaceae) are reported for the first time to be hosts of P.\ cinnamomi. The species from which P.\ cinnamomi was recovered were the native species: Chamaescilla corymbosa, Crassula closiana, Drosera erythrorhiza, Hydrocotyle callicarpa, Levenhookia pusilla, Paracaleana nigrita, Podotheca angustifolia, Pterochaeta paniculata, Rytidosperma caespitosum, Siloxerus multiflorus, Stylidium diuroides and Trachymene pilosa, and the introduced annual weeds Hypochaeris glabra, Lysimachia arvensis and Pentameris airoides.

}, keywords = {dieback, host species, jarrah forest, pathogen survival, Phytophthora cinnamomi, susceptibility rating}, issn = {1365-3059}, doi = {10.1111/ppa.12016}, url = {http://dx.doi.org/10.1111/ppa.12016}, author = {Crone, M. and McComb, J. A. and O{\textquoteright}Brien, P. A. and Hardy, G. E. St J.} } @article {4214, title = {Host removal as a potential control method for Phytophthora cinnamomi on severely impacted black gravel sites in the jarrah forest}, journal = {Forest Pathology}, volume = {44}, year = {2014}, month = {Jan-04-2014}, pages = {154 - 159}, abstract = {

Removal of living plants from an area of Eucalyptus marginata (jarrah) forest on black gravel sites infested with Phytophthora cinnamomi significantly reduced subsequent pathogen recovery. Vegetation, including trees and annual and herbaceous perennial plants, was killed on the sites by herbicide application. To determine whether this treatment efficiently eliminated P.\ cinnamomi, soil samples were seasonally collected and baited to test for the presence of the pathogen. There were no recoveries on treated sites in autumn, 28\ months after removal of all vegetation by herbicide application. To test whether this was the result of the complete elimination of the pathogen or whether inoculum remained, regrowth on sites was not controlled after this period leading to the re-establishment of annual and herbaceous perennial species, some of which are hosts of P.\ cinnamomi. Recovery of P.\ cinnamomi after plant regrowth on the formerly treated sites indicated that for complete pathogen removal, sites need to remain free of vegetation for longer than 28\ months. Overall, however, this study confirms that the pathogen is a weak saprophyte, and withdrawal of host material for a period of time may make eventual rehabilitation of these sites possible.

}, doi = {10.1111/efp.2014.44.issue-210.1111/efp.12080}, url = {http://doi.wiley.com/10.1111/efp.2014.44.issue-2http://doi.wiley.com/10.1111/efp.12080}, author = {Crone, M. and McComb, J. A. and O{\textquoteright}Brien, P. A. and Hardy, G. E. St J.}, editor = {Andrea, V.} } @article {4001, title = {Assessment of Australian native annual/herbaceous perennial plant species as asymptomatic or symptomatic hosts of Phytophthora cinnamomi under controlled conditions}, journal = {Forest Pathology}, volume = {43}, year = {2013}, month = {06/2013}, pages = {245{\textendash}251}, abstract = {

Phytophthora cinnamomi is a necrotrophic pathogen of woody perennials and devastates many biomes worldwide. A controlled perlite{\textendash}hydroponic system with no other hyphae-producing organisms as contaminants present allowed rapid assessment of ten annual and herbaceous perennial plant species most of which have a wide distribution within the jarrah (Eucalyptus marginata) forest in Western Australia where this pathogen has been introduced. As some annuals and herbaceous perennials have recently been reported as symptomatic and asymptomatic hosts, laboratory screening of some of the field-tested annuals and herbaceous perennials and additional species was used to further evaluate their role in the pathogen{\textquoteright}s disease cycle. Nine of the species challenged with the pathogen were asymptomatic, with none developing root lesions; however, Trachymene pilosa died. The pathogen produced thick-walled chlamydospores and stromata in the asymptomatic roots. Furthermore, haustoria were observed in the roots, indicating that the pathogen was growing as a biotroph in these hosts.

}, doi = {10.1111/efp.12027}, url = {http://onlinelibrary.wiley.com/doi/10.1111/efp.12027/abstract}, author = {Crone, M. and McComb, J. A. and O{\textquoteright}Brien, P. A. and Hardy, G. E. St J.}, editor = {Andrea, V.} } @article {PPA:PPA1718, title = {Phytophthora alni causing decline of black and grey alders in the Czech Republic}, journal = {Plant Pathology}, volume = {57}, number = {2}, year = {2008}, pages = {370{\textendash}370}, publisher = {Blackwell Publishing Ltd}, issn = {1365-3059}, doi = {10.1111/j.1365-3059.2007.01718.x}, url = {http://dx.doi.org/10.1111/j.1365-3059.2007.01718.x}, author = {Černy, K. and Gregorova, B. and Strnadov{\'a}, V. and Holub, V. and Tomsovsky, M. and Cervenka, M.} } @article {631, title = {Phytophthora alder decline: disease symptoms, causal agent and its distribution in the Czech Republic}, journal = {Plant Protect. Sci.}, volume = {46}, year = {2010}, pages = {12-18}, abstract = {

Phytophthora decline of riparian alder populations has recently become an important problem in many European countries, including the Czech Republic. The causal agent, Phytophthora alni, has spread quickly in the Czech Republic. Hundreds of kilometres of riparian alder stands, especially in the western part of the country, have been severely affected to date. Diseased trees show symptoms characteristic of Phytophthora root and collar rot; these include small, sparse and yellowing foliage, crown dieback, presence of exudates on the bark and necroses of collar and root tissues. Infected trees usually die within a few years, or they become irreversibly damaged, and their function in bank reinforcement declines. The ecological and mechanical functioning of severely affected alder stands may be seriously disrupted.

}, keywords = {alder decline, Alnus glutinosa, Alnus incana, bleeding canker, common alder, Czech Republic, grey alder, Phytophthora alni}, url = {http://www.agriculturejournals.cz/web/pps.htm?volume=46\&firstPage=12\&type=publishedArticle}, author = {Černy, K. and Strnadov{\'a}, V.} } @article {4690, title = {Migratory passerine birds in Britain carry Phytophthora ramorum inoculum on their feathers and {\textquotedblleft}feet{\textquotedblright} at low frequency}, journal = {Forest Pathology}, volume = {50}, year = {2020}, month = {Dec-09-2019}, pages = {e12569}, abstract = {

In this study, we investigated whether birds could be vectors facilitating long-distance spread of Phytophthora ramorum in Britain. Migratory bird species associated with the main sporangium-producing host plants and most likely to pick up P.\ ramorum spores were considered. Swabs were taken from the flank and {\textquotedblleft}feet{\textquotedblright} of 1,014 birds over a 12-month period (April 2011{\textendash}March 2012) in the west of Britain and subsequently analyzed for the presence of P.\ ramorum using nested PCR. Ten positive samples from 10 birds were identified: three in Cornwall, one in Devon, three in Gloucestershire, two in north Wales and one in Merseyside. Phytophthora ramorum was detected on samples from four species of thrushes (Redwing Turdus iliacus, Fieldfare T.\ pilaris, Blackbird T.\ merula and Song Thrush T.\ philomelos) and one species of warbler (Chiffchaff Phylloscopus collybita). All birds that tested positive were sampled in late autumn and winter (October{\textendash}February), when long-distance movements (over 100\ km) would have stopped. The low incidence of P.\ ramorum found using PCR suggests that the incidence of inoculum, whether viable or not, on birds was low. The apparently low incidence of inoculum on birds suggests migratory passerine birds can carry P.\ ramorum inoculum on their feathers and {\textquotedblleft}feet,{\textquotedblright} albeit at low frequency. The dates of positive samples indicate that birds would not have been moving long distances at the time but further work is needed to estimate the extent of their contribution to the spread of P.\ ramorum in Britain.

}, doi = {10.1111/efp.v50.110.1111/efp.12569}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/efp.12569}, author = {Dadam, Daria and Siasou, Eleni and Woodward, Stephen and Clark, Jacquie A.} } @article {4250, title = {The occurrence of Phytophthora palmivora (Butl.) Butl. in soil in Ghana}, journal = {Ghana Jnl. Agric. Sci}, volume = {7}, year = {1974}, pages = {37-41}, abstract = {

The occurrence of Phytophthora palmivora (But!.) But!. in soil was studied over 2 consecutive years by baiting the fungus with healthy cocoa pods. The fungus was frequently found in soils of a forest reserve, an abandoned cocoa farm and in farms still under cocoa cultivation; its activity, however, differed under the three soil conditions. Fluctuations in the occurrence of P. palmivora in soil did not depend on atmospheric temperature. At Obomeng, the fungus was isolated more frequently from a cocoa farm than from either an abandoned cocoa farm or a forest area. The isolation of P. palmivora from the uncultivated forest soil indicates that the fungus is indigenous to forest soils.

}, url = {http://gains.org.gh/articles/gjas_v7_1_p37_41.pdf}, author = {Dakwa, JT} } @article {4700, title = {Mitotic Recombination and Rapid Genome Evolution in the Invasive Forest Pathogen Phytophthora ramorum}, journal = {mBio}, volume = {10}, year = {2019}, month = {Mar-12-2019}, abstract = {

Invasive alien species often have reduced genetic diversity and must adapt to new environments. Given the success of many invasions, this is sometimes called the genetic paradox of invasion. Phytophthora ramorum is invasive, limited to asexual reproduction within four lineages, and presumed clonal. It is responsible for sudden oak death in the United States, sudden larch death in Europe, and ramorum blight in North America and Europe. We sequenced the genomes of 107 isolates to determine how this pathogen can overcome the invasion paradox. Mitotic recombination (MR) associated with transposons and low gene density has generated runs of homozygosity (ROH) affecting 2,698 genes, resulting in novel genotypic diversity within the lineages. One ROH enriched in effectors was fixed in the NA1 lineage. An independent ROH affected the same scaffold in the EU1 lineage, suggesting an MR hot spot and a selection target. Differences in host infection between EU1 isolates with and without the ROH suggest that they may differ in aggressiveness. Non-core regions (not shared by all lineages) had signatures of accelerated evolution and were enriched in putative pathogenicity genes and transposons. There was a striking pattern of gene loss, including all effectors, in the non-core EU2 genome. Positive selection was observed in 8.0\% of RxLR and 18.8\% of Crinkler effector genes compared with 0.9\% of the core eukaryotic gene set. We conclude that the P. ramorum lineages are diverging via a rapidly evolving non-core genome and that the invasive asexual lineages are not clonal, but display genotypic diversity caused by MR.

IMPORTANCE Alien species are often successful invaders in new environments, despite the introduction of a few isolates with a reduced genetic pool. This is called the genetic paradox of invasion. We found two mechanisms by which the invasive forest pathogen causing sudden oak and sudden larch death can evolve. Extensive mitotic recombination producing runs of homozygosity generates genotypic diversity even in the absence of sexual reproduction, and rapid turnover of genes in the non-core, or nonessential portion of genome not shared by all isolates, allows pathogenicity genes to evolve rapidly or be eliminated while retaining essential genes. Mitotic recombination events occur in genomic hot spots, resulting in similar ROH patterns in different isolates or groups; one ROH, independently generated in two different groups, was enriched in pathogenicity genes and may be a target for selection. This provides important insights into the evolution of invasive alien pathogens and their potential for adaptation and future persistence.

}, doi = {10.1128/mBio.02452-18}, url = {https://mbio.asm.org/content/10/2/e02452-18}, author = {Dale, Angela L. and Feau, Nicolas and Everhart, Sydney E. and Dhillon, Braham and Wong, Barbara and Sheppard, Julie and Bilodeau, Guillaume J. and Brar, Avneet and Tabima, Javier F. and Shen, Danyu and Brasier, Clive M. and Tyler, Brett M. and Gr{\"u}nwald, Niklaus J. and Hamelin, Richard C.}, editor = {Taylor, John W.} } @article {doi:10.1094/PHYTO-03-10-0064, title = {Forest type influences transmission of Phytophthora ramorum in California oak woodlands}, journal = {Phytopathology}, volume = {101}, number = {4}, year = {2011}, pages = {492-501}, abstract = {

The transmission ecology of Phytophthora ramorum from bay laurel (Umbellularia californica) leaves was compared between mixed-evergreen and redwood forest types throughout winter and summer disease cycles in central, coastal California. In a preliminary multisite study, we found that abscission rates of infected leaves were higher at mixed-evergreen sites. In addition, final infection counts were slightly higher at mixed-evergreen sites or not significantly different than at redwood sites, in part due to competition from other foliar pathogens at redwood sites. In a subsequent, detailed study of paired sites where P. ramorum was the main foliar pathogen, summer survival of P. ramorum in bay laurel leaves was lower in mixed-evergreen forest due to lower recovery from infected attached leaves and higher abscission rates of infected leaves. Onset of inoculum production and new infections of bay laurel leaves occurred later in mixed-evergreen forest. Mean inoculum levels in rainwater and final infection counts on leaves were higher in redwood forest. Based on these two studies, lower summer survival of reservoir inoculum in bay laurel leaves in mixed-evergreen forest may result in delayed onset of both inoculum production and new infections, leading to slower disease progress in the early rainy season compared with redwood forest. Although final infection counts also will depend on other foliar pathogens and disease history, in sites where P. ramorum is the main foliar pathogen, these transmission patterns suggest higher rates of disease spread in redwood forests during rainy seasons of short or average length.

}, doi = {10.1094/PHYTO-03-10-0064}, url = {http://apsjournals.apsnet.org/doi/abs/10.1094/PHYTO-03-10-0064}, author = {Davidson, Jennifer M. and Patterson, Heather A. and Wickland, Allison C. and Elizabeth J. Fichtner and Rizzo, David M.} } @article {doi:10.1094/PHYTO-98-8-0860, title = {Sources of inoculum for Phytophthora ramorum in a redwood forest}, journal = {Phytopathology}, volume = {98}, number = {8}, year = {2008}, pages = {860-866}, doi = {10.1094/PHYTO-98-8-0860}, url = {http://apsjournals.apsnet.org/doi/abs/10.1094/PHYTO-98-8-0860}, author = {J. M. Davidson and Patterson, H. A. and D. M. Rizzo} } @article {davidsonpathways, title = {Pathways of movement for Phytophthora ramorum, the causal agent of Sudden Oak Death}, journal = {The American Phytopathological Society Sudden Oak Death Online Symposium}, year = {2003}, publisher = {American Phytopathological Society}, author = {J. M. Davidson and Shaw, C.G.T.} } @article {doi:10.1094/PHYTO-95-0587, title = {Transmission of Phytophthora ramorum in mixed-evergreen forest in California}, journal = {Phytopathology}, volume = {95}, number = {5}, year = {2005}, pages = {587-596}, doi = {10.1094/PHYTO-95-0587}, url = {http://apsjournals.apsnet.org/doi/abs/10.1094/PHYTO-95-0587}, author = {Davidson, Jennifer M. and Wickland, Allison C. and Patterson, Heather A. and Falk, Kristen R. and Rizzo, David M.} } @article {davidson2003sudden, title = {Sudden oak death and associated diseases caused by Phytophthora ramorum.}, journal = {Plant Management Network - Plant Health Progress}, year = {2003}, month = {July 2003}, doi = {10.1094/PHP-2003-0707-01-DG}, url = {http://www.plantmanagementnetwork.org/php/shared/sod/}, author = {J. M. Davidson and Werres, S. and Garbelotto, M. and Hansen, E.M. and D. M. Rizzo} } @article {430, title = {Root-rot of sweet chestnut and beech caused by species of Phytophthora.}, journal = {Forestry}, volume = {12}, year = {1938}, pages = {101{\textendash}116}, author = {Day, W.R.} } @article {PPA:PPA2212, title = {Effect of host factors on the susceptibility of Rhododendron to Phytophthora ramorum}, journal = {Plant Pathology}, volume = {59}, number = {2}, year = {2010}, pages = {301{\textendash}312}, publisher = {Blackwell Publishing Ltd}, abstract = {

Phytophthora ramorum causes sudden oak death (SOD) in western coastal forests of the USA. In Europe, the pathogen is mainly present in the nursery industry, particularly on Rhododendron. Because of the primary role of Rhododendron as a host and potentially as a vector, the effect of Rhododendron host factors on P. ramorum susceptibility and sporulation was investigated. Inoculation methods using either wounded or non-wounded detached leaves were applied to 59 Rhododendron cultivars and 22 botanical species, replicated in three separate years. All Rhododendron species and cultivars were susceptible when using wounded leaves, but not when using non-wounded leaves, suggesting a resistance mechanism operating at the level of leaf penetration. Using a regression tree analysis, the cultivars and species were split into four susceptibility classes. Young leaves were more susceptible than mature leaves when wounded, but less susceptible when non-wounded. This effect was not correlated with leaf hydrophobicity or the number of leaf hairs. The presence or the type of rootstock did not affect the cultivar susceptibility level. Sporangia and chlamydospore production in the leaf lesions varied widely among Rhododendron cultivars and was not correlated with the susceptibility level. The susceptibility to P. ramorum correlated well with the susceptibility to P. citricola and P. hedraiandra\ {\texttimes}\ cactorum, suggesting that the resistance mechanisms against these species are non-specific. Susceptibility to P. kernoviae was low for most cultivars. These findings have implications for detection, spread and disease control, and are therefore important in pest risk assessment.

}, keywords = {host resistance, leaf age, leaf hairs, Phytophthora kernoviae, rootstock, sporulation}, issn = {1365-3059}, doi = {10.1111/j.1365-3059.2009.02212.x}, url = {http://dx.doi.org/10.1111/j.1365-3059.2009.02212.x}, author = {De Dobbelaere, I. and Vercauteren, A. and Speybroeck, N. and Berkvens, D. and Van Bockstaele, E. and Maes, M. and Heungens, K.} } @article {denitto1991first, title = {First report of Phytophthora lateralis on Pacific yew}, journal = {Plant Disease}, volume = {75}, number = {9}, year = {1991}, pages = {968}, doi = {10.1094/PD-75-0968C.}, url = {http://www.apsnet.org/publications/PlantDisease/BackIssues/Documents/1991Abstracts/PD_75_968C.htm}, author = {DeNitto, GA and J.T. Kliejunas} } @article {EPP:EPP2243, title = {Phytophthora ramorum and Phytophthora kernoviae on naturally infected asymptomatic foliage}, journal = {EPPO Bulletin}, volume = {39}, number = {1}, year = {2009}, pages = {105{\textendash}111}, publisher = {Blackwell Publishing Ltd}, abstract = {

Phytophthora ramorum and Phytophthora kernoviae are recently discovered invasive Phytophthoras causing leaf necrosis and shoot tip dieback mostly on ornamental and forest understorey species, but also cause bleeding cankers on stems of a wide range of tree species. Sporulation occurs only on infected shoots or fruits and foliage so foliar hosts are central to the disease epidemiology. In field trials to assess infection in trap plants exposed to natural inoculum of P. ramorum and P. kernoviae on rhododendron in south west England, it was discovered that leaves of the trap plants (Rhododendron {\textquoteleft}Cunninghams White{\textquoteright}) and holm oak (Quercus ilex) were asymptomatically infected and supported sporulation of both pathogens. More than half the rhododendron trap plants exposed to inoculum of P. kernoviae became infected compared with approximately a third of those exposed to P. ramorum in a natural situation. Approximately one third of the infections were detected from asymptomatic foliage for both pathogens. The significance of these findings for plant health regulation based on visual inspection as a measure to prevent introduction and dissemination of both these pathogens is explored and research gaps identified.

}, issn = {1365-2338}, doi = {10.1111/j.1365-2338.2009.02243.x}, url = {http://dx.doi.org/10.1111/j.1365-2338.2009.02243.x}, author = {Denman, S. and Kirk, S.A. and Moralejo, E. and Webber, JF} } @article {PPA:PPA1243, title = {In vitro leaf inoculation studies as an indication of tree foliage susceptibility to Phytophthora ramorum in the UK}, journal = {Plant Pathology}, volume = {54}, number = {4}, year = {2005}, pages = {512{\textendash}521}, publisher = {Blackwell Science Ltd}, abstract = {

Leaves of 11 coniferous and 23 broad-leaved tree species important to UK forestry were tested for their susceptibility to the quarantine pathogen Phytophthora ramorum using a detached leaf assay. Two European and two USA isolates were used. Wounded and unwounded leaves were dipped in zoospore suspensions during summer; conifers were also tested in winter. Successful infection of tissue and amount of necrosis were assessed. Highly susceptible broad-leaved hosts included Aesculus hippocastanum, Fraxinus excelsior, Quercus ilex, Ulmus procera and, to a lesser extent, Castanea sativa, Q. cerris and Q. petraea, together with Umbellularia californica and rhododendrons. Acer pseudoplatanus, Alnus glutinosa, Carpinus betulus, Corylus avellana, Fagus sylvatica, Prunus avium, Q. robur, Q. rubra and Q. suber showed consistently low susceptibility. Conifer species including Abies procera, Picea abies, P. sitchensis, Pseudotsuga menziesii, Sequoia sempervirens and Tsuga heterophylla were also susceptible. Pseudotsuga menziesii and A. procera were severely affected. Pinus contorta, P. nigra var. maritima and P. sylvestris were virtually resistant, while Taxus baccata was only slightly affected. Increased necrosis was apparent on leaves that were wounded prior to inoculation. These results extend the known range of trees that P. ramorum is able to attack and confirm its relative host-nonspecificity.

}, keywords = {broad-leaved species, conifers, detached leaf dip assay, foliage, forest species, Sudden oak death}, issn = {1365-3059}, doi = {10.1111/j.1365-3059.2005.01243.x}, url = {http://dx.doi.org/10.1111/j.1365-3059.2005.01243.x}, author = {Denman, S. and Kirk, S.A. and C.M. Brasier and Webber, JF} } @article {1106, title = {Victoria{\textquoteright}s Public Land Phytophthora cinnamomi Management Strategy}, year = {2008}, pages = {37 pp}, publisher = {Department of Sustainability and Environment, PO Box 500, East Melbourne, Victoria, Australia}, isbn = {978-1-74152-795-7}, url = {http://lakeshub.com/wp-content/uploads/2013/04/Phytophthora_cinnamomi_Strategy-1.pdf}, author = {Department of Sustainability and Environment} } @article {4631, title = {First Report of Phytophthora chlamydospora Causing Root Rot on Walnut (Juglans regia ) Trees in Turkey}, journal = {Plant Disease}, volume = {100}, year = {2016}, month = {Jan-11-2016}, pages = {2336}, abstract = {

Common or English (Persian) walnut (Juglans regia L.) is an important nut crop in Turkey, which is the fourth largest producer of walnut in the world. In August 2015, we observed sudden wilt and subsequent death associated with root rot. Approximately 15\% of 2,000 5- to 7-year-old J. regia cv. Chandler trees grafted on wild walnut (J. regia) in waterlogged areas of a commercial walnut orchard in Bing{\"o}l province of eastern Turkey were affected. Most fine roots were completely rotted and the inner bark of infected lateral and taproots showed a reddish brown discoloration. Tissue samples taken from the margins of root lesions of 10 symptomatic trees were placed on grated carrot corn meal agar (GCCMA) (T{\"u}rk{\"o}lmez et al. 2015) amended with 5 mg of pimaricin, 250 mg of ampicillin, 10 mg of rifampicin, 100 mg of pentachloronitrobenzene, and 50 mg of hymexazol per liter (P5ARPH). Plates were incubated for 5 days at 28{\textdegree}C in the dark. A Phytophthora species was consistently isolated from the tissues. On GCCMA, colonies had a distinct petaloid growth pattern and produced abundant spherical, thin-walled, intercalary and terminal chlamydospores (30 to 46 μm diameter) and hyphal chains of globose to subglobose swellings. After incubation of mycelial disks in nonsterile soil extracts at 25{\textdegree}C, all isolates produced hyaline, nonpapillate, noncaducous sporangia of ovoid to obpyriform shape, with internal proliferation, measuring 34.5 to 56.5 μm in length, 27.0 to 39.5 μm wide, with a length/breadth ratio of 1.4 to 1.7, formed on unbranched or sympodial sporangiophores. Growth rate on carrot agar (CA) at 25{\textdegree}C was 3.3 to 3.5 mm d-1; the optimum and maximum temperatures for mycelium growth on CA were 29 and 37{\textdegree}C, respectively. All these characteristics were similar to those described for Phytophthora chlamydospora Brasier and Hansen (Hansen et al. 2015), previously known as P. taxon Pgchlamydo. Genomic DNA was extracted from three representative isolates. The internal transcribed spacer (ITS) region of rDNA and cox2 gene regions were amplified using the ITS6/ITS4 and FMPhy10b/FMPhy8b primer pairs, respectively, and sequenced (GenBank accession nos. KU725882, KU725883, KU707216, KX446861, KX446862). BLAST searches of ITS region showed 100\% identity to many P. chlamydospora isolates, including the ex-type culture P236 (AF541900) (Brasier et al. 2003), deposited in GenBank and of cox2 gene regions of two isolates had 100\% identity with PD_01777_cox2 and PD_00174_cox2 accessions deposited at Phytophthora-ID databases, which confirmed the morphological identification. Pathogenicity of P. chlamydospora was evaluated using the soil infestation method on 10 1-year-old potted J. regia cv. Chandler seedlings by growing P. chlamydospora on sterilized millet seeds for 4 weeks at 29{\textdegree}C and adding infested millet seeds to potting soil at a rate of 3\% (w/v). In 10 noninoculated control plants, sterilized millet seeds were added to the potting soil. Both inoculated and control plants were flooded for 24 h at 2 week intervals. All inoculated plants showed severe wilting within a month and necrosis on lateral and taproots and rot on fineroots after 2 months of incubation in a greenhouse where air temperatures ranged from 24 to 30{\textdegree}C, while control plants remained asymptomatic. Koch{\textquoteright}s postulates were satisfied after reisolating P. chlamydospora, which was identified morphologically, from symptomatic roots of inoculated plants. P. chlamydospora has been previously recovered from several ornamental and woody species (Blomquist et al. 2012; Brasier et al. 2003; Ginetti et al. 2014), and to our knowledge, this is the first report of P. chlamydospora infection of walnut, which represents a new host for this pathogen.

}, issn = {0191-2917}, doi = {10.1094/PDIS-03-16-0306-PDN}, url = {http://apsjournals.apsnet.org/doi/10.1094/PDIS-03-16-0306-PDN}, author = {Dervi{\c s}, S. and T{\"u}rk{\"o}lmez, {\c S}. and {\c C}ift{\c c}i, O. and Ser{\c c}e, {\c C}. U.} } @inbook {4136, title = {Phytophthora diseases of Theobroma cacao}, booktitle = {Improvement of cocoa tree resistance to Phytophthora diseases}, year = {2004}, pages = {15{\textendash}44}, publisher = {CIRAD}, organization = {CIRAD}, address = {Montpellier, France}, author = {Despreaux, Denis}, editor = {Cilas, C. and Despreaux, Denis} } @article {4230, title = {Pathogenicity of Phytophthora pluvialis to Pinus radiata and its relation with red needle cast disease in New Zealand}, journal = {New Zealand Journal of Forestry Science}, volume = {44}, year = {2014}, month = {Jan-01-2014}, pages = {6}, abstract = {

Background

Red needle cast, a new foliage disease of Pinus radiata in New Zealand is described. The disease has been variable in incidence and severity both regionally and in different years. The early symptoms of discrete olive coloured lesions, often with a narrow dark resinous mark or band, were first recognised in winter of 2008 in plantation forests on the eastern coast of the North Island. These lesions develop further to result in rapid needle senescence and premature defoliation. The disease has been termed red needle cast in New Zealand as affected trees have a reddish appearance prior to the casting of the needles. The subsequent four years of monitoring have confirmed that, depending on location, symptoms are first observed in late autumn through late winter. Newly developing spring and summer foliage is seldom affected. Isolation from needles using a Phytophthora-selective medium frequently yielded an unknown species of Phytophthora which was subsequently found to be identical to Phytophthora pluvialis, a species described from Oregon, USA in 2013 where it is not associated with disease. Infection appears to be limited to the needles with no recoveries of Phytophthora pluvialis having been made from the roots, stems or branches. Occasionally a second species of Phytophthora, P. kernoviae, was also recovered from needles with the same symptoms.

Methods

Needle symptoms were described in the field from 2008-2012 with isolation onto Phytophthora selective media. Koch{\textquoteright}s postulates was completed on potted plants and detached needles.

Results

Symptoms were reproduced on both detached needles and potted plants of Pinus radiata when inoculated with zoospore suspensions of Phytophthora pluvialis.

Conclusions

This paper presents evidence that Phytophthora pluvialis is the primary cause of red needle cast in New Zealand.

}, issn = {1179-5395}, doi = {10.1186/s40490-014-0006-7}, url = {http://www.nzjforestryscience.com/content/44/1/6}, author = {Dick, Margaret and Williams, Nari and Bader, Martin and Gardner, Judy and Bulman, Lindsay} } @article {NPH:NPH2450, title = {Evidence for the role of synchronicity between host phenology and pathogen activity in the distribution of sudden oak death canker disease}, journal = {New Phytologist}, volume = {179}, number = {2}, year = {2008}, pages = {505{\textendash}514}, publisher = {Blackwell Publishing Ltd}, abstract = {

Variations in synchronicity between colonization rate by the pathogen and host phenology may account for unexplained spatial distribution of canker disease. The hypothesis that synchronous pathogenicity and host development are necessary for incidence of sudden oak death disease was tested by correlating seasonal variations in host cambial phenology and response to inoculation with Phytophthora ramorum.

}, keywords = {exotic pathogen, inoculation, Phytophthora ramorum, Quercus agrifolia, resistance, spatial distribution, synchronicity}, issn = {1469-8137}, doi = {10.1111/j.1469-8137.2008.02450.x}, url = {http://dx.doi.org/10.1111/j.1469-8137.2008.02450.x}, author = {Richard S. Dodd and H{\"u}berli, , Daniel and Mayer, Wasima and Harnik, Tamar Y. and Afzal-Rafii, Zara and Garbelotto, Matteo} } @article {655, title = {A crown rot of hollyhock caused by Phytophthora megasperma n. sp.}, journal = {J Wash Acad Sci}, volume = {21}, year = {1931}, pages = {513-526}, author = {Drechsler, C.} } @article {4335, title = {First evidence of genetic-based tolerance to red needle cast caused by Phytophthora pluvialis in radiata pine}, journal = {New Zealand Journal of Forestry Science}, volume = {44}, year = {2014}, pages = {31}, abstract = {

BACKGROUND:Red needle cast (RNC) is a new needle disease of Pinus radiata D. Don (radiata pine) in New Zealand that is causing significant, but as-yet un-quantified, loss of growth and productivity. This foliar disease has recently been attributed to the infection of the needles by Phytophthora pluvialis Reeser, Sutton \& E Hansen. Genetic improvement is seen as a possible solution to mitigate the effects of this needle disease on forest productivity.FINDINGS:To quantify the ability of genetics to provide a solution, RNC was assessed on a single clones-within-families genetics trial using two methods: the percentage needle cast that was attributable to red needle cast symptoms; and the percentage needle cast where the causal agent was not clearly identifiable. Both needle cast assessment methods were found to be heritable (h2 0.21-0.31).CONCLUSIONS:Selecting for tolerance to RNC is likely to deliver healthier trees. More assessments across a number of sites and seasons are required to confirm this result.

}, issn = {1179-5395}, doi = {10.1186/s40490-014-0028-1}, url = {http://www.nzjforestryscience.com/content/44/1/31}, author = {Dungey, Heidi and Williams, Nari and Low, Charlie and Stovold, Graham} } @article {4459, title = {An overview of Australia{\textquoteright}s Phytophthora species assemblage in natural ecosystems recovered from a survey in Victoria}, journal = {IMA Fungus}, volume = {7}, year = {2016}, month = {Jan-01-2016}, pages = {47-58}, abstract = {

Although Phytophthora species cause serious diseases worldwide, until recently the main focus on disease in natural ecosystems in southern Australia has been on the distribution and impact of P. cinnamomi. However, new Phytophthora pathogens have emerged from natural ecosystems, and there is a need to better understand the diversity and distribution of these species in our natural forests, woodlands and heathlands. From a survey along a 70 km pipeline easement in Victoria, Phytophthora species were isolated from 249 rhizosphere samples and 25 bait bags deployed in 21 stream, river, or wetland locations. Of the 186 Phytophthora isolates recovered, 130 were identified to species based on ITS sequence data. Ninety-five isolates corresponded to 13 described Phytophthora species while additionally 35 isolates were identified as Clade 6 hybrids. Phytophthora cinnamomi was the most common species isolated (31 \%), followed by P. elongata (6 \%), both species were only recovered from soil. Samples from sites with the highest soil moisture at the time of sampling had the highest yield of isolates. Consistent with other studies throughout the world, Clade 6 species and their hybrids dominated water samples, although many of these species were also recovered less frequently from soil samples. Many of the species recovered in this study have not previously been reported from eastern Australia, reinforcing that Phytophthora species are widespread, abundant and diverse in natural ecosystems. We have probably been underestimating Phytophthora diversity in Australia.

}, doi = {10.5598/imafungus.2016.07.01.04}, url = {http://www.ingentaconnect.com/content/ima/imafung/pre-prints/content-k4_Vol7_no1_Article4}, author = {William A. Dunstan and Kay Howard and Giles E. StJ. Hardy and Treena I. Burgess} } @article {murdoch2427, title = {Control of Phytophthora cinnamomi with phosphite: some recent developments in application methods}, journal = {Australasian Plant Conservation}, volume = {34}, number = {4}, year = {2005}, pages = {10{\textendash}11}, publisher = {Australian Network for Plant Conservation Inc.}, abstract = {

Phytophthora cinnamomi has a world-wide distribution, causes disease in a very wide range of plants and is responsible for the destruction of certain plant communities in Europe and Australia. P. cinnamomi was probably introduced into Australia in the nineteenth century and is now established in south-western Australia and Tasmania, and throughout eastern Australia, from South Australia to the wet tropics. P. cinnamomi is listed as a Key Threatening Process under the Commonwealth Environment Protection and Biodiversity Conservation Act 1999.

}, url = {http://researchrepository.murdoch.edu.au/2427/}, author = {Dunstan, W.A. and G.E.St.J. Hardy} } @article {483, title = {DNA-based method for rapid identification of the pine pathogen, Phytophthora pinifolia}, journal = {FEMS Microbiology Letters}, volume = {298}, year = {2009}, pages = {99-104}, abstract = {

Phytophthora pinifolia causes a needle and shoot disease in Pinus radiata, referred to as {\textquoteleft}Da{\~n}o Foliar del Pino{\textquoteright}. This newly discovered disease requires intensive research efforts that necessitate the processing of large numbers of samples for which accurate identification, often by people not experienced in Phytophthora taxonomy, is required. The aim of this study was, therefore, to develop species-specific primers for P. pinifolia that amplify the internal transcribed spacer region of the ribosomal operon and the nuclear Ypt1 gene, respectively. The primers were tested over several Phytophthora spp., as well as fungi isolated from P. radiata. In all cases, only P. pinifolia was amplified. In addition to the species-specific primers, a PCR-restriction fragment length polymorphism protocol using available Phytophthora genus-specific primers was also used to generate a species-specific profile for P. pinifolia. This provided a characteristic profile that allows the identification of P. pinifolia, and it could also discriminate between 27 different species of Phytophthora. Both techniques reported in this study make it possible to identify large numbers of P. pinifolia cultures accurately and efficiently, which will be important for both quarantine work and biological research on this important new pathogen.

}, keywords = {Monterey pine, oomycetes, Pinus radiata, tree defoliation}, doi = {DOI: 10.1111/j.1574-6968.2009.01700.x}, url = {http://onlinelibrary.wiley.com/doi/10.1111/j.1574-6968.2009.01700.x/abstract}, author = {Dur{\'a}n, Alvaro and Bernard Slippers and Marieka Gryzenhout and Rodrigo Ahumada and Drenth, Andre and Brenda D. Wingfield and Michael J. Wingfield} } @article {481, title = {Phytophthora pinifolia sp. nov. associated with a serious needle disease of Pinus radiata in Chile}, journal = {Plant Pathology}, volume = {57}, year = {2008}, pages = {715{\textendash}727}, abstract = {

During the course of the past three years, a new disease of ,em\>Pinus radiata, referred to as {\textquoteleft}Da{\~n}o Foliar del Pino{\textquoteright} (DFP) has appeared in the Arauco province of Chile and subsequently spread to other areas. The disease is typified by needle infections, exudation of resin at the bases of the needle brachyblasts and, in younger trees, necrotic lesions in the cambium, which eventually girdle the branches. The disease causes the death of young seedlings and mature trees can also succumb after a few years of successive infection, probably hastened by opportunistic fungi such as ,em\>Diplodia pinea. Isolations on selective medium for Phytophthora spp. led to the consistent isolation of a Phytophthora sp. from needle tissue. DNA sequence comparisons for the ITS rDNA and cox II gene regions, and morphological observation showed that this oomycete represents a previously undescribed species for which the name Phytophthora pinifolia sp. nov. is provided. This new species is characterized by unbranched sporangiophores, and non-papillate, sub-globose to ovoid sporangia that are occasionally free from the sporangiophore with medium length pedicels. Despite using a number of oospore inducing techniques, oogonia/antheridia were not observed in isolates of P. pinifolia. Pathogenicity trials with P. pinifolia showed that it is pathogenic to P. radiata and causes rapid death of the succulent apical parts of young plants. Phytophthora pinifolia is the first Phytophthora known to be associated with needles and shoots of a Pinus sp. and its aerial habit is well matched with the occurrence and symptoms of DFP in Chile.

}, keywords = {Monterey pine, oomycete phylogeny, plantation forestry}, doi = {10.1111/j.1365-3059.2008.01893.x}, url = {http://dx.doi.org/10.1111/j.1365-3059.2008.01893.x}, author = {Dur{\'a}n, A. and Gryzenhout, M. and Slippers, B. and Ahumada, R. and Rotella, A. and Flores, F. and Wingfield, B. D. and Wingfield, M. J.} } @article {Dur{\textperiodcentered}n2010746, title = {AFLP analysis reveals a clonal population of Phytophthora pinifolia in Chile}, journal = {Fungal Biology}, volume = {114}, number = {9}, year = {2010}, pages = {746 - 752}, keywords = {Pinus radiata}, issn = {1878-6146}, doi = {DOI: 10.1016/j.funbio.2010.06.008}, url = {http://www.sciencedirect.com/science/article/B9879-50GMMRW-1/2/c0c76996906d7b589f9430c65d0b2880}, author = {Dur{\'a}n, Alvaro and Marieka Gryzenhout and Andr{\`E} Drenth and Bernard Slippers and Rodrigo Ahumada and Brenda D. Wingfield and Michael J. Wingfield} } @article {934, title = {Scientific opinion on the pest risk analysis on Phytophthora ramorum prepared by the FP6 project RAPRA}, journal = {EFSA Journal}, volume = {9(6)}, year = {2011}, month = {28 June 2011}, pages = {107 pp.}, chapter = {2186}, abstract = {

The Panel on Plant Health was asked to deliver a scientific opinion on the Pest Risk Analysis on Phytophthora ramorum prepared by the FP6 project RAPRA, taking into account comments by Member States and additional information since RAPRA. P. ramorum is the oomycete causing sudden oak death in the USA and leaf and twig blight/dieback on a range of ornamental species in North America and Europe. Currently P. ramorum is not listed as a harmful organism in Council Directive 2000/29/EC, but the Commission adopted in 2002 provisional emergency measures to prevent introduction into and spread within the EU. Recent large-scale outbreaks in Japanese larch (Larix kaempferi) plantations in the UK and Ireland have worsened the potential consequences in the risk assessment area. However, the Panel concludes that the broad narrative in the RAPRA report stands and supports its conclusion that {\textquotedblleft}There is a risk of further entry (of known or new lineages and/or mating types), establishment and [{\textellipsis}] impact{\textquotedblright}. It is advisable to avoid introductions of different lineages because of inherent phenotypic differences and the potential for sexual recombination. The Panel supports the management options proposed in the RAPRA report and adds further measures for consideration. Uncertainty remains over the extent to which the association between control measures and gradual reduction in the number of cases in nurseries is causal. The emergency measures have not prevented outbreaks occurring in the natural environment. The many other remaining uncertainties (fitness of progeny, hybridisation with other Phytophthora species, host range and epidemiological role of new hosts, early detection of new outbreaks, understanding of long-range dispersal, structure of plant trade networks, origin of the pathogen) call for further research on P. ramorum across Europe. Regulatory work should keep updated with research results on P. ramorum and further development of the Japanese larch outbreaks. {\textcopyright} European Food Safety Authority, 2011

}, keywords = {Larix kaempferi, management options, Phytophthora ramorum, ramorum blight, RAPRA, risk assessment, Sudden oak death}, doi = {10.2903/j.efsa.2011.2186}, url = {http://www.efsa.europa.eu/en/efsajournal/pub/2186.htm}, author = {EFSA Panel on Plant Health (PLH)} } @article {1293, title = {Variation among Phytophthora cinnamomi isolates from oak forest soils in the eastern United States}, journal = {Plant Disease}, volume = {96}, year = {2012}, month = {11/2012}, pages = {1608-1614}, abstract = {

Phytophthora cinnamomi isolates from geographically diverse oak forest soils in the Mid-Atlantic regions were studied to determine the extent of genotypic, phenotypic, and pathogenic variation. Four microsatellite loci were targeted for genetic analysis. Phenotypic characteristics measured included sexual and asexual spore dimensions and colony growth rate and morphology. Red oak (Quercus rubra) logs were inoculated with selected isolates to determine relative pathogenicity. Microsatellite analysis showed that the genetic variability of P. cinnamomi isolates was low, with two predominant microsatellite fingerprint groups (MFG). Isolates in MFG1 (48\% of the total isolates examined) were characterized by DNA fragment lengths of 120 and 122 bp at locus d39, 169 and 170 bp at locus e16, and 254 and 255 bp at locus g13. MFG2 isolates were characterized by marker sizes of 122 and 124 bp at locus d39, 161 and 163 bp at locus e16, and 247 and 248 bp at locus g13. Asexual and sexual spore dimensions varied greatly among isolates but were similar to previously published descriptions. Phenotypic differences were most pronounced when data were grouped by MFG; the most significant were colony morphology and growth rate. Neither characteristic was a reliable predictor of isolate genotype. Differences in growth rates of MFGs were observed, with MFG1 being less tolerant at higher incubation temperatures. No variation in pathogenicity was observed on red oak logs. The low level of phenotypic and genotypic variation of P. cinnamomi suggest that other factors such as climate might play a more important role in its northern distribution and the diseases it causes.

}, doi = {10.1094/PDIS-02-12-0140-RE}, url = {http://dx.doi.org/10.1094/PDIS-02-12-0140-RE}, author = {Eggers, J. E. and Balci, Y. and MacDonald, W. L.} } @article {1228, title = {A statistical model to detect asymptomatic infectious individuals with an application in the Phytophthora alni-Induced alder decline}, journal = {Phytopathology}, volume = {100}, year = {2010}, pages = {1262-1269}, abstract = {

In some diseases{\textemdash}in particular, tree root infection{\textemdash}stages of infection and inoculum production level and timing are not readily observable because of uncertainty or time lags in symptom appearance. Here, we pose a criterion, based on relative hazard of disease symptoms, to discriminate between healthy and asymptomatic infected individuals. We design a statistical procedure to estimate the criterion for a 6-year survey of alder decline along a northeastern French river. Individual tree symptom hazard was modeled with Cox{\textquoteright}s regression model, taking estimation of local infection pressure as a risk factor. From an inoculum production experiment, we thereafter assessed the inoculum production level of target trees, including symptomatic and asymptomatic trees ranked according to their symptoms hazard. Using receiver operating characteristic methods, we first evaluated the criterion performance and determined the discrimination threshold to sort out asymptomatic individuals into healthy and infected. Then, we highlighted the fact that the infected asymptomatic trees were among the major inoculum producers whereas severely declining and dead trees were found to be poor inoculum sources.

}, keywords = {spatial point pattern analysis, survival analysis}, doi = {10.1094/PHYTO-05-10-0140}, url = {http://dx.doi.org/10.1094/PHYTO-05-10-0140}, author = {Elegbede, Chabi Fabrice and Pierrat, Jean-Claude and Aguayo, Jaime and Husson, Claude and Halkett, Fabien and Beno{\^{\i}t Mar{\c c}ais} } @article {4339, title = {An improved method for qPCR detection of three Phytophthora spp. in forest and woodland soils in northern Britain}, journal = {Forest Pathology}, volume = {45}, year = {2015}, month = {December 2015}, pages = {537{\textendash}539}, abstract = {

Summary

Using TaqMan qPCR assays, DNA of P.\ ramorum, P.\ kernoviae and P.\ austrocedri was detected in 500\ g soil samples collected from twelve infected forest and woodland sites in northern Britain. Phytophthora DNA was also amplified in soil adhering to boots after walking transects along footpaths or animal trails. At two sites, Phytophthora DNA was detected in soil over a 4-year period following removal of infected hosts. This new method enabling assessment of larger quantities of soil demonstrates the contamination risk of these pathogens in soil at infected sites and improves our understanding of the mechanisms of persistence and spread.

}, doi = {10.1111/efp.12224}, url = {http://doi.wiley.com/10.1111/efp.12224http://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111\%2Fefp.12224}, author = {Elliot, M. and Schlenzig, A. and Harris, C. M. and Meagher, T. R. and Green, S.}, editor = {Belbahri, L.} } @article {EFP:EFP627, title = {Phenotypic differences among three clonal lineages of Phytophthora ramorum}, journal = {Forest Pathology}, volume = {41}, number = {1}, year = {2011}, pages = {7{\textendash}14}, publisher = {Blackwell Publishing Ltd}, abstract = {

There are three major clonal lineages of Phytophthora ramorum present in North America and Europe named NA1, NA2, and EU1. Twenty-three isolates representing all three lineages were evaluated for phenotype including (i) aggressiveness on detached Rhododendron leaves and (ii) growth rate at minimum, optimum, and maximum temperatures. Closely related species P. foliorum and P. hibernalis were included in phenotypic tests since these species are encountered in nursery surveys for P. ramorum. Isolates from the NA2 and EU1 lineages were the most aggressive and isolates from the NA1 group were the least aggressive. The NA1 lineage of P. ramorum was the most variable in aggressiveness and growth rate. The variability in the NA1 lineage was due to the presence of non-wild type (nwt) isolates. There was no significant difference in growth rate among NA1 wild type (wt), NA2, and EU1 lineages at any temperature tested. The difference between wt and nwt P. ramorum isolates is discussed.

}, issn = {1439-0329}, doi = {10.1111/j.1439-0329.2009.00627.x}, url = {http://dx.doi.org/10.1111/j.1439-0329.2009.00627.x}, author = {Elliott, M. and Sumampong, G. and Varga, A. and Shamoun, S. F. and James, D. and Masri, S. and N. J. Gr{\"u}nwald} } @article {EFP:EFP586, title = {PCR-RFLP markers identify three lineages of the North American and European populations of Phytophthora ramorum}, journal = {Forest Pathology}, volume = {39}, number = {4}, year = {2009}, pages = {266{\textendash}278}, publisher = {Blackwell Publishing Ltd}, abstract = {

Phytophthora ramorum, the cause of sudden oak death and ramorum blight, has three major clonal lineages and two mating types. Molecular tests currently available for detecting P. ramorum do not distinguish between clonal lineages and mating type is determined by cultural methods on a limited number of samples. In some molecular diagnostic tests, cross-reaction with other closely related species such as P. hibernalis, P. foliorum or P. lateralis can occur. Regions in the mitochondrial gene Cox1 are different among P. ramorum lineages and mitochondrial genotyping of the North American and European populations seems to be sufficient to differentiate between mating types, because the EU1 lineage is mostly A1 and both NA1 and NA2 lineages are A2. In our study, we were able to identify P. ramorum isolates according to lineage using polymerase chain reaction-restriction fragment-length polymorphism (PCR-RFLP) of the Cox1 gene, first by using ApoI to separate P. ramorum from other species and EU1 from North American populations, and then AvaI to distinguish between NA1 and NA2 genotypes. However, P. foliorum had the same restriction profile as P. ramorum NA1 isolates.

}, issn = {1439-0329}, doi = {10.1111/j.1439-0329.2008.00586.x}, url = {http://dx.doi.org/10.1111/j.1439-0329.2008.00586.x}, author = {Elliott, M. and Sumampong, G. and Varga, A. and Shamoun, S. F. and James, D. and Masri, S. and Bri{\`e}re, S. C. and N. J. Gr{\"u}nwald} } @article {4029, title = {Development of a Nested Quantitative Real-Time PCR for Detecting Phytophthora cinnamomi in Persea americana Rootstocks}, journal = {Plant Disease}, volume = {97}, year = {2013}, month = {08/2013}, pages = {1012 - 1017}, abstract = {

Phytophthora cinnamomi causes Phytophthora root rot (PRR) in avocado (Persea americana), an important disease that causes severe economic losses to the avocado industry globally. To date, no PRR-resistant avocado rootstock variety has been discovered, although certain rootstock varieties have been shown to be more tolerant than others. In this study, we developed an accurate, low cost assay for in planta quantification of P. cinnamomi to evaluate disease tolerance. A nested real-time polymerase chain reaction assay was developed to sensitively detect pathogen DNA in plant tissues. Root samples from a highly tolerant (Dusa) and less tolerant (R0.12) rootstock were collected at 0, 3, 7, 14, and 21 days after inoculation with P. cinnamomi and used for pathogen quantification. Nested primers developed in this study were specific and sensitive and could detect P. cinnamomi in root tissues. The amount of P. cinnamomi quantified in roots was significantly higher in the less-tolerant R0.12 plants when compared with the highly tolerant Dusa plants at all time points. This study has confirmed the known status of disease tolerance of Dusa and R0.12 avocado rootstocks in a quantitative manner and provides a reliable molecular tool to assist with industry breeding programs for the selection of PRR-resistant avocado rootstock varieties.

}, issn = {0191-2917}, doi = {10.1094/PDIS-11-12-1007-RE}, url = {http://dx.doi.org/10.1094/PDIS-11-12-1007-RE }, author = {Engelbrecht, J. and Duong, T. A. and van den Berg, N.} } @article {183, title = {Interaction of light and sterol on sporangium and chlamydospore production by Phytophthora lateralis}, journal = {Phytopathology}, volume = {70}, year = {1980}, pages = {650-654}, abstract = {

Chlamydospore production by Phytophthora lateralis was most abundant in V8 broth with 20 μg/ml β-sitosterol, and maximum sporangium production occurred with 10 μg/ml. Growth (dry weight) was not enhanced by sterol concentrations ranging from 1 to 200 μg/ml. Cultures grown on V8 sterol agar or broth, and illuminated (680 μW cm2, combined Blacklight Blue and Cool White fluorescent lamps) either continuously or 12 hr daily, produced at least four times as many sporangia as were produced by cultures in the dark on sterol media, or in the light or dark on media not amended with sterol. Chlamydospores were produced most abundantly in the dark on V8 sterol agar or broth, with production greatly reduced by continuous or 12 hr of light daily. Chlamydospore production was suppressed by all light intensities tested (85, 170, 340, 680 μW cm2) compared with production in the dark. Few chlamydospores formed in cultures on media without sterol, whether incubated in the light or dark. Growth (dry weight or colony size) was not affected by illumination. None of numerous regimes of diurnal temperature cycles enhanced sporulation more than constant temperatures. Optimal sporangium production requires incubation on media with sterol at 14-16 C in the light; optimal chlamydospore production requires incubation at 24-25 C in the dark on media with sterol.

}, issn = {0031949X}, doi = {DOI: 10.1094/Phyto-70-650.}, author = {Englander, L. and L.F. Roth} } @article {LarryEnglander05012006, title = {Growth and sporulation of Phytophthora ramorum in vitro in response to temperature and light}, journal = {Mycologia}, volume = {98}, number = {3}, year = {2006}, pages = {365-373}, abstract = {

Phytophthora ramorum, recently found in the US, is causing concern for hardwood forests and the nursery industry. In an effort to identify some of the environmental limitations to growth and sporulation we undertook a laboratory study of four US and three European (EU) isolates. On V8 media, isolates grew when incubated at 2-28 C and produced chlamydospores at 8-28 C. Sporangia were produced at all temperatures tested: 10-30 C for US isolates and 6-26 C for EU isolates. Optimal temperatures were 16-26 C for growth, 14-26 C for chlamydospore production and 16-22 C for sporangia production. US isolates grew less and produced fewer spores when exposed to increasing doses of near-UV radiation (50-300 {micro}W/cm2) and visible radiation (250-1500 {micro}W/cm2). EU isolates were exposed to 300 {micro}W/cm2 near-UV only, which significantly reduced growth of one of three isolates and had no significant effect on spore production. In our studies P. ramorum tolerated a broad range of temperature and light conditions, which suggests that it is capable of establishment in a wide geographic area.

}, doi = {10.3852/mycologia.98.3.365}, url = {http://www.mycologia.org/cgi/content/abstract/98/3/365}, author = {Englander, Larry and Browning, Marsha and Tooley, Paul W.} } @article {springerlink:10.1007/s10658-008-9296-z, title = {Species hybrids in the genus Phytophthora with emphasis on the alder pathogen Phytophthora alni: a review}, journal = {European Journal of Plant Pathology}, volume = {122}, year = {2008}, note = {10.1007/s10658-008-9296-z}, pages = {31-39}, publisher = {Springer Netherlands}, abstract = {

This review provides a summary of recent examples of interspecific hybridisation within the oomycetous genus Phytophthora. Species hybrids either created in the laboratory or evolved in natural environments are discussed in association with evolutionary issues and possible threats they may pose to agriculture, horticulture and forestry. It is suggested that sustainable control of such hybrids will depend on the better understanding of temporal and spatial aspects of genetic mechanisms and environmental factors that lead to the hybridisation process and thus the genetic diversity in Phytophthora populations.

}, issn = {0929-1873}, doi = {10.1007/s10658-008-9296-z}, url = {http://dx.doi.org/10.1007/s10658-008-9296-z}, author = {{\'E}rsek, Tibor and Nagy, Zolt{\'a}n} } @book {117, title = {Phytophthora diseases worldwide.}, year = {1996}, pages = {562 pp}, publisher = {APS Press, American Phytopathological Society}, organization = {APS Press, American Phytopathological Society}, address = {St. Paul, MN}, author = {Erwin, D.C and Ribeiro, O.K.} } @article {PPA:PPA2471, title = {Phosphite primed defence responses and enhanced expression of defence genes in Arabidopsis thaliana infected with Phytophthora cinnamomi}, journal = {Plant Pathology}, volume = {60}, number = {6}, year = {2011}, pages = {1086{\textendash}1095}, publisher = {Blackwell Publishing Ltd}, abstract = {

This paper describes the effect of phosphite (Phi), a systemic chemical, on the induction of defence responses in Phytophthora cinnamomi-infected Arabidopsis thaliana accessions Ler and Col-0. Application of Phi to non-inoculated A. thaliana seedlings of accession Ler elevated transcription of defence genes in the salicylic acid (PR1 and PR5) and jasmonic acid/ethylene (THI2.1 and PDF1.2) pathways. Furthermore, a systemic increase in the expression of the PR1 gene was demonstrated in Phi-treated seedlings using the transgenic line PR1::GUS in the presence/absence of the pathogen by 72 h after inoculation. The cells of Phi-treated A. thaliana Ler leaves responded to P. cinnamomi zoospore inoculation with a rapid increase in callose deposition and hydrogen peroxide (H2O2) production. Phi treatment resulted in the production of callose papillae 6 h earlier than in non-Phi-treated inoculated seedlings and enhanced the production of H2O2 in the leaves of A. thaliana at the site of hyphal penetration and in cells away from the inoculation point. By 24 h after infection, clear differences in the amount of H2O2 production were observed between the Phi-treated and non-Phi-treated plants. These rapid host responses did not occur in non-Phi-treated inoculated seedlings. There was also a significant (P \< 0{\textperiodcentered}001) decrease in lesion size in Phi-treated plants. These results indicate that Phi primes the plant for a rapid and intense response to infection involving heightened activation of a range of defence responses.

}, keywords = {callose deposition, defence response, hydrogen peroxide, potassium phosphonate (phosphite), reactive oxygen species (ROS)}, issn = {1365-3059}, doi = {10.1111/j.1365-3059.2011.02471.x}, url = {http://dx.doi.org/10.1111/j.1365-3059.2011.02471.x}, author = {Eshraghi, L. and Anderson, J. and Aryamanesh, N. and Shearer, B. and McComb, J. and Hardy, G. E. StJ. and O{\textquoteright}Brien, P. A.} } @article {4267, title = {Detection, Diversity, and Population Dynamics of Waterborne Phytophthora ramorum Populations}, journal = {Phytopathology}, volume = {105}, year = {2015}, month = {Jan-01-2015}, pages = {57 - 68}, abstract = {

Sudden oak death, the tree disease caused by Phytophthora ramorum, has significant environmental and economic impacts on natural forests on the U.S. west coast, plantations in the United Kingdom, and in the worldwide nursery trade. Stream baiting is vital for monitoring and early detection of the pathogen in high-risk areas and is performed routinely; however, little is known about the nature of water-borne P. ramorum populations. Two drainages in an infested California forest were monitored intensively using stream-baiting for 2 years between 2009 and 2011. Pathogen presence was determined both by isolation and polymerase chain reaction (PCR) from symptomatic bait leaves. Isolates were analyzed using simple sequence repeats to study population dynamics and genetic structure through time. Isolation was successful primarily only during spring conditions, while PCR extended the period of pathogen detection to most of the year. Water populations were extremely diverse, and changed between seasons and years. A few abundant genotypes dominated the water during conditions considered optimal for aerial populations, and matched those dominant in aerial populations. Temporal patterns of genotypic diversification and evenness were identical among aerial, soil, and water populations, indicating that all three substrates are part of the same epidemiological cycle, strongly influenced by rainfall and sporulation on leaves. However, there was structuring between substrates, likely arising due to reduced selection pressure in the water. Additionally, water populations showed wholesale mixing of genotypes without the evident spatial autocorrelation present in leaf and soil populations.

}, issn = {0031-949X}, doi = {10.1094/PHYTO-07-13-0196-R}, url = {http://apsjournals.apsnet.org/doi/abs/10.1094/PHYTO-07-13-0196-R}, author = {Eyre, C. A. and Garbelotto, M.} } @article {4247, title = {Lineage, Temperature, and Host Species have Interacting Effects on Lesion Development in Phytophthora ramorum}, journal = {Plant Disease}, volume = {98}, year = {2014}, month = {12/2014}, pages = {1717 - 1727}, abstract = {

There are four recognized clonal lineages of the pathogen Phytophthora ramorum. The two major lineages present in North America are NA1 and NA2. With a few exceptions, NA1 is found in natural forest ecosystems and nurseries, and NA2 is generally restricted to nurseries. Isolates from the NA1 and NA2 lineages were used to infect rhododendron, camellia, and California bay laurel in detached leaf assays to study the effects of lineage, temperature, and host on pathogenicity and host susceptibility. Isolates within both lineages were highly variable in their ability to form lesions on each host. There was also a tendency toward reduced lesion size in successive trials, suggesting degeneration of isolates over time. Temperature had a significant effect on lesion size, with a response that varied depending on the host and isolate. Phenotypic differences between lineages appear to be heavily influenced by the representation of isolates used, host, and temperature. The importance of temperature, host, and lineage are discussed with respect to disease management, as well as future range expansions and migrations of the pathogen.

}, issn = {0191-2917}, doi = {10.1094/PDIS-02-14-0151-RE}, url = {http://apsjournals.apsnet.org/doi/abs/10.1094/PDIS-02-14-0151-RE}, author = {Eyre, C. A. and Hayden, K. J. and Kozanitas, M. and Gr{\"u}nwald, N. J. and Garbelotto, M.} } @article {PPA:PPA2506, title = {Infectivity and sporulation potential of Phytophthora kernoviae to select North American native plants}, journal = {Plant Pathology}, volume = {61}, year = {2011}, month = {04/2012}, pages = {224{\textendash}233}, publisher = {Blackwell Publishing Ltd}, abstract = {

Phytophthora kernoviae exhibits comparable epidemiology to Phytophthora ramorum in invaded UK woodlands. Because both pathogens have an overlapping geographic range in the UK and often concurrently invade the same site, it is speculated that P. kernoviae may also invade North American (NA) forests threatened by P. ramorum, the cause of Sudden Oak Death. This paper addresses the susceptibility of select NA plants to P. kernoviae, including measures of disease incidence and severity on wounded and unwounded foliage. The potential for pathogen transmission and survival was investigated by assessing sporangia and oospore production in infected tissues. Detached leaves of Rhododendron macrophyllum, Rhododendron occidentale and Umbellularia californica, and excised roots of U. californica and R. occidentale were inoculated with P. kernoviae and percent lesion area was determined after 6 days. Leaves were then surface sterilized and misted to stimulate sporulation and after 24 h sporangia production was assessed. The incidence of symptomless infections and sporulation were recorded. All NA native plants tested were susceptible to P. kernoviae and supported sporangia production; roots of U. californica and R. occidentale were both susceptible to P. kernoviae and supported sporangia production. Oospore production was also observed in U. californica roots. The results highlight the vulnerability of select NA native plants to infection by P. kernoviae, suggest that symptomless infections may thwart pathogen detection, and underscore the importance of implementing a proactive and adaptive biosecurity plan.

}, keywords = {forest biosecurity, host susceptibility, invasive disease, Phytophthora kernoviae}, issn = {1365-3059}, doi = {10.1111/j.1365-3059.2011.02506.x}, url = {http://dx.doi.org/10.1111/j.1365-3059.2011.02506.x}, author = {Fichtner, E. J. and D. M. Rizzo and Kirk, S.A. and Webber, JF} } @article {doi:10.1094/PHYTO-97-10-1366, title = {Detection, distribution, sporulation, and survival of Phytophthora ramorum in a California redwood-tanoak forest soil}, journal = {Phytopathology}, volume = {97}, number = {10}, year = {2007}, pages = {1366-1375}, doi = {10.1094/PHYTO-97-10-1366}, url = {http://apsjournals.apsnet.org/doi/abs/10.1094/PHYTO-97-10-1366}, author = {Fichtner, E. J. and Lynch, S. C. and D. M. Rizzo} } @proceedings {680, title = {Persistence of Phytophthora ramorum and Phytophthora kernoviae in U.K. natural areas and implications for North American forests}, volume = {Gen. Tech. Rep. PSW-GTR-229}, year = {2009}, month = {04/2010}, pages = {83-84}, publisher = {U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station.}, address = {Santa Cruz, California}, author = {Elizabeth J. Fichtner and Rizzo, David M. and Webber,Joan and Kirk, Susan A. and Alistair Whybrow}, editor = {Susan J. Frankel and John T. Kliejunas and Katharine M. Palmieri} } @article {doi:10.1094/PDIS-03-10-0236, title = {Root infections may challenge management of invasive Phytophthora spp. in U.K. woodlands}, journal = {Plant Disease}, volume = {95}, number = {1}, year = {2011}, pages = {13-18}, abstract = {

Because sporulation of Phytophthora ramorum and P. kernoviae on Rhododendron ponticum, an invasive plant, serves as primary inoculum for trunk infections on trees, R. ponticum clearance from pathogen-infested woodlands is pivotal to inoculum management. The efficacy of clearance for long-term disease management is unknown, in part due to lack of knowledge of pathogen persistence in roots and emerging seedlings. The main objectives of this work were to (i) investigate whether both pathogens infect R. ponticum roots, (ii) determine the potential for residual inoculum of P. kernoviae to infect R. ponticum seedlings in cleared woodlands, and (iii) assess potential for R. ponticum roots to support survival and transmission of P. kernoviae. Roots of R. ponticum were collected from both unmanaged and cleared woodlands and assessed for pathogen recovery. Both P. ramorum and P. kernoviae were recovered from asymptomatic roots of R. ponticum in unmanaged woodlands, and P. kernoviae was recovered from asymptomatic roots from seedlings in cleared woodland. Oospore production of P. kernoviae was observed in naturally infected R. ponticum foliage and in inoculated roots. Roots also supported P. kernoviae sporangia production. The results of this study suggest that post-clearance management of R. ponticum regrowth is necessary for long-term inoculum management in invaded woodlands.

}, issn = {0191-2917}, doi = {10.1094/PDIS-03-10-0236}, url = {http://apsjournals.apsnet.org/doi/abs/10.1094/PDIS-03-10-0236}, author = {Fichtner, E. J. and D. M. Rizzo and Kirk, S.A. and Webber, JF} } @article {doi:10.1094/PHYTO-99-5-0608, title = {Survival, dispersal, and potential soil-mediated suppression of Phytophthora ramorum in a California redwood-tanoak Forest}, journal = {Phytopathology}, volume = {99}, number = {5}, year = {2009}, note = {PMID: 19351257}, pages = {608-619}, doi = {10.1094/PHYTO-99-5-0608}, url = {http://apsjournals.apsnet.org/doi/abs/10.1094/PHYTO-99-5-0608}, author = {Fichtner, E. J. and Lynch, S. C. and D. M. Rizzo} } @article {408, title = {Cypress mortality (mal del cipr{\'e}s) in the Patagonian Andes: comparisons with similar forest diseases and declines in North America}, journal = {European Journal of Forest Pathology}, volume = {29}, year = {1999}, month = {April 1999}, pages = {89{\textendash}96}, abstract = {

Summary Widespread mortality of Cordilleran cypress (Austrocedrus chilensis) occurs in developed and pristine forests in south-western Argentina and possibly south-eastern Chile. Affected trees may die rapidly but mortality is commonly preceded by several decades of severely restricted radial stem growth. Roots are often affected by one or more types of decay. Cypress mortality, locally termed {\textquoteleft}mal del cipres{\textquoteright}, is similar to a major forest disease in North America: Port-Orford-cedar (Chamaecyparis lawsoniana) root disease in Oregon and California and a major tree decline: Alaska yellow-cedar (Chamaecyparis nootkatensis) decline in south-east Alaska. This paper discusses several hypotheses concerning mal del cipres and compares current forest decline research in Patagonia with North America.

}, doi = {10.1046/j.1439-0329.1999.00133.x}, url = {http://dx.doi.org/10.1046/j.1439-0329.1999.00133.x}, author = {Filip, G. M. and Rosso, P. H.} } @proceedings {417, title = {{\textquoteleft}{\textquoteleft}Mal del cipr{\'e}s{\textquoteright}{\textquoteright} disease: analysis of the association between aerial symptoms and vitality of trees.}, year = {2009}, pages = {282{\textendash}3}, publisher = {USDA Forest Service, Pacific Southwest Research Station: Gen. Tech. Rep. PSW-GTR-221, 282{\textendash}3}, address = {Albany, CA, USA}, author = {Floria, MP and Greslebin, A. G.} } @article {3949, title = {Distribution of the Phytophthora disease of alder}, number = {Retrieved 12 June 2010.}, year = {2006}, publisher = {UK Forestry Commission}, url = {http://www.forestry.gov.uk/fr/INFD-737J2S}, author = {Forestry_Commission_Great_Britain} } @article {4187, title = {Gene~{\texttimes}~environment tests discriminate the new EU2 evolutionary lineage of Phytophthora ramorum and indicate that it is adaptively different}, journal = {Forest Pathology}, volume = {44}, year = {2013}, month = {06/2014}, pages = {219-232}, abstract = {

A new evolutionary lineage of the destructive introduced tree pathogen Phytophthora ramorum, EU2 lineage, was recently discovered attacking larch and other hosts in Northern Ireland and south west Scotland, UK. Sixteen {\textquoteleft}medium\ {\texttimes}\ agar concentration\ {\texttimes}\ incubation temperature{\textquoteright} stress environments were tested to find a rapid and repeatable method to discriminate the known EU2 lineage from the EU1, NA1 and NA2 lineages in culture, in particular from the EU1 already prevalent across the UK; and to investigate whether EU2 might be adaptively different. At 28{\textdegree}C on both Carrot agar and V8 juice agar, the mean radial growth rates of all four lineages were significantly different, with NA2\ \>\ EU2\ \>\ EU1\ \>\ NA1. At this temperature, EU2 colonies were not only phenotypically distinct from EU1 and all other lineages but on average grew three times as fast as EU1. This indicates that EU2 is adaptively different from EU1. Twelve days growth in the environment {\textquoteleft}V8A/2\% agar/28{\textdegree}C gave excellent discrimination of all four lineages in three repeat experiments, including clear discrimination of EU2 from EU1. Each lineage exhibited a distinctive colony pattern. The utility of this test environment was examined further by screening fresh UK isolates of unknown lineage from new larch outbreak sites alongside standard isolates. The lineage assignments predicted were corroborated by gene sequencing and RFLP profiling. These results also revealed that the EU2 lineage was present at several new larch sites in south west Scotland, whereas isolates from geographically adjacent areas such as the Isle of Mull, north west Scotland, the Isle of Man and north west England were all of EU1 lineage.

}, issn = {1439-0329}, doi = {10.1111/efp.12085}, url = {http://dx.doi.org/10.1111/efp.12085}, author = {Franceschini, S. and Webber, J. F. and Sancisi-Frey, S. and Brasier, C. M.} } @article {4710, title = {Phytophthora Introductions in Restoration Areas: Responding to Protect California Native Flora from Human-Assisted Pathogen Spread}, journal = {Forests}, volume = {11}, year = {2020}, month = {Nov-30-2020}, pages = {1291}, abstract = {

Over the past several years, plantings of California native plant nursery stock in restoration areas have become recognized as a pathway for invasive species introductions, in particular Phytophthora pathogens, including first in the U.S. detections (Phytophthora tentaculata, Phytophthora quercina), new taxa, new hybrid species, and dozens of other soilborne species. Restoration plantings may be conducted in high-value and limited habitats to sustain or re-establish rare plant populations. Once established, Phytophthora pathogens infest the site and are very difficult to eradicate or manage{\textemdash}they degrade the natural resources the plantings were intended to enhance. To respond to unintended Phytophthora introductions, vegetation ecologists took a variety of measures to prevent pathogen introduction and spread, including treating infested areas by solarization, suspending plantings, switching to direct seeding, applying stringent phytosanitation requirements on contracted nursery stock, and building their own nursery for clean plant production. These individual or collective actions, loosely coordinated by the Phytophthoras in Native Habitats Work Group ensued as demands intensified for protection from the inadvertent purchase of infected plants from commercial native plant nurseries. Regulation and management of the dozens of Phytophthora species and scores of plant hosts present a challenge to the state, county, and federal agriculture officials and to the ornamental and restoration nursery industries. To rebuild confidence in the health of restoration nursery stock and prevent further Phytophthora introductions, a voluntary, statewide accreditation pilot project is underway which, upon completion of validation, is planned for statewide implementation.

}, doi = {10.3390/f11121291}, url = {https://www.mdpi.com/1999-4907/11/12/1291/htm}, author = {Frankel, Susan J. and Conforti, Christa and Hillman, Janell and Ingolia, Mia and Shor, Alisa and Benner, Diana and Alexander, Janice M. and Bernhardt, Elizabeth and Swiecki, Tedmund J.} } @proceedings {946, title = {Proceedings of the sudden oak death third science symposium}, year = {2007}, month = {2008}, pages = {491 pp.}, publisher = {Albany, CA: Pacific Southwest Research Station, Forest Service, U.S. Department of Agriculture}, address = {Santa Rosa, California}, abstract = {

The Sudden Oak Death Third Science Symposium provided a forum for current research on sudden oak death, caused by the exotic, quarantine pathogen, Phytophthora ramorum. One hundred and seventeen submissions describing papers and posters on the following sudden oak death/ P. ramorum topics are included: biology, genetics, nursery, and wildland management, monitoring, ecology, and diagnostics.

}, keywords = {coast live oak, invasive species, Phytophthora ramorum, Sudden oak death, tanoak}, url = {http://www.fs.fed.us/psw/publications/documents/psw_gtr214/}, author = {Frankel, Susan J. and Kliejunas, John T. and Palmieri, Katharine M.} } @article {4382, title = {Pest Alert: Phytophthora tentaculata.}, number = {December 18 2015}, year = {2015}, publisher = {Pacific Southwest Research Station, USDA Forest Service}, address = {Albany, CA . }, abstract = {

Phytophthora tentaculata has been detected in several California native plant nurseries and restoration sites. These are the first detections of P. tentaculata in the USA. Phytophthora tentaculata was initially noticed in a native plant nursery causing a severe root and crown rot in sticky monkey flower, Diplacus aurantiacus subsp. aurantiacus (Scrophulariaceae) in 2012 (figure 1). Since then it has been detected in four additional nurseries in three counties in CA in addition to three restoration sites where outplanted stock was found to be infected.

}, url = {http://www.suddenoakdeath.org/wp-content/uploads/2015/02/P.tentaculata.Pest_.Alert_.022315.pdf}, author = {Frankel, S and Swiecki, T and Bernhardt, E and Rooney-Latham, S and Blomquist, C} } @proceedings {944, title = {Proceedings of the sudden oak death second science symposium: the state of our knowledge}, year = {2005}, month = {2006}, pages = {571 pp.}, publisher = {Albany, CA: Pacific Southwest Research Station, Forest Service, U.S. Department of Agriculture}, address = {Monterey, California}, abstract = {

The Sudden Oak Death Second Science Symposium provided a forum for current research on sudden oak death, caused by the exotic, quarantine pathogen, Phytophthora ramorum. Ninety papers and forty-six posters on the following sudden oak death/P. ramorum topics are included: biology, genetics, nursery and wildland management, monitoring, ecology, and diagnostics. Several papers on P. kernoviae and other forest Phytophthora species are also presented.

}, keywords = {coast live oak, invasive species, Phytophthora ramorum, Sudden oak death, tanoak}, url = {http://www.fs.fed.us/psw/publications/documents/psw_gtr196/}, author = {Frankel, Susan J. and Shea, Patrick J. and Haverty, Michael I.} } @proceedings {945, title = {Proceedings of the sudden oak death fourth science symposium.}, year = {2009}, month = {2010}, pages = {378 pp.}, publisher = {Albany, CA: Pacific Southwest Research Station, Forest Service, U.S. Department of Agriculture}, address = {Santa Cruz, California}, abstract = {

The Sudden Oak Death Fourth Science Symposium provided a forum for current research on sudden oak death, caused by the exotic, quarantine pathogen, Phytophthora ramorum. Ninety submissions describing papers or posters on the following sudden oak death/P. ramorum topics are included: biology, genetics, nursery and wildland management, monitoring, ecology, and diagnostics.

}, keywords = {coast live oak, invasive species, Phytophthora ramorum, Sudden oak death, tanoak}, url = {http://www.fs.fed.us/psw/publications/documents/psw_gtr229/}, author = {Susan J. Frankel and John T. Kliejunas and Katharine M. Palmieri} } @article {951, title = {Sudden oak death and Phytophthora ramorum in the USA: a management challenge}, journal = {Australasian Plant Pathology}, volume = {37}, year = {2008}, pages = {19{\textendash}25}, abstract = {

Oaks and tanoaks in California and Oregon coastal forests are being ravaged by sudden oak death. The exotic causal agent, Phytophthora ramorum, is an oomycete in the Straminipile group, a relative of diatoms and algae. P. ramorum also infects many popular horticultural plants (i.e. camellia and rhododendron), causing ramorum blight, with symptoms expressed as leaf spots, twig blight and shoot dieback. P. ramorum has raised important biosecurity issues, which continue to reverberate through the agriculture, forestry and horticulture industries as well as associated government management, regulatory and scientific agencies. The continued spread of this and other new Phytophthora spp. presents significant impetus for adjustments in the management and regulation of forest pathogens and nursery stock.

}, url = {http://www.publish.csiro.au/?paper=AP07088}, author = {Susan J. Frankel} } @article {4691, title = {Impact of weather variables and season on sporulation of Phytophthora pluvialis and Phytophthora kernoviae}, journal = {Forest Pathology}, volume = {50}, year = {2020}, month = {Mar-03-2020}, pages = {e12588}, abstract = {

Phytophthora pluvialis and Phytophthora kernoviae are the causal agents of important needle diseases on Pinus radiata in New Zealand. Little is known about the epidemiology of the diseases, making the development of control strategies challenging. To investigate the seasonality and climatic drivers of sporulation, inoculum traps, consisting of pine fascicles floating on water in plastic containers, were exchanged fortnightly at five sites in P.\ radiata plantations between February 2012 and December 2014. Sections of needle baits were plated onto selective media and growth of Phytophthora\ pluvialis and P.\ kernoviae recorded. To explore the generalizability of these data, they were compared to detection data for both pathogens from the New Zealand Forest Health Database (NZFHDB). Further, equivalent analyses on infection of Rhododendron ponticum by P.\ kernoviae in Cornwall, UK allowed the comparison of the epidemiology of P.\ kernoviae across different host systems and environments. In New Zealand, inoculum of P.\ pluvialis and P.\ kernoviae was detected between January{\textendash}December and March{\textendash}November, respectively. Inoculum of both species peaked in abundance in late winter. The probability of detecting P.\ pluvialis and P.\ kernoviae was greater at lower temperatures, while the probability of detecting P.\ pluvialis also increased during periods of wet weather. Similar patterns were observed in NZFHDB data. However, the seasonal pattern of infection by P.\ kernoviae in the UK was the opposite of that seen for sporulation in New Zealand. Phytophthora kernoviae was likely limited by warmer and drier summers in New Zealand, but by colder winter weather in the UK. These results emphasize the importance of considering both environmental drivers and thresholds in improving our understanding of pathogen epidemiology.

}, doi = {10.1111/efp.v50.210.1111/efp.12588}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/efp.12588}, author = {Fraser, Stuart and Gomez-Gallego, Mireia and Gardner, Judy and Bulman, Lindsay S. and Denman, Sandra and Williams, Nari M.} } @article {4527, title = { Las especies de Phytophthora en la Argentina}, journal = { Revista de Investigaciones Agricoles}, volume = {4}, year = {1950}, pages = {47-133}, author = {Frezzi, MJ} } @article {4450, title = {Effects of Soil Solarization and Trichoderma asperellum on Soilborne Inoculum of Phytophthora ramorum and Phytophthora pini in Container Nurseries}, journal = {Plant Disease}, volume = {100}, year = {2016}, month = {Jan-02-2016}, pages = {438 - 443}, abstract = {

Infested container nursery beds are an important source of soilborne Phytophthora spp. for initiating disease through movement with surface water or splashing onto foliage. We investigated the effects of soil solarization, alone or with subsequent amendment with a Trichoderma asperellum biocontrol agent, on the survival of Phytophthora spp. inoculum. In field trials conducted with Phytophthora ramorum in San Rafael, CA and with P. pini in Corvallis, OR, infested rhododendron leaf inoculum was buried at 5, 15, and 30 cm below the soil surface. Solarization for 2 or 4 weeks during summer 2012 eliminated recovery of Phytophthora spp. buried at all depths in California trial 1, at 5 and 15 cm in California trial 2, but only at 5 cm in Oregon. There was no significant reduction of Phytophthora spp. recovery after T. asperellum application. Although the population densities of the introduced T. asperellum at the 5-cm depth were often two- to fourfold higher in solarized compared with nonsolarized plots, they were not significantly different (P = 0.052). Soil solarization appears to be a promising technique for disinfesting the upper layer of soil in container nurseries under certain conditions.

}, issn = {0191-2917}, doi = {10.1094/PDIS-04-15-0453-RE}, url = {http://apsjournals.apsnet.org/doi/10.1094/PDIS-04-15-0453-RE}, author = {Funahashi, F. and Parke, J. L.} } @article {4364, title = {Phytophthora heveae, a pathogen of kauri}, journal = {New Zealand Journal of Forestry Science}, volume = {4}, year = {1974}, pages = {59-63}, author = {Gadgil, P.D.} } @article {4235, title = {Real-time PCR assay to distinguish Phytophthora ramorum lineages using the cellulose binding elicitor lectin (CBEL) locus}, journal = {Canadian Journal of Plant Pathology}, volume = {36}, year = {2014}, month = {Mar-07-2014}, pages = {367 - 376}, abstract = {

Phytophthora ramorum is a pathogenic oomycete that causes sudden oak death in the Western USA and sudden larch death in the UK. Until recently, three genetically divergent clonal lineages of P. ramorum were known (EU1, NA1 and NA2), named according to the continent on which they were first detected. In 2009, a fourth lineage named EU2 was discovered in the UK. Sequencing and microsatellite genotyping revealed that the EU2 lineage is genetically distinct from all other lineages. Allele-specific oligonucleotide-PCR (ASO-PCR) assays using real-time PCR were developed in this study, allowing for the identification of the EU2 lineage. Also, a combination of ASO-PCR assays targeting the cellulose binding elicitor lectin (CBEL) locus was validated to rapidly identify all four lineages. Sequencing of the CBEL locus revealed eight single nucleotide polymorphisms (SNPs) that distinguished EU2 from the other three lineages. Two ASO-PCR assays were developed from these SNPs, providing the ability to rapidly identify EU2 individuals relative to EU1, NA1 and NA2 individuals. These new assays were combined with two existing assays targeting the same locus to allow rapid and simple identification of all four lineages. Blind tests performed on a panel of representative samples revealed diagnostic profiles unique to each lineage. These markers can be used with diseased field samples, making them well suited for routine procedures in diagnostic laboratories to identify P. ramorum.

}, issn = {0706-0661}, doi = {10.1080/07060661.2014.924999}, url = {http://www.tandfonline.com/doi/abs/10.1080/07060661.2014.924999}, author = {Gagnon, Marie-Claude and Bergeron, Marie-Jos{\'e}e and Hamelin, Richard C. and Gr{\"u}nwald, Niklaus J. and Bilodeau, Guillaume J.} } @book {1307, title = {Phytophthora: identifying species by morphology and DNA fingerprints}, year = {2008}, pages = {158}, publisher = {American Phytopathological Society (APS Press)}, organization = {American Phytopathological Society (APS Press)}, address = {St. Paul, MN}, abstract = {

This book presents morphological (chapter 1) and DNA fingerprint (chapter 2) keys to various Phytophthora species, as well as a section that combines morphological details and DNA fingerprints for 59 Phytophthora species (chapter 3). Tabulated data on host range and geographic origin are included.

}, issn = {978-0-89054-364-1}, author = {Gallegly, M. E. and Hong, Chuanxue} } @article {EFP:EFP17, title = {Etiology of oak decline in Spain}, journal = {European Journal of Forest Pathology}, volume = {29}, number = {1}, year = {1999}, pages = {17{\textendash}27}, publisher = {Blackwell Publishing Ltd}, abstract = {

In different areas of Extremadura, Western Spain, soil samples were taken at the bottom of holm oak (Quercus ilex) trees that were showing decline symptoms. Half of each sample was sterilized, and acorns were sown in both sterilized and nonsterilized soil samples. The resulting seedlings were used as baits for the isolation of fungi. Seedlings growing on the natural, nonsterilized substrate were characterized by having a lower vegetative growth than the ones growing on the sterilized soil samples, and most of them died. Phytophthora cinnnamomi was consistently isolated from their roots. Fusarium oxysporum was also isolated as well as different species of Pythium, although to a lesser extent. Pathogenicity tests were performed on holm oak seedlings with five different isolates of P. cinnamomi, with F. oxysporum, Pythium and with a mixture of the three fungi. All the inoculated seedlings with P. cinnamomi developed root rot and grew slowly, and 35.7\% of them died up to the end of the experiments. P. cinnamomi was consistently isolated from their roots, indicating that this fungus is the causal agent of holm oak decline. However, F. oxysporum caused similar symptoms on oak seedlings as P. cinnamomi, and was isolated also from the roots, although its frequency was lower than that of P. cinnamomi.

}, issn = {1439-0329}, doi = {10.1046/j.1439-0329.1999.00128.x}, url = {http://dx.doi.org/10.1046/j.1439-0329.1999.00128.x}, author = {Gallego, F. J. and Perez de Algaba, A. and Fernandez-Escobar, R.} } @article {4333, title = {Management of red needle cast, caused by Phytophthora pluvialis, a new disease of radiata pine in New Zealand}, journal = {New Zealand Plant Protection}, volume = {67}, year = {2014}, pages = {48{\textendash}53}, abstract = {

Ten years ago there were no known foliar diseases caused by Phytophthora on pine trees worldwide. Since then two significant Phytophthora diseases have emerged on radiata pine, one of which is only known in New Zealand. Red needle cast is a disease caused by the pathogen Phytophthora pluvialis, which is thought to have originated from northwestern USA. This paper reviews the challenges the New Zealand forestry industry faces when dealing with this disease and evaluates the management options, such as chemical control, biological control and breeding programmes, being investigated to minimise its effect on forest productivity. The distribution of the pathogen in New Zealand and research that shows bark, logs and wood are free of the pathogen, therefore unlikely to pose biosecurity threats through trade in these products, are also outlined.

}, issn = {1175-9003 (print), 1179-352X (online)}, url = {http://www.nzpps.org/nzpp_abstract.php?paper=670480}, author = {Ganley, R.J. and Williams, N.M. and Rolando, C.A. and Hood, I.A. and Dungey, H.S. and Beets, P.N. and Bulman, L.S.} } @article {PPA:PPA1894, title = {Efficacy of phosphonic acid, metalaxyl-M and copper hydroxide against Phytophthora ramorum in vitro and in planta}, journal = {Plant Pathology}, volume = {58}, number = {1}, year = {2009}, pages = {111{\textendash}119}, publisher = {Blackwell Publishing Ltd}, abstract = {

The ability of metalaxyl-M, phosphonic acid in the form of phosphonate, and copper hydroxide to inhibit different stages in the life cycle of Phytophthora ramorum, the causal agent of sudden oak death (SOD), was tested in vitro using 12 isolates from the North American forest lineage. In addition, experiments were conducted in planta to study the ability of phosphonic acid injections and metalaxyl-M drenches to control pathogen growth on saplings of California coast live oak (Quercus agrifolia), and of copper hydroxide foliar sprays to control infection of California bay laurel (Umbellularia californica) leaves. Phytophthora ramorum was only moderately sensitive to phosphonic acid in vitro, but was highly sensitive to copper hydroxide. In planta experiments indicated the broad efficacy of phosphonic acid injections and of copper hydroxide sprays in preventing growth of P. ramorum in oaks and bay laurels, respectively. Finally, although metalaxyl-M was effective in vitro, drenches of potted oak trees using this active ingredient were largely ineffective in reducing the growth rate of the pathogen in planta.

}, keywords = {disease management, phenotypic variability, Quercus agrifolia, Sudden oak death, Umbellularia californica}, issn = {1365-3059}, doi = {10.1111/j.1365-3059.2008.01894.x}, url = {http://dx.doi.org/10.1111/j.1365-3059.2008.01894.x}, author = {Garbelotto, M. and Harnik, T. Y. and Schmidt, D. J.} } @article {4709, title = {First reports of Phytophthora ramorum clonal lineages NA1 and EU1 causing Sudden Oak Death on tanoaks in Del Norte County, California}, journal = {Plant Disease}, year = {2021}, month = {Jan-18-2021}, abstract = {

A year of forest health surveys has led to the first detection of Phytophthora ramorum in Del Norte County followed by the first wildland detection of the EU1 clonal lineage (Grunwald et al. 2009) of this pathogen in California. In July 2019, leaves were sampled from two tanoaks (Notholithocarpus densiflorus) and 16 California bay laurels (Umbellularia californica) in Jedediah Smith State Park in Del Norte County, the northernmost coastal County of California. Leaves displayed lesions normally associated with Sudden Oak Death (SOD) caused by P. ramorum and were discovered during the citizen science-based survey known as SOD Blitz (Meentemeyer et al. 2015). Samples were surface sterilized using 75\% Ethanol and plated on PARPH-V8 agar (Jeffers and Martin 1986). After plating, DNA was extracted and amplified using two P. ramorum-specific assays (Hayden et al. 2006, Kroon et al. 2004). Leaves from two tanoaks exhibiting twig die-back had typical SOD lesions along the midvein, gave positive PCR results and yielded cultures with colony morphology, sporangia and chlamydospores typical of the NA1 lineage of P. ramorum originally isolated in California from tanoaks and coast live oaks (Quercus agrifolia) (Rizzo et al. 2002). The ITS locus and a portion of the Cox-1 locus were sequenced from DNA extracts of each culture using primers DC6-ITS4 (Bonants et al. 2004) and COXF4N-COXR4N (Kroon et al. 2004), respectively. ITS sequences (GB MN540639-40) were typical of P. ramorum and Cox-1 sequences (GB MN540142-3) perfectly matched the Cox-1 sequence of the NA1 lineage (GB DQ832718) (Kroon et al. 2004). Microsatellite alleles were generated as described in Croucher et al. (2013) for the two Del Norte cultures and for eight P. ramorum cultures, representative of the four main multilocus genotypes (MLGs) present in California, namely c1 (Santa Cruz/Commercial Nurseries), c3 (San Francisco Bay Area), c2 (Monterey County), and c4 (Humboldt County) (Croucher et al. 2013). The two Del Norte MLGs were identical to one another and most similar to MLG c1, with a single repeat difference at a single locus. SSR results suggest the inoculum source may not be from Humboldt County, neighboring to the South, but from a yet unidentified outbreak, possibly associated with ornamental plants. Jedediah Smith State Park was surveyed for 12 months following the initial detection, however the pathogen has yet to be re-isolated in that location. In July 2020, SOD symptomatic leaves from two tanoak trees exhibiting twig cankers were collected 8 Km north of Jedediah Smith State Park, where three additional tanoak trees displayed rapidly browned dead canopies consistent with late stage SOD. Leaves were processed as above. Colonies from these samples produced chlamydospores and sporangia typical of P. ramorum on PARPH-V8 agar, but displayed a growth rate faster than that of NA1 genotypes and were characterized by aerial hyphae, overall resembling the morphology of EU1 lineage colonies (Brasier 2003). The EU1 lineage was confirmed by the perfect match of the sequence of a portion of the Cox-1 gene (GB MW349116-7) with the Cox-1 sequence of EU1 genotypes (GB EU124926). The EU1 clonal lineage has been previously isolated from tanoaks in Oregon forests, approximately 55 Km to the North (Gr{\"u}nwald et al. 2016), but this is the first report for California wildlands and will require containment and government regulations. It is unknown whether the EU1 strains in Del Norte County originated from Oregon forests or elsewhere.

}, issn = {0191-2917}, doi = {10.1094/PDIS-12-20-2633-PDN}, url = {https://apsjournals.apsnet.org/doi/10.1094/PDIS-12-20-2633-PDN}, author = {Garbelotto, Matteo and Dovana, Francesco and Schmidt, Douglas and Chee, Cameron and Lee, Chris and Fieland, Valerie and {\"u}nwald, Niklaus J. and Valachovic, Yana} } @article {952, title = {Phosphonate controls sudden oak death pathogen for up to 2 years.}, journal = {California Agriculture}, volume = {63}, year = {2009}, pages = {10-17}, abstract = {

Since its emergence in the late 1990s, sudden oak death has killed mature oak trees and tanoaks in 14 California counties. Treatment options are now available to safeguard these trees from infection by Phytophthora ramorum, the aggressive and exotic pathogen responsible for sudden oak death. We provide an update on current knowledge regarding this emergent disease in California, and present results from three controlled experiments of two chemical treatments to manage the disease in oaks and tanoaks. Phosphonate treatments, legally registered in California to control sudden oak death, were effective in slowing both infection and growth rates for at least 18 months. Conversely, an alternative method consisting of an azomite soil amendment and bark lime wash was always ineffective, and did not reduce either growth or infection rates.

}, doi = {10.3733/ca.v063n01p10}, url = {http://ucanr.org/repository/cao/landingpage.cfm?article=ca.v063n01p10\&fulltext=yes$\#$}, author = {Matteo M. Garbelotto and Douglas J. Schmidt} } @article {4704, title = {Pathogenicity and infectivity of Phytophthora ramorum vary depending on host species, infected plant part, inoculum potential, pathogen genotype, and temperature}, journal = {Plant Pathology}, volume = {70}, year = {2021}, month = {Oct-19-2020}, pages = {287 - 304}, abstract = {

A total of 25 ornamental plant species representing 10 families were inoculated using three genotypes, each representing one of the genetic lineages NA1, NA2, and EU1 of the pathogen Phytophthora ramorum. Leaves were inoculated using suspensions with two zoospore concentrations and exposure at three temperatures, while stems were inoculated using agar plugs colonized by mycelia. Susceptibility was determined by measuring either the success of pathogen reisolation or lesion length caused by the pathogen. Infectivity was determined by counting sporangia in washes of inoculated leaves or stems. Results from all three pathogen genotypes combined were used to rank each of the 25 plant species for susceptibility and infectivity, while pooled results per genotype from all 25 hosts combined were employed for a preliminary comparison of pathogenicity and infectivity among genotypes. Statistical analyses showed that leaf results were affected by the concentration of zoospores, temperature, plant host, pathogen genotype, and by the interaction between host and pathogen genotype. Stem results were mostly affected by host and by the interaction between host and pathogen genotype. Hosts ranked differently when looking at the various parameters, and differences in rankings were also significant when comparing stem and leaf results. Differences were identified among the 25 hosts and the three pathogen genotypes for all parameters: results can be used for decision-making regarding regulations or selection of plants to be grown where infestations by P. ramorum are an issue.

}, issn = {0032-0862}, doi = {10.1111/ppa.v70.210.1111/ppa.13297}, url = {https://bsppjournals.onlinelibrary.wiley.com/doi/10.1111/ppa.13297}, author = {Garbelotto, Matteo and Schmidt, Doug and Popenuck, Tina} } @article {623, title = {Non-oak native plants are main hosts for sudden oak death pathogen in California.}, journal = {Cal Ag}, volume = {57}, year = {2003}, pages = {18-23}, abstract = {

The finding of Phytophthora ramorum {\textemdash} the pathogen that causes sudden oak death in four California native trees {\textemdash} on rhododendron in Europe led us to hypothesize that its host range in California{\textquoteright}s natural forests was much greater than previously suspected. In addition to the affected oak species, we have now identified an additional 13 species from 10 plant families that act as hosts for P. ramorum in California. Our data indicates that nearly all of the state{\textquoteright}s main tree species in mixed-evergreen and redwood-tanoak forests {\textemdash} including the coniferous timber species coast redwood and Douglas fir {\textemdash} may be hosts for P. ramorum. The broad host range of P. ramorum, the variability of symptoms among different hosts and the ability of the pathogen to disperse by air suggests that it may have the potential to cause long-term, landscape-level changes in California forests.

}, doi = {10.3733/ca.v057n01p18}, url = {http://ucanr.org/repository/cao/landingpage.cfm?article=ca.v057n01p18\&abstract=yes}, author = {Garbelotto, M. and Davidson, J. and K. Ivors and Maloney, P. and H{\"u}berli, D. and Koike, S. and Rizzo, D.} } @article {4197, title = {Sudden Oak Death: Interactions of the Exotic Oomycete Phytophthora ramorum with Na{\"\i}ve North American Hosts}, journal = {Eukaryotic Cell}, volume = {11}, year = {2012}, pages = {1313-1323}, abstract = {

Ten years after a threatening and previously unknown disease of oaks and tanoaks appeared in coastal California, a significant amount of progress has been made toward the understanding of its causal agent Phytophthora ramorum and of the novel pathosystems associated with this exotic organism. However, a complete understanding of the ecology and epidemiology of this species still eludes us. In part, our inability to fully understand this organism is due to its phylogenetic, phylogeographic, phenotypic, and epidemiological complexities, all reviewed in this paper. Most lines of evidence suggest that the high degree of disease severity reported in California is not simply due to a generalized lack of resistance or tolerance in na{\"\i}ve hosts but also to an innate ability of the pathogen to survive in unfavorable climatic conditions and to reproduce rapidly when conditions become once again favorable.

}, doi = {10.1128/EC.00195-12}, url = {http://ec.asm.org/content/11/11/1313.abstract}, author = {Garbelotto, Matteo and Hayden, Katherine J.} } @article {doi:10.1094/PD-90-0685C, title = {First report on an infestation of Phytophthora cinnamomi in natural oak woodlands of California and its differential impact on two native oak species}, journal = {Plant Disease}, volume = {90}, number = {5}, year = {2006}, pages = {685-685}, doi = {10.1094/PD-90-0685C}, url = {http://apsjournals.apsnet.org/doi/abs/10.1094/PD-90-0685C}, author = {Garbelotto, M. and Huberli, D. and Shaw, D.} } @article {Garbelotto21092012, title = {Sudden Oak Death: interactions of the exotic oomycete Phytophthora ramorum with na{\"\i}ve North American hosts}, journal = {Eukaryotic Cell}, volume = {Early release}, year = {2012}, abstract = {

Ten years after a threatening and previously unknown disease of oaks and tanoaks appeared in coastal California, a significant amount of progress has been made towards the understanding of its causal agent Phytophthora ramorum and of the novel pathosystems associated with this exotic organism. However, a complete understanding of the ecology and epidemiology of this species still eludes us. In part, our inability to fully understand this organism is due to its phylogenetic, phylogeographic, phenotypic, and epidemiological complexity, all reviewed in this paper. Most lines of evidence suggest the high disease severity reported in California is not simply due to a generalized lack of resistance or tolerance in na{\"{\i}ve hosts, but also to an innate ability of the pathogen to survive in unfavorable climatic conditions and to reproduce rapidly when conditions become once again favorable.

}, doi = {10.1128/EC.00195-12}, url = {http://ec.asm.org/content/early/2012/09/18/EC.00195-12.abstract}, author = {Garbelotto, Matteo and Katherine J. Hayden} } @article {4365, title = {Susceptibility of New Zealand flora to Phytophthora kernoviae and its seasonal variability in the field}, journal = {New Zealand Journal of Forestry Science}, volume = {45}, year = {2015}, month = {12 November 2015}, chapter = {23}, abstract = {

Background

The oomycete Phytophthora kernoviae is known from the United Kingdom and the Republic of Ireland, where it is considered to be a recent invader, from Chile where it was only discovered in 2014, and New Zealand where records date back to 1953. As there is little information in New Zealand linking P. kernoviae with plant disease, it may have been present for much longer and may be indigenous. Seasonal activity of P. kernoviae in a site known to have infested soil was tested by isolation from soil and foliage of existing shrubs and the use of indicator plants. In greenhouse studies, the susceptibility of a range of indigenous plants to P. kernoviae was tested via stem and foliar inoculation.

Methods

Soil, litter and understorey vegetation samples were collected for isolation of P. kernoviae at monthly intervals for a year. Plants of Rhododendron catawbiense, which is known to be susceptible to foliar and shoot infection, were placed in the stand as indicator species. In laboratory and greenhouse studies, stem and foliar inoculations of a selection of arborescent plants representing major groups within the New Zealand flora were carried out and compared with three exotic plants of known susceptibility.

Results

Phytophthora kernoviae was not isolated from foliage of understorey plants at the study site, but it was recovered from soil and litter from April to November (autumn through spring) inclusive. Little disease developed on the Rhododendron catawbiense indicator plants.

All of the exotic, and most of the indigenous, species developed a lesion in response to stem inoculation. Stem lesions were more developed on exotic species than on indigenous hosts. In contrast, few species formed foliar symptoms. Phytophthora kernoviae was recovered from asymptomatic tissue, stems and foliage, of a number of species.

Conclusions

Based on the results of the inoculations and the lack of historical records of disease of indigenous plants associated with P. kernoviae, this oomycete does not appear to be a damaging pathogen of New Zealand{\textquoteright}s indigenous flora. Although presence in the soil or litter was demonstrated at the study site, little disease developed on the indicator plants suggesting that at least part of the New Zealand population is of low pathogenicity to R. catawbiense.

}, doi = {10.1186/s40490-015-0050-y}, url = {http://www.nzjforestryscience.com/content/45/1/23}, author = {Gardner, Judy Frances and Dick, Margaret Anne and Bader, Martin Karl-Friedrich} } @article {4377, title = {First Report of Collar and Root Rot Caused by Phytophthora tentaculata on Witloof Chicory (Cichorium intybus ) in Italy}, journal = {Plant Disease}, volume = {94}, year = {2010}, month = {Jan-12-2010}, pages = {1504 - 1504}, abstract = {

Witloof chicory (Cichorium intybus L.) is an important crop in Italy where most of the crop is still produced in soil. In September 2009, chicory plants (cv. Pan di Zucchero) grown on a commercial farm in Tarquinia (central Italy) showed symptoms of a previously unknown disease. Symptoms, observed 20 days after transplanting, consisted of stunting, yellowing of leaves, and a crown and root rot. Affected plants turned brown, wilted, and eventually died. At the soil level, dark brown-to-black water-soaked lesions coalesced and often girdled the stem. All of the crown and root system was affected. At this location, the disease was severe and widespread, with 60\% of observed plants being affected. A Phytophthora-like organism was consistently isolated on a medium selective for oomycetes (4) after disinfestation of lower stem and root pieces of C. intybus for 1 min in a solution containing 1\% NaOCl. Tissue fragments of 1 mm2 were excised from the margins of the root and crown lesions. The pathogen genus was identified as Phytophthora based on morphological and physiological features. Sporangia were produced for identification by growing a pure culture for 15 days on modified V8 juice agar medium (Campbell V8 juice [200 ml], agar [15 g], CaCo3 [0.5 g], and sterile water [800 ml]) under alternating light and dark (12/12 h). Sporangia were pyriform to ovoid, papillate, and measured 33.3 to 59.2 {\texttimes} 18.9 to 30.2 μm (average 39.9 {\texttimes} 25.8 μm). Chlamydospores developed in 28-day-old cultures and measured 21.3 to 30.2 {\texttimes} 19.5 to 29.7 μm (average 24.4 {\texttimes} 23.6 μm). Oogonia were globose and measured 26 to 41 μm (average 32.5 μm). Eighty percent of antheridia were paragynous. Amphyginous antheridia (15 to 20\%) were also observed. Oospores were scarcely produced and measured 24 to 32 μm in diameter. The internal transcribed spacer (ITS) region of rDNA of a single isolate was amplified using the primers ITS4/ITS6 and sequenced. BLAST analysis (1) of the 851-bp segment showed 100\% homology with the sequence of Phytophthora tentaculata. The nucleotide sequence has been assigned GenBank Accession No. GU949536. Pathogenicity of this isolate was confirmed by inoculating C. intybus cv. Pan di Zucchero plants 20 days after transplant. The same isolate was grown for 15 days on a mixture of 70:30 wheat/hemp kernels and then 5 g/liter of the inoculum was mixed into a substrate containing a mixture of blond and black peat (15:85 vol/vol), pH 5.5. Five plants per 2-liter pot were transplanted and four replicates were carried out. Twenty noninoculated plants represented the control treatment. The trial was repeated. Plants were kept in two growth chambers at two temperatures (20 and 25{\textdegree}C). Symptoms similar to those observed in the field developed 7 days after inoculation. Twenty days later, 100 and 40\% of the plants were dead at 25 and 20{\textdegree}C, respectively. Control plants remained symptomless. P. tentaculata was consistently reisolated from symptomatic plants. To our knowledge, this is the first report of P. tentaculata on C. intybus in the world (http://nt.ars-grin.gov/fungaldatabases/index.cfm). P. tentaculata was recently reported on lavender in Spain (2) and oregano in Italy (3). The economic importance of this disease is relatively low on most commercial farms.

}, issn = {0191-2917}, doi = {10.1094/PDIS-03-10-0206}, url = {http://apsjournals.apsnet.org/doi/abs/10.1094/PDIS-03-10-0206}, author = {Garibaldi, A. and Gilardi, G. and Gullino, M. L.} } @article {376, title = {Root disease of alder in Britain}, number = {25}, year = {1995}, pages = {661{\textendash}664}, doi = {doi: 10.1111/j.1365-2338.1995.tb01118.x/abstract}, url = {http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2338.1995.tb01118.x/abstract}, author = {Gibbs, J. N.} } @article {377, title = {The impact of Phytophthora disease on riparian populations of common alder (Alnus glutinosa) in southern Britain}, journal = {European Journal of Forest Pathology}, volume = {29}, year = {1999}, pages = {39{\textendash}50}, abstract = {

Summary In 1994 a survey was established to obtain information on Phytophthora disease of common alder (Alnus glutinosa) on the riverbanks of southern England and east Wales. Within an area of 70 000 km2 63 observation plots were set up on stretches of river over 8 m wide. Average alder densities varied widely in different parts of the survey area; from 0.7 to 22.2 trees per 100 m of river. From the density figures and data on the total length of rivers over 8 m wide within the survey area, it was estimated that there were approximately 585 000 alder trees growing on the banks of such rivers. In 1994 3.9\% of the trees showed crown symptoms of Phytophthora disease, and an additional 1.2\% of trees were dead, although not all of these had been killed by Phytophthora. The disease occurred widely through the survey area with an indication that the highest percentage of affected trees was to be found in the south-east of England. Subsequent surveys showed that the combined percentage of symptomatic and dead trees rose to 6.0\% in 1995 and to 7.9\% in 1996. In the latter year, for an alder population of 585 000 trees, this would correspond to 32 800 symptomatic and 13 500 dead trees. The percentage of trees showing symptoms was seven times as high in trees growing within 1 m of the riverbank as in trees growing between 1 and 10 m of the bank. An examination of the relationships between disease incidence and various indices of water pollution revealed a positive association with total oxidized nitrogen. These results are discussed in relation to the biology and possible origin of the disease.

}, doi = {10.1046/j.1439-0329.1999.00129.x}, url = {http://dx.doi.org/10.1046/j.1439-0329.1999.00129.x}, author = {Gibbs, J. N. and Lipscombe, M. A. and Peace, A. J.} } @article {4632, title = {PhytophthoraTaxon Pgchlamydo is a Cause of Shoot Blight and Root and Collar Rot of Viburnum tinus in Italy}, journal = {Plant Disease}, volume = {98}, year = {2014}, month = {Jan-10-2014}, pages = {1432 - 1432}, abstract = {

The quarantine pathogen Phytophthora ramorum has recently been found on dying Viburnum tinus in the nursery area of Pistoia, central Italy (43{\textdegree}56'0" N, 11{\textdegree}1'0" E) (3). As part of a surveillance program aimed at detecting P. ramorum in this area, the Phytophthora taxon Pgchlamydo was consistently found associated with symptomatic V. tinus. The crowns of these plants were wilted, and some plants also showed root and collar rot and underbark necrosis. Water courses adjacent to the nursery with the infected V. tinus were tested for the pathogen. Samples from seven symptomatic plants were placed on a selective V8A-PARPNH medium within 24 h from sampling. Tissue pieces (2 mm2) of 12 baits (apple fruits) exposed for a week in water bodies were plated on the same medium. Cottony colonies arose after 2 to 3 days of incubation at 23{\textdegree}C in the dark and were transferred to potato dextrose agar (PDA) in purity. Mycelial DNA was extracted with a commercial kit (Sigma-Aldrich). The rDNA ITS region and a portion of the mtDNA cox1 gene were PCR-amplified and the amplicons digested with the restriction enzymes MspI and AluI (for the ITS region) and RsaI (for the cox1 gene region). Isolates R7 from V. tinus, and ES2M5, ES2M11, and ES1M12 from the water bodies belonged to the same taxon based on restriction analysis of both DNA regions coupled with ITS-rDNA sequence homology (GenBank Accession Nos. KJ396773 to 76). A BLAST search in GenBank found that all isolates had a 99\% identity in the ITS-rDNA with the Phytophthora ITS Clade 6 member P. taxon Pgchlamydo. Sporangia produced after incubation in filtered pond water for 24 h were mostly ovoid (sometimes obpyriform), non-papillate, non-caducous. Some sporangia were emptied with external proliferation and had hyphal swellings. Thirty sporangia were measured and averaged 42.4 {\textpm} 6.2 {\texttimes} 29.9 {\textpm} 3.5 μm (range 30.0 to 56.1 {\texttimes} 22.5 to 38.0), with a length/width ratio of 1.4 {\textpm} 0.2 (1.2 to 2.0), and exit pores of 11.7 {\textpm} 1.5 μm (9.0 to 14.6). Optimum colony growth on V8A at 30{\textdegree}C was 4.4 {\textpm} 0.4 mm day{\textendash}1, and the maximum temperature for growth was 32{\textdegree}C. Inoculation on twigs of Fagus sylvatica and V. tinus produced necrotic lesions of 2.6 {\textpm} 0.5 cm (2.1 to 3.5) and 4.7{\textpm} 0.5 cm (3.8 to 5.6) respectively after 3 weeks of incubation at 23{\textdegree}C in the dark. Inoculation on V. tinus leaves resulted in lesions averaging 3.3 {\textpm} 1.1 {\texttimes} 2.1 {\textpm} 0.6 cm (range 2 to 5 {\texttimes} 1.5 to 3) after 2 weeks of incubation at 23{\textdegree}C in the dark. Control plant material showed no symptoms.The Phytophthora taxon Pgchlamydo has been reported on several ornamental and woody species, including Arctostaphylos sp., Camellia spp., Laurus nobilis, Buxus sempervirens, Rhododendron sp., Arbutus unedo, Prunus sp., Pseudotsuga sp., and Sequoia sempervirens, in North America and Europe (1,2). This is the first report, to our knowledge, of this taxon on V. tinus in Italy. V. tinus is widely sold in European nurseries, and it is also one of the most common hosts of P. ramorum (4). The fact that V. tinus is a host for both oomycetes, and the two microorganisms induce a similar symptomology (wilt), might complicate the control efforts of the phytosanitary inspection services aimed at restricting P. ramorum foci in Europe.

}, issn = {0191-2917}, doi = {10.1094/PDIS-03-14-0282-PDN}, url = {http://apsjournals.apsnet.org/doi/10.1094/PDIS-03-14-0282-PDN}, author = {Ginetti, B. and Carmignani, S. and Ragazzi, A. and Moricca, S.} } @article {4199, title = {Foliar Blight and Shoot Dieback Caused by Phytophthora ramorum on Viburnum tinus in the Pistoia Area, Tuscany, Central Italy}, journal = {Plant Disease}, volume = {98}, year = {2014}, month = {03/2014}, pages = {423 - 423}, abstract = {

In spring 2013, pot-grown Viburnum tinus plants shipped to an ornamental nursery in Pescia (Pistoia, central Italy, 287 m a.s.l., 43{\textdegree}54'0" N, 10{\textdegree}41'0" E) from another local nursery were found to bear disease symptoms. Symptoms included brown to black foliar lesions, later expanding into larger blotches; necrosis of the petioles; shoot wilting and folding; browning of the stems; and necrosis of the cambium. Infected leaves, shoots, and entire plants eventually died. Tissue samples (2 mm2) were cut at the edge of active lesions from tissue of the phloem, the xylem, and the leaves and plated on selective PARPNH V8 agar (V8A) (1). Rose-shaped and finely lobed cottony colonies arose in 2 to 3 days. Mono-hyphal colonies were isolated and transferred to V8A. Square colony pieces (1 cm2) from isolates SB05a and SB05b were placed in filtered pond water after 5 to 7 days. Semipapillate, caducous sporangia with a rounded or conical base were produced within 24 h, individually or in pairs, on each sporangiophore. Sporangia (n = 30 per isolate) were examined: they were 56.2 {\textpm} 9.5 {\texttimes} 29.3 {\textpm} 4.3 μm (l:b ratio 1.9 {\textpm} 0.3). Exit pores averaged 7.0 {\textpm} 1.0 μm. Sporangia were ellipsoid (30\%), lemon-shaped (28.3\%), ovoid (20\%), obovoid (16.7\%), ampulliform (3.3\%), or {\textquotedblleft}peanut-like{\textquotedblright} (1.7\%). Globose chlamydospores, borne intercalarly or terminally, were abundant on both V8A and carrot agar (CA), and were on average 54.7 {\textpm} 8.5 μm. Mono-hyphal isolates incubated for 7 days at 23{\textdegree}C were also transferred to CA, corn meal agar (CMA), malt extract agar (MEA), potato dextrose agar (PDA), and V8A. Colonies on these media were identical in shape and appearance to those described in previous reports (2,4). Isolates were identified as Phytophthora ramorum Werres, De Cock \& Man in{\textquoteright}t Veld (4) on the basis of colony type; size, the average l:b ratio and shape of sporangia; and the type and size of the chlamydospores. Isolates were found to be the A1 mating type by pairing them with P. cryptogea BBA 63651 (mating type A2). PCR-amplification of the rDNA ITS region with specific primers Ph1/Ph4 (3) gave fragments of the expected size (GenBank Accession Nos. KF181162 and KF181163). A BLAST search of these ITS sequences in the database found that isolates of P. ramorum were the closest phylogenetically with 100\% homology (YQ653034 and HM004221). Pathogenicity tests were conducted on 16 detached V. tinus leaves. A small cut was made aseptically on each of the leaf surfaces and a V8A disc (0.5 cm {\O}) with mycelium was placed over the wounds. Control leaves received only sterile V8A discs. Inoculated and control leaves were incubated at 23{\textdegree}C in the dark. Necrotic areas (average 3.5 {\textpm} 1.3 cm2) arose on inoculated leaves after 6 days. Control leaves had no symptoms. Re-isolations on PARPNH V8A confirmed P. ramorum as the causal agent. P. ramorum was reported in Italy in 2003 on the exotic Rhododendron yakushimanum (2). This is the first report of the pathogen on a native species (V. tinus) in this country. The Pistoia area is important for nursery gardens and flowers. P. ramorum, which probably arrived on infected plant material, could compromise the export/import trade in stock plants. For this reason, the plant protection services were promptly alerted and the infected plants were destroyed.

}, issn = {0191-2917}, doi = {10.1094/PDIS-07-13-0767-PDN}, url = {http://apsjournals.apsnet.org/doi/abs/10.1094/PDIS-07-13-0767-PDN}, author = {Ginetti, B. and Carmignani, S. and Ragazzi, A. and Werres, S. and Moricca, S.} } @article {4067, title = {First Report of Phytophthora Taxon Walnut in Lombardy, North Italy}, journal = {Plant Disease}, volume = {98}, year = {2013}, month = {03/2014}, pages = {424}, abstract = {

The park Boscoincitt{\`a}, Milan, North Italy (136 m a.s.l., 45{\textordmasculine} 29{\textquoteright} 06" N, 9{\textordmasculine} 5{\textquoteright} 32" E) has an area of 110 hectares and includes tree stands, wood clearings, trails and watercourses. Recently, common walnut (Jugland regia) trees in the park have begun to suffer from a progressive dieback that has caused roughly 90\% mortality. Aerial symptoms were: stunted growth, loss of vigor, crown thinning and bark cankers with tarry exudates on the lower stem. The xylem tissue of trees showed large necrosis and flame-shaped discolouration below the bark. Since the dieback seemed caused by Phytophthora, samples were taken from 3 symptomatic trees and, by baiting, from the nearby soil and watercourses. Isolations from apple baits were carried out after a week. Isolations taken from tissue at the edge of active lesions of the trees were transferred on the selective medium V8A-PARPNH (1) and incubated at 24{\textordmasculine}C. Cottony colonies appeared after 3 days and single hyphal tip derivatives were transferred to V8A for a further 4-7 days. Fragments (1 cm2) of mycelium of the subcultured colonies were then placed in filtered ({\O} 0.22 μm nitrocellulose filters, Millipore) pond water. Three isolates were retrieved within 24 h, 2 from tree tissue and one from water. These produced ovoid, non-papillate sporangia (Fig A), thirty of which per isolate were measured. Sporangia averaged 52.5 {\textpm} 9.6 x 32.9 {\textpm} 4.7 {\textmu}m (range 30.8 {\textendash} 67 x 22.5 {\textendash} 42.8) with a l:b ratio of 1.59 {\textpm} 0.19 (range 1.27 {\textendash} 2.05), and exit pores of 11.1 {\textpm} 1.7 {\textmu}m (range 7.31 {\textendash} 14.21). External proliferation from previously emptied sporangia and hyphal swellings were observed on V8A. On V8A, colonies had optimal growth at 32{\textdegree}C (5.7 {\textpm} 0.8 mm d-1) with a maximum at 37{\textdegree}C. Colonies had a chrysanthemum-shaped, scanty fluffy aspect on PDA (Fig B). Isolates were identified as Phytophthora taxon walnut on the basis of macro- and micro-morphology and sequence information from the ITS-rDNA region, that was amplified with primers ITS6 and ITS4 (2) after DNA extraction with a commercial kit (Sigma Aldrich). A region of the cox1 gene of isolate B164 was also amplified with primers OomCoxILevup and Fm85mod (3) and sequenced (GenBank acc. no. KC291584) but this was irrelevant for identification purposes because that gene region has not been sequenced for other isolates of this taxon. A BLAST search in GenBank and the Phytophthora database revealed a 99\% identity of the ITS-rDNA from our isolate B164 (GenBank acc. no. KC291550) with the P. taxon walnut isolate P532 (AF541910) (4). Inoculation trials were conducted on 10 detached leaves. A little lesion was produced with a sterile scalpel on the lower leaf surfaces and a 0.5 cm {\O} agar plug was placed over the wounds. Necrotic lesions averaged 3.7{\textpm}1.6 x 2.0{\textpm}0.5 cm after 1 week of incubation at 20{\textdegree}C in the dark (Fig C). Control leaves showed no symptoms. Reisolations on V8-PARPNH agar confirmed P. taxon walnut as the causal agent. Members of the Phytophthora genus grouping with the P. taxon walnut in clade 6 are mainly reported as saprophytes or pathogens from riparian ecosystems and forests (4). This is the first report of P. taxon walnut from Italy. Since the oomycete proved in our growth trial to be distinctly thermophilic, we hypothesize that its spread is being favored by the rising temperatures observed during the last decades in the area.

}, issn = {0191-2917}, doi = {10.1094/PDIS-07-13-0766-PDN}, url = {http://dx.doi.org/10.1094/PDIS-07-13-0766-PDN }, author = {Ginetti, Beatrice and Ragazzi, Alessandro and Moricca, Salvatore} } @article {4191, title = {Phytophthora acerina sp. nov., a new species causing bleeding cankers and dieback of Acer pseudoplatanus trees in planted forests in northern Italy}, journal = {Plant Pathology}, volume = {63}, year = {2013}, month = {08/2014}, pages = {858{\textendash}876}, abstract = {

A severe dieback of Acer pseudoplatanus trees was noticed in planted forest stands in northern Italy in 2010. Affected trees showed collar rot and aerial bleeding cankers along the stems, leading to crown dieback and eventually death. An unknown Phytophthora species was consistently isolated from necrotic bark and xylem tissue and from rhizosphere soil. Based on its unique combination of morphological and physiological characters and phylogenetic analysis, this new taxon is here described as Phytophthora acerina sp. nov. Phylogenetic analysis of ITS, cox1 and β-tubulin gene regions demonstrated that P. acerina is unique and forms a separate cluster within the {\textquoteleft}P.\ citricola complex{\textquoteright}, closely related to P.\ plurivora. Phytophthora acerina is homothallic with smooth-walled oogonia, thick-walled, mostly aplerotic oospores with a high abortion rate, paragynous antheridia, and persistent, morphologically variable semipapillate sporangia. Four to 5-week-old cultures produced globose to subglobose, appressoria-like and coralloid hyphal swellings and characteristic stromata-like hyphal aggregations. Optimum and maximum temperatures for growth are 25{\textdegree}C and 32{\textdegree}C, respectively. Genetic uniformity of all 15 studied isolates and the apparent absence of this species in the extensive surveys of nurseries, forests and seminatural ecosystems conducted in the previous two decades across Europe indicate a recent clonal introduction to northern Italy. Under-bark inoculation tests demonstrated high aggressiveness of P.\ acerina to A.\ pseudoplatanus indicating that this pathogen might be a serious risk to maple plantations and forests in Europe.

}, keywords = {biosecurity, Clade 2, invasive, nursery pathway, phylogeny, Phytophthora citricola}, issn = {1365-3059}, doi = {10.1111/ppa.12153}, url = {http://dx.doi.org/10.1111/ppa.12153}, author = {Ginetti, B. and Moricca, S. and Squires, J. N. and Cooke, D. E. L. and Ragazzi, A. and Jung, T.} } @article {1304, title = {Sudden oak death caused by Phytophthora ramorum in Oregon}, journal = {Plant Disease}, volume = {86}, year = {2002}, month = {04/2002}, chapter = {441}, abstract = {

Sudden oak death, caused by Phytophthora ramorum (1,2), has been found for the first time in Oregon, killing tanoak, Lithocarpus densiflorus, trees. To our knowledge, this is the first report of the disease outside of the San Francisco to Monterey area in California, (300 km to the south). Nine areas of infestation, all within a 24-km2 area, were discovered on forest lands near Brookings, in southwest Oregon. Mortality centers ranged in size from 0.2 to 4.5 ha and included 5 to approximately 40 diseased trees. P. ramorum was isolated from stem cankers using Phytophthora-selective medium. Isolates had distinctive morphological features characteristic of P. ramorum, including abundant production of chlamydospores and caducous, semipapillate sporangia on solid media. Internal transcribed spacer (ITS) sequences of isolates of P. ramorum from Oregon were identical to ITS sequences of isolates from California (1). The pathogen also was isolated from necrotic lesions on leaves and stems of native Rhododendron macrophyllum and Vaccinium ovatum growing beneath diseased tanoaks. In July 2001, the disease was located by an aerial survey conducted cooperatively by the USDA Forest Service and Oregon Department of Forestry. All lands within 1.6 km (1 mile) of the mortality centers are subject to Oregon quarantine, which bars the transport of any host plant materials. An eradication effort is currently underway. Symptomatic plants and all known host plants within 15 to 30 m of symptomatic plants are being cut and burned in the first phase of this operation. The total treated area is approximately 16 ha.

}, doi = {10.1094/PDIS.2002.86.4.441C}, url = {http://dx.doi.org/10.1094/PDIS.2002.86.4.441C}, author = {Goheen, E. M. and Hansen, E.M. and Kanaskie, A. and McWilliams, M.G. and Osterbauer, N. and Sutton, W.} } @proceedings {3953, title = {Proceedings of the fourth meeting of the International Union of Forest Research Organizations (IUFRO) Working Party 07.02.09}, year = {2007}, pages = {334 p}, publisher = {U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station}, address = {Monterey, California}, abstract = {

The fourth meeting of the International Union of Forest Research Organizations (IUFRO) Working Party S07.02.09, Phytophthoras in Forests and Natural Ecosystems provided a forum for current research on Phytophthora species worldwide. Seventy-eight submissions describing papers and posters on recent developments in Phytophthora diseases of trees and natural ecosystems in Europe, Australasia, and the Americas are included. Research topics covered are Phytophthora biodiversity, ecology, epidemiology, management, and host- pathogen interactions.

}, url = {http://www.iufro.org/science/divisions/division-7/70000/70200/70209/}, author = {Goheen, E. M. and Frankel, S.J. and Goheen, E. M. and Frankel, S.J.} } @article {4240, title = {Histopathology of infection and colonization of Quercus ilex fine roots by Phytophthora cinnamomi}, journal = {Plant Pathology}, year = {2014}, month = {11/2014}, pages = {605{\textendash}616}, abstract = {

Quercus ilex is one of the European forest species most susceptible to root rot caused by the oomycete Phytophthora cinnamomi. This disease contributes to holm oak decline, a particularly serious problem in the {\textquoteleft}dehesas{\textquoteright} ecosystem of the southwestern Iberian Peninsula. This work describes the host{\textendash}pathogen interaction of Q.\ ilex and P.\ cinnamomi, using new infection indices at the tissue level. Fine roots of 6-month-old saplings inoculated with P.\ cinnamomi were examined by light microscopy and a random pool of images was analysed in order to calculate different indices based on the measured area of pathogen structures. In the early stages of invasion, P.\ cinnamomi colonizes the apoplast and penetrates cortical cells with somatic structures. On reaching the parenchymatous tissues of the central cylinder, the pathogen develops different reproductive and survival structures inside the cells and then expands through the vascular system of the root. Some host responses were identified, such as cell wall thickening, accumulation of phenolic compounds in the middle lamella of sclerenchyma tissues, and mucilage secretion blocking vascular cells. New insights into the behaviour of P.\ cinnamomi inside fine roots are described. Host responses fail due to rapid expansion of the pathogen and a change in its behaviour from biotrophic to necrotrophic.

}, doi = {10.1111/ppa.12310}, url = {http://doi.wiley.com/10.1111/ppa.12310}, author = {G{\'o}mez, F. J. and Navarro-Cerrillo, R. M. and S{\'a}nchez-Cuesta, R. and P{\'e}rez-de-Luque, A.} } @article {4558, title = {Two Phytophthora species causing decline of wild olive (Olea europaea subsp. europaea var. sylvestris )}, journal = {Plant Pathology}, year = {2016}, month = {Nov-2016}, abstract = {

Since 2009, a severe decline leading to mortality has been observed affecting nearly 5\ ha of a wild olive woodland of high ecological value in Seville, southern Spain. Phytophthora cryptogea and P.\ megasperma were consistently isolated from roots and rhizosphere of trees with symptoms sampled in 2009, 2011 and 2013. The isolates were identified on the basis of colony and reproductive structure morphology as well as temperature{\textendash}growth relationships, and identification was further corroborated by their ITS and β-tubulin sequences. Koch{\textquoteright}s postulates were demonstrated for both species on 1-year-old wild olives. Pathogenicity tests showed that both Phytophthora spp. are highly aggressive pathogens, although temperature{\textendash}growth requirements for each species were distinct. As a consequence, the two species may be active in different seasons and their epidemiology may be differently influenced by global climate change, and they may show their active periods in different climatic scenarios. The climate change models for the Mediterranean Basin forecast a global temperature increase that favours the more thermophilic P.\ cryptogea. The high susceptibility to phytophthora root rot should not be disregarded in olive breeding programmes where wild olive is used as a source of resistance to verticillium wilt.

}, doi = {10.1111/ppa.12649}, url = {https://doi.org/10.1111/ppa.12649 }, author = {Gonz{\'a}lez, M. and P{\'e}rez-Sierra, A. and Serrano, M. S. and Sanchez, M. E.} } @article {4693, title = {Phytophthora ramorum in Canada: Evidence for Migration Within North America and from Europe}, journal = {Phytopathology}, volume = {101}, year = {2011}, month = {Jan-01-2011}, pages = {166 - 171}, abstract = {

Phytophthora ramorum, the cause of sudden oak death on oak and ramorum blight on woody ornamentals, has been reported in ornamental nurseries on the West Coast of North America from British Columbia to California. Long-distance migration of P. ramorum has occurred via the nursery trade, and shipments of host plants are known to have crossed the U.S.-Canadian border. We investigated the genotypic diversity of P. ramorum in Canadian nurseries and compared the Canadian population with U.S. and European nursery isolates for evidence of migration among populations. All three of the P. ramorum clonal lineages were found in Canada but, unexpectedly, the most common was the NA2 lineage. The NA1 clonal lineage, which has been the most common lineage in U.S. nurseries, was found relatively infrequently in Canada, and these isolates may have been the result of migration from the United States to Canada. The EU1 lineage was observed almost every year and shared multilocus genotypes with isolates from Europe and the United States. Estimation of migration rates between Europe and North America indicated that migration was higher from Europe to North America than vice versa, and that unidirectional migration from Europe to North America was more likely than bidirectional migration.

}, issn = {0031-949X}, doi = {10.1094/PHYTO-05-10-0133}, url = {https://apsjournals.apsnet.org/doi/10.1094/PHYTO-05-10-0133}, author = {Goss, Erica M. and Larsen, Meg and Vercauteren, Annelies and Werres, Sabine and Heungens, Kurt and Gr{\"u}nwald, Niklaus J.} } @article {10.1371/journal.ppat.1000583, title = {Population genetic analysis infers migration pathways of Phytophthora ramorum in US nurseries}, journal = {PLoS Pathog}, volume = {5}, number = {9}, year = {2009}, month = {09}, pages = {e1000583}, publisher = {Public Library of Science}, abstract = {

Author Summary

Sudden oak death, caused by the fungus-like pathogen Phytophthora ramorum, has caused devastating levels of mortality of live oak and tanoak trees in coastal California forests and in urban and suburban landscapes in the San Francisco Bay Area. This pathogen also causes non-lethal disease on popular ornamental plants, including rhododendrons, viburnums, and camellias. P. ramorum was discovered in California in the late 1990s and is exotic to the United States. Recently, presence of the disease in wholesale nurseries in California, Oregon, and Washington has led to shipments of diseased plants across the US, thus risking the introduction of the pathogen to other vulnerable forests. We examined the genetic diversity of this pathogen in US nurseries in order to better understand its evolution in nurseries and movement between states. We found that California populations were genetically different enough from Oregon and Washington populations that infestations of the pathogen found in nurseries in other states could be distinguished as having originated from California or the Northwest. Our inferences were consistent with trace forward investigations by regulatory agencies.

}, doi = {10.1371/journal.ppat.1000583}, url = {http://dx.doi.org/10.1371\%2Fjournal.ppat.1000583}, author = {Goss, Erica M. and Larsen, Meg and Chastagner, Gary A. and Givens, Donald R. and Gr{\"u}nwald, Niklaus J.} } @article {doi:10.1094/PHYTO-05-10-0133, title = {Phytophthora ramorum in Canada: evidence for migration within North America and from Europe}, journal = {Phytopathology}, volume = {101}, number = {1}, year = {2011}, pages = {166-171}, doi = {10.1094/PHYTO-05-10-0133}, url = {http://apsjournals.apsnet.org/doi/abs/10.1094/PHYTO-05-10-0133}, author = {Goss, Erica M. and Larsen, Meg and Vercauteren, Annelies and Werres, Sabine and Heungens, Kurt and Gr{\"u}nwald, Niklaus J.} } @article {4049, title = {Florida Citrus Pest Management Guide: Brown Rot of Fruit}, volume = {Publication PP-148}, year = {2012}, pages = {2 pp.}, publisher = {University of Florida, IFAS Extension, Gainesville, Florida}, url = {http://edis.ifas.ufl.edu/pdffiles/CG/CG02200.pdf}, author = {JH Graham and LW Timmer and MM Dewdney} } @article {EFP:EFP788, title = {The destructive invasive pathogen Phytophthora lateralis found on Chamaecyparis lawsoniana across the UK}, journal = {Forest Pathology}, volume = {43}, year = {2012}, month = {02/2013}, pages = {19{\textendash}28}, abstract = {

In 2010{\textendash}2011, Phytophthora lateralis was isolated from diseased Chamaecyparis lawsoniana exhibiting dieback and mortality at eight geographically separate forest, parkland and shelterbelt locations in England, Scotland and Northern Ireland. In 2011, P.\ lateralis was also isolated from young symptomatic nursery plants of C.\ lawsoniana and Thuja occidentalis recently imported into Scotland from mainland Europe. These are the first findings of P.\ lateralis in the UK. At six of the field sites, only collar and root lesions were observed. However, at two sites, large stem and branch lesions unconnected to the collar region were also observed. Phytophthora lateralis was readily isolated from both aerial and basal lesions. In artificial inoculation experiments, two Scottish isolates of the pathogen caused lesions on C.\ lawsoniana shoots and were readily reisolated from the lesions, their pathogenicity being comparable to that of P.\ lateralis isolates originating from outside the UK. Isolates from six field sites and the two nursery interceptions exhibited ITS and coxII sequences identical to published sequences of French and North American isolates. However, the isolates from two field sites shared an ITS sequence with Taiwanese isolates and differed from North American, French and Taiwanese isolates by a single-base substitution in coxII, suggesting a separate evolutionary history. It is clear that P.\ lateralis now presents a significant threat to C.\ lawsoniana in Britain. The main source of the outbreaks is likely to be imported infested nursery stock.

}, issn = {1439-0329}, doi = {10.1111/j.1439-0329.2012.00788.x}, url = {http://dx.doi.org/10.1111/j.1439-0329.2012.00788.x}, author = {Green, S. and C.M. Brasier and Schlenzig, A. and McCracken, A. and MacAskill, G. A. and Wilson, M. and Webber, JF} } @article {4285, title = {Dieback and mortality of Juniperus communis in Britain associated with Phytophthora austrocedrae}, journal = {New Disease Reports}, volume = {26}, year = {2012}, month = {Jul-12-2014}, pages = {2}, abstract = {

In late 2010 reports were received of serious decline of native juniper (Juniperus communis) at the Upper Teesdale National Nature Reserve in northern England comprising more than 200 ha of juniper. Dead and dying juniper trees were scattered throughout an area of approximately 14 ha, mainly concentrated on wet, flat ground but also extending outwards across drier slopes. Affected trees had foliage reddening and browning over all or most of the crown (Figs. 1, 2). Examination of ten trees showing these symptoms revealed orange-brown lesions in the phloem at the stem collar and upper roots (Fig. 3). Scattered dieback of shoots or individual branches (Fig. 4a) was also observed, and three trees examined with these symptoms had discrete girdling orange-brown phloem lesions with no apparent connection to the base of the tree (Fig. 4b). Phloem samples from lesion margins were plated on to SMA + MRP Phytophthora selective medium (Brasier et al., 2005) and incubated at room temperature (15-24{\textdegree}C) in the dark. After transfer to V8 agar, colonies were very slow growing (\<0.5 mm per day at 17{\textdegree}C), forming dense, white mycelia (Fig. 5a) with coralloid hyphae (Fig. 5b); amphigynous antheridia measuring 10.8-19.9 {\textmu}m in diameter (mean 13.2-16.2 {\textmu}m); and globose oogonia with smooth hyaline to brown walls ranging in diameter between 23.5-41.2 {\textmu}m (mean 34.4 {\textmu}m). Semi- and non-papillate sporangia measuring 35.3-58.8 x 23.5-35.3 {\textmu}m were also observed on V8 agar. Based on the above morphological characteristics and sequencing of the ITS and coxII regions (GenBank Accession Nos. JQ346527 and JQ346528), the isolates were identified as Phytophthora austrocedrae Gresl. \& E.M. Hansen, associated with mortality of Austrocedrus chilensis in Argentina (Greslebin et al., 2007; Greslebin \& Hansen, 2010). Direct PCR and sequencing of diseased phloem from basal and branch lesions on juniper trees from which no Phytophthora was obtained yielded the same result.

Pathogenicity of the isolate was tested using the method of Greslebin \& Hansen (2010) in which the stem bases of six healthy, 30-40 cm high, potted junipers were inoculated with 6 mm diameter mycelial plugs from the margin of a five-week-old P. austrocedrae culture growing on V8 agar. The plants were incubated in a greenhouse at 17{\textdegree}C with natural lighting. Four weeks after inoculation, five of the juniper plants exhibited orange-brown phloem lesions of mean length 49 {\textpm} 8 mm extending both up the main stem and down into the root system. P. austrocedrae was successfully re-isolated on to SMA + MRP medium from lesion margins, thereby satisfying Koch{\textquoteright}s postulates. Control plants inoculated with sterile agar plugs remained healthy. This is the first finding of P. austrocedrae infecting a Juniperus species worldwide. Although P. austrocedrae is not currently a statutory listed organism within the European Union, biosecurity measures are being applied at the infested site to contain the pathogen. In February 2012 P. austrocedrae was confirmed infecting mature upland juniper at a second site in Britain, located in Perthshire, Scotland. Other juniper sites in Britain with similar decline symptoms are now under investigation.

}, doi = {10.5197/j.2044-0588.2012.02610.5197/j.2044-0588.2012.026.002}, url = {http://www.ndrs.org.uk/contents.php?vol=26http://www.ndrs.org.uk/article.php?id=026002}, author = {Green, S. and Hendry, S.J. and MacAskill, G.A. and Laue, B.E. and Steele, H.} } @article {4282, title = {Phytophthora austrocedrae emerges as a serious threat to juniper Juniperus communis in Britain}, journal = {Plant Pathology}, volume = {64}, year = {2015}, month = {Jan-04-2015}, pages = {456 - 466}, abstract = {

From 2011 to 2013, Phytophthora austrocedrae was isolated from diseased Juniperus communis exhibiting dieback and mortality at eight geographically separate sites in Scotland and northern England. The pathogen was also confirmed present either by standard PCR of the ITS locus and sequencing or by real-time PCR on J.\ communis with symptoms at a further 11 sites in northern Britain. Out of 167 J.\ communis sampled across the 19 sites, 154 had foliage dieback over all or part of the crown as a result of basal lesions, which extended up the stem. Thirteen sampled trees had aerial branch lesions or discrete stem lesions with no apparent connection to the base of the tree. At 13 sites, dieback was concentrated in areas of poor drainage and/or alongside streams and other watercourses. In artificial inoculation experiments, P.\ austrocedrae caused rapidly extending stem and root lesions on J.\ communis and was reisolated from these lesions. Lesions also developed on Chamaecyparis lawsoniana and Chamaecyparis nootkatensis but the pathogen was not reisolated. All P.\ austrocedrae isolates obtained from J.\ communis in Britain shared 100\% identity across the ITS locus but were distinct at one sequence position from P.\ austrocedrae isolates collected in Argentina from diseased Austrocedrus chilensis. This study provides clear evidence that P.\ austrocedrae is a primary pathogen of J.\ communis and now presents a significant threat to this species in Britain. Pathways for the emergence of P. austrocedrae in Britain, and possible ways in which the pathogen may have spread within the country, are discussed.

}, doi = {10.1111/ppa.2015.64.issue-210.1111/ppa.12253}, url = {http://doi.wiley.com/10.1111/ppa.2015.64.issue-2http://doi.wiley.com/10.1111/ppa.12253}, author = {Green, S. and Elliot, M. and Armstrong, A. and Hendry, S. J.} } @inbook {greenup_managing_1998, title = {Managing Chamaecyparis lawsoniana (Port-Orford-Cedar) to control the root disease caused by Phytophthora lateralis in the Pacific Northwest, USA.}, booktitle = {Coastally restricted forests}, year = {1998}, pages = {93{\textendash}100}, publisher = {New York : Oxford University Press, 1998}, organization = {New York : Oxford University Press, 1998}, keywords = {Chamaecyparis lawsoniana, disease control, literature reviews, Pacific States, Phytophthora lateralis, plant diseases and disorders, plant pathogenic fungi}, isbn = {0195075676 (alk. paper)}, author = {M. Greenup} } @article {4138, title = {Cocoa black pod: a reinterpretation}, journal = {Cocoa Growers{\textquoteright} Bulletin}, volume = {35}, year = {1984}, pages = {5{\textendash}22}, author = {Gregory, PH and Maddison, AC and Ward, MR} } @article {AlinaG.Greslebin01012005, title = {Phytophthora species from declining Austrocedrus chilensis forests in Patagonia, Argentina}, journal = {Mycologia}, volume = {97}, number = {1}, year = {2005}, pages = {218-228}, abstract = {

A survey of Phytophthora spp. in declining and healthy Austrocedrus chilensis forest was conducted to obtain an overview of the species that inhabit these forests. Seventeen declining and three healthy stands plus 11 associated streams were surveyed. Five Phytophthora species were recovered. P. syringae was the most common species isolated from soil and/or streams at nine declining sites and one healthy site. P. gonapodyides was isolated from streams only, at five declining sites. P. cambivora was isolated from soil and the undescribed taxa P. taxon Pgchlamydo{\textquoteright} and 22 P. taxon Raspberry{\textquoteright} were isolated from streams at one declining site each. The species were identified by ITS rDNA sequences and morphological features. Brief descriptions of each species and a discussion of their possible relationship with "mal del cipres" are presented.

}, doi = {10.3852/mycologia.97.1.218}, url = {http://www.mycologia.org/cgi/content/abstract/97/1/218}, author = {Greslebin, Alina G. and Hansen, Everett M. and Winton, Loretta M. and Rajchenberg, Mario} } @article {411, title = {Pathogenicity of Phytophthora austrocedrae on Austrocedrus chilensis and its relation with mal del cipr{\'e}s in Patagonia}, journal = {Plant Pathology}, volume = {59}, year = {2010}, month = {August 2010}, pages = {604{\textendash}612}, abstract = {

Field observations, isolations and pathogenicity tests were performed on Austrocedrus chilensis (Cupressaceae) trees to determine the pathogenicity of Phytophthora austrocedrae and its role in the aetiology of the cypress disease mal del cipr{\'e}s (MDC) in Argentina. It was found that P. austrocedrae is a primary pathogen of A. chilensis. It was isolated from large necrotic lesions in the inner bark, and superficially in the sapwood, at the root collar and stem, in most of the MDC-affected stands surveyed along the range of A. chilensis in Argentina. The main symptom in naturally infected trees was a necrotic lesion extending from killed roots up to 1\ m up the tree bole. Seedlings, saplings and adult trees were all susceptible to inoculation with P. austrocedrae. Under favourable experimental conditions (flooding), inoculated seedlings suffered massive mortality in less than a month. The importance of diseases caused by Phytophthora spp. in South American forests is discussed.

}, keywords = {cypress, forest pathology, root rot, soilborne pathogens}, doi = {10.1111/j.1365-3059.2010.02258.x}, url = {http://dx.doi.org/10.1111/j.1365-3059.2010.02258.x}, author = {Greslebin, A. G. and Hansen, E.M.} } @article {Greslebin2007308, title = {Phytophthora austrocedrae sp. nov., a new species associated with Austrocedrus chilensis mortality in Patagonia (Argentina)}, journal = {Mycological Research}, volume = {111}, number = {3}, year = {2007}, pages = {308 - 316}, abstract = {

Phytophthora austrocedrae is a new species isolated from necrotic lesions of stem and roots of Austrocedrus chilensis. It is a homothallic species characterized by semipapillate sporangia, oogonia with amphigynous antheridia, and very slow growth (1-2{\textdagger}mm{\textdagger}d-1 on V-8 agar at 17.5{\textdagger}${\i}nfty$C optimum temperature). Phylogenetic analysis of ITS rDNA sequence indicates that its closest relative is Phytophthora syringae, another species frequently isolated from soil and streams in A. chilensis forests.

}, keywords = {soil pathogens}, issn = {0953-7562}, doi = {DOI: 10.1016/j.mycres.2007.01.008}, url = {http://www.sciencedirect.com/science/article/B7XMR-4MWPSTC-2/2/cd293441766ba86e83832d81ab837e1a}, author = {Greslebin, Alina G. and Hansen, Everett M. and Sutton, Wendy} } @article {4022, title = {Phytophthora multivora causing leaf spot on rhododendrons in Argentina}, journal = {New Disease Reports}, volume = {27}, year = {2013}, month = {06/2013}, pages = {20}, abstract = {

Rhododendron is a genus belonging to the family Ericaceae and contains over 1000 species commonly known as rhododendrons and azaleas (Dimitri, 1978). Phytophthora multivora is a species that was described in Western Australia in 2008 but before that it was misidentified as . citricola (Scott et al., 2009). During the early spring of 2011, leaf spot symptoms were observed on rhododendrons in two gardens in Tigre (northern Buenos Aires province) and in containers in a nursery near Buenos Aires city. Leaf spots were dark brown to almost black, visible on both sides near the leaf tips and margins, while tissue death continued down the leaf along the midrib (Fig. 1A). The veins under the diseased area of the leaves presented a reddish tint (Fig. 1B). Some leaves became brown and died, while in others the infection remained as spots on leaves.

A Phytophthora species was consistently isolated from symptom-bearing leaf tissues on PARBH medium (Jeffers \& Martin, 1986). Hyphal tips reaching the surface of the medium were transferred onto potato dextrose agar (PDA) without inhibitors for purification and identification. Sporangia were produced abundantly in non-sterile soil extract. The majority of them were semi-papillate and ovoid, limoniform, ellipsoid or obpyriform (Fig. 2). Sporangia with two papillae were occasionally formed (Scott et al., 2009). Chlamydospores were not observed. Isolates were homothallic with plerotic oospores, 22.9 {\textpm} 1.9 μm and paragynous antheridia (Fig. 3). The optimum growth temperature was 25 {\textpm} 1{\textdegree}C on V8A (Scott et al., 2009) and the maximum growth temperature was 32 {\textpm} 1{\textdegree}C. The ITS was amplified and sequenced (GenBank Accession No. JQ812127) and showed that it was identical to P. multivora, ex-type CBS 124.094 (FJ237517) by BLAST analysis (Altschul et al., 1997). The isolate (ARod 110) was deposited in the culture collection of the Phytopathology Chair of the Faculty of Agronomy of Buenos Aires (FAUBA).

Due to the difficulty of performing pathogenicity tests in the field, detached leaves of Rhododendron spp., Camellia sp. Viburnum tinus and Photinia fraseri were inoculated in the laboratory with the ARod 110 isolate. The tests were performed by inoculating five detached leaves with a 5 mm mycelium plug taken from a seven-day-old PDA culture. Controls were inoculated with PDA discs. Leaves were incubated at 20-22{\textordmasculine}C under 12h light/12h dark cycle. All the inoculated leaves, except Camellia sp., developed necrotic lesions seven days after inoculation. . multivora was re-isolated from infected tissue. Symptoms were not detected on the controls. These characteristics conformed to those of Phytophthora multivora Scott \& Jung. To our knowledge, this is the first record of P. multivora causing leaf spot on Rhododendron in Argentina and in Latin America, and it may be a potential pathogen for Viburnum tinus and Photinia fraseri.

}, doi = {10.5197/j.2044-0588.2013.02710.5197/j.2044-0588.2013.027.020}, url = {http://www.ndrs.org.uk/article.php?id=027020}, author = {Grijalba, P.E. and Palmucci, H.E. and Guillin, E. and Herrera, C.} } @article {4280, title = {Role of salicylic acid in phosphite-induced protection against Oomycetes; a Phytophthora cinnamomi - Lupinus augustifolius model system}, journal = {European Journal of Plant Pathology}, volume = {141}, year = {2015}, month = {Jan-03-2015}, pages = {559 - 569}, abstract = {

Phosphite is used to control Oomycetes in a wide range of horticultural and native plant species worldwide. However, phosphite can be phytotoxic, and some pathogens have exhibited a reduction in the effectiveness of phosphite due to prolonged use. In this study, salicylic acid (SA) was investigated as an alter- native, or supplementary, treatment to be used to protect plant species. With the use of aeroponics chambers, foliar application of phosphite, SA, and phosphite/SA to Lupinus augustifolius was assessed in relation to root tip damage, in planta phosphite and SA concentration and lesion development. Both phosphite and SA were measurable at the root tip within 24 h of application, and all treatments significantly (P<=0.05) reduced the lesion length at 7 days. However, while phosphite and SA application increased the in planta SA concentration, phosphite caused significantly more damage to the root tip by reducing root cap layers and length than the SA, or phosphite/SA application. This study supports the notion that phosphite-induced sensitivity may be SA- dependent, as both phosphite and SA were found to control P. cinnamomi and stimulate SA accumulation. A combination of phosphite and SA may be more beneficial to plants if it can reduce phytotoxic effects and reduce the chance of pathogen sensitivity to phosphite.

}, issn = {0929-1873}, doi = {10.1007/s10658-014-0562-y}, url = {http://link.springer.com/article/10.1007\%2Fs10658-014-0562-y}, author = {Groves, Emma and Howard, Kay and Hardy, Giles and Burgess, Treena} } @article {doi:10.1094/PDIS-08-10-0609, title = {Phytophthora-ID.org: a sequence-based Phytophthora identification tool}, journal = {Plant Disease}, volume = {95}, number = {3}, year = {2011}, pages = {337-342}, doi = {10.1094/PDIS-08-10-0609}, url = {http://apsjournals.apsnet.org/doi/abs/10.1094/PDIS-08-10-0609}, author = {Gr{\"u}nwald, Niklaus J. and Martin, Frank N. and Larsen, Meredith M. and Sullivan, Christopher M. and Press, Caroline M. and Michael D. Coffey and Hansen, Everett M. and Parke, Jennifer L.} } @article {MPP:MPP500, title = {Phytophthora ramorum: a pathogen with a remarkably wide host range causing sudden oak death on oaks and ramorum blight on woody ornamentals}, journal = {Molecular Plant Pathology}, volume = {9}, number = {6}, year = {2008}, pages = {729{\textendash}740}, publisher = {Blackwell Publishing Ltd}, abstract = {

Phytophthora ramorum is an oomycete plant pathogen classified in the kingdom Stramenopila. P.\ ramorum is the causal agent of sudden oak death on coast live oak and tanoak as well as ramorum blight on woody ornamental and forest understorey plants. It causes stem cankers on trees, and leaf blight or stem dieback on ornamentals and understorey forest species. This pathogen is managed in the USA and Europe by eradication where feasible, by containment elsewhere and by quarantine in many parts of the world. Genomic resources provide information on genes of interest to disease management and have improved tremendously since sequencing the genome in 2004. This review provides a current overview of the pathogenicity, population genetics, evolution and genomics of P.\ ramorum. Taxonomy: Phytophthora ramorum (Werres, De Cock \& Man in{\textquoteright}t Veld): kingdom Stramenopila; phylum Oomycota; class Peronosporomycetidae; order Pythiales; family Pythiaceae; genus Phytophthora.Host range: The host range is very large and the list of known hosts continues to expand at the time of writing. Coast live oak and tanoak are ecologically, economically and culturally important forest hosts in the USA. Rhododendron, Viburnum, Pieris, Syringa and Camellia are key ornamental hosts on which P.\ ramorum has been found repeatedly, some of which have been involved in moving the pathogen via nursery shipments. Disease symptoms: P.\ ramorum causes two different diseases with differing symptoms: sudden oak death (bleeding lesions, stem cankers) on oaks and ramorum blight (twig dieback and/or foliar lesions) on tree and woody ornamental hosts.Useful websites: http://nature.berkeley.edu/comtf/, http://rapra.csl.gov.uk/, http://www.aphis.usda.gov/plant_health/plant_pest_info/pram/index.shtml, http://genome.jgi-psf.org/Phyra1_1/Phyra1_1.home.html, http://pamgo.vbi.vt.edu/, http://pmgn.vbi.vt.edu/, http://vmd.vbi.vt.edu./, http://web.science.oregonstate.edu/bpp/labs/grunwald/resources.htm, http://www.defra.gov.uk/planth/pramorum.htm, http://www.invasive.org/browse/subject.cfm?sub=4603, http://www.forestry.gov.uk/forestry/WCAS-4Z5JLL

}, issn = {1364-3703}, doi = {10.1111/j.1364-3703.2008.00500.x}, url = {http://dx.doi.org/10.1111/j.1364-3703.2008.00500.x}, author = {Gr{\"u}nwald, Niklaus J. and Goss, Erica M. and Press, Caroline M.} } @article {doi:10.1080/07060661.2012.664568, title = {Genome sequences of Phytophthora enable translational plant disease management and accelerate research}, journal = {Canadian Journal of Plant Pathology}, volume = {34}, number = {1}, year = {2012}, pages = {13-19}, abstract = {

Whole and partial genome sequences are becoming available at an ever-increasing pace. For many plant pathogen systems, we are moving into the era of genome resequencing. The first Phytophthora genomes, P. ramorum and P. sojae, became available in 2004, followed shortly by P. infestans in 2006. Availability of whole genome sequences has provided rapid and immediate advances in several areas also resulting in many practical applications and critical new insights. Availability of comparative genome data facilitated discovery of new classes of effectors, such as the RxLR-dEER and crinkler effector families. Genome data also enabled development of molecular markers for population genomic approaches that provided critical new insights into the evolutionary history of species and clades of Phytophthora. Several select examples of advances resulting from comparative genomic approaches in a concerted effort of the Oomycete research community are reviewed.

}, doi = {10.1080/07060661.2012.664568}, url = {http://www.tandfonline.com/doi/abs/10.1080/07060661.2012.664568}, author = {Gr{\"u}nwald, Niklaus J.} } @article {4476, title = {First Report of the EU1 Clonal Lineage of Phytophthora ramorum on Tanoak in an Oregon Forest}, journal = {Plant Disease}, volume = {100}, year = {2016}, month = {Jan-05-2016}, pages = {1024 - 1024}, abstract = {

Initially reported in California as the causal agent of sudden oak death (SOD), efforts to limit spread of Phytophthora ramorum in Oregon natural forests have concentrated on quarantine regulations and eradication of the pathogen from infested areas. P. ramorum has four clonal lineages: NA1; NA2; EU1; and EU2 (Gr{\"u}nwald et al. 2012; Van Poucke et al. 2012). Forest infestations in Oregon have been limited to the NA1 clonal lineage, whereas EU1, NA1, and NA2 clonal lineages have all been found in U.S. nurseries (Kamvar et al. 2015; Prospero et al. 2007). In February 2015, in response to an aerial survey, P. ramorum was isolated from a dying Notholithocarpus densiflorus tree in the South Fork Pistol River drainage of Curry Co., Oregon. The isolated strain was identified as P. ramorum based on presence of chlamydospores, characteristic hyphae, and sporangial morphology. Microsatellite genotyping at 14 loci (Vercauteren et al. 2011) and comparison with reference cultures revealed that these isolates belonged to the EU1 clonal lineage. Subsequently, five more isolates were obtained from the original tree stump and the EU1 lineage was confirmed. Microsatellite alleles of the forest EU1 isolates were nearly identical to EU1 isolates collected in 2012 from a nearby nursery during routine P. ramorum nursery monitoring, except for one allele at locus PrMS145a. Interestingly, several isolates differed at locus ILVOPrMS131a within both the 2015 forest and the 2012 nursery findings with identical allele frequencies in each population for this locus. These data provide inconclusive support for the introduction of EU1 into Curry Co. from the 2012 populations found in nurseries, given that no direct match was found probably owing to the paucity of EU1 samples from nurseries. These results provide further evidence that multiple distinct P. ramorum introduction events into the Curry Co. forest are a critical component of the epidemic (Kamvar et al. 2015). The impact of the EU1 clonal lineage of P. ramorum on Oregon natural forests is uncertain, but it may result in potential sexual reproduction given that EU1 is of A1 mating type while the prior population consisted of NA1 A2 mating type individuals. While sexual populations of P. ramorum have not been observed in nature or were aberrant in the laboratory, the presence of both A1 and A2 mating types makes the potential for sexual recombination more likely. The EU1 forest infestation is undergoing eradication treatments. Additional monitoring is necessary to determine if the EU1 clonal lineage occurs elsewhere in Curry Co. forests.

}, issn = {0191-2917}, doi = {10.1094/PDIS-10-15-1169-PDN}, url = {http://apsjournals.apsnet.org/doi/10.1094/PDIS-10-15-1169-PDN}, author = {Gr{\"u}nwald, N. J. and Larsen, M. M. and Kamvar, Z. N. and Reeser, P. W. and Kanaskie, A. and Laine, J. and Wiese, R.} } @article {Gr{\~A}{\textonequarter}nwald2012131, title = {Emergence of the sudden oak death pathogen Phytophthora ramorum}, journal = {Trends in Microbiology}, volume = {20}, number = {3}, year = {2012}, pages = {131 - 138}, abstract = {

The recently emerged plant pathogen Phytophthora ramorum is responsible for causing the sudden oak death epidemic. This review documents the emergence of P. ramorum based on evolutionary and population genetic analyses. Currently infection by P. ramorum occurs only in Europe and North America and three clonal lineages are distinguished: EU1, NA1 and NA2. Ancient divergence of these lineages supports a scenario in which P. ramorum originated from reproductively isolated populations and underwent at least four global migration events. This recent work sheds new light on mechanisms of emergence of exotic pathogens and provides crucial insights into migration pathways.

}, issn = {0966-842X}, doi = {10.1016/j.tim.2011.12.006}, url = {http://www.sciencedirect.com/science/article/pii/S0966842X11002277}, author = {Gr{\"u}nwald, Niklaus J. and Garbelotto, Matteo and Goss, Erica M. and Heungens, Kurt and Prospero, Simone} } @article {doi:10.1094/PHYTO-99-7-0792, title = {Standardizing the nomenclature for clonal lineages of the sudden oak death pathogen, Phytophthora ramorum}, journal = {Phytopathology}, volume = {99}, number = {7}, year = {2009}, note = {PMID: 19522576}, pages = {792-795}, abstract = {

{Phytophthora ramorum, the causal agent of sudden oak death and ramorum blight, is known to exist as three distinct clonal lineages which can only be distinguished by performing molecular marker-based analyses. However, in the recent literature there exists no consensus on naming of these lineages. Here we propose a system for naming clonal lineages of P. ramorum based on a consensus established by the P. ramorum research community. Clonal lineages are named with a two letter identifier for the continent on which they were first found (e.g.

}, doi = {10.1094/PHYTO-99-7-0792}, url = {http://apsjournals.apsnet.org/doi/abs/10.1094/PHYTO-99-7-0792}, author = {Gr{\"u}nwald, Niklaus J. and Goss, Erica M. and Ivors, Kelly and Garbelotto, Matteo and Martin, Frank N. and Prospero, Simone and Everett Hansen and Peter J.M. Bonants and Hamelin, Richard C. and Chastagner, Gary and Werres, Sabine and Rizzo, David M. and Abad, Gloria and Beales, Paul and Bilodeau, Guillaume J. and Cheryl L. Blomquist and Brasier,Clive and Bri{\`e}re, Stephan C. and Chandelier, Anne and Davidson, Jennifer M. and Denman,Sandra and Elliott, Marianne and Susan J. Frankel and Goheen, Ellen M. and de Gruyter, Hans and Heungens, Kurt and James, Delano and Kanaskie, Alan and Michael G McWilliams and Man in {\textquoteleft}t Veld, Willem and Moralejo, Eduardo and Osterbauer, Nancy K. and Palm, Mary E. and Parke, Jennifer L. and Sierra, Ana Maria Perez and Shamoun, Simon F. and Shishkoff, Nina and Tooley, Paul W. and Vettraino, Anna Maria and Webber,Joan and Timothy L. Widmer} } @article {PPA:PPA2538, title = {Phytophthora obscura sp. nov., a new species of the novel Phytophthora subclade 8d}, journal = {Plant Pathology}, volume = {61}, year = {2012}, month = {June 2012}, pages = {610{\textendash}622}, publisher = {Blackwell Publishing Ltd}, abstract = {

A new Phytophthora species was detected (i) in the USA, infecting foliage of Kalmia latifolia, (ii) in substrate underneath Pieris, and (iii) in Germany in soil samples underneath Aesculus hippocastanum showing disease symptoms. The new species Phytophthora obscura sp. nov. is formally named based on phylogenetic analysis, host range, Koch{\textquoteright}s postulates and morphology. Phytophthora obscura is homothallic with paragynous antheridia and semipapillate sporangia. It is genetically closely related to P.\ syringae and P.\ austrocedrae and together these three species define a new Phytophthora subclade 8d, with significant support for all genetic loci analysed including seven nuclear genes and the mitochondrial gene coxII. The morphological and ecological characteristics are very similar to P.\ syringae, and it is likely that P.\ obscura was not described earlier because it was identified as P.\ syringae. Artificial inoculations indicated that horse chestnut, kalmia, pieris and rhododendron might be hosts, and Koch{\textquoteright}s postulates were confirmed for kalmia from which it was isolated. This pathogen was named after its elusive nature since it has to date rarely been detected in the US and Germany.

}, keywords = {Aesculus hippocastanum, Kalmia latifolia, oomycete, Pieris, Rhododendron, taxonomy}, issn = {1365-3059}, doi = {10.1111/j.1365-3059.2011.02538.x}, url = {http://dx.doi.org/10.1111/j.1365-3059.2011.02538.x}, author = {N. J. Gr{\"u}nwald and Werres, S. and Goss, E. M. and Taylor, C. R. and Fieland, V. J.} } @article {4707, title = {The influence of time, soil moisture and exogenous factors on the survival potential of oospores and chlamydospores of Phytophthora cinnamomi}, journal = {Forest Pathology}, volume = {n/a}, year = {2020}, month = {Nov/2020}, pages = {e12637}, abstract = {

The mode of persistence of Phytophthora cinnamomi, a highly aggressive soil- and water-borne pathogen, remains unclear. This study investigated the survival of viable oospores and chlamydospores of P. cinnamomi when present as free propagules in untreated soil, or in soil subject to four exogenous treatments: smoke water, fish emulsion and two fungicides (ridomil and furalaxyl). The exogenous treatments were applied under moist and dry soil conditions. Spore viability was determined by the thiazolyl blue tetrazolium bromide (MTT) staining technique, with a qPCR assay used to compare general patterns of decline. Over 96\% of oospores lost viability over a period of 48 weeks irrespective of soil moisture conditions. The mean percentage viability for oospores decreased from 91\% at time zero to 72, 35, 20 and 1\% after 6, 12, 24 and 48 weeks, respectively. Reduction in viability of chlamydospores was more rapid than oospores, with viability declining from 92\% to zero after 12 weeks. There was no significant difference between untreated soil and the exogenous treatments. The RNA-based qPCR assay indicated a strong presence of viable oospores of P.{\textlnot}{\textdagger}cinnamomi up to week 12 for moist soil and week 3 for dry soil, but thereafter failed to detect RNA even though viable oospores could be detected by MTT staining. Based on the MTT staining, this study indicated that viability of P. cinnamomi oospores may be entirely lost within 1 year and that of chlamydospores within 3 months for the soil type tested. Therefore, oospores and chlamydospores when existing as free propagules in soil appear unlikely to be involved in the long-term survival of P. cinnamomi.

}, keywords = {dormancy, long-term survival, phytophthora dieback, spore viability, vital stain}, doi = {https://doi.org/10.1111/efp.12637}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/efp.12637}, author = {Gyeltshen, Jamba and Dunstan, William A. and Grigg, Andrew H. and Burgess, Treena I. and St. J. Hardy, Giles E.} } @article {hamm1987identification, title = {Identification of Phytophthora spp. known to attack conifers in the Pacific Northwest}, journal = {Northwest Sci.}, volume = {61}, year = {1987}, month = {1987}, pages = {103-109}, publisher = {WSU Press}, author = {P.B. Hamm and Hansen, E.M.} } @article {EFP:EFP167, title = {Pathogenicity of Phytophthora species to Pacific Northwest conifers}, journal = {European Journal of Forest Pathology}, volume = {12}, number = {3}, year = {1982}, pages = {167{\textendash}174}, publisher = {Blackwell Publishing Ltd}, abstract = {

Phytophthora root rot is described for the first time killing sugar pine (Pinus lambertiana) in a seed orchard and four species of true fir (Abies spp.) in a forest nursery. P. cactorum was recovered from true firs and P. megasperma was recovered from sugar pine. P. cryptogea was recovered from sugar pine and true fir but isolates from the two locations differed from each other in pathogenicity and colony appearance. Isolates recovered from these hosts and isolates of 6 Phytophthora species previously recovered from Douglas-fir (Pseudotsuga menziesii) were then tested for pathogenicity on seedlings of 9 Northwest conifers. P. megasperma Group 1, P. cryptogea, and P. cinnamomi were pathogenic to all tree species except western redcedar (Thujaplicata). Western hemlock (Tsuga heterophylla) and true firs were susceptible to most species tested; ponderosa (P. ponderosa) and sugar pines were damaged only by P. cryptogea and P. cinnamomi; western redcedar was resistant to all isolates.

}, issn = {1439-0329}, doi = {10.1111/j.1439-0329.1982.tb01390.x}, url = {http://dx.doi.org/10.1111/j.1439-0329.1982.tb01390.x}, author = {P.B. Hamm and Hansen, E.M.} } @article {654, title = {Phytophthora pseudotsugae, a new species causing root rot of Douglas-fir}, journal = {Can. J. Bot.}, volume = {61}, year = {1983}, pages = {2626{\textendash}2631}, abstract = {

Phytophthora pseudotsugae n. sp. was isolated from rotted roots of Douglas-fir growing in forest tree nurseries in Oregon and Washington. It is distinguished by large oogonia and oospores, mostly paragynous antheridia, and predominantly spherical or ovoid, persistent sporangia borne primarily on simple and unbranched sporangiophores. Sporangia are formed occasionally in liquid culture, rarely in solid media. Phytophthora pseudotsugae is distinguished most readily from P. cactorum by its unbranched sporangiophores and persistent sporangia. It also differs in growth on defined media, electrophoretic protein patterns, and pathogenicity. Comparison is also made with P. iranica, the other species in group 1 of Waterhouse.

}, doi = {10.1139/b83-289}, url = {http://rparticle.web-p.cisti.nrc.ca/rparticle/AbstractTemplateServlet?calyLang=eng\&journal=cjb\&volume=61\&year=1983\&issue=10\&msno=b83-289}, author = {P.B. Hamm and Hansen, E.M.} } @article {200, title = {Improved method for isolating Phytophthora lateralis from soil.}, journal = {Plant disease}, volume = {68}, year = {1984}, month = {June 1984}, pages = {517-519}, issn = {01912917}, doi = {10.1094/PD-68-517}, author = {P.B. Hamm and Hansen, E.M.} } @article {657, title = {Survival, spread, and pathogenicity of Phytophthora spp. on Douglas-fir seedlings planted on forest sites.}, journal = {Phytopathology 70:}, volume = {70}, year = {1980}, pages = {422-425}, abstract = {

Douglas-fir seedling stock infected in the nursery with Phytophthora cryptogea, P. drechsleri, P. megasperma, P. cactorum, and an unidentified Phytophthora sp. were outplanted on commercial forest sites to test survival of the diseased trees and of the pathogens. Mortality of trees initially classified in severe, moderate, and inconspicuous symptom classes at outplanting reached 61, 26, and 11\%, respectively, after 18 mo. Phytophthora was recovered about equally from roots of trees in each symptom class (15, 13, and 12\%). Surviving trees regenerated healthy roots above old lesions even though Phytophthora persisted. Disease spread was limited. None of 360 healthy trees planted 0.6 m downslope from diseased trees became infected, and only 2 of 720 healthy trees became infected after each was paired with a diseased tree in the same planting hole.

}, doi = {10.1094/Phyto-70-422}, url = {http://www.apsnet.org/publications/phytopathology/backissues/Documents/1980Abstracts/Phyto70_422.htm}, author = {Hansen, E.M. and L.F. Roth and P.B. Hamm and A. J. Julis.} } @article {res2008alien, title = {Alien forest pathogens: Phytophthora species are changing world forests}, journal = {Boreal Env. Res.}, volume = {13}, year = {2008}, pages = {33{\textendash}41}, issn = {1797-2469}, author = {Hansen, E.M.} } @article {doi:10.1094/PDIS.2000.84.1.4, title = {Managing Port-Orford-Cedar and the Introduced Pathogen Phytophthora lateralis}, journal = {Plant Disease}, volume = {84}, number = {1}, year = {2000}, pages = {4-14}, doi = {10.1094/PDIS.2000.84.1.4}, url = {http://apsjournals.apsnet.org/doi/abs/10.1094/PDIS.2000.84.1.4}, author = {Hansen, Everett M. and Goheen, Donald J. and Jules, Erik S. and Ullian, Barbara} } @article {Hansen:1 May 2008:0045-5067:1133, title = {Epidemiology of Phytophthora ramorum in Oregon tanoak forests}, journal = {Canadian Journal of Forest Research}, volume = {38}, year = {Submitted}, pages = {1133-1143(11)}, abstract = {

We followed the local intensification and dispersal of Phytophthora ramorum Werres, De Cock, \& Man In{\textquoteright}t Veld in Oregon tanoak (Lithocarpus densiflorus (Hook \& Arn.) Rehd.) forests from its initial detection in 2001 through 2006, coincident with a continuing eradication effort. The initial infested area included nine scattered sites below 400m elevation, close to the Pacific Ocean near Brookings, Oregon. In subsequent years, one-half of new infections were within 122m of a previous infection, and 79\% of the newly detected trees occurred within 300m of a previously identified tree. Dispersal up to 4km was occasionally recorded. Initial infection occurred in the upper crowns of tanoak trees. The pathogen was recovered in rainwater collected beneath diseased tanoak trees in every month from November 2006 through October 2007. Twenty-four multilocus microsatellite genotypes were identified among 272 P. ramorum isolates collected from Curry County. Genotypic analysis provided independent estimates of time of origin of the Oregon infestation, its clustered distribution, and dispersal distances. In all sampling years, 60\%-71\% of the isolates belonged to the same multilocus genotype. In 2001, 12 genotypes were detected and new genotypes were identified in each of the subsequent years, but all isolates belonged to the same clonal lineage. Knowledge of local intensification of the disease and long-distance dispersal should inform both Oregon eradication efforts and national quarantine regulations.

}, doi = {10.1139/X07-217}, url = {http://www.nrcresearchpress.com/doi/abs/10.1139/X07-217$\#$.UNIUO7aKS0c}, author = {Hansen, E.M. and Kanaskie, A. and Prospero, S and McWilliams, M. and Goheen, E. M. and Osterbauer, N. and P. Reeser and Sutton, W.} } @article {hansen1989testing, title = {Testing Port-Orford-cedar for resistance to Phytophthora.}, journal = {Plant Disease}, volume = {73}, number = {10}, year = {1989}, pages = {791{\textendash}794}, issn = {0191-2917}, author = {Hansen, E.M. and P.B. Hamm and L.F. Roth} } @article {EverettM.Hansen01012009, title = {Phytophthora rosacearum and P. sansomeana, new species segregated from the Phytophthora megasperma "complex"}, journal = {Mycologia}, volume = {101}, number = {1}, year = {2009}, pages = {129-135}, abstract = {

Phytophthora megasperma sensu lato was a conglomeration of morphologically similar but phylogenetically unrelated species. In this paper we continue the segregation of species from the old P. megasperma complex, formally naming two previously recognized isolate groups. Isolates recovered from rosaceous fruit trees (especially apple and cherry) are in ITS clade 6, related to but distinct from P. megasperma sensu strictu. They are named here Phytophthora rosacearum. They have been referred to previously as the "AC" or "high temperature small oospore" group of P. megasperma. A second group of isolates, earlier called "soybean race non-classifiable", recovered from soybeans in Indiana and other Midwestern states, are morphologically similar to P. megasperma sensu strictu but unrelated to that species, falling in ITS clade 8. They are named here P. sansomeana. Isolates recovered from Douglas-fir seedlings in nurseries in the Pacific Northwest and various weedy hosts in New York State, referred to in earlier work as "P. megasperma DF1", appear to be conspecific with the soybean isolates, although they include certain ITS DNA polymorphisms. Both new species are supported by a combination of new and previously published morphological, growth and molecular data.

}, doi = {10.3852/07-203}, url = {http://www.mycologia.org/cgi/content/abstract/101/1/129}, author = {Hansen, Everett M. and Wilcox, Wayne F. and Reeser, Paul W. and Sutton, Wendy} } @article {hansen1979isolation, title = {Isolation, incidence and management of Phytophthora in forest tree nurseries in the Pacific Northwest [USA]}, journal = {Plant Disease Reporter}, volume = {63}, year = {1979}, pages = {607-611}, issn = {0032-0811}, author = {Hansen, E.M. and P.B. Hamm and Julis, AJ and L.F. Roth} } @article {3992, title = {Phytophthora beyond agriculture}, journal = {Annual Review of Phytopathology}, volume = {50}, year = {2012}, month = {09/2012}, pages = {359 - 378}, abstract = {

Little is known about indigenous Phytophthora species in natural ecosystems. Increasing evidence, however, suggests that a diverse, trophically complex Phytophthora community is important in many forests. The number of described species has steadily increased, with a dramatic spike in recent years as new species have been split from old and new species have been discovered through exploration of new habitats. Forest soil, streams, and the upper canopies of trees are now being explored for Phytophthora diversity, and a new appreciation for the ecological amplitude of the genus is emerging. Ten to twenty species are regularly identified in temperate forest surveys. Half or more of this Phytophthora diversity comes from species described since 2000. Taxa in internal transcribed spacer (ITS) Clade 6 are especially numerous in forest streams and may be saprophytic in this habitat. Three ecological assemblages of forest Phytophthora species are hypothesized: aquatic opportunists, foliar pathogens, and soilborne fine-root and canker pathogens. Aggressive invasive species are associated with all three groups.

}, issn = {0066-4286}, doi = {10.1146/annurev-phyto-081211-172946}, url = {http://www.annualreviews.org/doi/pdf/10.1146/annurev-phyto-081211-172946}, author = {Hansen, Everett M. and Reeser, Paul W. and Sutton, Wendy} } @article { refId, title = {Phytophthora species in oak forests of north-east France}, journal = {Ann. For. Sci.}, volume = {56}, number = {7}, year = {1999}, pages = {539-547}, abstract = {

Phytophthora species were surveyed from the end of 1997 through July 1998 in oak forests in NE France. Healthy (Amance) or declining (Illwald) forests were compared. The Phytophthora population in both was diverse and locally abundant. At least eight species were present at Amance and six at Illwald. At Amance Phytophthora species had a localized distribution in water and low-lying soils. At Illwald distribution was more uniform apparently due to flooding events. Most often recovered were P. citricola, P. gonapodyides and P. quercina. P. gonapodyides was ubiquitous in water and colonized leaf debris. P. quercina was widely distributed in soil but not abundant, and was found in sites that did not otherwise appear to favor Phytophthora. No correlation was detected between presence of Phytophthora in soil and health of trees. Unusual combinations of environmental factors may be required for resident Phytophthora to have a detrimental impact on oaks. {\textcopyright} 1999 Editions scientifiques et m{\'e}dicales Elsevier SAS.

}, doi = {10.1051/forest:19990702}, url = {http://dx.doi.org/10.1051/forest:19990702}, author = {Hansen, E.M. and Delatour, Claude} } @article {doi:10.1094/PD-89-0063, title = {Susceptibility of Oregon forest trees and shrubs to Phytophthora ramorum: a comparison of artificial inoculation and natural infection}, journal = {Plant Disease}, volume = {89}, number = {1}, year = {2005}, pages = {63-70}, abstract = {

Phytophthora ramorum is an invasive pathogen in some mixed-hardwood forests in California and southwestern Oregon, where it causes sudden oak death (SOD) on some members of Fagaceae, ramorum shoot dieback on some members of Ericaceae and conifers, and ramorum leaf blight on diverse hosts. We compared symptoms of P. ramorum infection resulting from four different artificial inoculation techniques with the symptoms of natural infection on 49 western forest trees and shrubs; 80\% proved susceptible to one degree or another. No single inoculation method predicted the full range of symptoms observed in the field, but whole plant dip came closest. Detached-leaf-dip inoculation provided a rapid assay and permitted a reasonable assessment of susceptibility to leaf blight. Both leaf age and inoculum dose affected detached-leaf assays. SOD and dieback hosts often developed limited leaf symptoms, although the pattern of midrib and petiole necrosis was distinctive. Stem-wound inoculation of seedlings correlated with field symptoms for several hosts. The results suggested that additional conifer species may be damaged in the field. Log inoculation provided a realistic test of susceptibility to SOD, but was cumbersome and subject to seasonal variability. Pacific rhododendron, salmonberry, cascara, and poison oak were confirmed as hosts by completing Koch{\textquoteright}s postulates. Douglas-fir was most susceptible to shoot dieback shortly after budburst, with infection occurring at the bud.

}, doi = {10.1094/PD-89-0063}, url = {http://apsjournals.apsnet.org/doi/abs/10.1094/PD-89-0063}, author = {Hansen, E.M. and Parke, J. L. and Sutton, W.} } @article {361, title = {Species of the Phytophthora megasperma complex}, journal = {Mycologia,}, volume = {83}, year = {1991}, month = {May - Jun., 1991}, pages = {376-381}, issn = {00275514}, url = {http://www.jstor.org/stable/3759999}, author = {Hansen, E.M. and D. P. Maxwell} } @article {Hansen1986557, title = {The taxonomic structure of Phytophthora megasperma: Evidence for emerging biological species groups}, journal = {Transactions of the British Mycological Society}, volume = {87}, number = {4}, year = {1986}, pages = {557 - 573}, abstract = {

Nomenclatural uncertainty surrounds P. megasperma as various authors, working with limited groups of isolates, offer their interpretations of this species based on pathology, morphology, or cytology. We compared 93 isolates, including many described by others, for classical morphological features, growth behaviour and appearance, electrophoretic pattern of total proteins, chromosome number and nuclear DNA content. Nine distinct sub-groups were distinguished. While most groups could be distinguished by each of the criteria, protein electrophoresis was the most sensitive. The groups included: ALF, pathogenic to alfalfa, n = 12{\textendash}15; SOY, pathogenic to soybean, n = 12{\textendash}15; CLO, pathogenic to clover, n = 11{\textendash}15; DF, pathogenic to Douglas fir, n = 17{\textendash}24; AC, isolated from rosaceous fruit trees; and BHR, a major group obtained from a broad range of hosts. The last two groups, distinguished primarily by protein pattern, comprised at least four karyotypes: KI, n = 12{\textendash}17; KII, n = 15{\textendash}23; KIII, n = 22{\textendash}28; and KIV, n= 26{\textendash}34. All four karyotypes occur within the BHR protein group, suggesting a polyploid series within a closely related genotype.

Two broad lines of evolution are hypothesized, a legume line comprising ALF, SOY, CLO, and perhaps DF isolates, and a Broad Host Range line of AC and BHR isolates. Sub-groups within each line may represent emerging biological species, isolated by host specificity or karyotype. Taxonomic designation for the various groups must await confirmation of the hypothesis by demonstration of the extent of barriers to gene flow between the groups.

}, issn = {0007-1536}, doi = {10.1016/S0007-1536(86)80097-3}, url = {http://www.sciencedirect.com/science/article/pii/S0007153686800973}, author = {Hansen, E.M. and C.M. Brasier and D.S. Shaw and P.B. Hamm} } @article {4655, title = {First Confirmation of Phytophthora lateralis in Europe}, journal = {Plant Disease}, volume = {83}, year = {1999}, month = {Jan-06-1999}, pages = {587 - 587}, abstract = {

Phytophthora lateralis, a pathogen of Chamaecyparis lawsoniana (Port-Orford cedar or Lawson{\textquoteright}s cypress), was confirmed in France, but isolates from Germany identified as P. lateralis or {\textquotedblleft}similar to{\textquotedblright} P. lateralis proved to be P. gonapodyides. Previously, P. lateralis was known only from western North America, where it has been destructive in nurseries, ornamental plantings, and the forest since its introduction about 1920 (1). Reports from other locations have proved to be misidentifications or impossible to confirm. In France, P. lateralis was isolated and identified from C. lawsoniana on two occasions (1996 and 1998) in different parts of the country, probably stemming from a single original infestation of young, potted, greenhouse-propagated cedars in a commercial nursery. German isolates were from an old culture collection and from irrigation water in a nursery growing a wide range of woody ornamentals. Identifications were confirmed by comparison (2) with authentic isolates. P. lateralis isolates from France and Oregon formed laterally proliferating, elongated obpyriform sporangia that under the conditions of our tests could be dislodged by agitation, leaving a short pedicel. Also, brown chlamydospores formed laterally on the hyphae or terminally on a short stalk and oospores were not formed on standard media. Radial growth was about 2 mm per day. In contrast, sporangia of German isolates and known P. gonapodyides isolates were similar. They exhibited nested pro liferation, were broader than P. lateralis sporangia, and were not readily dehiscent. Some P. gonapodyides isolates, including those from Germany, formed chlamydospores, but these were nearly all catenulate and not lateral, and isolates grew faster (3 to 4 mm per day). Pathogenicity was tested by stem inoculation of C. lawsoniana. P. lateralis from France and Oregon produced lesions averaging 4.7 cm after 2 months (range 2.0 to 8.1 cm, six replicates per isolate, five isolates) while the six replicates of the two German isolates averaged 1.2- and 1.6-cm lesion lengths. Furthermore, sequences of internal transcribed spacer (ITS) DNA from French and Oregon P. lateralis isolates were identical, while sequences of German isolates were similar to P. gonapodyides (J. Duncan and D. Cooke, personal communiation). P. lateralis is a dangerous pathogen of C. lawsoniana and is also pathogenic to Taxus spp. (1), although less aggressive on this host. If established, it would be a serious threat to the widespread ornamental plantings and scattered forest plantations of C. lawsoniana in Europe.

}, issn = {0191-2917}, doi = {10.1094/PDIS.1999.83.6.587B}, url = {http://apsjournals.apsnet.org/doi/10.1094/PDIS.1999.83.6.587B}, author = {Hansen, E. M. and Streito, Jean-Claude and Delatour, Claude} } @article {doi:10.1094/PDIS.1999.83.6.587B, title = {First confirmation of Phytophthora lateralis in Europe}, journal = {Plant Disease}, volume = {83}, number = {6}, year = {1999}, pages = {587-587}, doi = {10.1094/PDIS.1999.83.6.587B}, url = {http://apsjournals.apsnet.org/doi/abs/10.1094/PDIS.1999.83.6.587B}, author = {Hansen, E.M. and Streito, Jean-Claude and Delatour, Claude} } @article {4293, title = {First Report of Phytophthora pluvialis Causing Needle Loss and Shoot Dieback on Douglas-fir in Oregon and New Zealand}, journal = {Plant Disease}, volume = {99}, year = {2015}, month = {Jan-05-2015}, pages = {727 - 727}, abstract = {

Douglas-fir (DF, Pseudotsuga menziesii) is the most important forest tree in Oregon and is the second most valuable conifer in New Zealand. Phytophthora pluvialis was described (Reeser et al. 2013) from mixed evergreen forests in southwest Oregon. It was subsequently identified as the cause of red needle cast of radiata pine in New Zealand (Dick et al. 2014). There it was also isolated from chlorotic DF needles that dislodged readily from trees growing close to diseased radiata pine. In spring 2014, raintraps baited with rhododendron leaves were paired with nine 2-year-old DF seedlings at three or four locations in each of three 20- to 30-year-old DF plantations in western Oregon (11 raintraps and 99 seedlings total); control raintraps and seedlings were at two sites with no overstory (two raintraps and 18 seedlings total). Baits were collected at 2-week intervals and plated in corn meal agar (CMA) amended with natamycin, ampicillin, and rifamycin SV (CARP, Reeser et al. 2013). Symptomatic tissues from the seedlings were surface disinfested and plated in CARP. P. pluvialis was identified by sequencing the mitochondrial cox spacer region. Zoospores or sporangia produced from Oregon DF isolate 3661-NDL-041514 (GenBank KM491217) were used to inoculate four 2-year-old DF seedlings. Sporangia were induced by flooding cultures grown in pea broth with filtered stream water; zoospore release was stimulated by chilling. About 20 ml of inoculum was applied to DF seedlings using an airbrush sprayer. Two control seedlings were sprayed with filtered stream water. Inoculum contained 200 to 300 sporangia/ml or 5 {\texttimes} 104 zoospores/ml. Inoculated trees were enclosed in polyethylene bags for 48 h with supplemental mist and incubated in a growth chamber at 16 to 18{\textdegree}C with 12-h photoperiod. Symptomatic tissues were collected starting at 14 days, surface disinfested, and plated in CARP. Isolates were collected and identified as above. P. pluvialis was isolated from baits in nine of the 11 raintraps and from 54\% of seedlings across all three plantations. All isolations from control sites were negative. Overstory trees exhibited thin crowns from needle loss. Symptoms on seedlings included partial needle loss of 1- and 2-year-old needles and irregular mottled needle chlorosis. P. pluvialis was isolated from needles on 54\% of the seedlings associated with positive raintraps. Isolation success from individual symptomatic needles from locations where raintraps were positive was \~{}13\%. Twig symptoms were not visible on overstory trees, but trees were not felled for close examination. Twig symptoms on seedlings included tip dieback and stem lesions extending from bud scars. Twig symptoms developed on 37\% of seedlings from locations with positive raintraps; P. pluvialis was isolated from 47\% of these twig lesions. Needle and twig symptoms similar to those on naturally infected seedlings developed on artificially inoculated seedlings and P. pluvialis was isolated from seedlings inoculated with both sporangia and zoospores, but not from control seedlings. This is the first report of a foliar Phytophthora species on DF. There is as yet little information on epidemiology or impact in the forest in Oregon. In New Zealand, DF defoliation was most evident in plantations growing close to radiata pine plantations on sites prone to red needle cast.

}, issn = {0191-2917}, doi = {10.1094/PDIS-09-14-0943-PDN}, url = {http://apsjournals.apsnet.org/doi/10.1094/PDIS-09-14-0943-PDN}, author = {Hansen, E. M. and Reeser, P. and Sutton, W. and Gardner, J. and Williams, N.} } @article {hansen1996survival, title = {Survival of Phytophthora lateralis in infected roots of Port Orford cedar}, journal = {Plant Disease}, volume = {80}, number = {9}, year = {1996}, pages = {1075{\textendash}1078}, publisher = {[St. Paul, Minn.: American Phytopathological Society], 1980-}, issn = {0191-2917}, author = {Hansen, E.M. and P.B. Hamm} } @article {360, title = {Phytophthora nemorosa, a new species causing cankers and leaf blight of forest trees in California and Oregon, U.S.A.}, journal = {Mycotaxon}, volume = {88}, year = {2003}, pages = {129{\textendash}138}, abstract = {

Phytophthora nemorosa, a new species isolated from stem cankers on two species of Fagaceae and leaves of various hosts, is described. The new species resembles P. ilicis with homothallic, amphigynous antheridia and deciduous, semi-papillate sporangia, and has a related ITS-DNA sequence. Symptoms and host range are similar to P. ramorum, cause of Sudden Oak Death and leaf blight and shoot dieback diseases in California and Oregon forests, although P. nemorosa does not appear to cause wide-spread mortality of oak trees.

}, keywords = {Lithocarpus densiflorus, Phytophthora ilicis, Phytophthora ramorum, Quercus agrifolia, Umbellularia californica}, url = {http://www.mycotaxon.com/vol/abstracts/88/88-129.html}, author = {Hansen, E.M. and P. Reeser and J. M. Davidson and Garbelotto, M. and K. Ivors and L. Douhan and D. M. Rizzo} } @article {4633, title = {Redesignation of Phytophthora taxon Pgchlamydo as Phytophthora chlamydospora sp. nov.}, journal = {North American Fungi}, volume = {10}, year = {2015}, pages = {1{\textendash}14}, abstract = {

A new species, Phytophthora chlamydospora, is described. P. chlamydospora, previously known informally as P. taxon Pgchlamydo, is found in streams and wet soil worldwide and is a pathogen of some riparian tree species. It is self-sterile, and produces persistent non-papillate sporangia, usually on unbranched sporangiophores. Clamydospores are formed most regularly at warmer temperatures. Phytophthora chlamydospora is classified in ITS Clade 6.

}, keywords = {chlamydospora, new species, Pg chlamydo, Phytophthora, soil, streams}, issn = {1937-786X}, url = {https://www.pnwfungi.org/index.php/pnwfungi/article/view/1414}, author = {Everett Hansen and Paul Reeser and Wendy Sutton and Clive Brasier} } @article {4654, title = {Phytophthora species in oak forests of north-east France}, journal = {ANNALS OF FOREST SCIENCE}, volume = {56}, year = {1999}, month = {Jan-01-1999}, pages = {539 - 547}, abstract = {

Phytophthora species were surveyed from the end of 1997 through July 1998 in oak forests in NE France. Healthy (Amance) or declining (Illwald) forests were compared. The Phytophthora population in both was diverse and locally abundant. At least eight species were present at Amance and six at Illwald. At Amance Phytophthora species had a localized distribution in water and low-lying soils. At Illwald distribution was more uniform apparently due to flooding events. Most often recovered were P. citricola, P. gonapodyides and P. quercina. P. gonapodyides was ubiquitous in water and colonized leaf debris. P. quercina was widely distributed in soil but not abundant, and was found in sites that did not otherwise appear to favor Phytophthora. No correlation was detected between presence of Phytophthora in soil and health of trees. Unusual combinations of environmental factors may be required for resident Phytophthora to have a detrimental impact on oaks. {\textcopyright} 1999 Editions scientifiques et m{\'e}dicales Elsevier SAS.

}, issn = {0003-4312}, doi = {10.1051/forest:19990702}, url = {http://www.afs-journal.org/10.1051/forest:19990702}, author = {Hansen, Everett and Delatour, Claude} } @article {4069, title = {First report of Phytophthora plurivora causing collar rot on common alder in Spain}, journal = {Plant Disease}, volume = {98}, year = {2013}, month = {03/2014}, pages = {425}, abstract = {

Phytophthora decline of riparian alder (Alnus spp.) has been reported in several European countries. Death of common alder (Alnus glutinosa) due to Phytophthora alni has also been reported in Spain. During several surveys of alder trees in September 2012, typical die-back symptoms, including sparse small yellowish foliage and the presence of rusty exudates on the bark at the collar and lower stem were observed in A.glutinosa growing on the banks of the river Tera (Langa de Duero, Soria, 41{\textdegree}36'34"N, 3{\textdegree}25'10"W, elevation 851 m) and the river Tormes (La Maya, Salamanca, 40{\textdegree}41'42"N, 5{\textdegree}35'36"W, elevation 833 m). Bark samples plus cambium were taken from the active lesions at collar region, cut into small pieces, dried on filter paper and plated on V8-PARPH agar. The samples were incubated for four days at 20 {\textdegree}C in the dark before obtaining the Phytophthora isolates. Colonies developed on V8 juice agar (V8A) had limited aerial mycelium at the centre and displayed radiate and slightly chrysanthemum-like growth pattern. Mycelial growth was optimal at 25 {\textdegree}C (radial growth rate, 8.2 mm d-1), whereas no growth was observed at 32 {\textdegree}C. Isolates were homothallic with paragynous antheridia, smooth-walled spherical (very rarely elongated) oogonia (22.8{\textendash}30.6 μm diam.) and both plerotic and aplerotic golden brown oospores (21.3{\textendash}28.5 μm diam.). In non sterile soil extracts, the isolates produced abundant sporangia (31.5{\textendash}57.2 {\texttimes} 21.3{\textendash}38.4 μm; length:breadth ratio 1.2 to 1.6) borne terminally on unbranched or sympodial sporagiophores, occasionally attached laterally to the sporangiophores. Sporagia were non-caducous, semipapillate, mainly ovoid and obpyriform, obovoid to limoniform but sometimes distorted with two apices. On the basis of the morpho-physiological features, the isolates resembled P. plurivora (formerly identified as P. citricola). To confirm this, genomic DNA was extracted and subjected to Polymerase Chain Reaction (PCR). The internal transcribed spacer (ITS) region of the rDNA was amplified using the ITS-6 (5{\textquoteright} GAA GGT GAA GTC GTA ACA AGG 3{\textquoteright}) and ITS-4 (5{\textquoteright} TCC TCC GCT TAT TGA TAT GC 3{\textquoteright}) primers before sequencing (Secugen, Madrid, Spain). The sequences were deposited in the EMBL/GenBank database (GenBank Accession No. KF413074 and KF413075). In order to perform the pathogenicity test, 10 A. glutinosa seedlings (two-year-old) per isolate were inoculated by using the under bark inoculation technique and 10 control seedlings were inoculated with V8A. Seedlings were incubated in a growth chamber at 22.5 {\textordmasculine}C with a 14-h photoperiod. Three months after inoculation, all inoculated plants wilted and died, whereas the control plants showed no disease symptoms. To fulfil Koch{\textquoteright}s postulates, the pathogen was re-isolated from the necrotic lesions developed around inoculation points, thus confirming its pathogenicity. Phytophthora plurivora has been found to be present in rhizosphere soil beneath Alnus spp. and to cause aerial canker and collar rot on alder trees in Austria, Germany and Romania. Further studies and surveys are essential to determine the distribution, extent of damage and potential interactions with other alder pathogens (e.g. P. alni). To our knowledge, this is the first record of P. plurivora affecting A. glutinosa in Spain.

}, issn = {0191-2917}, doi = {10.1094/PDIS-07-13-0784-PDN}, url = {http://dx.doi.org/10.1094/PDIS-07-13-0784-PDN }, author = {Haque, Mohammed Masum Ul and Mart{\'\i}nez-{\'A}lvarez, Pablo and Lomba, {\'e} Mar{\'\i}a and Mart{\'\i}n-Garc{\'\i}a, Jorge and Diez, Julio Javier} } @article {4288, title = {Variation in pathogenicity among the three subspecies of Phytophthora alni on detached leaves, twigs and branches of Alnus glutinosa}, journal = {Forest Pathology}, volume = {45}, year = {2015}, month = {December 2015}, pages = {484{\textendash}491}, abstract = {

Pathogenicity tests were carried out on leaves, twigs and branches of Alnus glutinosa using several isolates of Phytophthora alni ssp. alni, P.\ alni ssp. multiformis and P.\ alni ssp. uniformis in\ vitro. Healthy fresh leaves were collected from disease-free areas and inoculated with mycelium on agar discs or by dipping in zoospore suspensions. In addition, twigs and branches were collected from both disease-free and disease-affected areas, inoculated with mycelium on agar discs and incubated at four temperatures (15, 20, 25, 30{\textdegree}C). All subspecies tested were pathogenic but with varied level of virulence. In inoculation tests on foliage, wounding was a key factor in causing infections: lesions on inoculated wounded leaves were larger than on non-wounded leaves. In the twig and branch inoculation tests, no differences in virulence were observed among the P.\ alni subspecies in terms of sampling locations, but lesions differed in size according to incubation temperature, with the largest lesions occurring on tissues incubated at 25{\textdegree}C. The work is the first to report foliar necrosis caused by P.\ alni on A.\ glutinosa. P.\ alni ssp. uniformis was the least virulent of the subspecies in branch inoculations. These findings demonstrate that various tissues of A.\ glutinosa could act as sources of pathogen inoculum and may disseminate alder Phytophthora in natural ecosystems.

}, doi = {10.1111/efp.12198}, url = {http://doi.wiley.com/10.1111/efp.12198}, author = {Haque, M. M. U. and Mart{\'\i}n-Garc{\'\i}a, J. and Diez, J. J.} } @article {4470, title = {Temporal metabolic profiling of the Quercus suber - Phytophthora cinnamomi system by middle-infrared spectroscopy}, journal = {Forest Pathology}, volume = {46}, year = {2016}, month = {Jan-04-2016}, pages = {122 - 133}, abstract = {

The oomycete Phytophthora cinnamomi is an aggressive plant pathogen, detrimental to many ecosystems including cork oak (Quercus suber) stands, and can inflict great losses in one of the greatest {\textquoteleft}hotspots{\textquoteright} for biodiversity in the world. Here, we applied Fourier transform-infrared (FT-IR) spectroscopy combined with chemometrics to disclose the metabolic patterns of cork oak roots and P.\ cinnamomi mycelium during the early hours of the interaction. As early as 2\ h post-inoculation (hpi), cork oak roots showed altered metabolic patterns with significant variations for regions associated with carbohydrate, glycoconjugate and lipid groups when compared to mock-inoculated plants. These variations were further extended at 8\ hpi. Surprisingly, at 16\ hpi, the metabolic changes in inoculated and mock-inoculated plants were similar, and at 24\ hpi, the metabolic patterns of the regions mentioned above were inverted when compared to samples collected at 8\ hpi. Principal component analysis of the FT-IR spectra confirmed that the metabolic patterns of inoculated cork oak roots could be readily distinguished from those of mock-inoculated plants at 2, 8 and 24\ hpi, but not at 16\ hpi. FT-IR spectral analysis from mycelium of P.\ cinnamomi exposed to cork oak root exudates revealed contrasting variations for regions associated with protein groups at 16 and 24\ h post-exposure (hpe), whereas carbohydrate and glycoconjugate groups varied mainly at 24\ hpe. Our results revealed early alterations in the metabolic patterns of the host plant when interacting with the biotrophic pathogen. In addition, the FT-IR technique can be successfully applied to discriminate infected cork oak plants from mock-inoculated plants, although these differences were dynamic with time. To a lesser extent, the metabolic patterns of P.\ cinnamomi were also altered when exposed to cork oak root exudates.

}, doi = {10.1111/efp.2016.46.issue-210.1111/efp.12229}, url = {http://doi.wiley.com/10.1111/efp.2016.46.issue-2http://doi.wiley.com/10.1111/efp.12229http://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111\%2Fefp.12229}, author = {Hardoim, P. R. and Guerra, R. and Rosa da Costa, A. M. and Serrano, M. S. and Sanchez, M. E. and Coelho, A. C.}, editor = {Stenlid, J.} } @article {4689, title = {Insights into the potential host range of Phytophthora foliorum}, journal = {Forest Pathology}, volume = {49}, year = {2019}, month = {Sep-18-2019}, pages = {e12556}, abstract = {

During a survey for Phytophthora ramorum undertaken in north-west Scotland in early 2016, Phytophthora foliorum was found infecting foliage of the invasive shrub Rhododendron ponticum. Prior to this, P.\ foliorum had only been reported from foliage of hybrid azaleas in nurseries in California and Tennessee and from azalea plants in an ornamental nursery in Spain. No other hosts were known, and much of the behaviour of P.\ foliorum remained enigmatic. The species is classified in Phytophthora Clade 8c, with closest relatives, P.\ ramorum and Phytophthora lateralis, both of which are highly damaging tree pathogens. To explore the threat that P.\ foliorum might pose to trees, its growth{\textendash}temperature responses on agar media and ability to cause lesions in the living bark of various hosts were contrasted with the behaviours of P.\ ramorum and P.\ lateralis. Phytophthora foliorum proved faster growing and more tolerant of temperature extremes than the other Phytophthora species. Comparisons of bark colonization initially focussed on R.\ ponticum and larch species Larix decidua and Larix kaempferi as all three are significant hosts of P.\ ramorum in the UK. Further experiments included another P.\ ramorum host, Fagus sylvatica (European beech), and the main host of P.\ lateralis, Chamaecyparis lawsoniana (Lawson cypress). Findings suggested that as well as being a significant pathogen of R.\ ponticum, damage caused by P.\ foliorum to both species of larch and beech was very similar to that of the EU1 lineage of P.\ ramorum, although growth in host tissue was also influenced by season.

}, doi = {10.1111/efp.v49.610.1111/efp.12556}, url = {https://onlinelibrary.wiley.com/doi/10.1111/efp.12556}, author = {Harris, Anna R. and Webber, Joan F.} } @article {4708, title = {Fitness characteristics of the European lineages of Phytophthora ramorum}, journal = {Plant Pathology}, volume = {70}, year = {2021}, month = {Oct-12-2020}, pages = {275 - 286}, abstract = {

As an introduced pathogen, Phytophthora ramorum exists as four near-clonal evolutionary lineages, of which only EU1 and EU2 are established in the UK. EU1 has become widespread since the first findings in 2002 whereas EU2, detected in 2011, has a more limited distribution. Both lineages are epidemic in plantation-grown larch, sporulating asexually on needles, but also causing heavy dieback and mortality. To understand whether EU1 and EU2 pose different threats to forest health, we compared their growth characteristics on agar, pathogenicity on several hosts, and sporulation on Japanese larch needles. When pathogenicity was evaluated by measuring colonization at 20\ {\textdegree}C in mature bark (phloem) of Japanese and European larch (Larix kaempferi and L. decidua), English oak (Quercus robur), and beech (Fagus sylvatica), Japanese larch was the most susceptible and oak the least susceptible. On average, EU2 isolates produced significantly larger lesions than EU1 isolates in Japanese larch and oak although not in the other hosts. With tests using young saplings of Japanese and European larch, damaging bark lesions formed at both 10\ {\textdegree}C and 20\ {\textdegree}C, but EU2 was significantly more pathogenic at 20\ {\textdegree}C on both hosts compared with EU1. In contrast, both lineages caused similar amounts of necrosis on inoculated leaves of rhododendron (Rhododendron ponticum). Moreover, EU2 isolates usually sporulated less abundantly on larch needles compared with EU1 isolates, suggesting a trade-off in pathogenicity and sporulation between lineages. As EU2 tends to have smaller sporangia than EU1, this could also reduce the inoculum potential of EU2.

}, issn = {0032-0862}, doi = {10.1111/ppa.v70.210.1111/ppa.13292}, url = {https://bsppjournals.onlinelibrary.wiley.com/doi/abs/10.1111/ppa.13292?af=R}, author = {Harris, Anna R. and Brasier, Clive M. and Scanu, Bruno and Webber, Joan F.} } @article {4557, title = {Sporulation potential, symptom expression and detection of Phytophthora ramorum on larch needles and other foliar hosts}, journal = {Plant Pathology}, volume = {65}, year = {2016}, month = {Jan-12-2016}, pages = {1441 - 1451}, abstract = {

Phytophthora ramorum has caused extensive dieback and mortality of commercially grown Japanese larch (Larix kaempferi) in many parts of the UK, as infected foliage generates spores that then cause bark lesions and girdling cankers on trees. Following inoculation, individual needles of Japanese, European (L.\ decidua) and hybrid (L.\ {\texttimes}\ eurolepis) larch infected with P.\ ramorum can produce thousands of sporangia. Mean numbers of sporangia ranged from 806 to 1778 per cm2 (hybrid larch and Japanese larch, respectively), surpassing mean sporulation levels on foliar hosts previously associated with P.\ ramorum outbreaks in Britain, namely Rhododendron ponticum, Castanea sativa and Vaccinium myrtillus. Sporulation on larch even exceeded that of California bay laurel (Umbellularia californica), which drives the sudden oak death epidemic in California. Inoculation of foliage selected at different times of year revealed that foliage age significantly affected sporulation levels, but this varied with host species. However, symptom development and sporulation were often not correlated. Symptoms on larch were frequently insignificant or even absent at certain times of year, with sometimes the only evidence of infection being the emergence of sporangia from needles, without any sign of discolouration or necrosis. Plating infected but symptomless needles onto Phytophthora selective medium also often failed to yield the pathogen. Symptomless infection of larch needles apparently occurs, but is only detectable with microscopy. More generally, it is suggested that diagnosis of Phytophthora infection in conifers is often underestimated due to isolation difficulties and delayed symptom expression.

}, doi = {10.1111/ppa.2016.65.issue-910.1111/ppa.12538}, url = {https://doi.org/10.1111/ppa.12538 }, author = {Harris, A. R. and Webber, J. F.} } @inbook {4177, title = {Phytophthora omnivora (Phytophthora fagi und Peronospora sempervivi)}, booktitle = {Lehrbuch der Baumkrankheiten}, year = {1882}, pages = {42-46}, publisher = {Verlag von Julius Springer}, organization = {Verlag von Julius Springer}, address = {Berlin}, author = {Hartig, R.} } @article {4176, title = {Der Buchenkeimlingspilz, Phytophthora (Peronospora fagi M). (The beech seedling fungus Phytophthora (Peronospora fagi M))}, journal = {Untersuchungen aus dem Forstbotanischen Institut zu M{\"u}nchen}, volume = {1}, year = {1880}, pages = {33-57}, author = {Hartig, R.} } @article {4175, title = {Die Buchencotyledonen-Krankheit (The cotyledon disease of beech)}, journal = {Zeitschrift f{\"u}r Forst- und Jagdwissenschaft}, volume = {8}, year = {1876}, pages = {117-123}, author = {Hartig, R.} } @article {4178, title = {Beschadigung der Nadelhozsaatbeete durch Phytophthora omnivora (Fagi). (Damage in conifer seed beds by Phytophthora omnivora [Fagi]}, journal = {Forstwissenschaftliches Centralblatt}, volume = {27}, year = {1883}, pages = {593-596}, author = {Hartig, R.} } @article {412, title = {Austrocedrus chilensis: contribution to the study of its mortality in Argentina (Austrocedrus chilensis: contribuci{\'o}n al estudio de su mortalidad en Argentina)}, journal = {Bosque (Valdivia)}, volume = {10}, year = {1989}, pages = {29-36}, url = {http://mingaonline.uach.cl/scielo.php?pid=S0717-92001989000100004\&script=sci_arttext}, author = {Havrylenko, M and Rosso, P. H. and Fontela, SB} } @article {962, title = {Detection and quantification of Phytophthora ramorum from California forests using a real-time polymerase chain reaction assay-0}, journal = {Phytopathology}, volume = {94}, year = {2004}, pages = {1075-1083}, abstract = {

The timely and accurate detection of pathogens is a critical aid in the study of the epidemiology and biology of plant diseases. In the case of regulated organisms, the availability of a sensitive and reliable assay is essential when trying to achieve early detection of the pathogen. We developed and tested a real-time, nested polymerase chain reaction (PCR) assay for the detection of Phytophthora ramorum, causal agent of sudden oak death. This technique then was implemented as part of a widespread environmental screen throughout California. The method here described is sensitive, detecting less than 12 fg of pathogen DNA, and is specific for P. ramorum when tested across 21 Phytophthora spp. Hundreds of symptomatic samples from 33 sites in 14 California counties were assayed, resulting in the discovery of 10 new host species and 23 infested areas, including 4 new counties. With the exception of a single host, PCR-based discovery of new hosts and infested areas always was confirmed by traditional pathogen isolations and inoculation studies. Nonetheless, molecular diagnostics were key in early pathogen detection, and steered the direction of further research on this newly discovered and generalist Phytophthora species.

}, doi = {DOI: 10.1094/PHYTO.2004.94.10.1075}, url = {http://apsjournals.apsnet.org/doi/abs/10.1094/PHYTO.2004.94.10.1075}, author = {Katherine J. Hayden and David Rizzo and Justin Tse and Garbelotto, Matteo} } @article {Hayden20111781, title = {Will all the trees fall? Variable resistance to an introduced forest disease in a highly susceptible host}, journal = {Forest Ecology and Management}, volume = {261}, number = {11}, year = {2011}, pages = {1781 - 1791}, abstract = {

Although tanoak (Notholithocarpus densiflorus syn. Lithocarpus densiflorus) is the species most affected by the introduced pathogen Phytophthora ramorum, with demonstrable risk of extirpation, little is known about the origin, range or structuring of the tree{\textquoteright}s susceptibility. We examined variation in resistance to P. ramorum using a wound inoculation assay of detached leaves from trees at five geographically separated sites, and a non-wound inoculation assay on twigs from trees at two sites. The structure of variation in resistance was compared to the structure at nine nuclear microsatellite markers. Resistance varied quantitatively, with 23\% and 12\% of the variation among individuals and populations, respectively. There was a significant correlation between resistance in detached leaves and lesion size in non-wounding twig inoculations. Among-population genetic diversity at nine microsatellite loci was weakly structured but significantly non-zero, with 9.5\% of variation among populations. Within-population neutral genetic diversity was a poor predictor of resistance, and estimates of phenotypic distances for resistance were no greater than neutral genetic distances. The limited phenotypic and genetic structure we found indicates that tanoaks at all study sites are susceptible, and there is no evidence of prior selection for disease resistance. We conclude that tanoak populations across the species{\textquoteright} range are at risk, but local disease dynamics will depend on both host genetics and environmental conditions.

}, keywords = {Sudden oak death}, issn = {0378-1127}, doi = {DOI: 10.1016/j.foreco.2011.01.042}, url = {http://www.sciencedirect.com/science/article/B6T6X-52F7TF6-1/2/55216e9ccfc0fafe0035e3d3f20ff81b}, author = {Katherine J. Hayden and Alejandro Nettel and Richard S. Dodd and Garbelotto, Matteo} } @article {4245, title = {First Report of Phytophthora hedraiandra Causing Rhododendron Dieback and Root Rot of Common Beech in the Czech Republic}, journal = {Plant Disease}, volume = {98}, year = {2014}, month = {10/2014}, pages = {1434 - 1434}, abstract = {

From 2010 to 2012, Phytophthora isolates were obtained from brownish diffusion leaf lesions usually up to 2 to 3 cm in diameter of Rhododendron caucasicum {\textquoteleft}Cheer,{\textquoteright} from withered twigs of Rhododendron sp. with blackish elongated lesions up to ~5 cm in length, and from rotten feeder roots of 2-year-old, chlorotic, wilting seedlings of Fagus sylvatica collected from ornamental and forest nurseries in three areas (central and eastern Bohemia and northern Moravia) in the Czech Republic. Isolates formed chrysanthemum-like to slightly stellate, appressed colonies with sparse aerial mycelium on V8 agar (V8A) plates at 20{\textdegree}C after 5 days, whereas on carrot agar (CA) plates the pattern was vague with no aerial mycelium. The cardinal growth temperatures were: min. 3{\textdegree}C, optimum 23 to 27{\textdegree}C, and max. 31{\textdegree}C. Radial growth was 5.7 to 6.6 mm/day at 20{\textdegree}C on V8A. The isolates were homothallic and produced colorless, smooth-walled, spherical oogonia with an average diameter 29.9 to 33.8 μm on CA. Oospores were aplerotic (avg. 26.4 to 29.3 μm), oospore wall was hyaline and averaged 1.3 to 1.7 μm thick, oospore wall index was 0.26 to 0.32. Paragynous or occasionally amphigynous antheridia averaged 13.4 to 15.0 {\texttimes} 10.9 to 12.5 μm (height {\texttimes} width). Sporangia were caducous, papillate, globose, spherical to ovoid, with short pedicels (avg. 2.1 to 2.6 μm) and averaged 30.9 to 41.5 {\texttimes} 25.5 to 30.6 μm, L:B ratio was 1.2 to 1.4. Chlamydospores were not observed. Morphological characters resembled those described for P. hedraiandra (1). The isolates were deposited in the collection of phytopathogenic oomycetes of RILOG Pruhonice and given accession nos. 450.11, 531.11, and 578.12. The isolates were sequenced for nuclear rDNA ITS region and partial Cox I gene. Obtained sequences were compared with sequences present in GenBank database using BLAST. The ITS sequences of all isolates (GenBank Accession Nos. KJ567081, 82, and 83) of overall length of 792 bp were identical to that of P. hedraiandra AY707987 (1). The Cox I sequences of overall length of 880 bp (KJ567084, 85, and 86) showed 99\% homology (1 bp substitution) with AY769115 (1) and 100\% identity with other Cox I sequences of P. hedraiandra, i.e., JN376067 (4) and EF174432 (3). Koch{\textquoteright}s postulates were confirmed by wound-inoculating of 3-year-old rhododendron and common beech plants (10 host plants per corresponding isolate). Rhododendron leaves were gently abraded near the midrib, whereas 5-mm-diameter bark plugs were removed from the beech collars. The inoculum (5-mm-diameter V8A plug with actively growing mycelium) was placed over wounds and sealed with Parafilm. Control plants were treated in the same manner with sterile agar plugs. Plants were maintained in a greenhouse at 22{\textdegree}C. All inoculated plants showed disease symptoms after 10 days of incubation; the lesions were up to 2 cm in rhododendron leaves and ~1 cm in beech collars. Control plants remained healthy. The pathogen was re-isolated from all infected plants. To our knowledge, this is the first report of P. hedraiandra in the Czech Republic. Besides it, the pathogen was found in southern and western Europe (Italy, Slovenia, Spain, the Netherlands) and in the United States (2)

}, issn = {0191-2917}, doi = {10.1094/PDIS-04-14-0339-PDN}, url = {http://apsjournals.apsnet.org/doi/abs/10.1094/PDIS-04-14-0339-PDN}, author = {Hejna, M. and Cerny, K. and Havrdova, L. and Mrazkova, M.} } @article {4604, title = {Morphological and genetic analyses of the invasive forest pathogen Phytophthora austrocedri reveal that two clonal lineages colonized Britain and Argentina from a common ancestral population}, journal = {Phytopathology}, volume = {107}, year = {2017}, month = {Jan-12-2017}, pages = {1532 - 1540}, abstract = {

Phytophthora austrocedri is causing widespread mortality of Austrocedrus chilensis in Argentina and Juniperus communis in Britain. The pathogen has also been isolated from J. horizontalis in Germany. Isolates from Britain, Argentina, and Germany are homothallic, with no clear differences in the dimensions of sporangia, oogonia, or oospores. Argentinian and German isolates grew faster than British isolates across a range of media and had a higher temperature tolerance, although most isolates, regardless of origin, grew best at 15{\textdegree}C and all isolates were killed at 25{\textdegree}C. Argentinian and British isolates caused lesions when inoculated onto both A. chilensis and J. communis; however, the Argentinian isolate caused longer lesions on A. chilensis than on J. communis and vice versa for the British isolate. Genetic analyses of nuclear and mitochondrial loci showed that all British isolates are identical. Argentinian isolates and the German isolate are also identical but differ from the British isolates. Single-nucleotide polymorphisms are shared between the British and Argentinian isolates. We concluded that British isolates and Argentinian isolates conform to two distinct clonal lineages of P. austrocedri founded from the same as-yet-unidentified source population. These lineages should be recognized and treated as separate risks by international plant health legislation.

}, issn = {0031-949X}, doi = {10.1094/PHYTO-03-17-0126-R}, url = {https://apsjournals.apsnet.org/doi/10.1094/PHYTO-03-17-0126-Rhttps://apsjournals.apsnet.org/doi/pdf/10.1094/PHYTO-03-17-0126-R}, author = {Henricot, B{\'e}atrice and P{\'e}rez-Sierra, Ana and Armstrong, April C. and Sharp, Paul M. and Green, Sarah} } @article {4044, title = {Studies on the chemical control of Phytophthora palmivora (Butl.) Butl. on Theobroma cacao L. in Nigeria.}, journal = {Annals of Applied Biology}, volume = {52}, year = {1963}, month = {12/1963}, pages = {465 - 480}, abstract = {

In laboratory trials, phenyl mercury nitrate at 0{\textperiodcentered}02 p.p.m. and fentin acetate at 0{\textperiodcentered}2 p.p.m. severely retarded growth of four isolates of Phytophthora palmivora on cassava agar. These two chemicals, with captan, maneb and a dithiocarbamate-copper chelate, were also highly toxic to encysted zoospores of a {\textquoteleft}rubber{\textquoteright} group isolate of P. palmivora.

Deposits of captan on pods were readily removed by artificial rain, but some improvement in tenacity was obtained by the addition of a sticker. In other laboratory trials, the deposit from low-volume sprays of cuprous oxide dried more quickly on pods than that from high-volume sprays but showed no advantage in subsequent resistance to weathering.

In a field trial in 1961, seven fungicide treatments were applied three-weekly and compared with an unsprayed control. The lowest percentage black-pod infection followed treatment with fentin acetate: Bordeaux mixture and carbide Bordeaux both gave good control. The captan treatments were completely ineffective. More black pods were harvested from close-spaced trees than from those wide-spaced.

Weekly applications of 0{\textperiodcentered}15\% fentin acetate to seedlings induced no significant damage.

In a field trial made in 1962 very heavy rainfall provided a severe test of the fungicides, the most effective being Bordeaux mixture and carbide Bordeaux mixture applied three-weekly, carbide Bordeaux mixture applied four-weekly and fentin acetate applied two-weekly. Captan with added sticker was again no better than the control. There was no marked effect of spacing.

Comparisons of Bordeaux and carbide Bordeaux mixtures made at two other sites in 1962 showed no difference in disease control. It is suggested that carbide Bordeaux mixture could be replaced by the cheaper preparation made with lime.

}, issn = {0003-4746}, doi = {10.1111/aab.1963.52.issue-310.1111/j.1744-7348.1963.tb03770.x}, url = {http://onlinelibrary.wiley.com/doi/10.1111/j.1744-7348.1963.tb03770.x/abstract;jsessionid=FA42764CD24DC2258C2776AF065DAB4F.d01t01}, author = {Hislop, E. C.} } @article {ho2002phytophthora, title = {Phytophthora cinnamomi var. robiniae var. nova on black locust in jiangsu province of China}, journal = {Mycotaxon}, volume = {82}, year = {2002}, pages = {391{\textendash}396}, publisher = {Mycotaxon}, issn = {0093-4666}, author = {Ho, HH} } @article {698, title = {Synoptic keys to the species of Phytophthora}, journal = {Mycologia}, volume = {73}, year = {1981}, pages = {705-714}, publisher = {Mycological Society of America}, abstract = {

Three synoptic keys to the species of Phytophthora are presented to facilitate identification of, respectively, the plant pathogenic species in culture, the plant pathogenic species known only on hosts, and the aquatic species.

}, url = {http://www.jstor.org/stable/3759497}, author = {Ho, HH} } @article {4045, title = {Efficacy of Neutralised Phosphonic Acid (Phosphorous Acid) Against Phytophthora Palmivora Pod Rot and Canker of Cocoa.}, journal = {Australasian Plant Pathology}, volume = {19}, year = {1990}, month = {1990}, pages = {130}, abstract = {

In comparative trials under a wide range of environmental conditions and management inputs, injection of cocoa trees with partially pH-neutralised phosphonic acid (H3PO3) gave similar, or better, control of pod rot caused by Phytophthora palmivora to that obtained with metalaxyl/cuprous oxide pod sprays. lnjection reduced canker incidence by up to 90\% at some sites. Foliar sprays of phosphonic acid had little effect on yield or pod rot incidence at rates up to 24 g a.i./tree/application. Studies to determine the optimum dose and frequency of injection have shown a clear benefit of treatment, with both increased yields and reduced pod rot incidence, but no yield advantage was obtained through high dose rates. Alginate gel paints and direct root uptake were evaluated as alternative application methods, but were less effective than injection. H3PO3 was ineffective against vascular-streak dieback disease of cocoa, caused by Oncobasidium theobromae.

}, issn = {0815-3191}, doi = {10.1071/APP9900130}, url = {http://link.springer.com/article/10.1071\%2FAPP9900130}, author = {Holderness, M} } @article {ChuanxueHong03012011, title = {Phytophthora pini Leonian resurrected to distinct species status}, journal = {Mycologia}, volume = {103}, number = {2}, year = {2011}, pages = {351-360}, abstract = {

Phytophthora pini was named by Leonian in 1925, but this species was largely ignored until 1956 and then merged with P. citricola by Waterhouse in 1963. This study compared the ex-type and ex-authentic cultures of these two species with isolates of P. plurivora and the P. citricola subgroups Cil I and III reported previously. Examination of these isolates revealed that the ex-type culture of P. pini is identical to P. citricola I. Phytophthora pini Leonian therefore is resurrected to distinct species status and redescribed here with a Latin description, replacing P. citricola I. Molecular, physiological and morphological descriptions of this species are presented. The molecular description includes DNA sequences of five nuclear and mitochondrial regions as well as PCR-SSCP fingerprints. The relationship among the above species and other species recently segregated from the P. citricola complex also is discussed.

}, doi = {10.3852/10-058}, url = {http://www.mycologia.org/cgi/content/abstract/103/2/351}, author = {Hong, Chuanxue and Gallegly, Mannon E. and Richardson, Patricia A. and Kong, Ping} } @article {4081, title = {Crown rot of Abies balsamea var. phanerolepis caused by Phytophthora cactorum in Virginia}, journal = {Plant Disease}, volume = {89}, year = {2005}, month = {04/2005}, pages = {433 - 433}, abstract = {

In early July 2004, a severe crown rot of Canaan fir (Abies balsamea var. phanerolepis Fern.) was reported to the Virginia Cooperative Extension, Frederick County Office, and subsequently to the Virginia Tech Disease Clinic in Virginia Beach. One thousand five-year-old Canaan fir transplants (approximately 11 mm in caliper and 31 cm high) had been purchased from a tree nursery in Oregon and planted in the field in Frederick County, VA, in April of 2004. The field site had not been cultivated for 4 years after an apple orchard had been removed in 2000. By mid-May, needle browning had become serious, affecting the lower crown first. By August, transplants had suffered 40\% mortality. Basal stems of affected plants were obviously discolored. Root and basal stem samples from several infected plants were then cultured on PARP-V8 agar on three different dates. Phytophthora sp. isolates were recovered from all stem samples but none from the roots. These isolates produced a large number of papillate sporangia that were caducous with short pedicels. Abundant oogonia with paragynous antheridia formed oospores directly on isolation plates within 7 days. The isolates were keyed as P. cactorum (2). This identification was confirmed using a single-strand-conformation polymorphism analysis of ribosomal DNA internal transcribed spacer (ITS)-1 (4). It appears that the source of inoculum was P. cactorum associated with the previous apple crop, since Canaan fir from the same transplant lot planted in a nearby field without a history of apples remained healthy. P. cactorum has been reported to cause root rot of noble fir (A. procera Rhedo), Pacific silver fir (A. amabilis (Dougl.) Forbes), and Shasta red fir (A. magnifica var. shastensis Lemm.) in the Pacific Northwest (3). It has also caused crown rot of Fraser fir (A. fraseri (Pursh) Poir.), noble fir, white fir (A. concolor (Gord. \& Glend.) Lindl.), and balsam fir (A. balsamea (L.) Mill.) in Michigan (1). To our knowledge, this is the first report of P. cactorum attacking Canaan fir. Canaan fir currently is a recommended Christmas tree species for areas where Fraser fir does not do well due to root rot caused by Phytophthora cinnamomi. This study suggests that such a recommendation must be used with caution. Growing Canaan fir trees in P. cactorum-infested soil could result in devastating crop losses as reported in this note.

}, issn = {0191-2917}, doi = {10.1094/PD-89-0433B}, url = { http://dx.doi.org/10.1094/PD-89-0433B }, author = {Hong, C. X. and Marston, C. D.} } @article {4229, title = {Decline in vitality of propagules of Phytophthora pluvialis and Phytophthora kernoviae and their inability to contaminate or colonise bark and sapwood in Pinus radiata export log simulation studies}, journal = {New Zealand Journal of Forestry Science}, volume = {44}, year = {2014}, month = {Jan-12-2014}, pages = {13 pp}, abstract = {

Background: Phytophthora pluvialis Reeser, W.L. Sutton \& E.M. Hansen is the cause of a newly described disease, red needle cast, in certain stands of Pinus radiata D. Don in New Zealand that experience periodic foliage browning, while Phytophthora kernoviae Brasier, Beales \& Kirk is also infrequently isolated from symptomatic needles.

Methods: Studies were undertaken to test the possibility that these species may be transported on pine logs either as superficial contaminants or as colonists of bark or wood.

Results: Pine-needle baiting found no evidence of Phytophthora species in bark samples or aqueous bark washes from stems of 603 symptomatic trees in 17 affected stands implying that survival after natural deposition of sporangia or zoospores is low or absent. The persistence of zoospores or oospores was evaluated at intervals after applying them at artificially high surface densities to the bark on log segments and incubating at five temperatures between 15{\textdegree}C and 35{\textdegree}C in the laboratory. The ability to re-isolate Phytophthora kernoviae decreased with time and increasing temperature, but this species was s till obtained at low frequencies after 4 weeks at 15{\textdegree}C and 20{\textdegree}C following treatment with oospores of Phytophthora kernoviae. Phytophthora pluvialis could not be isolated under any conditions of time or temperature tested. Percentage vitality of oospores of both species as determined using tetrazolium bromide vital staining also decreased with time, although some oospores of both species remained alive after 4 weeks at all temperatures tested. In a further study to test potential log colonisation, Phytophthora spp. were not isolated from bark or xylem at or near points where zoospores, oospores or mycelium of either species were applied to the bark or sapwood of pine segments and incubated for 6 weeks under ambient or humid conditions at 17{\textdegree}C.

Conclusion: The results of these studies suggest that occurrence of Phytophthora kernoviae or Phytophthora pluvialis on export logs from affected stands is negligible. In addition, although some remained alive, the substantial decline in vitality among artificially applied oospores implies that the survival of any few that may be naturally present on logs is likely to be slight. Based on the evidence from this work there appears to be little risk of transporting these Phytophthora species on New Zealand radiata pine logs.

}, doi = {10.1186/s40490-014-0007-6}, url = {http://www.nzjforestryscience.com/content/44/1/7}, author = {Hood, Ian A and Williams, Nari M and Dick, Margaret A and Arhipova, Natalija and Kimberley, Mark O and Scott, Peter M and Gardner, Judy F} } @article {4456, title = {Phosphorus acid for controlling Phytophthora {\textquoteleft}taxon Agathis{\textquoteright} in kauri: glasshouse trials. }, journal = {New Zealand Plant Protection}, volume = {66}, year = {2013}, pages = {242-248}, abstract = {

Phytophthora taxon Agathis (PTA) is a serious problem in Auckland and Northland kauri forests. Phosphorous acid (phosphite) is a potential treatment for infected or threatened trees. In vitro tests on phosphite-amended agar showed that PTA was more sensitive to phosphite than other Phytophthora species commonly controlled by this chemical. Before progressing to forest trials, phosphite efficacy was tested on PTA-inoculated kauri seedlings in the glasshouse. Two-year-old kauri seedlings were inoculated with PTA applied directly to trunk wounds or by soil application. Phosphite was applied as a foliar spray, as a trunk injection or as a soil drench either 5 days before or 5 days after inoculation. All untreated control trees died, whether trunk- or soil-inoculated. With phosphite injection, survival was 100\% following PTA soil inoculation and 67\% following trunk inoculation. Foliar spray and soil drench-applied phosphite treatments were less effective than trunk injection, although some trees survived.

}, issn = {1175-9003 (print), 1179-352X (online)},}, url = {http://www.nzpps.org/nzpp_abstract.php?paper=662420}, author = {Horner, I.J. and Hough, E.G.} } @article {3979, title = {Identification of Phytophthora species baited and isolated from forest soil and streams in northwestern Yunnan province, China}, journal = {Forest Pathology}, year = {2013}, month = {01/2013}, pages = {n/a - n/a}, abstract = {

Phytophthora species were surveyed by collecting soil samples and placing bait leaves in selected streams during June{\textendash}October in the years 2005, 2006 and 2010 at three sites in oak forests in Diqing Tibetan Autonomous Prefecture of NW Yunnan province, China. Seventy-three isolates of Phytophthora spp. were recovered from 135 baited leaf samples and 81 soil samples. Eight Phytophthora species were identified by observation of morphological features and ITS1-5.8S-ITS2 rDNA sequence analysis. The eight taxa included two well-known species P.\ gonapodyides and P.\ cryptogea, two recently described species P.\ gregata and P.\ plurivora, two named but as yet undescribed taxa, P.\ taxon PgChlamydo and P.\ taxon Salixsoil, and two previously unrecognized species, Phytophthora sp.1 and P. sp.2. The most numerous species, P.\ taxon PgChlamydo, and the second most abundant species, P.\ taxon Salixsoil, were recovered at all three sites. Phytophthora cryptogea was detected only once at site Nixi. Phytophthora gregata and P. sp.2 were isolated from a stream only at site Bitahai, while the other three species were each found at two sites. Phylogenetic analysis revealed that the isolates belonged to three ITS clades, one species including six isolates in clade 2, six species including 66 isolates in clade 6 and one species in clade 8. There was a relatively rich species and genetic diversity of Phytophthora detected in the investigated regions where the forest biotic and abiotic factors affecting the growth and evolution of Phytophthora populations were diverse.

}, doi = {10.1111/efp.12015}, author = {Huai, W.-x. and Tian, G. and Hansen, E.M. and Zhao, W.-x. and Goheen, E. M. and N. J. Gr{\"u}nwald and Cheng, C.}, editor = {Belbahri, L.} } @article {1264, title = {First report of Phytophthora cambivora causing leaf and stem blight and root rot on Taiwan cherry (Prunus campanulata) in Taiwan}, journal = {Plant Disease}, volume = {96}, year = {2012}, pages = {1065-1065}, abstract = {

Taiwan cherry or Formosan cherry (Prunus campanulata Maxim.) is a beautiful ornamental tree that is native to Taiwan. In spring 2005, a severe disease was observed on 1- to 3-year-old seedlings of Taiwan cherry in a garden in Tungshih, Taichung, Taiwan. Infected plants showed symptoms of greenish water-soaked spots on leaves that became dark brown, 2 to 3 cm in diameter. Infected leaves withered and fell to the ground in 3 to 5 days and young shoots showed symptoms of withering and drooping. Infected roots showed symptoms of necrosis. Severely infected plants eventually died. A Phytophthora sp. was isolated consistently from diseased samples of Taiwan cherry and associated soil. Six isolates of Phytophthora, of the A1 mating type (1), were isolated from single zoospores. Two of these isolates, Tari 25141 (deposited as BCRC34932 in Bioresource Collection and Research Center, Shinchu, Taiwan) and Tari 25144 (BCRC34933), were used for pathogenicity tests on 1-year-old seedlings of Taiwan cherry to fulfill Koch{\textquoteright}s postulates. Inoculation was done by placing a cotton swab containing zoospore suspension on leaves or stem, or by soaking seedlings in the zoospore suspension. Inoculated seedlings were kept in a greenhouse at 20 to 25{\textdegree}C for 30 days and examined for appearance of symptoms. Results showed that both isolates were pathogenic on seedlings of Taiwan cherry, causing symptoms similar to those observed on naturally infected seedlings. The temperature range for growth of the six isolates of Phytophthora was 8 to 32{\textdegree}C with optimum temperature at 24{\textdegree}C. The linear growth rate was 72 mm per day on V8A culture (5\% V8 vegetable juice, 0.02\% CaCO3, and 2\% Bacto agar) at 24{\textdegree}C. The colonies on potato dextrose agar produced sparse aerial mycelia with conspicuous radiate patterns. Sporangia were sparse on V8A agar blocks, but abundant when the agar blocks were placed in water under continuous white fluorescent light (average 2,000 lux) for 2 days. Sporangiophores branched sympodially. Sporangia were pear shaped, nonpapillate and nondeciduous, 50 to 75 (62) {\texttimes} 30 to 48 (40) μm, with a length/width ratio of 1.2 to 2.2 (1.6). New internal nested proliferate sporangia were formed inside the empty sac of old matured sporangia after releasing zoospores. No chlamydospores were formed on V8A. Hyphal swellings with distinctive irregular catenulation were produced on V8A and in water. The pathogen was stimulated to form its own oospores by the A2 tester using the method described by Ko (1). Oogonia were 28 to 50 (40) μm in diameter with smooth or irregularly protuberant walls. Oospores were mostly aplerotic and 18 to 42 (31) μm in diameter. Antheridia were amphigynous, mostly two-celled, and 10 to 42 (29) {\texttimes} 12 to 24 (19) μm. The sequence of the internal transcribed spacers (ITS) region of nuclear ribosomal DNA of isolate Tari 25141 (GenBank Accession No. GU111589) was 831 bp and had 99\% sequence identity with a number of Phytophthora cambivora isolates such as GenBank Accession Nos. HM004220 (2), AY787030, and EF486692. Based on the morphological characteristics of sporangia and sexual structures and the molecular analysis of ITS sequences, the pathogen from Taiwan cherry was identified as P. cambivora (Petri) Buis. To our knowledge, this is the first report of P. cambivora on native Taiwan cherry in Taiwan and, so far, no other natural hosts have been reported.

}, doi = {10.1094/PDIS-01-12-0025-PDN}, url = {http://dx.doi.org/10.1094/PDIS-01-12-0025-PDN}, author = {J.H. Huang and Ann, PJ and Y.H. Chiu and J.N. Tsai} } @article {EFP:EFP715, title = {Phytophthora ramorum is a generalist plant pathogen with differences in virulence between isolates from infectious and dead-end hosts}, journal = {Forest Pathology}, volume = {42}, number = {1}, year = {2012}, pages = {8{\textendash}13}, publisher = {Blackwell Publishing Ltd}, abstract = {

Variation in virulence was examined among isolates of Phytophthora ramorum from epidemiologically important or infectious (non-oak) and transmissive dead-end (oak) hosts from North America. Twelve isolates representative of the genetic, geographic and host range of P.\ ramorum in the western United States were inoculated on leaves of Umbellularia californica (bay laurel or bay) and stems of Quercus agrifolia (coast live oak). In spite of extreme genetic similarity among the isolates employed, and even within the same genotype, significant differences in lesion size were measured, suggesting virulence in this pathogen is also controlled by epigenetic factors. A strong positive correlation between lesion size on bay laurel and coast live oak provides experimental evidence P.\ ramorum is a generalist pathogen that lacks host specificity. Isolates from non-transmissive oaks were significantly less pathogenic both on oaks and bays than isolates from infectious hosts. These results are essential to further our understanding of the epidemiology and evolutionary potential of this pathogen. A quantitative differential in virulence of isolates from hosts with different epidemiological roles has been described for many animal diseases, but is a novel report for a plant disease.

}, issn = {1439-0329}, doi = {10.1111/j.1439-0329.2011.00715.x}, url = {http://dx.doi.org/10.1111/j.1439-0329.2011.00715.x}, author = {H{\"u}berli, D. and Garbelotto, M.} } @article {1365, title = {Development of a real-time PCR assay for detection of Phytophthora kernoviae and comparison of this method with a conventional culturing technique}, journal = {European Journal of Plant Pathology}, volume = {131}, year = {2011}, pages = {695-703}, publisher = {Springer Netherlands}, abstract = {

Phytophthora kernoviae is a recently described pathogen causing leaf blight, aerial dieback and bleeding cankers on trees and shrubs in parts of Great Britain and Ireland and recently reported in New Zealand. This paper describes the development of a TaqMan real-time PCR assay based on internal transcribed spacer (ITS) sequence to aid diagnosis of this pathogen in culture and in plant material. The assay showed no cross reaction with 29 other Phytophthora species, including the closely related species P. boehmeriae, and detected at least 1.2\ pg of P. kernoviae DNA per reaction. A rapid and simple method can be used to extract DNA prior to testing by real-time PCR, and a plant internal control assay can be used to aid interpretation of negative results. A comparison of real-time PCR and plating for 526 plant samples collected in the UK indicated that this assay is suitable for use in routine screening for P. kernoviae.

}, keywords = {Diagnostic sensitivity, Diagnostic specificity, plant health, Rhododendron}, issn = {0929-1873}, doi = {10.1007/s10658-011-9843-x}, url = {http://dx.doi.org/10.1007/s10658-011-9843-x}, author = {Hughes, KelvinJ.D. and Tomlinson, JennyA. and Giltrap, PatriciaM. and Barton, Victoria and Hobden, Ellie and Boonham, Neil and Lane, CharlesR.} } @article {4083, title = {First report of bleeding canker caused by Phytophthora cactorum on horse chestnut in Turkey}, journal = {Plant Disease}, volume = {86}, year = {2002}, month = {06/2002}, pages = {697 - 697}, abstract = {

Bleeding canker on horse chestnut (Aesculus sp.), caused by Phytophthora cactorum (Lebert and Cohn) Schr{\"o}eter previously has been reported from the United States and Europe (1). In August 2000, it was found for the first time in a park in Ankara Province, Turkey. Symptoms included sparse yellowish brown foliage with abnormally small leaves, and dark-stained spots or dark brown necrosis of the bark on the trunk and main branches, with or without a reddish black gummy exudate. P. cactorum was isolated from tissues taken from the margins of necrotic bark. Pure cultures were slightly radiate, fluffy but not dense, and had short aerial hyphae when grown on carrot agar, potato dextrose agar, or V8 agar. Sporangia were ovoid, strongly papillate, and averaged 35.6 μm in length and 26.8 μm in width (range: 24 to 55 μm {\texttimes} 19 to 40 μm). The isolates were homothallic with smooth-walled paragynous oogonia ranging from 23.5 to 34.5 μm in diameter. To satisfy Koch{\textquoteright}s postulates, mycelium of P. cactorum was placed under the bark of six branches of healthy horse chestnut. Noninoculated wounds served as controls. Four months later a reddish black gummy exudate was observed oozing from the inoculated wounds, and the bark tissue was necrotic for 3 to 4 cm around each infection. P. cactorum was successfully reisolated from the necrotic bark tissue. Control wounds remained healthy. To our knowledge, this is the first report of this disease on horse chestnut in Asia Minor.

}, issn = {0191-2917}, doi = {10.1094/PDIS.2002.86.6.697C}, url = {http://dx.doi.org/10.1094/PDIS.2002.86.6.697C}, author = {Intini, M. and Gurer, M. and Ozturk, S.} } @article {Ioos2006511, title = {Genetic characterization of the natural hybrid species Phytophthora alni as inferred from nuclear and mitochondrial DNA analyses}, journal = {Fungal Genetics and Biology}, volume = {43}, number = {7}, year = {2006}, pages = {511 - 529}, abstract = {

The different subspecies of Phytophthora alni, P. alni subsp. alni (Paa), P. alni subsp. uniformis (Pau), and P. alni subsp. multiformis (Pam), are recent and widespread pathogens of alder in Europe. They are believed to be a group of emergent heteroploid hybrids between two phylogenetically close Phytophthora species. Nuclear and mitochondrial DNA analyses were performed, using a broad collection of P. alni and two closely related species, P. cambivora and P. fragariae. (Paa) possesses three different alleles for each of the nuclear genes we studied, two of which are present in Pam as well, whereas the third matches the single allele present in Pau. Moreover, Paa displays common mtDNA patterns with both Pam and Pau. A combination of the data suggests that Paa may have been generated on several occasions by hybridization between Pam and Pau, or their respective ancestors. Pau might have P. cambivora as a species ancestor, whereas Pam seems to have either been generated itself by an ancient reticulation or by autopolyploidization.

}, keywords = {Interspecific hybridization}, issn = {1087-1845}, doi = {DOI: 10.1016/j.fgb.2006.02.006}, url = {http://www.sciencedirect.com/science/article/B6WFV-4JS1TK3-1/2/aead0efc6dc22a393ebadec5b3211855}, author = {Renaud Ioos and Axelle Andrieux and Beno{\'O}t Mar{\'A}ais and Pascal Frey} } @article {MEN:MEN1554, title = {Characterization of microsatellite markers in the interspecific hybrid Phytophthora alni ssp. alni, and cross-amplification with related taxa}, journal = {Molecular Ecology Notes}, volume = {7}, number = {1}, year = {2007}, pages = {133{\textendash}137}, publisher = {Blackwell Publishing Ltd}, abstract = {

Phytophthora alni ssp. alni is an interspecific hybrid oomycete causing a large-scale decay of alders throughout Europe. In this study we developed a set of 10 microsatellite markers that shows promise for population studies and for studying hybridization events between the parental species of the hybrid. Moreover, the genotype and the ploidy of the different subspecies of P. alni might be inferred from the quantitative ratio of amplified genome-specific alleles. Nine primer pairs cross amplified with the related species Phytophthora cambivora and Phytophthora fragariae and yielded distinct alleles.

}, keywords = {genotyping, oomycete, polyploidy}, issn = {1471-8286}, doi = {10.1111/j.1471-8286.2006.01554.x}, url = {http://dx.doi.org/10.1111/j.1471-8286.2006.01554.x}, author = {Renaud Ioos and Barr{\'e}s, Beno{\^{\i}t and Axelle Andrieux and Pascal Frey} } @article {springerlink:10.1007/s10658-005-6233-2, title = {SCAR{\textendash}based PCR primers to detect the hybrid pathogen Phytophthora alni and its subspecies causing alder disease in Europe}, journal = {European Journal of Plant Pathology}, volume = {112}, year = {2005}, note = {10.1007/s10658-005-6233-2}, pages = {323-335}, publisher = {Springer Netherlands}, abstract = {

Since the 1990s, a new Phytophthora species hybrid has been jeopardizing the natural population of alders throughout Europe. This new Phytophthora, P. alni, has been suggested as a natural hybrid between two closely related species of Phytophthora. Little is known about the epidemiology of this pathogen, because its direct isolation is not always satisfactory. In this study we developed three pairs of Polymerase Chain Reaction (PCR) primers derived from Sequence Characterized Amplified Regions (SCAR) that allow discrimination among the three subspecies of P. alni: P. alni subsp. alni, P. alni subsp. uniformis and P. alni subsp. multiformis. These molecular tools were successfully used to detect P. alni directly in different substrates such as infested river water and soil, and necrotic alder bark, without the need for any prior baiting or isolation stages. An Internal Amplification Control (IAC) was included to help discriminate against false negative samples due to the potential presence of inhibitory compounds in DNA extracts. These molecular tools should be useful for epidemiological studies on this emerging disease.

}, issn = {0929-1873}, url = {http://dx.doi.org/10.1007/s10658-005-6233-2}, author = {Renaud Ioos and Husson, Claude and Axelle Andrieux and Pascal Frey} } @article {1227, title = {Distribution and expression of elicitin genes in the interspecific hybrid oomycete Phytophthora alni}, journal = {Appl. Environ. Microbiol.}, volume = {73}, year = {2007}, pages = {5587-5597}, abstract = {

Phytophthora alni subsp. alni, P. alni subsp. multiformis, and P. alni subsp. uniformis are responsible for alder disease in Europe. Class I and II elicitin gene patterns of P. alni subsp. alni, P. alni subsp. multiformis, P. alni subsp. uniformis, and the phylogenetically close species P. cambivora and P. fragariae were studied through mRNA sequencing and 3{\textquoteright} untranslated region (3{\textquoteright}UTR)-specific PCRs and sequencing. The occurrence of multiple 3{\textquoteright}UTR sequences in association with identical elicitin-encoding sequences in P. alni subsp. alni indicated duplication/recombination events. The mRNA pattern displayed by P. alni subsp. alni demonstrated that elicitin genes from all the parental genomes are actually expressed in this allopolyploid taxon. The complementary elicitin patterns resolved confirmed the possible involvement of P. alni subsp. multiformis and P. alni subsp. uniformis in the genesis of the hybrid species P. alni subsp. alni. The occurrence of multiple and common elicitin gene sequences throughout P. cambivora, P. fragariae, and P. alni sensu lato, not observed in other Phytophthora species, suggests that duplication of these genes occurred before the radiation of these species.

}, doi = {doi:10.1128/AEM.00721-07}, url = {http://aem.asm.org/content/73/17/5587.abstract}, author = {Renaud Ioos and Panabi{\`e}res, Franck and Industri, Beno{\^{\i}t and Axelle Andrieux and Pascal Frey} } @article {EFP:EFP755, title = {Potential susceptibility of Australian flora to a NA2 isolate of Phytophthora ramorum and pathogen sporulation potential}, journal = {Forest Pathology}, volume = {42}, year = {2011}, pages = {305{\textendash}320}, publisher = {Blackwell Publishing Ltd}, abstract = {

Phytophthora ramorum is an invasive plant pathogen and the cause of considerable and widespread damage in nurseries, gardens and natural woodland ecosystems of the USA and Europe. It is considered to be a significant plant disease as it could cause biodiversity loss and severe economic losses in plant industries in areas where it is not yet known to exist, such as Australasia. Foliar susceptibility and sporulation potential were tested using detached-leaf assays for 70 Australian native plant species sourced from established gardens and arboreta in California using a NA2 isolate of P. ramorum. Correa {\textquoteright}Sister Dawn{\textquoteright}, Eucalyptus regnans, Isopogon cuneatus, I. formosus, Leptospermum scoparium, L. lanigerum and Melaleuca squamea were identified as potentially highly susceptible host species. Hedycarya angustifolia, Olearia argophylla, Phyllocladus aspleniifolius, Pittosporum undulatum and Podocarpus lawrencei were identified as potentially resistant. All 70 species were able to be infected with P. ramorum, as confirmed by reisolation. Putative sporulating hosts include five members of the Myrtaceae, Agonis flexuosa, Corymbia ficifolia, Eucalyptus haemastoma, E. delegatensis and E. viminalis. As a part of a precautionary strategy, the potentially highly susceptible species found in this study are suitable candidates for targeted surveillance programmes in high-risk incursion areas of Australia and within the global horticultural trade.

}, issn = {1439-0329}, doi = {10.1111/j.1439-0329.2011.00755.x}, url = {http://dx.doi.org/10.1111/j.1439-0329.2011.00755.x}, author = {Ireland, K. B. and H{\"u}berli, D. and Dell, B. and Smith, I. W. and D. M. Rizzo and Hardy, G. E. St. J.} } @article {PPA:PPA2513, title = {Potential susceptibility of Australian native plant species to branch dieback and bole canker diseases caused by Phytophthora ramorum}, journal = {Plant Pathology}, volume = {61}, number = {2}, year = {2012}, pages = {234{\textendash}246}, publisher = {Blackwell Publishing Ltd}, abstract = {

Susceptibility to branch dieback caused by Phytophthora ramorum was tested using a detached branch assay for 66 Australian native plant species sourced from established gardens and arboreta in California. Six of these species were further tested for their susceptibility to bole cankers caused by P.\ ramorum using a sealed log assay. Isopogon formosus and Eucalyptus denticulata were identified as potentially highly susceptible Australian branch dieback hosts. Thirteen potentially tolerant Australian host species included Banksia attenuata, B.\ marginata, E. haemastoma, E.\ regnans, Pittosporum undulatum and Billardiera heterophylla. Eucalyptus regnans was identified as a potentially highly susceptible bole canker host, while E.\ diversicolor and E.\ viminalis were considered potentially tolerant species to bole cankers caused by P.\ ramorum. Phytophthora ramorum was able to infect all 66 species, as confirmed by reisolation. These results extend the known potential host range for P.\ ramorum, confirm it as a possible threat to Australian plant industries and ecosystems and highlight additional associated hosts that are important in the global horticultural trade, native forests and plantation forestry.

}, keywords = {invasive organism, oomycete, ramorum branch dieback, Sudden oak death}, issn = {1365-3059}, doi = {10.1111/j.1365-3059.2011.02513.x}, url = {http://dx.doi.org/10.1111/j.1365-3059.2011.02513.x}, author = {Ireland, K. B. and H{\"u}berli, D. and Dell, B. and Smith, I. W. and D. M. Rizzo and Hardy, G. E. St. J.} } @article {Ivors2004378, title = {AFLP and phylogenetic analyses of North American and European populations of Phytophthora ramorum}, journal = {Mycological Research}, volume = {108}, number = {4}, year = {2004}, pages = {378 - 392}, abstract = {

The genetic structure within and between USA and European populations of the emerging phytopathogen Phytophthora ramorum was examined. Four primer combinations were used for amplified fragment length polymorphism (AFLP) fingerprinting of 67 USA isolates from California and Oregon, and 18 European isolates from Belgium, Germany, The Netherlands, Spain and the UK. In addition, three DNA regions (ITS, cox II, and nad 5) of additional Phytophthora species were amplified by polymerase chain reaction, sequenced, and analysed to provide better phylogenetic understanding of P. ramorum within the genus Phytophthora. AFLP banding patterns indicate that the 85 isolates form two distinct lineages within a monophyletic group, distinct from the closely related outgroup species P. lateralis. With the exception of two isolates from an Oregon nursery, European and USA isolates clustered separately within individual clades. The AFLP profiles also indicate that a single clonal lineage dominates the North American population, while the European population consists of an array of mainly unique, closely related AFLP types. Sequences from the three DNA regions were identical among all P. ramorum isolates, and phylogenetic analysis indicates that P. ramorum is closely related to P. lateralis and P. hibernalis.

}, issn = {0953-7562}, doi = {10.1017/S0953756204009827}, url = {http://www.sciencedirect.com/science/article/pii/S0953756208615609}, author = {Ivors, Kelly L. and Katherine J. Hayden and Peter J.M. Bonants and Rizzo, David M. and Garbelotto, Matteo} } @article {MEC:MEC2864, title = {Microsatellite markers identify three lineages of Phytophthora ramorum in US nurseries, yet single lineages in US forest and European nursery populations}, journal = {Molecular Ecology}, volume = {15}, number = {6}, year = {2006}, pages = {1493{\textendash}1505}, publisher = {Blackwell Publishing Ltd}, abstract = {

Analysis of 12 polymorphic simple sequence repeats identified in the genome sequence of Phytophthora ramorum, causal agent of {\textquoteleft}sudden oak death{\textquoteright}, revealed genotypic diversity to be significantly higher in nurseries (91\% of total) than in forests (18\% of total). Our analysis identified only two closely related genotypes in US forests, while the genetic structure of populations from European nurseries was of intermediate complexity, including multiple, closely related genotypes. Multilocus analysis determined populations in US forests reproduce clonally and are likely descendants of a single introduced individual. The 151 isolates analysed clustered in three clades. US forest and European nursery isolates clustered into two distinct clades, while one isolate from a US nursery belonged to a third novel clade. The combined microsatellite, sequencing and morphological analyses suggest the three clades represent distinct evolutionary lineages. All three clades were identified in some US nurseries, emphasizing the role of commercial plant trade in the movement of this pathogen.

}, keywords = {exotic microbe, oomycete, population genetics, SSR, Sudden oak death}, issn = {1365-294X}, doi = {10.1111/j.1365-294X.2006.02864.x}, url = {http://dx.doi.org/10.1111/j.1365-294X.2006.02864.x}, author = {K. Ivors and Garbelotto, M. and Vries, I. D. E. and Ruyter-Spira, C. and Hekkert, B. TE. and Rosenzweig, N. and Bonants, P.} } @article {4694, title = {Potential host range of four Phytophthora interspecific hybrids from Clade 8a}, journal = {Plant Pathology}, volume = {69}, year = {2020}, month = {May-11-2020}, pages = {1281 - 1290}, abstract = {

In recent years several interspecific hybrids have been reported in the plant pathogenic oomycete genus Phytophthora. Due to the large genotypic and phenotypic changes, these hybrids might have broader or more limited host ranges compared with their parental species. It is crucial to understand the host range of Phytophthora hybrids to minimize the economic losses caused by their infection. The potential host range of four hybrids belonging to Clade 8a of the Phytophthora phylogenetic tree was investigated in this study. Thirty species of herbaceous plants as well as eight species of woody plants were inoculated and monitored for any symptom of infection. In addition, the detached twigs of 32 tree species, fruits of six plant species, tubers of potato, and roots of carrot and sugar beet were investigated for susceptibility to these hybrids. Almost all hybrids caused severe rot on all tested fruits, tubers, and roots, although different isolates showed different pathogenicity on detached tree twigs. All hybrids tested had a different host range compared with their parental species: they were able to infect plants outside the host range of their parents, infect hosts of both parental species, although these parents did not have overlapping hosts, or, in some cases, they were not able to infect hosts infected by the parents.

}, issn = {0032-0862}, doi = {10.1111/ppa.v69.710.1111/ppa.13205}, url = {https://bsppjournals.onlinelibrary.wiley.com/doi/abs/10.1111/ppa.13205}, author = {Jafari, Fatemeh and Mostowfizadeh-Ghalamfarsa, Reza and Safaiefarahani, Banafsheh and Burgess, Treena I.} } @article {4082, title = {Enhancing detection of Phytophthora cactorum in naturally infested soil}, journal = {Phytopathology}, volume = {77}, year = {1987}, month = {1987}, pages = {1475}, abstract = {

Reliable methods were needed to detect P. cactorum, one of the primary causal agents of P. crown rot of apple trees, in its natural soil environment. Apple or pear fruits, used in a baiting bioassay, were ineffective at detecting P. cactorum in naturally infested soil. Apple seedlings, cotyledons and seedling leaf pieces were successful baits, but cotyledons were the most sensitive and efficient. Completely air drying soil subsamples and then remoistening them for several days before flooding and adding plant tissue baits (extended baiting procedure) greatly enhanced detection when compared with the standard direct baiting procedure without prior manipulation of soil moisture. Bioassay incubation temp., volume of water added to remoisten air-dried soil subsamples, and incubation period following remoistening all affected detection, but the photoperiod during incubation did not. The advantages of an extended baiting bioassay with apple cotyledons were: greater sensitivity than with pear or apple fruits or by direct baiting, readily available and inexpensive baits, formation of sporangia of P. cactorum directly on necrotic cotyledons, and lack of interference by contaminating Pythium species. Cotyledons were also colonized by zoospores of P. cambivora, P. citricola and P. cryptogea, but not by those of P. megasperma, P. syringae, P. drechsleri, or an unidentified Phytophthora sp. The extended bioassay procedure routinely has provided a relatively rapid and efficient means of detecting P. cactorum in a diversity of soils within and around New York apple orchards.

}, issn = {0031949X}, doi = {10.1094/Phyto-77-1475}, author = {Jeffers, S. N.} } @article {4437, title = {Host Phenology and Leaf Effects on Susceptibility of California Bay Laurel to Phytophthora ramorum}, journal = {Phytopathology}, volume = {106}, year = {2016}, month = {Jan-01-2016}, pages = {47 - 55}, abstract = {

Spread of the plant pathogen Phytophthora ramorum, causal agent of the forest disease sudden oak death, is driven by a few competent hosts that support spore production from foliar lesions. The relationship between traits of a principal foliar host, California bay laurel (Umbellularia californica), and susceptibility to P. ramorum infection were investigated with multiple P. ramorum isolates and leaves collected from multiple trees in leaf-droplet assays. We examined whether susceptibility varies with season, leaf age, or inoculum position. Bay laurel susceptibility was highest during spring and summer and lowest in winter. Older leaves (\>1 year) were more susceptible than younger ones (8 to 11 months). Susceptibility was greater at leaf tips and edges than the middle of the leaf. Leaf surfaces wiped with 70\% ethanol were more susceptible to P. ramorum infection than untreated leaf surfaces. Our results indicate that seasonal changes in susceptibility of U. californica significantly influence P. ramorum infection levels. Thus, in addition to environmental variables such as temperature and moisture, variability in host plant susceptibility contributes to disease establishment of P. ramorum.

}, issn = {0031-949X}, doi = {10.1094/PHYTO-01-15-0016-R}, url = {http://apsjournals.apsnet.org/doi/10.1094/PHYTO-01-15-0016-R}, author = {Johnston, Steven F. and Cohen, Michael F. and Torok, Tamas and Meentemeyer, Ross K. and Rank, Nathan E.} } @article {3968, title = {Relationships between health of Quercus robur, occurrence of Phytophthora species and site conditions in southern Sweden}, journal = {Plant Pathology}, volume = {54}, year = {2005}, month = {08/2005}, pages = {502 - 511}, abstract = {

The effect of Phytophthora species, soil chemistry, precipitation and temperature on the vitality of oak was evaluated in 32 oak stands in southern Sweden. In addition, the relationship between the occurrence of Phytophthora species and soil conditions was determined. The results showed that there was a weak association between the presence of P. quercina, the most frequently recovered Phytophthora species in southern Sweden, and the vitality of the oak stands (determined from estimates of crown defoliation of individual trees). The pathogens occurred more frequently in clayey and loamy soils that were less acidic and which had higher base saturation. However, they were found in all but the most acidic soils (pH\ \<\ 3{\textperiodcentered}5). In stands where Phytophthora species were not present, positive correlations between the average crown defoliation and proportion of damaged trees with average summer precipitation and average annual precipitation were found. There were no significant differences in soil chemistry between healthy and declining stands included in this study, and no significant correlations were found between any soil parameter and crown vitality. Based on the results from these 32 oak stands, it is likely that the decline of oaks in southern Sweden can be attributed to several different site-specific factors, such as infection by P. quercina or unusual weather events, which interact with a number of biotic and abiotic factors, leading to oak decline.

}, issn = {0032-0862}, doi = {10.1111/ppa.2005.54.issue-410.1111/j.1365-3059.2005.01228.x}, author = {Jonsson, U. and T. Jung and Sonesson, K. and Rosengren, U.} } @article {3972, title = {Pathogenicity of Swedish isolates of Phytophthora quercina to Quercus robur in two different soils}, journal = {New Phytologist}, volume = {158}, year = {2003}, month = {05/2003}, pages = {355 - 364}, abstract = {
}, issn = {0028-646X}, doi = {10.1046/j.1469-8137.2003.00734.x}, author = {J{\"o}nsson, Ulrika and Thomas Jung and Rosengren, Ulrika and Nihlg{\r a}rd, Bengt and Sonesson, Kerstin} } @article {3971, title = {First records of soilborne Phytophthora species in Swedish oak forests}, journal = {Forest Pathology}, volume = {33}, year = {2003}, month = {06/2003}, pages = {175 - 179}, abstract = {

Thirty-two oak stands in southern Sweden, 27 with predominantly declining trees and five with a higher proportion of healthy trees were investigated regarding the presence of soilborne Phytophthora species. Phytophthora quercina, an oak-specific fine root pathogen, was isolated from rhizosphere soil samples in 10 of the 27 declining stands. Additionally, P. cactorum and P. cambivora were recovered from one stand each. No Phytophthora species were isolated from the healthy oak stands. The soil conditions at the sites from which Phytophthora spp. were recovered ranged from mesic sediments to moraines, with clayey to silty textures and with soil pH (BaCl2) between 3.5 and 5.0. The results show that P. quercina is geographically widespread in oak stands in southern Sweden and indicate that this pathogen may be one of the factors involved in oak decline in Northern Europe as has already been shown for western, Central and parts of southern Europe.

}, issn = {1437-4781}, doi = {10.1046/j.1439-0329.2003.00320.x}, author = {J{\"o}nsson, U. and Lundberg, L. and Sonesson, K. and T. Jung} } @article {doi:10.1890/0012-9658(2002)083[3167:SOAIPO]2.0.CO;2, title = {Spread of an invasive pathogen over a variable landscape: a non-native root rot on Port Orford cedar}, journal = {Ecology}, volume = {83}, number = {11}, year = {2002}, pages = {3167-3181}, issn = {00129658}, doi = {10.1890/0012-9658(2002)083[3167:SOAIPO]2.0.CO;2}, url = {http://www.esajournals.org/doi/abs/10.1890/0012-9658\%282002\%29083\%5B3167\%3ASOAIPO\%5D2.0.CO\%3B2}, author = {Jules, Erik S. and Kauffman, Matthew J. and Ritts, William D. and Carroll, Allyson L.} } @article {4248, title = {Update on the 35-year expansion of the invasive root pathogen, Phytophthora lateralis, across a landscape of Port Orford cedar (Chamaecyparis lawsoniana)}, journal = {Forest Pathology}, year = {2014}, month = {11/2014}, pages = {165-168}, abstract = {

Port Orford cedar (Chamaecyparis lawsoniana) is endemic to northern California and southwestern Oregon and is considered a foundation species that plays critical roles in riparian areas and on nutrient-poor soils. Since 1952, a non-native, pathogenic oomycete (Phytophthora lateralis) has been spreading throughout the range of the cedar. Most spread occurs by vehicles carrying infested soil along gravel roads primarily used for timber harvest. In a previous study conducted in 1998 and 1999, Port Orford cedar and P.\ lateralis were censused in a 37-km2 study area and dendrochronology was used to reconstruct the history of pathogen invasion. That work, which represents the only detailed analysis of spread rates for P.\ lateralis, showed that the first successful invasion into the study area took place in 1977 and that 43\% of the susceptible host sites (stream crossings) were infested by 1999. In the work presented here, all sites that were uninfested in 1999 were re-censused in 2012, extending the historical reconstruction of P. lateralis spread to 35\ years. Two new infestations were initiated between 1999 and 2012, suggesting that the rate of spread of P. lateralis has slowed greatly. Between 1980 and 1989, the average number of new site infestations was 1.8 infestations per year, while between 1990 and 1999 the average was 0.4 infestations per year and between 2000 and 2009 the average was 0.2 infestations per year. Several potential explanations for the reduced number of new infestations are discussed.

}, doi = {10.1111/efp.12158}, url = {http://doi.wiley.com/10.1111/efp.12158}, author = {Jules, E. S. and Steenbock, C. M. and Carroll, A. L.}, editor = {Vannini, {\'A}.} } @article {Julich20114070, title = {Development of a lab-on-a-chip device for diagnosis of plant pathogens}, journal = {Biosensors and Bioelectronics}, volume = {26}, number = {10}, year = {2011}, pages = {4070 - 4075}, abstract = {

A lab-on-a-chip system for rapid nucleic acid-based analysis was developed that can be applied for diagnosis of selected Phytophthora species as a first example for use in plant pathology. All necessary polymerase chain reaction process (PCR) and hybridization steps can be performed consecutively within a single chip consisting of two components, an inflexible and a flexible one, with integrated microchannels and microchambers. Data from the microarray is collected from a simple electrical measurement that is based on elementary silver deposition by enzymatical catalyzation. Temperatures in the PCR and in the hybridization zone are managed by two independent Peltier elements. The chip will be integrated in a compact portable system with a pump and power supply for use on site. The specificity of the lab-on-a-chip system could be demonstrated for the tested five Phytophthora species. The two Pythium species gave signals below the threshold. The results of the electrical detection of the microarray correspond to the values obtained with the control method (optical grey scale analysis).

}, keywords = {detection}, issn = {0956-5663}, doi = {10.1016/j.bios.2011.03.035}, url = {http://www.sciencedirect.com/science/article/pii/S0956566311001916}, author = {Sandra Julich and Marko Riedel and Mark Kielpinski and Matthias Urban and Robert Kretschmer and Stefan Wagner and Wolfgang Fritzsche and Thomas Henkel and Robert M{\"o}ller and Werres, Sabine} } @article {3974, title = {Involvement of soilborne Phytophthora species in Central European oak decline and the effect of site factors on the disease}, journal = {Plant Pathology}, volume = {49}, year = {2000}, month = {12/2000}, pages = {706 - 718}, abstract = {

A survey was made on the occurrence of soilborne Phytophthora species in 35 oak stands on a range of geologically different sites in Bavaria. The most widespread species were P. quercina, P. cambivora and P. citricola. Seven other Phytophthora species were isolated infrequently. The fine root systems of 106 healthy and 111 declining mature trees of Quercus robur and Q. petraea were intensively investigated. The results indicate that, depending on the site conditions, at least two different complex diseases are referred to under the name {\textquoteleft}oak decline{\textquoteright}. On sites with a mean soil pH (CaCl2) 3{\textperiodcentered}5 and sandy-loamy to clayey soil texture Phytophthora spp. were commonly isolated from rhizosphere soil, and highly significant correlations existed between crown transparency and various root parameters. Oaks with P. quercina or other Phytophthora spp. in their rhizosphere had markedly higher levels of fine root damage than oaks without Phytophthora spp., and were subject to a relative risk of severe crown symptoms of 2{\textperiodcentered}1 and 2{\textperiodcentered}8, respectively. In contrast, in stands with sandy to sandy-loamy soils and a mean soil pH\  3{\textperiodcentered}9, Phytophthora spp. were not found. In these stands, correlations between crown transparency and various root parameters were either less significant or not significant. It is concluded that Phytophthora species are strongly involved in oak decline on sandy-loamy to clayey sites with a mean soil-pH (CaCl2).

}, issn = {0032-0862}, doi = {10.1046/j.1365-3059.2000.00521.x}, author = {T. Jung and Blaschke, H. and W. O{\ss}wald} } @article {3997, title = {New insights into the survival strategy of the invasive soilborne pathogen Phytophthora cinnamomi in different natural ecosystems in Western Australia}, journal = {Forest Pathology}, volume = {43}, year = {2013}, month = {08/2013}, pages = {266{\textendash}288}, abstract = {

Despite its importance as one of the most notorious, globally distributed, multihost plant pathogens, knowledge on the survival strategy of Phytophthora cinnamomi in seasonally dry climates is limited. Soil and fine roots were collected from the rhizosphere of severely declining or recently dead specimens of 13 woody species at 11 dieback sites and two dieback spots and from healthy specimens of five woody species at four dieback-free sites in native forests, woodlands and heathlands of the south-west of Western Australia (WA). Phytophthora cinnamomi was recovered from 80.4, 78.1 and 100\% of tested soil, fine root and soil{\textendash}debris slurry samples at the 11 dieback sites, in some cases even after 18-month storage under air-dry conditions, but not from the small dieback spots and the healthy sites. Direct isolations from soil{\textendash}debris slurry showed that P. cinnamomi colonies exclusively originated from fine roots and root fragments not from free propa- gules in the soil. Microscopic investigation of P. cinnamomi-infected fine and small woody roots and root fragments demonstrated in 68.8, 81.3 and 93.8\% of samples from nine woody species the presence of thick-walled oospores, stromata-like hyphal aggregations and intracellular hyphae encased by lignitubers, respectively, while thin-walled putative chlamydospores were found in only 21.2\% of samples from five woody species. These findings were confirmed by microscopic examination of fine roots from artificially inoculated young trees of 10 woody species. It is suggested that (i) the main function of chlamydospores is the survival in moderately dry conditions between consecutive rain events and (ii) selfed oospores, hyphal aggregations, and encased hyphae and vesicles in infected root tissue of both host and non-host species are the major long-term survival propagules of P. cinnamomi during the extremely dry summer conditions in WA.

}, doi = {10.1111/efp.12025}, url = {http://onlinelibrary.wiley.com/doi/10.1111/efp.12025/abstract}, author = {T. Jung and Colquhoun, I. J. and Hardy, G. E. St. J.}, editor = {S. Woodward} } @article {3964, title = {Re-evaluation of Phytophthora citricola isolates from multiple woody hosts in Europe and North America reveals a new species, Phytophthora plurivora sp. nov.}, journal = {Persoonia - Molecular Phylogeny and Evolution of Fungi}, volume = {22}, year = {2009}, month = {06/2009}, pages = {95 - 110}, abstract = {

During large-scale surveys for soilborne Phytophthora species in forests and semi-natural stands and nurseries in Europe during the last decade, homothallic Phytophthora isolates with paragynous antheridia, semipapillate persistent sporangia and a growth optimum around 25 {\textdegree}C which did not form catenulate hyphal swellings, were recovered from 39 host species in 16 families. Based on their morphological and physiological characters and the similarity of their ITS DNA sequences with P. citricola as designated on GenBank, these isolates were routinely identified as P. citricola. In this study DNA sequence data from the internal transcribed spacer regions (ITS1 and ITS2) and 5.8S gene of the rRNA operon, the mitochondrial cox1 and β-tubulin genes were used in combination with morphological and physiological characteristics to characterise these isolates and compare them to the ex-type and the authentic type isolates of P. citricola, and two other taxa of the P. citricola complex, P. citricola I and the recently described P. multivora. Due to their unique combination of morphological, physiological and molecular characters these semipapillate homothallic isolates are described here as a new species, P. plurivora sp. nov.

}, keywords = {Beech, citricola, Decline, dieback, forest, multivora, nursery, oak, phylogeny}, issn = {00315850}, doi = {10.3767/003158509X442612}, author = {T. Jung and Burgess, T. I.} } @article {3973, title = {Three new species of Phytophthora from European oak forests}, journal = {Mycological Research}, volume = {106}, year = {2002}, month = {4/2002}, pages = {397 - 411}, abstract = {

In several studies of oak decline in Europe, one semi-papillate (Phytophthora psychrophila sp. nov.) and two nonpapillate homothallic Phytophthora species (P. europaea sp. nov. and P. uliginosa sp. nov.) were isolated, together with other Phytophthora species, from rhizosphere soil samples which could not be assigned to existing taxa. P. psychrophila differs from other semi-papillate species of Waterhouse{\textquoteright}s morphological Group IV, like P. ilicis and P. hibernalis, by its uniform, dome-shaped and cotton wool-like colony growth pattern on V8 juice agar and malt extract agar, the occurrence of sympodially branched primary hyphae, the high variation in size and shape of the sporangia, shorter pedicels, lower optimum temperature for growth, and internal transcribed spacer (ITS) sequences. P. europaea is distinguished from related nonpapillate Group V and VI species, namely P. fragariae, P. cambivora, and the {\textquoteright}alder phytophthora{\textquoteright}, by producing oogonia with tapered bases, irregular walls and exclusively paragynous antheridia, its cardinal temperatures for growth, and ITS sequences. P. uliginosa differs from related Group V and VI species by its large oogonia with exclusively paragynous antheridia, the predominant occurrence of ellipsoid sporangia with markedly wide exit pores, its slow growth, low cardinal temperatures, its colony growth patterns, and ITS sequences. P. uliginosa is separated from P. europaea by its larger oospores without tapering bases, lower cardinal temperatures and growth rates, different colony growth patterns, and greater aggressiveness on Q. robur.

}, issn = {09537562}, doi = {10.1017/S0953756202005622}, author = {Thomas Jung and Hansen, Everett M. and Winton, Lori and O{\ss}wald, Wolfgang and Delatour, Claude} } @article {JUNG2005159, title = {Involvement of Phytophthora species in the decline of European beech in Europe and the USA}, journal = {Mycologist}, volume = {19}, number = {4}, year = {2005}, pages = {159 - 166}, keywords = {detection}, issn = {0269-915X}, doi = {DOI: 10.1017/S0269-915X(05)00405-2}, url = {http://www.sciencedirect.com/science/article/B7XMS-4R10WR2-5/2/37dcb413ca17af3b17f99e6101570c65}, author = {T. Jung and G. W. Hudler and S.L. Jensen-Tracy and H.M. Griffiths and F. Fleischmann and W. Osswald} } @article {4657, title = {Multiple new Phytophthora species from ITS Clade 6 associated with natural ecosystems in Australia: evolutionary and ecological implications}, journal = {Persoonia - Molecular Phylogeny and Evolution of Fungi}, volume = {26}, year = {2011}, month = {Jun-06-2013}, pages = {13 - 39}, abstract = {

During surveys of dying vegetation in natural ecosystems and associated waterways in Australia many new taxa have been identified from Phytophthora ITS Clade 6. For representative isolates, the region spanning the internal transcribed spacer region of the ribosomal DNA, the nuclear gene encoding heat shock protein 90 and the mitochondrial cox 1 gene were PCR amplified and sequenced. Based on phylogenetic analysis and morphological and physiological comparison, four species and one informally designated taxon have been described; Phytophthora gibbosa, P. gregata, P. litoralis, P. thermophila and P. taxon paludosa. Phytophthora gibbosa, P. gregata and P. taxon paludosa form a new cluster and share a common ancestor; they are homothallic and generally associated with dying vegetation in swampy or water-logged areas. Phytophthora thermophila and P. litoralis are sister species to each other and more distantly to P. gonapodyides. Both new species are common in waterways and cause scat tered mortality within native vegetation. They are self-sterile and appear well adapted for survival in an aquatic environment and inundated soils, filling the niche occupied by P. gonapodyides and P. taxon salixsoil in the northern hemisphere. Currently the origin of these new taxa, their pathogenicity and their role in natural ecosystems are unknown. Following the precautionary principle, they should be regarded as a potential threat to native ecosystems and managed to minimise their further spread.

}, issn = {00315850}, doi = {10.3767/003158511X557577}, url = {http://www.ingentaconnect.com/content/nhn/pimj/2011/00000026/00000001/art00002}, author = {Jung, T. and Stukely, M.J.C. and Hardy, G.E.St.J. and White, D. and Paap, T. and Dunstan, W.A. and Burgess, T.I.} } @article {1294133220040401, title = {Phytophthora root and collar rot of alders in Bavaria: distribution, modes of spread and possible management strategies.}, journal = {Plant Pathology}, volume = {53}, number = {2}, year = {2004}, pages = {197 - 208}, abstract = {

A survey of symptoms of phytophthora root and collar rot of common (Alnus glutinosa) and grey alder (A. incana) in riparian and forest stands in Bavaria was conducted by the Bavarian State Forestry and river authorities. Symptoms were seen in 1041 out of 3247 forest alder stands. The majority of the affected stands (80{\textperiodcentered}9\%) were less than 21 years old; 46\% of these young stands were growing on nonflooded sites and 92\% had been planted. The riparian survey showed that symptoms were widespread along more than 50\% of the river systems. Along some rivers the disease incidence exceeded 50\%. The {\textquoteleft}alder Phytophthora{\textquoteright} was recovered from 166 of 185 riparian and forest alder stands with symptoms. In 58 of the 60 rivers and streams investigated in detail, the source of inoculum was traced back to infested young alder plantations growing on the river banks or on forest sites that drain into the rivers. Once introduced to a river system, the {\textquoteleft}alder Phytophthora{\textquoteright} infects alders downstream. Baiting tests showed that the {\textquoteleft}alder Phytophthora{\textquoteright} was present in rootstocks of alders from three out of four nurseries which regularly bought in alder plants for re-sale, but not in rootstocks from four nurseries that grew their own alders from seed. In addition, the infected nurseries used water from infested water courses for irrigation. The Bavarian State Ministry for Agriculture and Forestry has developed a code of practice for producing healthy alder plants in forest nurseries. This includes a 3-year fallow period between bare-rooted alder crops because of poor survival of the {\textquoteleft}alder Phytophthora{\textquoteright} in soil.

}, keywords = {ALDER {\textendash} Diseases \& pests, Alnus, Bavaria, diseases, fungal diseases of plants, GERMANY, nursery, pathway, Phytophthora, plantation, riparian areas}, issn = {00320862}, doi = {10.1111/j.0032-0862.2004.00957.x}, url = {http://onlinelibrary.wiley.com/doi/10.1111/j.0032-0862.2004.00957.x/abstract}, author = {T. Jung and Blaschke, M.} } @article {4682, title = {A Survey in Natural Forest Ecosystems of Vietnam Reveals High Diversity of both New and Described Phytophthora Taxa including P. ramorum}, journal = {Forests}, volume = {11}, year = {2020}, month = {Jan-01-2020}, pages = {93}, abstract = {

In 2016 and 2017, surveys of Phytophthora diversity were performed in 25 natural and semi-natural forest stands and 16 rivers in temperate and subtropical montane and tropical lowland regions of Vietnam. Using baiting assays from soil samples and rivers and direct isolations from naturally fallen leaves, 13 described species, five informally designated taxa and 21 previously unknown taxa of Phytophthora were isolated from 58 of the 91 soil samples (63.7\%) taken from the rhizosphere of 52 of the 64 woody plant species sampled (81.3\%) in 20 forest stands (83.7\%), and from all rivers: P. capensis, P. citricola VII, VIII, IX, X and XI, P. sp. botryosa-like 2, P. sp. meadii-like 1 and 2, P. sp. tropicalis-like 2 and P. sp. multivesiculata-like 1 from Phytophthora major phylogenetic Clade 2; P. castaneae and P. heveae from Clade 5; P. chlamydospora, P. gregata, P. sp. bitahaiensis-like and P. sp. sylvatica-like 1, 2 and 3 from Clade 6; P. cinnamomi (Pc), P. parvispora, P. attenuata, P. sp. attenuata-like 1, 2 and 3 and P. {\texttimes}heterohybrida from Clade 7; P. drechsleri, P. pseudocryptogea, P. ramorum (Pr) and P. sp. kelmania from Clade 8, P. macrochlamydospora, P. sp. {\texttimes}insolita-like, P. sp. {\texttimes}kunnunara-like, P. sp. {\texttimes}virginiana-like s.l. and three new taxa, P. sp. quininea-like, P. sp. {\texttimes}Grenada 3-like and P. sp. {\texttimes}Peru 4-like, from Clade 9; and P. sp. gallica-like 1 and 2 from Clade 10. The A1 and A2 mating types of both Pc and Pr co-occurred. The A2 mating type of Pc was associated with severe dieback of montane forests in northern Vietnam. Most other Phytophthora species, including Pr, were not associated with obvious disease symptoms. It is concluded that (1) Vietnam is within the center of origin of most Phytophthora taxa found including Pc and Pr, and (2) Phytophthora clades 2, 5, 6, 7, 8, 9, and 10 are native to Indochina.

}, doi = {10.3390/f11010093}, url = {https://www.mdpi.com/1999-4907/11/1/93https://www.mdpi.com/1999-4907/11/1/93/pdf}, author = {Jung, Thomas and Scanu, Bruno and Brasier, Clive M. and Webber, Joan and Milenkovi{\'c}, Ivan and Corcobado, Tamara and Tom{\v s}ovsk{\'y}, Michal and P{\'a}nek, Mat{\v e}j and Bakonyi, Jozsef and Maia, Cristiana and Ba{\v c}ov{\'a}, Aneta and Raco, Milica and Rees, Helen and P{\'e}rez-Sierra, Ana and Horta Jung, Marilia} } @article {3967, title = {Phytophthora gallica sp. nov., a new species from rhizosphere soil of declining oak and reed stands in France and Germany}, journal = {Mycological Research}, volume = {112}, year = {2008}, month = {10/2008}, pages = {1195 - 1205}, abstract = {

A non-papillate, slow-growing Phytophthora species, which could not be assigned to any existing taxon, was isolated from rhizosphere soil of a declining oak in Northeast France, and from the rhizosphere of Phragmites australis at Lake Constance in south-west Germany in 1998 and 2004, respectively. We describe this species, previously informally designated Phytophthora taxon {\textquoteleft}G{\textquoteright}, as Phytophthora gallica sp. nov. Morphology, growth rates, and pathogenicity against cuttings of riparian tree species and leaves of reed are described and compared with those of morphologically and phylogenetically similar Phytophthora species. P. gallica produces colonies with limited aerial mycelium and variable growth patterns. Gametangia are not formed in single or mixed cultures with tester strains of known mating types. P. gallica produces globose and elongated irregular chlamydospores, of which a high proportion is abortive. In water culture irregular hyphal swellings and non-papillate persistent sporangia are formed abundantly. P. gallica is moderately aggressive to Alnus glutinosa and Fagus sylvatica, weakly aggressive to Quercus robur and Salix alba and non-pathogenic to Fraxinus excelsior and Phragmites australis. According to ITS and mtDNA sequence data P. gallica belongs to a distinct Phytophthora clade, with P. boehmeriae and P. kernoviae being the closest relatives. The origin of P. gallica and its ecological role in wet ecosystems remain unclear.

}, issn = {09537562}, doi = {10.1016/j.mycres.2008.04.007}, author = {Thomas Jung and Nechwatal, Jan} } @article {4656, title = {Phytophthora root and collar rot of alders in Bavaria: distribution, modes of spread and possible management strategies}, journal = {Plant Pathology}, volume = {53}, year = {2004}, month = {Jan-04-2004}, pages = {197 - 208}, abstract = {

A survey of symptoms of phytophthora root and collar rot of common (Alnus glutinosa) and grey alder (A. incana) in riparian and forest stands in Bavaria was conducted by the Bavarian State Forestry and river authorities. Symptoms were seen in 1041 out of 3247 forest alder stands. The majority of the affected stands (80{\textperiodcentered}9\%) were less than 21\ years old; 46\% of these young stands were growing on nonflooded sites and 92\% had been planted. The riparian survey showed that symptoms were widespread along more than 50\% of the river systems. Along some rivers the disease incidence exceeded 50\%. The {\textquoteleft}alder Phytophthora{\textquoteright} was recovered from 166 of 185 riparian and forest alder stands with symptoms. In 58 of the 60 rivers and streams investigated in detail, the source of inoculum was traced back to infested young alder plantations growing on the river banks or on forest sites that drain into the rivers. Once introduced to a river system, the {\textquoteleft}alder Phytophthora{\textquoteright} infects alders downstream. Baiting tests showed that the {\textquoteleft}alder Phytophthora{\textquoteright} was present in rootstocks of alders from three out of four nurseries which regularly bought in alder plants for re-sale, but not in rootstocks from four nurseries that grew their own alders from seed. In addition, the infected nurseries used water from infested water courses for irrigation. The Bavarian State Ministry for Agriculture and Forestry has developed a code of practice for producing healthy alder plants in forest nurseries. This includes a 3-year fallow period between bare-rooted alder crops because of poor survival of the {\textquoteleft}alder Phytophthora{\textquoteright} in soil.

}, issn = {0032-0862}, doi = {10.1111/j.0032-0862.2004.00957.x}, url = {http://doi.wiley.com/10.1111/j.0032-0862.2004.00957.x}, author = {Jung, T. and Blaschke, M.} } @article {3976, title = {Phytophthora quercina sp. nov., causing root rot of European oaks}, journal = {Mycological Research}, volume = {103}, year = {1999}, month = {7/1999}, pages = {785 - 798}, abstract = {

In a 3 year study of oak (Quercus robur, Q. petraea, Q. cerris, Q. pubescens and Q. ilex) decline in Central and Southern Europe, a papillate homothallic Phytophthora species was isolated consistently, with other Phytophthora spp., from necrotic fine roots by direct plating on to selective agar medium and from rhizosphere soil samples by baiting with leaves of Quercus robur. The morphology, physiology, RAPD banding patterns and pathogenicity against apple fruits of this Phytophthora sp. are described and compared with those of other papillate Phytophthora species from Waterhouse{\textquoteright}s Group I, namely P. cactorum, P. clandestina, P. idaei, P. iranica, P. pseudotsugae and P. tentaculata, and papillate Group III P. citricola. The papillate Phytophthora isolates from oak differed from all other Group I species by their uniform, dome-shaped and cottonwool-like colony growth pattern on V8 juice agar and malt extract agar, the frequent occurrence of sympodially branched primary hyphae, a high proportion of elongated, ellipsoid or ovoid oogonia, the absence of amphigynous antheridia and RAPD banding patterns. Additionally, there was no other species in Group I with as much variation in size and shape of the sporangia or large proportion of sporangia with a curved apex, hyphal projections, lateral displacement of the papilla and lateral attachment to the sporangiophore. In pathogenicity tests with infested soil, the isolates proved to be more pathogenic to Q. robur than any other Phytophthora sp. recovered from declining oaks in Central Europe. Based on their unique combination of cultural, sporangial and gametangial morphology, pathogenicity and close association with Quercus but not other trees, the papillate Phytophthora isolates from oak are described as Phytophthora quercina sp. nov.

}, issn = {09537562}, doi = {10.1017/S0953756298007734}, url = {http://www.sciencedirect.com/science/article/pii/S0953756208606115}, author = {T. Jung and Cooke, D. E. L. and Blaschke, H. and Duncan, J. M. and W. O{\ss}wald} } @article {4485, title = {Diversity of Phytophthora species in natural ecosystems of Taiwan and association with disease symptoms}, journal = {Plant Pathology}, volume = {66}, year = {2017}, month = {Jan-07-2016}, pages = {194{\textendash}211}, abstract = {

In 2013 a survey of Phytophthora diversity was performed in 25 natural and seminatural forest stands and 25 rivers in temperate montane and subtropical lowland regions of Taiwan. Using baiting assays, 10 described species and 17 previously unknown taxa of Phytophthora were isolated from 71.5\% of the 144 rhizosphere soil samples from 33 of 40 tree species sampled in 24 forest stands, and from 19 rivers: P.\ capensis, P.\ citrophthora, P.\ plurivora, P.\ tropicalis, P.\ citricola VII, P.\ sp.\ {\texttimes}\ botryosa-like, P.\ sp.{\texttimes}\ meadii-like and P.\ sp. occultans-like from Clade 2; P.\ palmivora from Clade 4; P.\ castaneae and P.\ heveae from Clade 5; P.\ chlamydospora and P.\ sp. forestsoil-like from Clade 6; P.\ cinnamomi (Pc), P.\ parvispora, P.\ attenuata nom. prov., P.\ flexuosa nom. prov., P.\ formosa nom. prov., P.\ intricata nom. prov., P.\ {\texttimes}\ incrassata nom. prov. and P.\ {\texttimes}\ heterohybrida nom. prov. from Clade 7; P.\ sp. palustris and five new hybrid species from Clade 9. The A1 mating type of Pc was widespread in both montane and lowland forests and rarely associated with disease, whereas the A2 mating type was limited to lowland forests and in some cases causing severe dieback. Most other Phytophthora species were not associated with obvious disease symptoms. It is concluded that (i) Taiwan is within the centre of origin of most Phytophthora taxa found, (ii) Pc A2 is an introduced invasive pathogen, and (iii) interspecific hybridizations play a major role in speciation and species radiations in diverse natural ecosystems.

}, doi = {10.1111/ppa.12564}, url = {http://doi.wiley.com/10.1111/ppa.12564http://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111\%2Fppa.12564}, author = {Jung, T. and Chang, T. T. and Bakonyi, J. and Seress, D. and P{\'e}rez-Sierra, A. and Yang, X. and Hong, C. and Scanu, B. and Fu, C. H. and Hsueh, K. L. and Maia, C. and Abad-Campos, P. and Le{\'o}n, M. and Horta Jung, M.} } @article {4616, title = {Diversity of Phytophthora species in Valdivian rainforests and association with severe dieback symptoms}, journal = {Forest Pathology}, year = {2018}, pages = {e12443}, abstract = {

The Valdivian rainforest, one of the global hotspots of biodiversity, is a temperate rainforest originating as a Tertiary relic from the supercontinent Gondwana. In November 2014, a survey of Phytophthora diversity was performed in 13 natural forest stands and 20 forest streams and rivers in two protected areas near Valdivia and in a temperate montane forest in the Concepci{\'o}n area. One planted stand each of the introduced tree species Castanea sativa and Fagus sylvatica were also included. Using baiting assays, eight described species and four previously unknown taxa of Phytophthora were isolated from 86\% of the 50 rhizosphere soil samples from seven of the eight tree species sampled in 12 forest stands, and from 20 streams: P.\ chlamydospora, P.\ cinnamomi, P.\ kernoviae, P.\ lacustris, P.\ plurivora, P.\ pseudosyringae, P.\ {\texttimes}cambivora, P.\ {\texttimes}stagnum, P.\ valdiviana nom. prov. from Clade 2b, P.\ madida nom. prov. from Clade 8a, and P.\ chilensis nom. prov. and P.\ pseudokernoviae nom. prov. The latter two species are the closest relatives of P.\ kernoviae from Clade 10. Phytophthora pseudokernoviae nom. prov. was also isolated from necrotic leaves of Drimys winteri. From the Valdivia river, a swarm of three Clade 6 hybrids was recovered. Each hybrid isolate resulted from multiple reticulation events with P.\ thermophila as maternal and both P.\ amnicola and P.\ chlamydospora as paternal parents. In addition, three previously unknown and recently described Nothophytophthora species, N.\ caduca, N.\ chlamydospora and N.\ valdiviana, were isolated from several forest streams. Phytophthora cinnamomi, the most common and widespread species in soils of native forests, was associated with severe dieback of Valdivian rainforest trees, in particular D.\ winteri, Luma apiculata, Nothofagus dombeyi and the endangered Saxegothaea conspicua. A first pathogenicity test demonstrated high aggressiveness of P.\ cinnamomi to several native tree species, including N.\ dombeyi, Blepharocalyx cruckshanksii and Gevuina avellana.

}, doi = {https://doi.org/10.1111/efp.12443}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/efp.12443}, author = {Jung, Thomas and Dur{\'a}n, Alvaro and Sanfuentes von Stowasser, Eugenio and Schena, Leonardo and Mosca, Saveria and Fajardo, Sebastian and Gonz{\'a}lez, Mariela and Navarro Ortega, Angella D. and Bakonyi, Jozsef and Seress, Diana and Tom{\v s}ovsk{\'y}, Michal and Cravador, Alfredo and Maia, Cristiana and Horta Jung, Marilia}, editor = {Woodward, S.} } @article {Jung:2011:0031-5850:13, title = {Multiple new Phytophthora species from ITS Clade 6 associated with natural ecosystems in Australia: evolutionary and ecological implications}, journal = {Persoonia - Molecular Phylogeny and Evolution of Fungi}, volume = {26}, number = {1}, year = {2011}, pages = {13-39}, abstract = {

During surveys of dying vegetation in natural ecosystems and associated waterways in Australia many new taxa have been identified from Phytophthora ITS Clade 6. For representative isolates, the region spanning the internal transcribed spacer region of the ribosomal DNA, the nuclear gene encoding heat shock protein 90 and the mitochondrial cox 1 gene were PCR amplified and sequenced. Based on phylogenetic analysis and morphological and physiological comparison, four species and one informally designated taxon have been described; Phytophthora gibbosa, P. gregata, P. litoralis, P. thermophila and P. taxon paludosa. Phytophthora gibbosa, P. gregata and P. taxon paludosa form a new cluster and share a common ancestor; they are homothallic and generally associated with dying vegetation in swampy or water-logged areas. Phytophthora thermophila and P. litoralis are sister species to each other and more distantly to P. gonapodyides. Both new species are common in waterways and cause scat tered mortality within native vegetation. They are self-sterile and appear well adapted for survival in an aquatic environment and inundated soils, filling the niche occupied by P. gonapodyides and P. taxon salixsoil in the northern hemisphere. Currently the origin of these new taxa, their pathogenicity and their role in natural ecosystems are unknown. Following the precautionary principle, they should be regarded as a potential threat to native ecosystems and managed to minimise their further spread.

}, doi = {doi:10.3767/003158511X557577}, url = {http://www.ingentaconnect.com/content/nhn/pimj/2011/00000026/00000001/art00002}, author = {T. Jung and Stukely, M. J. C. and Hardy, G.E.S.t.J. and White, D. and Paap, T. and Dunstan, W.A. and Burgess, T. I.} } @article {4610, title = {Canker and decline diseases caused by soil- and airborne Phytophthora species in forests and woodlands}, journal = {Persoonia - Molecular Phylogeny and Evolution of Fungi}, volume = {40}, year = {2018}, month = {Jan-01-2018}, pages = {182-220}, abstract = {

Most members of the oomycete genus Phytophthora are primary plant pathogens. Both soil- and airborne Phytophthora species are able to survive adverse environmental conditions with enduring resting structures, mainly sexual oospores, vegetative chlamydospores and hyphal aggregations. Soilborne Phytophthora species infect fine roots and the bark of suberized roots and the collar region with motile biflagellate zoospores released from sporangia during wet soil conditions. Airborne Phytophthora species infect leaves, shoots, fruits and bark of branches and stems with caducous sporangia produced during humid conditions on infected plant tissues and dispersed by rain and wind splash. During the past six decades, the number of previously unknown Phytophthora declines and diebacks of natural and semi-natural forests and woodlands has increased exponentially, and the vast majority of them are driven by introduced invasive Phytophthora species. Nurseries in Europe, North America and Australia show high infestation rates with a wide range of mostly exotic Phytophthora species. Planting of infested nursery stock has proven to be the main pathway of Phytophthora species between and within continents. This review provides insights into the history, distribution, aetiology, symptomatology, dynamics and impact of the most important canker, decline and dieback diseases caused by soil- and airborne Phytophthora species in forests and natural ecosystems of Europe, Australia and the Americas.

}, issn = {0031-5850}, doi = {10.3767/persoonia.2018.40.08}, url = {http://www.ingentaconnect.com/content/nhn/pimj/10.3767/persoonia.2018.40.08}, author = {Jung, T. and P{\'e}rez-Sierra, A. and Dur{\'a}n, A. and Horta Jung, M. and Balci, Y. and Scanu, B.} } @article {3970, title = {Phytophthora pseudosyringae sp. nov., a new species causing root and collar rot of deciduous tree species in Europe}, journal = {Mycological Research}, volume = {107}, year = {2003}, month = {7/2003}, pages = {772 - 789}, abstract = {

In several studies of oak decline in Europe, a semi-papillate homothallic Phytophthora taxon was consistently isolated, together with other Phytophthora species, from rhizosphere soil samples. It was also found associated with necrotic fine roots and stem necroses of Fagus sylvatica and Alnus glutinosa. Due to morphological and physiological similarities, the semi-papillate isolates were previously identified as P. syringae by various authors. The morphology, physiology and pathogenicity against fine roots of Quercus robur, Q. petraea and F. sylvatica, bark of A. glutinosa, leaves of Ilex aquifolium and apple fruits of this Phytophthora species are described and compared with those of related and similar Phytophthora species, namely P. ilicis, P. psychrophila, P. quercina, P. citricola and P. syringae. The phylogenetic placement on the basis of ITS and mtDNA sequence data was also examined. Isolates of this taxon produce colonies with stellate to rosaceous growth patterns and limited aerial mycelium on various agar media. Antheridia are predominantly paragynous. In water culture catenulate hyphal swellings and semi-papillate caducous sporangia, that are usually limoniform, ellipsoid or ovoid, are formed abundandly, mostly in lax or dense sympodia. This taxon is a moderately slow growing, low temperature species with optimum and maximum temperatures around 20 and 25 {\textdegree}C, respectively. Tested isolates are moderately aggressive to fine roots of oaks and beech, highly aggressive to holly leaves and apple fruits, and slightly pathogenic to alder bark. Thirteen tested isolates had an identical and distinct ITS sequence which was more similar to that of P. ilicis and P. psychrophila than any other known taxa. On the basis of their unique combination of morphological characters, colony growth patterns, cardinal temperatures for growth, growth rates, pathogenicity to oaks, beech, alder, apple and holly, their host range, and ITS and mtDNA sequences the semi-papillate caducous Phytophthora isolates from oaks, beech and alder are clearly separated from related and similar Phytophthora spp., and described as a new species, P. pseudosyringae sp. nov.

}, issn = {09537562}, doi = {10.1017/S0953756203008074}, author = {Thomas Jung and Nechwatal, Jan and David E.L. Cooke and Hartmann, {\"u}nther and Blaschke, Markus and O{\ss}wald, Wolfgang F. and James M. Duncan and Delatour, Claude} } @article {3965, title = {Beech decline in Central Europe driven by the interaction between Phytophthora infections and climatic extremes}, journal = {Forest Pathology}, volume = {39}, year = {2009}, month = {04/2009}, pages = {73 - 94}, abstract = {

During the past decade, and in particular after the wet year 2002 and the dry year 2003, an increasing number of trees and stands of European beech (Fagus sylvatica L.) in Bavaria were showing symptoms typical for Phytophthora diseases: increased transparency and crown dieback, small-sized and often yellowish foliage, root and collar rot and aerial bleeding cankers up to stem heights of \>20\ m. Between 2003 and 2007 134 mature beech stands on a broad range of geological substrates were surveyed, and collar rot and aerial bleeding cankers were found in 116 (86.6\%) stands. In most stands the majority of beech trees were declining and scattered or clustered mortality occurred. Bark and soil samples were taken from 314 trees in 112 stands, and 11 Phytophthora species were recovered from 253 trees (80.6\%) in 104 stands (92.9\%). The most frequent species were P. citricola, P. cambivora and P. cactorum. Primary Phytophthora lesions were soon infected by a series of secondary bark pathogens, including Nectria coccinea, and wood decay fungi. In addition, infected trees were often attacked by several bark and wood boring insects leading to rapid mortality. Bark necroses were examined for their probable age in order to determine whether the onset of the current Phytophthora epidemic was correlated to rainfall rates recorded at 22 Bavarian forest ecosystem monitoring stations. A small-scale survey in nine Bavarian nurseries demonstrated regular infestations of all beech fields with the same range of Phytophthora species. The results indicate that (1) Phytophthora species are regularly associated with beech decline and may also be involved in the complex of {\textquoteleft}Beech Bark Disease{\textquoteright}, (2) excessive rainfalls and droughts are triggering the disease, and (3) widespread Phytophthora infestations of nursery stock might endanger current and future silvicultural projects aiming on the replacement of non-natural conifer stands by beech dominated mixed stands.

}, issn = {14374781}, doi = {10.1111/j.1439-0329.2008.00566.x}, url = {http://onlinelibrary.wiley.com/doi/10.1111/efp.2009.39.issue-2/issuetoc}, author = {T. Jung} } @proceedings {955, title = {Detection and eradication of Phytophthora ramorum from Oregon forests, 2001{\textendash}2008}, volume = {Gen. Tech. Rep. PSW-GTR-229}, year = {2010}, pages = {3-5}, publisher = {U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station}, address = {Santa Cruz, California}, url = {http://www.fs.fed.us/psw/publications/documents/psw_gtr229/}, author = {Kanaskie, A. and Hansen, E.M. and Goheen, E. M. and Osterbauer, N. and McWilliams, M. and J. Laine and M. Thompson and S. Savona and H. Timeus and B. Woosley and Sutton, W. and P. Reeser and R. Schultz and D. Hilburn}, editor = {Frankel, S.J. and T. Kliejunas and K. M. Palmieri} } @article {4468, title = {Phytophthora {\texttimes}alni and Phytophthora lacustris associated with common alder decline in Central Portugal}, journal = {Forest Pathology}, volume = {46}, year = {2016}, month = {Jan-04-2016}, pages = {174 - 176}, abstract = {

Since the early 1990s, an emerging disease induced by the highly aggressive oomycete Phytophthora {\texttimes}alni has caused widespread alder decline across Europe. In parallel, P.\ lacustris, a recently described species associated with riparian habitats, has been subject of increasing interest. A field survey conducted in 2014 showed high mortality rates in alder stands located in the riparian gallery along two rivers in Central Portugal. The pathogens isolated from necrotic alder stem base during this study were identified as P.\ {\texttimes}alni and P.\ lacustris. This paper is the first to report the occurrence of P.\ lacustris in Portugal and presents the first finding of P.\ {\texttimes}alni affecting mature trees in natural ecosystems located in Central Portugal.

}, doi = {10.1111/efp.2016.46.issue-210.1111/efp.12273}, url = {http://doi.wiley.com/10.1111/efp.2016.46.issue-2http://doi.wiley.com/10.1111/efp.12273}, author = {Kanoun-Boul{\'e}, M. and Vasconcelos, T. and Gaspar, J. and Vieira, S. and Dias-Ferreira, C. and Husson, C.}, editor = {Woodward, S.} } @article {10.1371/journal.pone.0034728, title = {Phenotypic diversification Is associated with host-induced transposon derepression in the sudden oak death pathogen Phytophthora ramorum}, journal = {PLoS ONE}, volume = {7}, number = {4}, year = {2012}, month = {04/2012}, pages = {e34728}, publisher = {Public Library of Science}, abstract = {

The oomycete pathogen Phytophthora ramorum is responsible for sudden oak death (SOD) in California coastal forests. P. ramorum is a generalist pathogen with over 100 known host species. Three or four closely related genotypes of P. ramorum (from a single lineage) were originally introduced in California forests and the pathogen reproduces clonally. Because of this the genetic diversity of P. ramorum is extremely low in Californian forests. However, P. ramorum shows diverse phenotypic variation in colony morphology, colony senescence, and virulence. In this study, we show that phenotypic variation among isolates is associated with the host species from which the microbe was originally cultured. Microarray global mRNA profiling detected derepression of transposable elements (TEs) and down-regulation of crinkler effector homologs (CRNs) in the majority of isolates originating from coast live oak (Quercus agrifolia), but this expression pattern was not observed in isolates from California bay laurel (Umbellularia californica). In some instances, oak and bay laurel isolates originating from the same geographic location had identical genotypes based on multilocus simples sequence repeat (SSR) marker analysis but had different phenotypes. Expression levels of the two marker genes analyzed by quantitative reverse transcription PCR were correlated with originating host species, but not with multilocus genotypes. Because oak is a nontransmissive dead-end host for P. ramorum, our observations are congruent with an epi-transposon hypothesis; that is, physiological stress is triggered on P. ramorum while colonizing oak stems and disrupts epigenetic silencing of TEs. This then results in TE reactivation and possibly genome diversification without significant epidemiological consequences. We propose the P. ramorum-oak host system in California forests as an ad hoc model for epi-transposon mediated diversification.

}, doi = {10.1371/journal.pone.0034728}, url = {http://dx.doi.org/10.1371\%2Fjournal.pone.0034728}, author = {Kasuga, , Takao and Kozanitas, , Melina and Bui, , Mai and H{\"u}berli, , Daniel and Rizzo, David M. and Garbelotto, Matteo} } @article {doi:10.1890/05-0211, title = {Heterogeneity shapes invasion: host size and environment influence susceptibility to a nonnative pathogen}, journal = {Ecological Applications}, volume = {16}, number = {1}, year = {2006}, pages = {166-175}, doi = {10.1890/05-0211}, url = {http://www.esajournals.org/doi/abs/10.1890/05-0211}, author = {Kauffman, Matthew J. and Jules, Erik S.} } @article {kegley_family_2009, title = {Family variation in Phytophthora lateralis resistance in Port-Orford-cedar: Greenhouse and raised bed testing}, journal = {PHYTOPATHOLOGY}, volume = {99}, number = {6}, year = {2009}, pages = {S122}, issn = {0031-949X}, author = {A. Kegley and S. Kolpak and P. Reeser and E. Hansen and R. A. Sniezko} } @article {701, title = {Chestnut cultivation and breeding in Korea: Part II}, journal = {Journal of The American Chestnut Foundation}, volume = {20}, year = {2006}, pages = {26-34}, author = {Mahn-Jo Kim} } @article {700, title = {Chestnut cultivation and breeding in Korea}, journal = {Journal of The American Chestnut Foundation}, volume = {20}, year = {2006}, pages = {31 - 37}, author = {Mahn-Jo Kim} } @article {4445, title = {In planta detection used to define the distribution of the European lineages of Phytophthora ramorum on larch (Larix ) in the UK}, journal = {Plant Pathology}, volume = {64}, year = {2015}, month = {Jan-10-2015}, pages = {1168 - 1175}, abstract = {

Two genetically distinct evolutionary lineages of the oomycete pathogen Phytophthora ramorum are responsible for the major epidemic on larch (Larix spp.) in the UK: EU1 (historically widespread) and the recently identified EU2 (reported only from Northern Ireland and a small area in southwest Scotland). Methods for lineage discrimination have required pure cultures of P.\ ramorum but, as the pathogen is challenging to isolate from infected larch tissue, only limited data have been available on the distribution of EU2. In this study a protocol was developed to determine the lineage of P.\ ramorum in infected larch tissue without the need for isolation. The protocol was applied to 134 UK samples collected during 2013{\textendash}14. In addition, lineage testing was applied to over 300 P.\ ramorum isolates cultured from a wide range of hosts between 2002 and 2012. Combined data confirmed that EU2 is restricted to Northern Ireland and a small area of southwest Scotland where it is the dominant lineage. There was no evidence of EU2 spread into England and Wales where only EU1 was found. However, EU2 was more widely distributed in southern and eastern parts of Scotland than previously reported. Furthermore, EU1 and EU2 were detected \<10\ km apart in larch plantations. This study provides the first reports of natural EU2 infection on European larch (Larix decidua), hybrid larch (Larix\ {\texttimes} eurolepis), beech (Fagus sylvatica), noble fir (Abies procera) and western hemlock (Tsuga heterophylla).

}, doi = {10.1111/ppa.2015.64.issue-510.1111/ppa.12345}, url = {http://doi.wiley.com/10.1111/ppa.2015.64.issue-5http://doi.wiley.com/10.1111/ppa.12345http://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111\%2Fppa.12345}, author = {King, K. M. and Harris, A. R. and Webber, J. F.} } @article {1241, title = {A risk assessment of climate change and the impact of forest diseases on forest ecosystems in the Western United States and Canada.}, year = {2011}, pages = {70 p.}, publisher = {U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station, Albany, CA}, keywords = {Armillaria, canker diseases, Climate change, dwarf mistletoe, environmental risk assessment, foliar diseases, forest pathogens, Phytophthora, root diseases, stem rusts, yellow-cedar decline}, issn = {Gen. Tech. Rep. PSW-GTR-236}, url = {http://www.fs.fed.us/psw/publications/documents/psw_gtr236/}, author = {John T. Kliejunas} } @article {kliejunas_phytophthora_1981, title = {Phytophthora root rot of Port-Orford-cedar in California.}, journal = {Plant disease}, volume = {65}, number = {5}, year = {1981}, pages = {446{\textendash}447}, abstract = {

Phytophthora Root Rot of {Port-Orford-Cedar} in California. John T. Kliejunas, Plant Pathologist, Forest Pest Management, Forest Service, {U.S.} Department of Agriculture, San Francisco, {CA} 94111. David H. Adams, Forest Pathologist, Department of Forestry, State of California, Sacramento 95814. Plant Dis. 65:446-447. . This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1981. {DOI:} {10.1094/PD-65-446.} The {Port-Orford-cedar} stands on federal, state, and private lands in northern California were surveyed in the spring of 1980 for Phytophthora root rot caused by Phytophthora lateralis. The disease was present at six sites on the Gasquet Ranger District, Six Rivers National Forest, and Jedediah Smith Redwoods State Park, Del Norte County, and on six ornamental cedars at a residence in Eureka, Humboldt County.

}, keywords = {California, Chamaecyparis lawsoniana}, issn = {01912917}, author = {J.T. Kliejunas and D.H. Adams} } @article {kliejunas1979phytophthora, title = {Phytophthora cinnamomi in Hawaiian forest soils: seasonal variations in population levels}, journal = {Phytopathology}, volume = {69}, year = {1979}, pages = {1268{\textendash}1272}, abstract = {

Soils from three ohia forest sites with trees showing varying degrees of decline, and from adjacent healthy and declining sites, were sampled biweekly for population levels of Phytophthora cinnamomi over an 8- to 13-mo period. Population levels varied considerably among sites and within the same site throughout the course of the study. At the three sites, the fungus generally was undetectable or its population levels were lowest in the winter months when minimum soil temperatures were near 10 C and then they increased as soil temperatures increased. Population levels decreased after extended periods of heavy rain and measurements at six of the eight monthly sampling times were significantly higher at the decline site than at the adjacent healthy site. Significant correlations between P. cinnamomi population levels and maximum soil temperature, minimum soil temperature, and rainfall were found at some sites but not at others. Soil matric potentials at all sites ranged from 0 to {\textendash}30 mb and were seldom less than {\textendash}25 mb. High water holding capacity of the soils combined with rainfall averages ranging 2,984{\textendash}3,489 mm/yr apparently were favorable for sporangium formation. Zoospores were prevalent at certain times of the year.

}, doi = {10.1094/Phyto-69-1268}, url = {http://www.apsnet.org/publications/phytopathology/backissues/Documents/1979Abstracts/Phyto69_1268.htm}, author = {J.T. Kliejunas and Nagata, JT} } @article {600, title = {Sudden oak death and Phytophthora ramorum: a summary of the literature}, year = {2010}, pages = {181 p.}, publisher = {U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station.}, address = {Albany, CA, USA}, url = {http://www.treesearch.fs.fed.us/pubs/36591}, author = {John T. Kliejunas} } @article {4723, title = {Preventing Phytophthora infestations in restoration nurseries: a key to protecting wildland plant communities.}, journal = {Oregon State University Extension Service}, year = {2022}, url = { https://catalog.extension.oregonstate.edu/sites/catalog/files/project/pdf/em9330.pdf}, author = {Kline, N. and Elliott, M. and Parke, J. and Stark, D. and Shaw, D. and Christiansen, A.} } @article {ko2006possible, title = {The possible origin and relation of Phytophthora katsurae and P. heveae, discovered in a protected natural forest in Taiwan}, journal = {Botanical Studies}, volume = {47}, number = {3}, year = {2006}, pages = {273{\textendash}277}, author = {Ko, W. H. and Wang, SY and Ann, PJ} } @article {1979, title = {Phytophthora katsurae, a new name for P. castaneae}, journal = {Mycologia}, volume = {71}, number = {4}, year = {1979}, pages = {pp. 840-844}, publisher = {Mycological Society of America}, abstract = {

P. katsurae is proposed to replace P. castaneae Katsura \& Uchida from chestnut [RPP 57, 2024] which is illegitimate, being a later homonym of P. castaneae (Mangin) Clements \& Shear.

}, issn = {00275514}, url = {http://www.jstor.org/stable/3759198}, author = {Ko, W. H. and Chang, H. S.} } @article {FML:FML2574, title = {Survival of Phytophthora alni, Phytophthora kernoviae, and Phytophthora ramorum in a simulated aquatic environment at different levels of pH}, journal = {FEMS Microbiology Letters}, volume = {332}, year = {2012}, month = {07/2012}, pages = {54{\textendash}60}, abstract = {

Phytophthora ramorum, Phytophthora alni, and Phytophthora kernoviae present significant threats to biosecurity. As zoosporic oomycetes, these plant pathogens may spread through natural waterways and irrigation systems. However, survival of these pathogens in aquatic systems in response to water quality is not well understood. In this study, we investigated their zoospore survival at pH 3{\textendash}11 in a 10\% Hoagland{\textquoteright}s solution over a 14-day period. The results showed that all three pathogens were most stable at pH 7, although the populations declined overnight irrespective of pH. Extended survival of these species depended on the tolerance of pH of their germinants. Germinants of P.\ alni ssp.\ alni and P.\ ramorum were more basic tolerant (pH 5{\textendash}11), while those of P.\ kernoviae were more acidic tolerant (pH 3{\textendash}9). These tolerant germinants formed compact hyphae or secondary sporangia to allow longer survival of these pathogens. Long-term survival at a broad pH range suggests that these pathogens, especially P.\ ramorum, are adapted to an aquatic environment and pose a threat to new production areas through water dispersal.

}, keywords = {quarantine Phytophthora species, water pH, zoospore survival}, issn = {1574-6968}, doi = {10.1111/j.1574-6968.2012.02574.x}, url = {http://dx.doi.org/10.1111/j.1574-6968.2012.02574.x}, author = {Kong, Ping and Lea-Cox, John D. and Moorman, Gary W. and Hong, Chuanxue} } @article {PPA:PPA2614, title = {Effect of electrical conductivity on survival of Phytophthora alni, P.~kernoviae and P.~ramorum in a simulated aquatic environment}, journal = {Plant Pathology}, volume = {61}, year = {2012}, pages = {1179{\textendash}1186}, publisher = {Blackwell Publishing Ltd}, abstract = {

This study investigated survival of the pathogens Phytophthora ramorum, P.\ alni and P.\ kernoviae as zoospores or sporangia in response to an important water quality parameter, electrical conductivity (EC), at its range in irrigation water reservoirs and irrigated cropping systems. Experiments with different strengths of Hoagland{\textquoteright}s solution showed that all three pathogens survived at a broad range of EC levels for at least 3\ days and were stimulated to grow and sporulate at ECs\ \>\ 1{\textperiodcentered}89\ dS\ m-1. Recovery of initial populations after a 14-day exposure was over 20\% for P.\ alni subsp. alni and P.\ kernoviae, and 61{\textperiodcentered}3\% and 130\% for zoospores and sporangia of P.\ ramorum, respectively. Zoospore survival of these pathogens at ECs\ \<\ 0{\textperiodcentered}41\ dS\ m-1 was poor, barely beyond 3\ days in pure water; only 0{\textperiodcentered}3\% (P.\ alni), 2{\textperiodcentered}9\% (P.\ kernoviae) and 15{\textperiodcentered}1\% (P.\ ramorum) of the initial population survived after 14\ days at EC\ =\ 0{\textperiodcentered}21\ dS\ m-1. The variation in rates of survival at different EC levels suggests that these pathogens survive better in cropping systems than in irrigation water. Containment of run-off and reduction in EC levels may therefore be non-chemical control options to reduce the risk of pathogen spread through natural waterways and irrigation systems.

}, keywords = {aquatic biology, electrical conductivity, quarantine pathogen, zoospores}, issn = {1365-3059}, doi = {10.1111/j.1365-3059.2012.02614.x}, url = {http://dx.doi.org/10.1111/j.1365-3059.2012.02614.x}, author = {Kong, P. and Lea-Cox, J. D. and Hong, C. X.} } @article {4446, title = {Potential of Ypt1 and ITS gene regions for the detection of Phytophthora species in a lab-on-a-chip DNA hybridization array}, journal = {Plant Pathology}, volume = {64}, year = {2015}, month = {Jan-10-2015}, pages = {1176 - 1189}, abstract = {

A novel DNA-chip hybridization assay that uses the ras-related GTP-binding protein 1 gene (Ypt1) was developed for the identification of several devastating Phytophthora species. The hybridization was conducted in a portable microfluidic lab-on-a-chip device for fast and accurate detection of 40 Phytophthora, two Pythium and one Phytopythium species. Moreover, the functionality of the Ypt1 region was examined in comparison to an array for the internal transcribed spacer (ITS) region by in silico modelling. The difference in species-specific capture probe sequences was lower for the ITS than for the Ypt1 region. While ITS-probes of Phytophthora ramorum, Phytophthora fragariae and Phytophthora lateralis cross-reacted with up to 11 non-target species, Ypt1-probes were specific except for P.\ fragariae/Phytophthora rubi. First analyses of artificially inoculated Rhododendron leaves successfully demonstrated the usability of the respective capture probes for the Ypt1 and the ras-related plant protein Rab1a gene region. The on-chip hybridization enabled the detection of up to 1\ pg\ μL-1 target DNA depending on the species examined. Due to the complementarity of ITS and Ypt1 genetic features, the use of multiple loci is recommended to identify targets of different taxonomic rank.

}, doi = {10.1111/ppa.2015.64.issue-510.1111/ppa.12357}, url = {http://doi.wiley.com/10.1111/ppa.2015.64.issue-5http://doi.wiley.com/10.1111/ppa.12357http://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111\%2Fppa.12357}, author = {K{\"o}nig, S. and Schwenkbier, L. and Pollok, S. and Riedel, M. and Wagner, S. and Popp, J. and Weber, K. and Werres, S.} } @article {4486, title = {Multiplex detection and identification of Phytophthora spp.~using target-specific primer extension and Luminex xTAG technology}, journal = {Plant Pathology}, volume = {65}, year = {2016}, month = {Jan-08-2016}, pages = {1008 - 1021}, abstract = {

There are more than 100 species that belong to the fungus-like genus Phytophthora, many of which can cause severe damage to plants in both natural and agricultural ecosystems. The availability of techniques for detection and identification are crucial for monitoring and control of these pathogens. In recent years, new methods using molecular approaches have been developed. However, the majority of them are designed to detect single Phytophthora species. Techniques that are able to target multiple species in one sample would offer advantages, especially for the assessment of Phytophthora diversity in the environment. This paper describes a multiplex assay for simultaneous detection and identification of 26 members of Phytophthora down to species level and another 22 to clade or subclade level through target-specific primer extension (TSPE) and the Luminex xTAG array detection system. The assay starts with PCR amplification of two genomic regions, ITS and coxI, followed by a multiplex TSPE reaction with clade-, subclade- and species-specific probes. As a result, biotin-dCTP labelled products are generated and subsequently detected through hybridization with a set of anti-TAG coupled, colour-coded paramagnetic beads. The specificity of the method has been tested using DNA extracts from over 400 isolates representing 110 Phytophthora species and subspecies. The sensitivity and robustness have been determined by the use of DNA mixtures, dilution series and environmental samples. Thus the developed technique allows simultaneous identification of multiple Phytophthora species, particularly useful for the detection of these pathogens in environmental samples such as soil, water and plant tissue.

}, doi = {10.1111/ppa.2016.65.issue-610.1111/ppa.12481}, url = {http://doi.wiley.com/10.1111/ppa.2016.65.issue-6http://doi.wiley.com/10.1111/ppa.12481http://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111\%2Fppa.12481}, author = {Kostov, K. and Verstappen, E. C. P. and Bergervoet, J. H. W. and De Weerdt, M. and Schoen, C. D. and Slavov, S. and Bonants, P. J. M.} } @article {4701, title = {Interspecific interactions between the Sudden Oak Death pathogen Phytophthora ramorum and two sympatric Phytophthora species in varying ecological conditions}, journal = {Fungal Ecology}, volume = {28}, year = {2017}, month = {Aug-08-2017}, pages = {86 - 96}, abstract = {

Even when introduced invasive pathogens lack their natural predators or competitors, they must still interact with other organisms in their introduced range. Sudden Oak Death (SOD), caused by Phytophthora ramorum (Oomycota), is an introduced disease causing large-scale tree mortality. Two additional Phytophthora species, Phytophthora\ nemorosa and Phytophthora\ pseudosyringae, cause significantly lower oak mortality, yet they also commonly colonize leaves of Umbellularia californica, the major transmissive host of SOD in California. We combined field surveys and inoculation experiments to understand disease prevalence dynamics and competitive interactions among these pathogen species. Despite the broader geographic distribution of P.\ nemorosa with respect to that of P.\ ramorum, our results suggest that P.\ nemorosa exhibits a narrower ecological amplitude and, in any given region, occupies fewer sites than P.\ ramorum. Our results additionally suggest that, perhaps due to priority effects, P.\ nemorosa can persist at levels comparable to those of P.\ ramorum in ecologically suitable plots when climate favors P.\ ramorum dormancy. However, P.\ ramorum prevalence increases to levels higher than those of the competing species when abundant rainfall triggers its sporulation. Understanding the determinants and outcomes of competition between these species has important implications for understanding the epidemiology and possible control strategies for Sudden Oak Death.

}, issn = {17545048}, doi = {10.1016/j.funeco.2017.04.006}, url = {https://www.sciencedirect.com/science/article/abs/pii/S1754504817300600?via\%3Dihub}, author = {Kozanitas, Melina and Osmundson, Todd W. and Linzer, Rachel and Garbelotto, Matteo} } @article {4379, title = {Phytophthora tentaculata sp. nov. und Phytophthora cinnamomi var. parvispora var. nov., zwei neue Pilze von Zierpflanzen in Deutschland}, journal = {Journal of Plant Diseases and Protection }, volume = {100}, year = {1993}, pages = {250-258}, abstract = {

W{\"a}hrend der letzten beiden Jahre sind in Deutschland in einigen stark gesch{\"a}digten Gew{\"a}chshausbest{\"a}nden von Zierpflanzen wiederholt zwei Vertreter der Gattung Phytophthora isoliert worden, die bisher noch nicht bekannt waren. Sie werden hier als P. tentaculata und als P. cinnamomi vai. parvispora beschrieben.

From severely damaged ornamental plants found in greenhouses in Germany, two representatives of the genus Phytophthora were isolated. Because these fungi are unknown until now they are described in this treatise as new fungi, namely P. tentaculata and P. cinnamomi var. parvispora.

}, url = {http://www.jstor.org/stable/43386173}, author = {Krober, K and Marwitz, RZ} } @article {kroeber1993phytophthora, title = {Phytophthora tentaculata sp. nov. and Phytophthora cinnamomi var. parvispora var. nov., two new fungi from ornamental plants in Germany}, journal = {Zeitschrift fuer Pflanzenkrankheiten und Pflanzenschutz (Germany)}, volume = {v. 100(3)}, year = {1993}, pages = {p. 250-258}, issn = {0340-8159}, author = {Kroeber, H. and Marwitz, R.} } @article {3991, title = {The genus Phytophthora anno 2012}, journal = {Phytopathology}, volume = {102}, year = {2012}, month = {04/2012}, pages = {348 - 364}, abstract = {

Plant diseases caused by Phytophthora species will remain an ever increasing threat to agriculture and natural ecosystems. Phytophthora literally means plant destroyer, a name coined in the 19th century by Anton de Bary when he investigated the potato disease that set the stage for the Great Irish Famine. Phytophthora infestans, the causal agent of potato late blight, was the first species in a genus that at present has over 100 recognized members. In the last decade, the number of recognized Phytophthora species has nearly doubled and new species are added almost on a monthly basis. Here we present an overview of the 10 clades that are currently distinguished within the genus Phytophthora with special emphasis on new species that have been described since 1996 when Erwin and Ribeiro published the valuable monograph {\textquoteleft}Phytophthora diseases worldwide{\textquoteright} (35).

}, issn = {0031-949X}, doi = {10.1094/PHYTO-01-11-0025}, url = {http://apsjournals.apsnet.org/doi/abs/10.1094/PHYTO-01-11-0025}, author = {Kroon, Laurens P. N. M. and Brouwer, Henk and de Cock, Arthur W. A. M. and Govers, Francine} } @article {4252, title = {Phylogenetic analysis of Phytophthora species based on mitochondrial and nuclear DNA sequences}, journal = {Fungal Genetics and Biology}, volume = {41}, year = {2004}, month = {Jan-08-2004}, pages = {766 - 782}, abstract = {

A molecular phylogenetic analysis of the genus Phytophthora was performed, 113 isolates from 48 Phytophthora species were included in this analysis. Phylogenetic analyses were performed on regions of mitochondrial (cytochrome c oxidase subunit 1; NADH dehydrogenase subunit 1) and nuclear gene sequences (translation elongation factor 1α; β-tubulin) and comparisons made to test for incongruence between the mitochondrial and nuclear data sets. The genus Phytophthora was confirmed to be monophyletic. In addition, results confirm that the classical taxonomic grouping as described by [Waterhouse (1963)] does not reflect true phylogenetic relations. Phytophthora species were redistributed into 8 clades, providing a more accurate representation of phylogenetic relationships within the genus Phytophthora. The evolution and transition of morphological, pathogenic, and reproductive traits was inferred from the cladogram generated in this study. Mating system was inferred to be a homoplasious trait, with at least eight independent transitions from homothallism to heterothallism observed.

}, issn = {10871845}, doi = {10.1016/j.fgb.2004.03.007}, url = {http://linkinghub.elsevier.com/retrieve/pii/S1087184504000611}, author = {Kroon, L.P.N.M and Bakker, F.T and van den Bosch, G.B.M and Bonants, P.J.M and Flier, W.G} } @article {4360, title = {Absence of evidence is not evidence of absence: Feral pigs as vectors of soil-borne pathogens}, journal = {Austral Ecology}, volume = {38}, year = {2013}, month = {Jan-08-2013}, pages = {534 - 542}, abstract = {

Invasive soil-borne pathogens are a major threat to forest ecosystems worldwide. The newly discovered soil pathogen, Phytophthora {\textquoteleft}taxon Agathis{\textquoteright} (PTA), is a serious threat to endemic kauri (Agathis australis: Araucariaceae) in New Zealand. This study examined the potential for feral pigs to act as vectors of PTA. We investigated whether snouts and trotters of feral pigs carry soil contaminated with PTA, and using these results determined the probability that feral pigs act as a vector. We screened the soil on trotters and snouts from 457 pigs for PTA using various baiting techniques and molecular testing. This study detected 19 species of plant pathogens in the soil on pig trotters and snouts, including a different Phytophthora species (Phytophthora cinnamomi). However, no PTA was isolated from the samples. A positive control experiment showed a test sensitivity of 0{\textendash}3\% for the baiting methods and the data obtained were used in a Bayesian probability modelling approach. This showed a posterior probability of 35{\textendash}90\% (dependent on test sensitivity scores and design prevalence) that pigs do vector PTA and estimated that a sample size of over 1000 trotters would be required to prove a negative result. We conclude that feral pigs cannot be ruled out as a vector of soil-based plant pathogens and that there is still a high probability that feral pigs do vector PTA, despite our negative results. We also highlight the need to develop a more sensitive test for PTA in small soil samples associated with pigs due to unreliable detection rates using the current method.

}, doi = {10.1111/aec.2013.38.issue-510.1111/j.1442-9993.2012.02444.x}, url = {http://doi.wiley.com/10.1111/aec.2013.38.issue-5http://doi.wiley.com/10.1111/j.1442-9993.2012.02444.xhttp://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111\%2Fj.1442-9993.2012.02444.x}, author = {Krull, C. R. and Waipara, N. W. and Choquenot, D. and Burns, B. R. and Gormley, A. M. and Stanley, M. C.} } @article {PPA:PPA2593, title = {Response of selected South Australian native plant species to Phytophthora cinnamomi}, journal = {Plant Pathology}, volume = {61}, year = {2012}, month = {12/2012}, pages = {1165{\textendash}1178}, publisher = {Blackwell Publishing Ltd}, abstract = {

Thirty-seven South Australian native plant species from 11 families, including 15 threatened species in the state (of which six are listed as threatened under the federal Environment Protection and Biodiversity Conservation Act 1999) were assessed for response to infection by Phytophthora cinnamomi. Seedlings, 3-6 months old and grown in a greenhouse, were inoculated by placing infested pine wood plugs in the potting mix, maintained in moist conditions and assessed for mortality and disease symptoms for between 3 and 10 months. Thirty species were found to be susceptible, of which nine were highly susceptible, 15 moderately susceptible and six slightly susceptible. Three species were found to be resistant and results for four species were inconclusive. Six of the 15 threatened, rare or locally endangered species tested (Eucalyptus viminalis var. viminalis, Correa aemula, C. calycina, Olearia pannosa ssp. pannosa, Pomaderris halmaturina ssp. halmaturina and Prostanthera eurybioides) were moderately susceptible, while two (Allocasuarina robusta and Pultenaea graveolens) were highly susceptible.Significant populations of at least five of the threatened species susceptible to the disease are located close to confirmed or suspected Phytophthora-infested areas or growing in areas conducive for P.cinnamomi. An effective management strategy is therefore required to avoid extinction of such species due to infection by the phytophthora dieback pathogen.

}, keywords = {native vegetation, phytophthora dieback, survival, susceptibility, threatened species}, issn = {1365-3059}, doi = {10.1111/j.1365-3059.2012.02593.x}, url = {http://dx.doi.org/10.1111/j.1365-3059.2012.02593.x}, author = {Kueh, K. H. and McKay, S. F. and Facelli, E. and Facelli, J. M. and Velzeboer, R. M. A. and Able, A. J. and Scott, E. S.} } @article {4666, title = {A qPCR Assay for the Detection of Phytophthora cinnamomi Including an mRNA Protocol Designed to Establish Propagule Viability in Environmental Samples}, journal = {Plant Disease}, volume = {103}, year = {2019}, month = {Jan-09-2019}, pages = {2443 - 2450}, abstract = {

Phytophthora cinnamomi causes root and collar rot in many plant species in natural ecosystems and horticulture. A species-specific primer and probe PCIN5 were designed based on a mitochondrial locus encoding subunit 2 of cytochrome c oxidase (cox2). Eight PCR primers, including three forward and five reverse, were designed and tested in all possible combinations. Annealing temperatures were optimized for each primer pair set to maximize both specificity and sensitivity. Each set was tested against P. cinnamomi and two closely related clade 7 species, P. parvispora and P. niederhauseri. From these tests, five primer pairs were selected based on specificity and, with a species-specific P. cinnamomi probe, used to develop quantitative real-time PCR (qPCR) assays. The specificity of the two most sensitive qPCR assays was confirmed using the genomic DNA of 29 Phytophthora isolates, including 17 isolates of 11 species from clade 7, and representative species from nine other clades (all except clade 3). The assay was able to detect as little as 150 ag of P. cinnamomi DNA and showed no cross-reaction with other Phytophthora species, except for P. parvispora, a very closely related species to P. cinnamomi, which showed late amplification at high DNA concentrations. The efficiency of the qPCR protocol was evaluated with environmental samples including roots and associated soil from plants artificially infected with P. cinnamomi. Different RNA isolation kits were tested and evaluated for their performance in the isolation of RNA from environmental samples, followed by cDNA synthesis, and qPCR assay. Finally, a protocol was recommended for determining the presence of P. cinnamomi in recalcitrant environmental samples.

}, issn = {0191-2917}, doi = {10.1094/PDIS-09-18-1641-RE}, url = {https://apsjournals.apsnet.org/doi/10.1094/PDIS-09-18-1641-RE}, author = {Kunadiya, Manisha B. and Dunstan, William D. and White, Diane and Hardy, Giles E. St. J. and Grigg, Andrew H. and Burgess, Treena I.} } @article {4634, title = {Phytophthora chlamydospora and P. megasperma associated with root and crown rot of sour cherry in Turkey}, journal = {Journal of Plant Diseases and Protection}, volume = {124}, year = {2017}, month = {Jan-08-2017}, pages = {403 - 406}, abstract = {

Sour cherry is a very important commercial crop of Turkey. In a newly established orchard in Ankara province of Turkey, some of young sour cherry trees did not leaf out or collapsed after a while turning green in spring, 2014. Lateral and hairy roots of symptomatic trees showed poor growth. Occurrence of necrotic and decay tissues girdling the whole roots resulted in tree mortality. Two Phytophthora spp. were isolated from necrotic tissues on taproots and crowns. The pathogens were identified as Phytophthora chlamydospora and P. megasperma based on morphological characteristics and DNA sequences of the internal transcribed spacer region. Pathogenicity of the isolates was tested by stem inoculation to sour cherry seedlings. P. chlamydospora caused canker lesions and killed the seedlings within 4\ weeks, while no cankers occurred on stem of the plants inoculated with P. megasperma and on control plants. Also P. megasperma was found as pathogen on roots of sour cherry seedlings in soil infestation test. This is the first report of P. chlamydospora and P. megasperma causing crown and root rot of sour cherry in Turkey. In addition, P. chlamydospora is a new pathogen of sour cherry grafted on Prunus mahaleb.

}, issn = {1861-3829}, doi = {10.1007/s41348-017-0075-y}, url = {http://link.springer.com/content/pdf/10.1007/s41348-017-0075-y.pdf}, author = {Kurbetli, {\.I}lker and Aydo{\u g}du, Mehmet and S{\"u}l{\"u}, G{\"o}rkem} } @article {Manna2004345, title = {The decline of Austrocedrus chilensis forests in Patagonia, Argentina: soil features as predisposing factors}, journal = {Forest Ecology and Management}, volume = {190}, number = {2-3}, year = {2004}, pages = {345 - 357}, keywords = {Topography}, issn = {0378-1127}, doi = {DOI: 10.1016/j.foreco.2003.10.025}, url = {http://www.sciencedirect.com/science/article/B6T6X-4BD5PHG-4/2/6181ecf7a2cf4ba397d9afef97ee478d}, author = {La Manna, Ludmila and Rajchenberg, Mario} } @article {la2008seedling, title = {Seedling recruitment of Austrocedrus chilensis in relation to cattle use, microsite environment and forest disease}, journal = {Ecologia Austral.(Abr}, volume = {18}, number = {1}, year = {2008}, pages = {27{\textendash}41}, author = {La Manna, L. and Collantes, M. and Bava, J.} } @article {LaManna20081087, title = {Abiotic factors related to the incidence of the Austrocedrus chilensis disease syndrome at a landscape scale}, journal = {Forest Ecology and Management}, volume = {256}, number = {5}, year = {2008}, pages = {1087 - 1095}, abstract = {In this paper, the incidence of the A. chilensis disease syndrome in the "16 de Octubre" Valley (Chubut, Argentinean Patagonia) was related to landscape climatic, topographic and edaphic attributes, using remote sensing, geographic information systems and statistical methods. A strong relationship between the occurrence and incidence of the A. chilensis disease syndrome and site variables related to poor soil drainage was found. Non-allophanized soils with fine textures on flat and wavy soil phases, geomorphologies associated to alluvial processes, and low elevations and gentle slopes were positively related to the incidence of the disease. These relationships at a landscape scale agree with previous studies carried out at the stand level. A logistic predictive model of diseased occurrence was developed for the study area considering aspect, elevation, slope, mean annual precipitation and soil phase (classified according to predominant slopes).}, keywords = {Patagonia}, issn = {0378-1127}, doi = {DOI: 10.1016/j.foreco.2008.06.023}, url = {http://www.sciencedirect.com/science/article/B6T6X-4T4JDN7-1/2/6ec5c810e304a848ea7deb23b39e8977}, author = {La Manna, L. and S.D. Matteucci and T. Kitzberger} } @article {springerlink:10.1007/s10342-011-0503-7, title = {Modelling Phytophthora disease risk in Austrocedrus chilensis forests of Patagonia}, journal = {European Journal of Forest Research}, year = {2011}, note = {10.1007/s10342-011-0503-7}, pages = {1-15}, publisher = {Springer Berlin / Heidelberg}, abstract = {

Austrocedrus chilensis forests suffer from a disease caused by Phytophthora austrocedrae, which is found often in wet soils. We applied three widely used modelling techniques, with different data requirements, to model disease potential distribution under current environmental conditions: Mahalanobis distance, Maxent and Logistic regression. Each model was built using field data of health condition and landscape layers of environmental conditions (distance to streams, slope, aspect, elevation, mean annual precipitation and soil pH NaF). We compared model predictions by area under the receiver operating characteristic curve and Kappa statistics. A reasonable ability to predict observed disease distribution was found for each of the three modelling techniques. However, Maxent and Logistic regression presented the best predictive performance, with significant differences with respect to the Mahalanobis distance model. Our results suggested that if good absence data are available, Logistic regression should be used in order to better discriminate sites with high risk of disease. On the other hand, if absence data are not available or doubtful, Maxent could be a very good option. The three models predicted that around 50\% (49{\textendash}56\%) of the currently asymptomatic forests are located on sites at risk of disease according to abiotic factors. Most of these asymptomatic forests surround the current diseased patches, at distances lower than 100 m from diseased patches. Management considerations and the scope of future studies were discussed in this article.

}, issn = {1612-4669}, url = {http://dx.doi.org/10.1007/s10342-011-0503-7}, author = {La Manna, L. and Matteucci, S. and T. Kitzberger} } @article {4179, title = {{\"U}ber die F{\"a}ule der Cactusst{\"a}mme}, journal = {Bietr. Biol. Pflantz}, volume = {1}, year = {1870}, pages = {51-57}, author = {Lebert, H. and Cohn, F} } @article {4608, title = {First Report of Phytophthora ramorum Lineage EU1 Infecting Douglas Fir and Grand Fir in Oregon}, journal = {Plant Disease}, volume = {102}, year = {2018}, month = {Jan-02-2018}, pages = {455 - 455}, abstract = {

Sudden oak death (SOD) is caused by the introduced oomycete pathogen Phytophthora ramorum S. Werres, A. W. A. M. de Cock \& W. A. Man in{\textquoteright}t Veld. This fungus-like organism has four clonal lineages: NA1, NA2, EU1, and EU2 (Gr{\"u}nwald et al. 2016; Prospero et al. 2007). Until recently, the NA1 lineage was the only clonal lineage of P. ramorum reported in wildland forests in the western United States. In contrast, EU1, NA1, and NA2 have all been found in U.S. nurseries (Gr{\"u}nwald et al. 2012). In the winter of 2015, a symptomatic Notholithocarpus densiflorus Manos, Cannon \& S.H.Oh (tanoak) was identified during a SOD helicopter survey in Curry County, OR. P. ramorum was isolated from symptomatic bark tissue. Subsequently, the isolate was determined to be of the EU1 lineage based on 14 microsatellite loci (Gr{\"u}nwald et al. 2016). Continued monitoring of the area in 2016 and 2017 has identified symptomatic Abies grandis (Douglas ex D. Don) Lindl. (grand fir; n = 3) and Pseudotsuga menziesii (Mirb.) Franco (Douglas fir; n = 2) saplings growing near infected tanoak trees in the mixed conifer forest of Curry County, OR. Symptoms with shoot blight for these species were similar to those described in the literature, including wilting and dieback of new shoots, brown discoloration of needles, and needle loss on young shoots. Isolations were made by plating surface-sterilized tip dieback tissue from A. grandis and P. menziesii on a Phytophthora-selective medium. Based on the presence of chlamydospores, characteristic hyphae, and sporangial morphology, the isolates were identified as P. ramorum. DNA was extracted from hyphae, and a portion of the cellulose binding elicitor lectin (CBEL) gene was amplified and sequenced using the CBEL5U and CBEL6L primers (Gagnon et al. 2014). The sequences of the unknown lineage were aligned to sequences of CBEL for NA1, NA2, EU1, and EU2 using the Staden package in GAP version 4.11.2. The lineage of the isolates from A. grandis and P. menziesii (GenBank accession nos. MF918374 and MF918375, respectively) had 100\% identity to the EU1 reference sequences (GenBank nos. EU688952 and EF117945). To satisfy Koch{\textquoteright}s postulates, three branches of A. grandis and P. menziessii were inoculated with the original EU1 isolates of P. ramorum from those hosts. Ten days after inoculation, the same pathogen was reisolated from symptomatic stem tissue of both tree species. The EU1 lineage is considered more aggressive than the NA1 lineage and is of opposite mating type to NA1, thus potentially resulting in establishment of sexual populations.

}, issn = {0191-2917}, doi = {10.1094/PDIS-05-17-0681-PDN}, url = {https://apsjournals.apsnet.org/doi/10.1094/PDIS-05-17-0681-PDNhttps://apsjournals.apsnet.org/doi/full/10.1094/PDIS-05-17-0681-PDN}, author = {LeBoldus, J. M. and Sondreli, K. L. and Sutton, W. and Reeser, P. and Navarro, S. and Kanaskie, A. and Gr{\"u}nwald, N. J.} } @article {dbpia1207770, title = {Isolation, identification and characterization of Phytophthora katsurae, causing chestnut ink disease in Korea}, journal = {The Plant Pathology Journal}, volume = {25}, number = {2}, year = {2009}, pages = {121-127}, publisher = {Korean Society of Plant Pathology}, abstract = {

Since July 2005, survey of chestnut ink disease was carried out in chestnut stands located at southern parts of Korea. Dead chestnut trees showing inky ooze on necrotic trunks were found in two different locations. In order to isolate and identify the causal fungus, infected tissues and soil samples around dead or dying trees were collected and placed on Phytophthora-selective medium. Rhododendron and chestnut tree leaves were used as a bait to isolate the fungus from soil samples by attracting zoospores in soil suspensions. On V-8 culture medium, the isolates produced homothallic oogonia with protuberances (34.0-46.2{\texttimes}21.9-26.7㎛) abundantly, but did not produced sporangia. Mass production of sporangia was possible by immersing agar plugs with actively growing mycelium in the creek water at 18oC for 3 days. Sporangia were papillate, and ovoid to obpyriform (17.0-38.9{\texttimes}14.6-29.2㎛) in shape. Comparison of the ITS sequences revealed that the isolates had 100\% identity to the P. katsurae isolates from Japan and New Zealand and 99.6\% identity to other P. katsurae isolates. All of the examined isolates from Korea were completely identical to each other in ITS sequence. Numerous sporangia were formed in filtered as well as unfiltered creek water, but no sporangia formed in sterilized distilled water. Light induced sporangia formation, but has no influence on oospore formation. Amendments of β-sitosterol in culture media have no significant effect on mycelial growth but significantly stimulate oospore and sporangia formation.

}, keywords = {amphigynous antheridium, chestnut ink disease, homothallic oogonium, Phytophthora katsurae, sporangia}, url = {http://www.dbpia.co.kr/view/ar_view.asp?arid=1207770}, author = {Jong Kyu Lee and Jong Won Jo and Keum Chul Shin and Sang Hyun Lee and Sang Yong Lee} } @article {4084, title = {A survey of Phytophthora spp. in midwest nurseries, greenhouses, and landscapes}, journal = {Plant Disease}, volume = {97}, year = {2013}, month = {05/2013}, pages = {635 - 640}, abstract = {

A survey of nurseries, greenhouses, and landscapes was conducted from 2006 to 2008 in order to determine the prevalence and diversity of Phytophthora spp. From sites in Iowa, Michigan, Ohio, and, predominantly, Indiana, 121 Phytophthora isolates were obtained from 1,657 host samples spanning 32 host genera. Based on sequence of the internal transcribed spacer (ITS) region of the ribosomal DNA, 11 Phytophthora spp. and two hybrid species were identified. A majority of the isolates were P. citricola (35.9\%) or P. citrophthora (27.4\%). Six isolates were confirmed as hybrids (four of P. cactorum {\texttimes} hedraiandra and two of P. nicotianae {\texttimes} cactorum) by cloning and sequencing the ITS region. Three P. cactorum {\texttimes} hedraiandra isolates were obtained from the same site, from three Rhododendron spp., which are known hosts to the parental species. The fourth isolate, however, was recovered out of a different location in a Dicentra sp., which is not a known host to either parental species, suggesting an expansion of host range of the hybrid isolate as compared with either parental species.

}, issn = {0191-2917}, doi = {10.1094/PDIS-07-12-0689-RE}, author = {Leonberger, A. J. and Speers, C. and Ruhl, G. and Creswell, T. and Beckerman, J. L.} } @article {4246, title = {The Microscopic Examination of Phytophthora cinnamomi in Plant Tissues Using Fluorescent In Situ Hybridization}, journal = {Journal of Phytopathology}, volume = {162}, year = {2014}, month = {12/2014}, pages = {747 - 757}, abstract = {

The microscopic examination of Phytophthora cinnamomi in plant tissues is often difficult as structures such as hyphae, chlamydospores and oospores are frequently indistinguishable from those of other fungi and oomycetes, with histological stains not enabling species differentiation. This lack of staining specificity makes the localization of P.\ cinnamomi hyphae and reproductive structures within plant tissues difficult, especially in woody tissues. This study demonstrates that with the use of a species-specific fluorescently labelled DNA probe, P.\ cinnamomi can be specifically detected and visualized directly using fluorescent in situ hybridization (FISH) without damage to plant or pathogen cell integrity or the need for subculturing. This approach provides a new application for FISH with potential use in the detailed study of plant{\textendash}pathogen interactions in plants.

}, doi = {10.1111/jph.2014.162.issue-11-1210.1111/jph.12257}, url = {http://doi.wiley.com/10.1111/jph.2014.162.issue-11-12http://doi.wiley.com/10.1111/jph.12257}, author = {Li, Andrew Y. and Crone, Michael and Adams, Peter J. and Fenwick, Stanley G. and Hardy, Giles E. S. J. and Williams, Nari} } @article {4295, title = {Phytophthora on Betula spp. (birch)}, journal = {JKI Data Sheets {\textendash} Plant Diseases and Diagnosis}, volume = {80}, year = {2013}, pages = {7 pp}, abstract = {

Birch is an important forest tree especially in colder climates. It is monoecious and wind polli- nated species, and it has wind-dispersed seeds. The genus contains more than 60 taxa including trees and shrubs. B. pendula Roth (silver birch) and B pubescens Ehrh. (downy birch) have both wide distribution in Europe and are also found in northern parts of Asia (Hämet-Ahti et al., 1989, Niemistö et al., 2008). B. alleghaniensis Britton (yellow birch), B. lenta L. (sweet birch), B. papyrifera Marshall (paper birch) B. populifolia Marsh. (grey birch) and B. nigra L. (river birch) are species typical for North America (Hämet-Ahti et al., 1989; Verkasalo, 1990). In Scandinavia and northern Europe B. pendula is an important tree species for forest industry, but also used as amenity trees in parks, alleys and in gardens. B. alleghaniensis, B. lenta and B. papyrifera are also valuable for forest industry. Birches are cold tolerant pioneer species and in southern Europe they are found mainly on higher altitudes. Many Betula species such as B. nana L. (dwarf birch), B. pubescens subsp. czerepanovii (Orlova) Hämet-Ahti (arctic moor birch) and B. utilis D. Don (Himalayan birch) are typi- cal for treeline. B. nana and it{\textquoteright}s subspecies are shrubs native to arctic and cool temperate regions of northern Europe, northern Asia and northern North America. They are also present in Greenland as well as in mountains in Scotland and the Alps. B. utilis is growing as a shrub or tree native to the the Himalayas (Hämet-Ahti et al., 1989; http://www.discoverlife.org).

}, issn = {2191-1398}, doi = {10.5073/jkidspdd.2013.080}, url = {http://www.jki.bund.de/fileadmin/dam_uploads/_veroeff/JKI_Datenblaetter/Phytophthora/englisch/final_Betula_en.pdf}, author = {Lilja, Arja and Thinggaard, K. and Munda, Alenka} } @article {4725, title = {First Report of Root Rot Caused by Phytophthora acerina on Metasequoia glyptostroboides in China}, journal = {Plant Disease}, year = {2022}, month = {Aug-02-2022}, abstract = {

Metasequoia glyptostroboides Hu \& W. C. Cheng (Taxodiaceae), commonly called the Chinese redwood or dawn redwood, is a well-known "living fossil" and rare relict plant species endemic to China, which has been successfully cultivated throughout the world (Ma 2007). In July to September 2020, trees of Chinese redwood which were more than thirty years-old, showed symptoms of decline and death associated with branch dieback, root and collar rot (Fig. 1) in Yangtze River shelter-forests of Jiangling County in Hubei Province, China (112{\textdegree}15'19"E, 30{\textdegree}11'56"N; 40m). Diseased roots and rhizosphere soils were collected in September 2020 and April 2021. Using the baiting method, a homothallic Phytophthora sp. was recovered consistently from diseased roots and soil samples of Chinese redwood. All the isolates of this Phytophthora sp. formed similar colonies on V8 agar and corn meal agar (Fig. 2), and then three representative isolates (L4-5-4, L4-5-5 and L4-5-6) were randomly selected for morphological and molecular identification. In distilled water, semipapillate persistent sporangia were borne in simple sympodial branched sporangiophores. Sporangia were predominantly ovoid (Fig. 3a, d and f), but other shapes were observed including subglobose (Fig. 3b), limoniform (Fig. 3c) or distorted shapes (Fig. 3e), averaging 44.1 {\textpm} 7.7 {\textmu}m (n=102) in length and 32.8 {\textpm} 5.2 {\textmu}m (n=102) in width, with narrow exit pores of 8.0 {\textpm} 1.4 {\textmu}m (n=93) and a length/breadth ratio of 1.3 {\textpm} 0.10 (n=102). Chlamydospores were not observed. Oogonia were globose or subglobose, 20.51 to 40.15 {\textmu}m (av. 33.1 {\textpm} 3.9 {\textmu}m) (n=119) in diameter, with smooth walls and paragynous antheridium (Fig. 3g-i). Oospores were globose or subglobose in elongated oogonia with medium wall thickness of 1.9 {\textpm} 0.5 {\textmu}m (n=36), aplerotic or plerotic and 16.9 to 32.6 {\textmu}m in diameter (av. 26.6 {\textpm} 3.8 {\textmu}m) (n=40). According to the above morphological characteristics, this Phytophthora sp. was placed in Waterhouse{\textquoteright}s (1963) group III. The sequences of the internal transcribed spacers (ITS) region of nuclear ribosomal DNA of each isolate (GenBank Accession No. OK087320, OK087321 and OK087322) was 760 bp and had identity of 99.84\% with three P. acerina isolates (JX951285, JX951291 and JX951296), while the 800 bp β-tubulin (BTUB) sequences (OK140540, OK140541 and OK140542) showed 99.97\% homology to the sequence of P. acerina (KC201283) (Ginetti, Moricca and Squires 2014) (Table 1). The ML phylogenetic trees were established by comparing ITS and BTUB sequences of three Phytophthora strains (L4-5-4, L4-5-5 and L4-5-6) with reference sequences of isolates of Phytophthora in ITS and BTUB in GenBank (Fig. 4-5). Based on the morphological and molecular characteristics, the strains were identified as namely P. acerina. In addition, pathogenicity assays were performed with one of the three strains (L4-5-4) on M. glyptostroboides using both one year old and three years old seedlings. Inoculum was prepared by subculturing agar plugs from edges of CMA cultures into V8 medium plates, incubating at 20 {\textcelsius} in darkness for 10 days. Six seedlings planted in pots filled with sterilized soil were inoculated by mycelium plug at root collar and stem wounded by a 8 mm diameter puncher. Six control seedlings were inoculated in the same manner as above, and sterile agar plugs were used. After 35 days, inoculated seedlings all had necrotic lesions at the inoculation sites, and some seedlings had the symptoms of foliage blight and dieback, whereas control seedlings remained healthy (Fig. 6). The number of fibrous roots after inoculation was significantly less than the control, and the roots of inoculated seedlings blackened or even rotted, while there were no obvious symptoms in the control (Fig. 7). Phytophthora isolates recovered from the symptomatic tissues of artificially inoculated plants were identical to isolate L4-5-4 in morphological characters and ITS sequencing. This is the first report of P. acerina causing root rot on the Chinese redwood in China. As only the seedlings were inoculated, further research is needed to address the epidemiology and pathogenicity of P. acerina to adult trees of Chinese red wood. References: Ginetti, B. et al. 2014. Plant Pathology, 63(4): 858-876. Ma, J. S. 2007. Bulletin of the Peabody Museum of Natural History, 48(2): 235-253. Waterhouse, G. M. 1963. Mycological Papers 92:1-22

}, issn = {0191-2917}, doi = {10.1094/PDIS-12-21-2722-PDN}, url = {https://apsjournals.apsnet.org/doi/pdf/10.1094/PDIS-12-21-2722-PDN}, author = {Liu, Duanchong and Zhao, Wenxia and Huai, Wen-Xia and Xia, Jianping and Cai, Sanshan and Zhang, Ru-bin and Li, Bin} } @article {PPA:PPA627, title = {Phytophthora katsurae from cocoa}, journal = {Plant Pathology}, volume = {38}, number = {4}, year = {1989}, pages = {627{\textendash}629}, publisher = {Blackwell Publishing Ltd}, abstract = {Phytophthora katsurae is reported for the first time from cocoa.}, issn = {1365-3059}, doi = {10.1111/j.1365-3059.1989.tb01463.x}, url = {http://dx.doi.org/10.1111/j.1365-3059.1989.tb01463.x}, author = {Liyanage, NIS and Wheeler, BEJ} } @article {springerlink:10.1007/s10530-008-9321-3, title = {Ecological impacts of non-indigenous invasive fungi as forest pathogens}, journal = {Biological Invasions}, volume = {11}, year = {2009}, note = {10.1007/s10530-008-9321-3}, pages = {81-96}, publisher = {Springer Netherlands}, issn = {1387-3547}, doi = {10.1007/s10530-008-9321-3}, url = {http://dx.doi.org/10.1007/s10530-008-9321-3}, author = {Loo, Judy} } @article {4678, title = {CPHST Pest Datasheet for Phytophthora kernoviae}, year = {2015}, publisher = {USDA-APHIS-PPQ-CPHST}, url = {http://download.ceris.purdue.edu/file/2780}, author = {Mackesy, D. and Sullivan, M.} } @article {3999, title = {Analyses of the population structure in a global collection of Phytophthora nicotianae isolates inferred from mitochondrial and nuclear DNA sequences}, journal = {Phytopathology}, volume = {Early release}, year = {2013}, month = {02/2013}, abstract = {

Genetic variation within the heterothallic cosmopolitan plant pathogen Phytophthora nicotianae was determined in 96 isolates from a wide range of hosts and geographic locations by characterizing four mitochondrial (10\% of the genome) and three nuclear loci. Fifty-two SNPs (average of 1 every 58 bp) and 313 sites with gaps representing 5450 bases, enabled the identification of 50 different multilocus mitochondrial haplotypes. Similarly, 24 SNPs (average of 1 every 69 bp), with heterozygosity observed at each locus, were observed in three nuclear regions (hyp, scp, β-tub) differentiating 40 multilocus nuclear genotypes. Both mitochondrial and nuclear markers revealed a high level of dispersal of isolates and an inconsistent geographic structuring of populations. However, a specific association was observed for host of origin and genetic grouping with both nuclear and mitochondrial sequences. In particular, the majority of citrus isolates from Italy, California, Florida, Syria, Albania and Philippines clustered in the same mitochondrial group and shared at least one nuclear allele. A similar association was also observed for isolates recovered from Nicotiana spp. and Solanum spp. The present study suggests an important role of nursery populations in increasing genetic recombination within the species and the existence of extensive phenomena of migration of isolates that have been likely spread worldwide with infected plant material.

}, issn = {0031-949X}, doi = {10.1094/PHYTO-10-12-0263-R}, author = {Mammella, Marco A. and Martin, Frank N. and Cacciola, Santa O. and Coffey, Michael and Faedda, Roberto and Schena, Leonardo} } @article {4481, title = {Limited morphological, physiological and genetic diversity of Phytophthora palmivora from cocoa in Papua New Guinea}, journal = {Plant Pathology}, volume = {66}, year = {2017}, month = {Jan-05-2016}, pages = {124{\textendash}130}, abstract = {

In Papua New Guinea (PNG) cocoa (Theobroma cacao) is one of the most important cash crops grown in the tropical lowland and island regions. As in most cocoa-growing areas, phytophthora black pod and canker cause significant yield losses. Cocoa breeding activities in PNG are focused in East New Britain province where disease control recommendations are also developed. This study tested the hypothesis that there was no diversity in the Phytophthora palmivora population causing black pod on cocoa by characterizing the variation in pathogen populations within and between the five major cocoa-growing areas. Diseased pods were sampled hierarchically from the five locations and additional isolates were collected from soil, stem and leaf lesions, or retrieved from culture collections. Morphological characters showed continuous variation within the range described for P.\ palmivora. Genetic analysis revealed that the isolates belonged to one dominant clonal lineage, with restricted distributions of several other subpopulations. Lowest diversities were found in the geographically isolated Karkar Island and East Sepik province. Soil isolates showed greater genetic diversity than isolates from cocoa lesions. Intra-farm variation was as much as inter-farm or inter-province variation. Both mating types were detected, although no strong evidence of sexual recombination was observed. The analysis revealed limited geographic, temporal or host specialization, suggesting continuous selection for pathogenicity from a genetic pool of P.\ palmivora. These findings have significant implications on the deployment of cocoa genotypes, enforcement of inter-province quarantine and sustainable disease management strategies.

}, doi = {10.1111/ppa.12557}, url = {http://doi.wiley.com/10.1111/ppa.12557}, author = {Maora, J. S. and Liew, E. C. Y. and Guest, D. I.} } @article {269, title = {Modelling the influence of winter frosts on the development of the stem canker of red oak, caused by Phytophthora cinnamomi.}, journal = {Annales des Sciences Forestiere}, volume = {53}, year = {1996}, pages = {369-382}, doi = {DOI: 10.1051/forest:19960219}, url = {http://dx.doi.org/10.1051/forest:19960219}, author = {Mar{\c c}ais, B. and Dupuis, F. and Desprez-Loustau, M.L.} } @article {martin_phylogenetic_2003, title = {Phylogenetic relationships of Phytophthora ramorum, P. nemorosa, and P. pseudosyringae, three species recovered from areas in California with sudden oak death.}, journal = {Mycological research}, volume = {107}, year = {2003}, pages = {1379{\textendash}1391}, keywords = {California, cytochrome-c oxidase, forest trees, fungal anatomy, internal transcribed spacers, mitochondrial DNA, molecular systematics, phylogeny, Phytophthora, Phytophthora ramorum, plant pathogenic fungi, Quercus, ribosomal DNA, sequence analysis}, issn = {09537562}, doi = {http://dx.doi.org/10.1017/S0953756203008785}, author = {F.N. Martin and P.W. Tooley} } @article {1297, title = {Molecular detection of Phytophthora ramorum, the causal agent of sudden oak death in California, and two additional species commonly recovered from diseased plant material}, journal = {Phytopathology}, volume = {94}, year = {2004}, pages = {621-631}, abstract = {

Sudden oak death is a disease currently devastating forest ecosystems in several coastal areas of California. The pathogen causing this is Phy-tophthora ramorum, although species such as P. nemorosa and P. pseudo-syringae often are recovered from symptomatic plants as well. A molecular marker system was developed based on mitochondrial sequences of the cox I and II genes for detection of Phytophthora spp. in general, and P. ramorum, P. nemorosa, and P. pseudosyringae in particular. The first-round multiplex amplification contained two primer pairs, one for amplification of plant sequences to serve as an internal control to ensure that extracted DNA was of sufficient quality to allow for polymerase chain reaction (PCR) amplification and the other specific for amplification of sequences from Phytophthora spp. The plant primers amplified the desired amplicon size in the 29 plant species tested and did not interfere with amplification by the Phytophthora genus-specific primer pair. Using DNA from purified cultures, the Phytophthora genus-specific primer pair amplified a fragment diagnostic for the genus from all 45 Phytophthora spp. evaluated, although the efficiency of amplification was lower for P. lateralis and P. sojae than for the other species. The genus-specific primer pair did not amplify sequences from the 30 Pythium spp. tested or from 29 plant species, although occasional faint bands were observed for several additional plant species. With the exception of one plant species, the resulting amplicons were smaller than the Phytophthora genus-specific amplicon. The products of the first-round amplification were diluted and amplified with primer pairs nested within the genus-specific amplicon that were specific for either P. ramorum, P. nemorosa, or P. pseudo-syringae. These species-specific primers amplified the target sequence from all isolates of the pathogens under evaluation; for P. ramorum, this included 24 isolates from California, Germany, and the Netherlands. Using purified pathogen DNA, the limit of detection for P. ramorum using this marker system was ≈2.0 fg of total DNA. However, when this DNA was spiked with DNA from healthy plant tissue extracted with a commercial miniprep procedure, the sensitivity of detection was reduced by 100- to 1,000-fold, depending on the plant species. This marker system was validated with DNA extracted from naturally infected plant samples collected from the field by comparing the sequence of the Phytophthora genus-specific amplicon, morphological identification of cultures recovered from the same lesions and, for P. ramorum, amplification with a previously published rDNA internal transcribed spacer species-specific primer pair. Results were compared and validated with three different brands of thermal cyclers in two different laboratories to provide information about how the described PCR assay performs under different laboratory conditions. The specificity of the Phytophthora genus-specific primers suggests that they will have utility for pathogen detection in other Phytophthora pathosystems.

}, url = {http://dx.doi.org/10.1094/PHYTO.2004.94.6.621}, author = {Martin, Frank N. and Tooley, Paul W. and Cheryl Blomquist} } @article {1273, title = {Identification and detection of Phytophthora: reviewing our progress, identifying our needs}, journal = {Plant Disease}, volume = {96}, year = {2012}, pages = {1080-1103}, abstract = {

With the increased attention given to the genus Phytophthora in the last decade in response to the ecological and economic impact of several invasive species (such as P. ramorum, P. kernoviae, and P. alni), there has been a significant increase in the number of described species. In part, this is due to the extensive surveys in historically underexplored ecosystems (e.g., forest and stream ecosystems) undertaken to determine the spread of invasive species and the involvement of Phytophthora species in forest decline worldwide (e.g., oak decline). The past decade has seen an approximate doubling in the number of described species within the genus Phytophthora, and the number will likely continue to increase as more surveys are completed and greater attention is devoted to clarifying phylogenetic relationships and delineating boundaries in species complexes. The development of molecular resources, the availability of credible sequence databases to simplify identification of new species, and the sequencing of several genomes have provided a solid framework to gain a better understanding of the biology, diversity, and taxonomic relationships within the genus. This information is much needed considering the impact invasive or exotic Phytophthora species have had on natural ecosystems and the regulatory issues associated with their management. While this work is improving our ability to identify species based on phylogenetic grouping, it has also revealed that the genus has a much greater diversity than previously appreciated.

}, url = {http://dx.doi.org/10.1094/PDIS-12-11-1036-FE}, author = {Martin, Frank N. and Z. Gloria Abad and Yilmaz Balci and Ivors, Kelly} } @mastersthesis {martin_developing_2008, title = {Developing techniques for evaluating the susceptibility of root-disease resistant Port-Orford-Cedar to foliar and stem canker diseases.}, year = {2008}, type = {mastersphd}, author = {Danielle Martin} } @article {4374, title = {First Report of Phytophthora tentaculata Causing Root and Stem Rot of Oregano in Italy}, journal = {Plant Disease}, volume = {93}, year = {2009}, month = {Jan-08-2009}, pages = {843 - 843}, abstract = {

Oregano (Origanum vulgare L.; Lamiaceae) is cultivated for culinary and medicinal purposes and as an ornamental. In October of 2007, 1- to 2-year-old potted plants of oregano showed symptoms of decline associated with root and basal stem rot in a nursery in Liguria (northern Italy) that produces 1 million to 1.5 million potted aromatic plants per year. Aboveground symptoms included leaf russeting and chlorosis, wilt, defoliation and dieback of twigs, browning of the basal stem, and subsequent collapse of the entire plant. Approximately 80\% of the plants died within 30 days after the appearance of the first symptoms on the canopy. Approximately 20\% of a stock of 30,000 oregano plants was affected. Stocks of other aromatic species, such as mint, lavender, rosemary, and sage, appeared healthy. A Phytophthora species was consistently isolated from symptomatic stems and roots of oregano plants on BNPRAH selective medium (2). Ten pure cultures were obtained by single-hypha transfers, and the species was identified as Phytophthora tentaculata Kr{\"o}ber \& Marwitz by morphological criteria and sequencing of the internal transcribed spacer (ITS) region of rDNA using the ITS 4 and ITS 6 universal primers for DNA amplification. Isolates from oregano formed stoloniferous colonies with arachnoid mycelium on potato dextrose agar and had a growth rate of 2 to 3 mm per day at 24{\textdegree}C with optimum, minimum, and maximum temperatures of 24, 8, and 34{\textdegree}C, respectively. Sporangia formed in soil extract solution and were papillate and spherical or ovoid to obpyriform with a length/breadth ratio of 1.3:1. Few sporangia were caducous and all had a short pedicel (\<5 μm). Hyphal swellings and chlamydospores were produced in sterile distilled water and corn meal agar, respectively. All isolates were homothallic and produced globose terminal oogonia (mean diameter of 34 μm) with one or occasionally two paragynous, monoclinous, or diclinous antheridia. Amphigynous antheridia were also observed. The sequence of the ITS region of the rDNA (GenBank No. FJ872545) of an isolate from oregano (IMI 395782) showed 99\% similarity with sequences of two reference isolates of P. tentaculata (Accession Nos. AF266775 and AY881001). To test for pathogenicity, the exposed root crowns of 10 6-month-old potted plants of oregano were drench inoculated with 10 ml of a suspension of 2 {\texttimes} 104 zoospores/ml of isolate IMI 395782. Sterile water was pipetted onto the roots of 10 control plants. All plants were maintained in 100\% humidity at 22 to 24{\textdegree}C in a greenhouse under natural light and watered once a week. Within 3 weeks after inoculation, all inoculated plants developed symptoms identical to those observed in the nursery and died within 30 to 40 days after the appearance of the first symptoms. Control plants remained healthy. P. tentaculata was reisolated solely from symptomatic plants. P. tentaculata has been reported previously on several herbaceous ornamental plants (1,3). However, to our knowledge, this is the first report of this species on O. vulgare. Root and basal stem rot caused by P. tentaculata is the most serious soilborne disease of oregano reported in Italy so far.

}, issn = {0191-2917}, doi = {10.1094/PDIS-93-8-0843B}, url = {http://apsjournals.apsnet.org/doi/abs/10.1094/PDIS-93-8-0843B}, author = {Martini, P. and Pane, A. and Raudino, F. and Chimento, A. and Scibetta, S. and Cacciola, S. O.} } @article {MEC:MEC3773, title = {Reconstruction of the sudden oak death epidemic in California through microsatellite analysis of the pathogen Phytophthora ramorum}, journal = {Molecular Ecology}, volume = {17}, number = {11}, year = {2008}, pages = {2755{\textendash}2768}, publisher = {Blackwell Publishing Ltd}, abstract = {

The genetic structure of the clonally reproducing Sudden Oak Death (SOD) pathogen in California was investigated using seven variable microsatellites. A total of 35 multilocus genotypes were identified among 292 samples representative of populations from 14 forest sites and of the nursery trade. amova indicated significant genetic variability both within (44.34\%) and among populations (55.66\%). Spatial autocorrelation analyses indicated that Moran{\textquoteright}s index of similarity reached a minimum of 0.1 at 350 m, increased to 0.4 at 1500 m and then decreased to zero at 10 km. These results suggest a bimodal pattern of spread, with medium range dispersal (1500{\textendash}10 000 m) putatively attributed to the presence of strong winds. Lack of genetic structure was identified for three groups of populations. One group notably included the nurseries{\textquoteright} population and two forest populations, both linked to early reports of the pathogen. A neighbour-joining analysis based on pairwise ΦST values indicated that the clade inclusive of the nurseries{\textquoteright} populations is basal to all California populations. A network analysis identified three common genotypes as the likely founders of the California infestation and proposes a stepwise model for local evolution of novel genotypes. This was supported by the identification in the same locations of novel genotypes and of their 1- or 2-step parents. We hypothesize that the few undifferentiated population groups indicate historical human spread of the pathogen, while the general presence of genetically structured populations indicates that new infestations are currently generated by rare medium or long-range natural movement of the pathogen, followed by local generation of new genotypes.

}, keywords = {genetic structure, microsatellite, network analysis, Phytophthora ramorum, spatial autocorrelation, Sudden oak death}, issn = {1365-294X}, doi = {10.1111/j.1365-294X.2008.03773.x}, url = {http://dx.doi.org/10.1111/j.1365-294X.2008.03773.x}, author = {Mascheretti, S. and Croucher, P. J. P. and Vettraino, A. Vettraino and Prospero, S and Garbelotto, M.} } @article {4079, title = {Two new Phytophthora species from South African Eucalyptus plantations}, journal = {Mycological Research}, volume = {111}, year = {2007}, month = {11/2007}, pages = {1321 - 1338}, abstract = {

A recent study to determine the cause of collar and root rot disease outbreaks of cold tolerant Eucalyptus species in South Africa resulted in the isolation of two putative new Phytophthora species. Based on phylogenetic comparisons using the ITS and β-tubulin gene regions, these species were shown to be distinct from known species. These differences were also supported by robust morphological characteristics. The names, Phytophthora frigida sp. nov. and Phytophthora alticola sp. nov. are thus provided for these taxa, which are phylogenetically closely related to species within the ITS clade 2 (P. citricola, P. tropicali and P.multivesiculata) and 4 (P. arecae and P. megakarya), respectively. Phytophthora frigida is heterothallic, and produces stellate to rosaceous growth patterns on growth medium, corraloid hyphae, sporangia with a variety of distorted shapes and has the ability to grow at low temperatures. Phytophthora alticola is homothallic and has a slower growth rate in culture. Both P. frigida and P. alticola are pathogenic to Eucalyptus dunnii. In pathogenicity tests, they were, however, less pathogenic than P. cinnamomi, which is a well-known pathogen of Eucalyptus in South Africa.

}, issn = {09537562}, doi = {10.1016/j.mycres.2007.08.011}, url = {http://www.sciencedirect.com/science/article/pii/S0953756207001955}, author = {Maseko, Bongani and Burgess, Treena I. and Coutinho, Teresa A. and Michael J. Wingfield} } @mastersthesis {612, title = {An undescribed Phytophthora sp. recovered from beneath stands of Pinus radiata.}, volume = {MS}, year = {1970}, pages = {63}, school = {Auckland University}, type = {mastersMS}, address = {New Zealand}, author = {McAlonan, M.J.} } @article {4198, title = {Phytophthora cinnamomi as a Contributor to White Oak Decline in Mid-Atlantic United States Forests}, journal = {Plant Disease}, volume = {98}, year = {2014}, month = {Jan-03-2014}, pages = {319 - 327}, abstract = {

To evaluate Phytophthora cinnamomi as a cause of white oak (Quercus alba) decline in mid-Atlantic forests, sampling was conducted at 102 sites from 2011 to 2012. Soil and roots from healthy and declining white oak trees were collected. Phytophthora spp. were isolated using baiting and CFU of P. cinnamomi quantified using wet-sieving. Fine roots were scanned and measured. Phytophthora spp. were isolated from 43\% of the sites. P. cinnamomi was common; six other species were isolated infrequently. Little difference in lesion size existed on white oak seedlings inoculated with 32 isolates of P. cinnamomi; only 13 isolates caused significant mortality. Soils from white oak versus nine other hosts did not have significantly different CFU. P. cinnamomi was restricted to United States Department of Agriculture hardiness zones six and seven and never found in zone five. The presence of Phytophthora spp. in soil can be associated with white oak fine root health. When Phytophthora spp. were present, white oak trees in zones five and six had less fine roots. In mid-Atlantic oak forests, however, environmental conditions appear to play a key role in determining the impact of P. cinnamomi on the root system. P. cinnamomi alone does not appear to be a causal factor of white oak decline.

}, issn = {0191-2917}, doi = {10.1094/PDIS-06-13-0649-RE}, url = {http://apsjournals.apsnet.org/doi/abs/10.1094/PDIS-06-13-0649-RE}, author = {McConnell, M. E. and Balci, Y.} } @article {4046, title = {Isozyme diversity in Phytophthora palmivora: evidence for a southeast Asian centre of origin}, journal = {Mycological Research}, volume = {98}, year = {1994}, month = {9/1994}, pages = {1035 - 1043}, abstract = {

Isozyme and morphological data were obtained for 93 isolates of P. palmivora and six described as P. arecae. Sporangial shape for both species ranged from spherical to ellipsoid with a high percentage of sporangia predominantly ellipsoid with a broad base and a short occluded pedicel less than 5 m in length. Fourteen enzymes stained in starch gels yielding 17 putative loci, 11 of which were monomorphic, the remainder being polymorphic (GPI, HEX2, IDH1, MDH1, PEP and SOD). Phosphoglucose isomerase (GPI) and isocitric dehydrogenase (IDH1) were the most variable loci. Isozyme analysis of the 99 isolates revealed 18 electrophoretic types (ETs). Isolates of P. arecae clustered with P. palmivora in ET7 and ET8, the most common ETs found in P. palmivora. Considerable genetic diversity was found amongst P. palmivora isolates from coconut (Cocos nucifera) with 8 ETs, durian (Durio zibethinus) with 5 ETs and other non-cacao hosts from Indonesia, Malaysia, Philippines and Thailand. Since coconut and durian are indigenous to the region, a southeast Asian origin for P. palmivora seems probable. Finally, since no significant differences were found in either morphology or isozymes between isolates of P. palmivora and P. arecae, this study provides definitive evidence that the two species are conspecific.

}, issn = {09537562}, doi = {10.1016/S0953-7562(09)80430-9}, url = {http://www.sciencedirect.com/science/article/pii/S0953756209804309}, author = {Mchau, Godwin R.A. and Michael D. Coffey} } @mastersthesis {mcwilliams_port-orford-cedar_2000, title = {Port-Orford-cedar and Phytophthora lateralis: grafting and heritability of resistance in the host, and variation in the pathogen}, volume = {PhD}, year = {2000}, school = {Oregon State University}, type = {masters}, address = {Corvallis}, abstract = {

Port-Orford-cedar (Chamaecyparis lawsoniana) is a forest tree native to a small area of Oregon and California. A root disease caused by Phytophthora lateralis causes widespread mortality of Port-Orford-cedar. This dissertation examines three important elements of the Port-Orford-cedar P. lateralis pathosystem related to breeding for disease resistance: use of resistant rootstocks to maintain genotypes of Port-Orford-cedar for breeding; the heritability and genetic basis of disease resistance; and variability in virulence and DNA fingerprint among a sample of P. lateralis isolates. Port-Orford-cedar was reciprocally grafted to western redcedar (Thuja plicata), incense cedar (Calocedrus decurrens), and Alaska yellow-cedar (Chamaecyparis nootkatensis). Port-Orford-cedar scion graft success was moderate with western red cedar and incense cedar, but extreme overgrowth of the rootstock by the scion indicated incompatibility. Xylem union was good, but phloem union was incomplete or lacking. Nearly all Port-Orford-cedar rootstocks and seedlings exposed to P. lateralis died of root disease. Four percent of the Alaska yellow-cedar exposed also died, confirming this tree as a host for P. lateralis. Resistance of Port-Orford-cedar to P. lateralis is rare. A small number of trees have been identified exhibiting resistance. A number of families were tested to determine the genetic basis for resistance. Estimates of narrow-sense and family mean heritability of resistance, as exhibited by restriction of lesion length after inoculation, were determined. Both narrow-sense and family mean heritabilities were between 0.61 and 0.98 in most tests. Between 21\% and 32\% of the variance was due to differences among families. Thirteen isolates of P. lateralis were collected from three hosts throughout the geographic range of the fungus. Variation in growth rate on artificial media at three temperatures, virulence when used to inoculate Port-Orford-cedar, and DNA fingerprint were compared. There were significant differences in growth rate among isolates at 24C, but fewer differences at lower temperatures and on a rich medium. One isolate produced significantly shorter lesions in three different inoculation tests. Isolates differed at only two of 189 bands produced by Inter Simple Sequence Repeat (ISSR) DNA primers, indicating very little genetic variation among isolates.

}, url = {http://oasis.oregonstate.edu/record=b2155969}, author = {Michael G McWilliams} } @article {doi:10.1094/PDIS-07-10-0505, title = {Effects of fuel reduction treatments on incidence of Phytophthora species in soil of a southern Appalachian Mountain forest}, journal = {Plant Disease}, volume = {95}, number = {7}, year = {2011}, pages = {811-820}, abstract = {

The National Fire and Fire Surrogate Study was initiated to study the effects of fuel reduction treatments on forest ecosystems. Four fuel reduction treatments were applied to three sites in a southern Appalachian Mountain forest in western North Carolina: prescribed burning, mechanical fuel reduction, mechanical fuel reduction followed by prescribed burning, and a nontreated control. To determine the effects of fuel reduction treatments on Phytophthora spp. in soil, incidences were assessed once before and twice after fuel reduction treatments were applied. Also, the efficiency of the baiting bioassay used to detect species of Phytophthora was evaluated, and the potential virulence of isolates of Phytophthora spp. collected from forest soils was determined. Phytophthora cinnamomi and P. heveae were the only two species recovered from the study site. Incidences of these species were not significantly affected by fuel reduction treatments, but incidence of P. cinnamomi increased over time. In the baiting bioassay, camellia leaf disks were better than hemlock needles as baits. P. cinnamomi was detected best in fresh soil, whereas P. heveae was detected best when soil was air-dried and remoistened prior to baiting. Isolates of P. heveae were weakly virulent and, therefore, potentially pathogenic{\textemdash}causing lesions only on wounded mountain laurel and rhododendron leaves; however, isolates of P. cinnamomi were virulent and caused root rot and mortality on mountain laurel and white pine plants.

}, doi = {10.1094/PDIS-07-10-0505}, url = {http://apsjournals.apsnet.org/doi/abs/10.1094/PDIS-07-10-0505}, author = {Meadows, I. M. and Zwart, D. C. and Jeffers, S. N. and Waldrop, T. A. and Bridges, W. C.} } @article {doi:10.1890/ES10-00192.1, title = {Epidemiological modeling of invasion in heterogeneous landscapes: spread of sudden oak death in California (1990{\textendash}2030)}, journal = {Ecosphere}, volume = {2}, number = {2}, year = {2011}, pages = {art17}, doi = {10.1890/ES10-00192.1}, url = {http://www.esajournals.org/doi/abs/10.1890/ES10-00192.1}, author = {Meentemeyer, Ross K. and Cunniffe, Nik J. and Cook, Alex R. and Filipe, Joao A. N. and Hunter, Richard D. and Rizzo, David M. and Gilligan, Christopher A.} } @article {4375, title = {First Report of Stalk Rot Caused by Phytophthora tentaculata on Aucklandia lappa in China}, journal = {Plant Disease}, volume = {92}, year = {2008}, month = {Jan-09-2008}, pages = {1365 - 1365}, abstract = {

Phytophthora tentaculata causes root and stalk rot of Chrysanthemum spp., Delphinium ajacis, and Verbena spp. in nurseries in the Netherlands and Germany (2). In later years, P. tentaculata was isolated from Verbena hybrids (3) and lavender cotton (Santolina chamaecyparissus) in Spain (1). In August 2007, stalk rot symptoms were observed on Aucklandia lappa (Asteraceae), an economically important Chinese medicinal plant, in some fields in Yunnan Province of China. Small groups of infected plants were randomly distributed throughout the fields. Plants showing stalk rot and wilting died rapidly. Diseased tissues were cut into 10-mm pieces and plated onto Phytophthora selective medium, P5ARP (2), to obtain the pure cultures. Seven isolates were obtained, and five isolates were grown on solidified LBA (60 g of lima bean powder and 15 g of agar per 10,000 ml of distilled water) and 10\% V8 juice liquid medium for examination of morphological and physiological characteristics (4). The colony surface texture was uniform and formed sparse, loosely branched mycelium on LBA medium. Radial growth rate was 2 to 3 mm per day at 24{\textdegree}C on LBA. In water, relatively small swellings were formed at hyphal branches. Sporangia were spherical or ovoid to obpyriform and some were distorted and papillate with a narrow exit pore. Approximately 10\% of the sporangia were caducous with a short pedicel. Sporangial dimensions were 28 to 47 (35) {\texttimes} 21 to 36 (29) μm, length/breadth ratio 1.2. Chlamydospores formed on LBA after 1 week and were terminal, spherical, thin walled, and 21 to 31 (27) μm in diameter. The isolates were homothallic. Oogonia abundantly formed on LBA and were 25 to 36 (31) μm in diameter. One or two paragynous antheridia (15 {\texttimes} 10 μm) were attached to the oogonia. Oospores were spherical, hyaline, aplerotic, and 20 to 32 (25) μm in diameter. The minimum temperature for mycelium growth was 8{\textdegree}C and maximum temperature was 34{\textdegree}C. The internal transcribed spacer (ITS) region was amplified and sequenced and agreed 100\% with sequences of four P. tentaculata isolates deposited in GenBank (Accession Nos. AJ854302, AY881001, DQ335634, and AF266775). Pathogenicity was assessed by flooding three potted A. lappa plants with a 104 ml{\textendash}1 zoospore suspension and incubating at 20 to 22{\textdegree}C. As controls, two potted A. lappa plants were flooded with deionized water. All three inoculated A. lappa plants exhibited stalk rot after 15 days, from which the pathogen was reisolated using selective medium, P5ARP. Controls remained healthy 15 days after inoculation, To our knowledge, this is the first report of P. tetaculata H. Kroeber \& R. Marwitz infection of A. lappa in China. We speculate that the pathogen might have been introduced from other countries on seeds.

}, issn = {0191-2917}, doi = {10.1094/PDIS-92-9-1365B}, url = {http://apsjournals.apsnet.org/doi/abs/10.1094/PDIS-92-9-1365B}, author = {Meng, J. and Wang, Y. C.} } @article {Mfegue01092012, title = {Microsatellite markers for population studies of Phytophthora megakarya (Pythiaceae), a cacao pathogen in Africa}, journal = {American Journal of Botany}, volume = {99}, year = {2012}, pages = {e353-e356}, abstract = {

{\quotesinglbase}{\"A}{\textcent} Premise of the study: Phytophthora megakarya is the agent of black pod disease of cacao and is the main pathogen of this crop in Africa. Population genetic studies are required to investigate how this pathogen emerged. To this end, we developed 12 novel polymorphic microsatellite markers for P. megakarya.{\quotesinglbase}{\"A}{\textcent} Methods and Results: Microsatellite sequences were obtained by pyrosequencing of multiplex-enriched libraries. Candidate loci with di- or trinucleotide motifs were selected, and primer pairs were tested with nine P. megakarya isolates. The 12 most polymorphic and unambiguous loci were selected to develop three multiplex PCR pools. The total number of alleles varied from two to nine, depending on loci, and higher than expected heterozygosity was observed.{\quotesinglbase}{\"A}{\textcent} Conclusions: These markers were used for population genetic studies of P. megakarya in Cameroon and for comparison with reference strains from West Africa. This is the first time that microsatellite markers have been developed for P. megakarya.

}, doi = {10.3732/ajb.1200053}, url = {http://www.amjbot.org/content/early/2012/08/29/ajb.1200053.abstract}, author = {Mfegue, C. V. and Herail, C. and Adreit, H. and Mbenoun, M. and Techou, Z. and Ten Hoopen, M. and Tharreau, D. and Ducamp, M.} } @article {253, title = {The occurrence of Phytophthora and Pythium species on roots of native plants in northern California and southern Oregon.}, journal = {Phytopathology}, volume = {45}, year = {1955}, pages = {694 (abstract)}, author = {Middleton, J.T. and Baxter, D.V.} } @article {4658, title = {Taxonomic structure of Phytophthora cryptogea and P. drechsleri based on isozyme and mitochondrial DNA analyses}, journal = {Mycological Research}, volume = {95}, year = {1991}, month = {Jan-01-1991}, pages = {31 - 48}, abstract = {

Intra- and interspecific isozyme variation was evaluated for 123 isolates assigned to either Phytophthora cryptogea or P. drechsleri, and compared with that of 15 isolates of P. erythroseptica and 11 isolates of P. lateralis. Isolates of P. cryptogea and P. drechsleri were from worldwide sources and displayed a high degree of variability. The majority of these isolates were subsequently divided into ten distinct groups based on numerical analysis of 24 putative enzyme loci. None of the enzyme loci were monomorphic for all ten groups. Analysis of mitochondrial (mt) DNA restriction fragment length polymorphisms of selected isolates from each isozyme group supported the isozyme data. Differences in morphological features of the ten isozyme groups of P. cryptogea and P. drechsleri were not sufficiently distinct to readily distinguish between them. Isozyme analysis of P. erythroseptica revealed that it is a uniform and distinct taxon. The isolates of P. lateralis also formed a homogeneous and discrete group. An interspecific comparison revealed that the variation among the ten isozyme groups of P. cryptogea and P. drechsleri was as great as that observed among P. cinnamomi, P. cambivora, P. lateralis, P. erythroseptica and P. richardiae. The combined results of isozyme and mtDNA analysis indicate that there are at least seven distinct molecular species represented by the 123 isolates of P. cryptogea and P. drechsleri evaluated in this study.

}, issn = {09537562}, doi = {10.1016/S0953-7562(09)81359-2}, url = {https://linkinghub.elsevier.com/retrieve/pii/S0953756209813592}, author = {Mills, Scott D. and F{\"o}rster, Helga and Coffey, Michael D.} } @article {Mills199131, title = {Taxonomic structure of Phytophthora cryptogea and P. drechsleri based on isozyme and mitochondrial DNA analyses}, journal = {Mycological Research}, volume = {95}, number = {1}, year = {1991}, pages = {31 - 48}, abstract = {

Intra- and interspecific isozyme variation was evaluated for 123 isolates assigned to either Phytophthora cryptogea or P. drechsleri, and compared with that of 15 isolates of P. erythroseptica and 11 isolates of P. lateralis. Isolates of P. cryptogea and P. drechsleri were from worldwide sources and displayed a high degree of variability. The majority of these isolates were subsequently divided into ten distinct groups based on numerical analysis of 24 putative enzyme loci. None of the enzyme loci were monomorphic for all ten groups. Analysis of mitochondrial (mt) DNA restriction fragment length polymorphisms of selected isolates from each isozyme group supported the isozyme data. Differences in morphological features of the ten isozyme groups of P. cryptogea and P. drechsleri were not sufficiently distinct to readily distinguish between them. Isozyme analysis of P. erythroseptica revealed that it is a uniform and distinct taxon. The isolates of P. lateralis also formed a homogeneous and discrete group. An interspecific comparison revealed that the variation among the ten isozyme groups of P. cryptogea and P. drechsleri was as great as that observed among P. cinnamomi, P. cambivora, P. lateralis, P. erythroseptica and P. richardiae. The combined results of isozyme and mtDNA analysis indicate that there are at least seven distinct molecular species represented by the 123 isolates of P. cryptogea and P. drechsleri evaluated in this study.

}, issn = {0953-7562}, doi = {DOI: 10.1016/S0953-7562(09)81359-2}, url = {http://www.sciencedirect.com/science/article/B7XMR-4VN66D4-6/2/554a78ec5ee059d8f8ca3d1ba95638fd}, author = {Scott D. Mills and Helga F{\"o}rster and Michael D. Coffey} } @mastersthesis {4516, title = {Produtividade e sustentabilidade de planta{\c c}{\~o}es de ac{\'a}cia-negra (Acacia mearnsii De Wild.) no Rio Grande do Sul. Curitiba}, volume = {Doctoral}, year = {2007}, month = {03/2007}, pages = {266}, school = {Universidade Federal do Paran{\'a}}, address = {Curitiba, Brazil}, abstract = {

This work aimed to evaluate the factors related to the productivity, sustainability and environmental impacts of the black wattle plantation in Rio Grande do Sul, Brazil. The studies made about those plantations analyzed the utilization of the genetically improved seeds, the soil attributes influence, the P and K fertilization profit, the uptake, cycling and exportation of nutrients, the biomass production and partition, the black wattle invasion in the grassland area and riparian forest, the forest succession and the understorey herbaceous vegetation of the black wattle plantation. The timber production at the age of five years increased in 9.1 m3/ha through the seed improvement adoption that represented a net profit of R$ 180.00 per ha; however those increments depended on the utilization of suitable silvicultural practices. The gummosis (Phytophthora sp.) was observed in 33.9\% of the dead trees during the period from three to five years and reduced in 9.0\% the growth of attacked plants. The optimal economic rotation defined by the net present worth, considering an infinite horizon, was at the age of four years for the land owner and at the age of six years for the renters. The P, K and organic matter on the soil had positive effects on the black wattle growth. Similarly, it was found the response to the P and K fertilization, with a medium increase of 36.2\% in the timber volume, and the P also promoted the greatest increments and the response to the K were great on the optimal dose of the P. The greatest foliage efficiency for the biomass production and the maximum timber productivity occurred at the age of five years. At the age of seven years the trunk represented around 80\% of the aboveground biomass and stored a greater quantity of P,K, Ca and Mg. The N and S accumulation was greater in the crown trees compartments. The nutrients cycling rate via litter during de rotation of seven years varied from 25.3 to 59.6\% and after the age of four years they represented more then 60\% of the nutrients absorbed by the plants. The Ca and K were the nutrients exported in a greater quantity by the forest harvest. The best efficiency of the nutrients to the trunk biomass production and the least nutrients exportation per biomass unit harvested occurred when the plantations were six and seven years old. The black wattle was able to invade only disturbed grassland area with total exposure of the soil, for this reason it must be considered as a causal invasive plant. The native vegetation recomposition of those areas provoked mortality of a greater number of invasive plants. In the other hand, the black wattle does not become an invasive plant in the riparian forest and when planted in those areas proportioned an abundant and diversified succession in its understorey. The black wattle plantation in grassland area reduced part of the floristic diversity of the herbaceous vegetation and propitiated the typical species settlement in the understorey forests, however they did not affected the site environmental resilience.

}, url = {http://www.floresta.ufpr.br/pos-graduacao/defesas/pdf_dr/2007/t218_0266-D.pdf}, author = {Mochiutti, S.} } @article {4378, title = {First report of Phytophthora tentaculata on Verbena sp. in Spain}, journal = {Plant Pathology}, volume = {53}, year = {2004}, month = {Jan-12-2004}, pages = {806 - 806}, abstract = {

The oomycete Phytophthora tentaculata causes root and stalk rot of Chrysanthemum spp., Delphinium ajacis and Verbena spp. in nurseries in the Netherlands and Germany (Kr{\"o}ber \& Marwitz, 1993). In June 2001, P. tentaculata was isolated from a young potted Verbena hybrid, showing a collar and stalk rot, in a nursery in Majorca (Balearic Islands, Spain). It was initially recovered by plating \~{}10\ mm pieces of necrotic tissue from the leading lesion on to a phytophthora selective medium, P5ARP (Erwin \& Ribeiro, 1996). A pure culture (isolate CBS 115458) was obtained by transferring aseptically a hyphal tip onto corn meal agar (CMA) and was first identified from morphological characters.

The colony surface texture was uniform and formed sparse, loosely branched mycelium on carrot piece agar (CPA: 50\ g carrot pieces and 20\ g agar per 1000\ mL distilled water) and CMA. The radial growth rate was 2{\textendash}3\ mm\ day-1 at 20{\textdegree}C on CMA. Sporangia did not appear on either agar media but formed readily in soil extract (50\ g soil from a holm oak forest suspended in 1\ L ionized water for 24 h at 20{\textdegree}C and then filtered and autoclaved). The sporangia were ovoid to globose, 27{\textendash}52 (36{\textperiodcentered}9)\ {\texttimes}\ 17{\textendash}31 (24{\textperiodcentered}6) {\textmu}m, length:breadth ratio 1{\textperiodcentered}4, papillate with a narrow exit pore, and some were caducous with a short pedicel (\<\ 5\ {\textmu}m). Hyphal swellings were present in water. Chlamydospores were only seen on CMA after 2 weeks. Oogonia, readily produced on CPA in pure culture, were globose, mostly terminal or a few lateral, and ranged from 17 to 41 (34{\textperiodcentered}0) {\textmu}m in diameter. Single paragynous, monoclinous or diclinous, usually long-stalked antheridia were club-shaped or spherical, 9{\textendash}16 (12{\textperiodcentered}7) {\textmu}m in diameter and many had appendages. Occasionally two paragynous antheridia per oogonium, as well as some amphigynous antheridia, were observed. Oospores were aplerotic 16{\textendash}33 (28{\textperiodcentered}4)\ {\textmu}m in diameter and thin-walled.

To further confirm its identity, isozyme analysis based on malate dehydrogenase (EC 1.1.1.37) and malic enzymes (EC 1.1.1.40) was performed. Isozyme profiles fitted exactly those of three P. tentaculata strains: two strains ex-Chrysanthemum (including CBS 552.96 paratype) and one strain ex-Verbena; and differing from those of all other papillate species (Oudemans \& Coffey, 1991a,b). Pathogenicity was assessed by flooding three potted Verbena plants with a 104 mL-1 zoospore suspension for 48 h at 20{\textendash}22{\textdegree}C. As controls, two potted Verbena plants were flooded with ionized water. Controls remained healthy 15\ days after inoculation. All three inoculated Verbena plants exhibited collar rot after 15\ days, from which the pathogen was reisolated using PARP medium, thus confirming Koch{\textquoteright}s postulates. This is the first report of P. tentaculata in Spain.

}, issn = {0032-0862}, doi = { http://dx.doi.org/10.1111/j.1365-3059.2004.01089.x }, url = {http://www.blackwell-synergy.com/toc/ppa/53/6http://doi.wiley.com/10.1111/j.1365-3059.2004.01089.xhttp://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111\%2Fj.1365-3059.2004.01089.x}, author = {Moralejo, E. and Puig, M. and Man in{\textquoteright}t Veld, W. A.} } @article {EFP:EFP674, title = {Diplanetism and microcyclic sporulation in Phytophthora ramorum}, journal = {Forest Pathology}, volume = {41}, number = {5}, year = {2011}, pages = {349{\textendash}354}, publisher = {Blackwell Publishing Ltd}, abstract = {

The zoosporic phase of the pathogen Phytophthora ramorum plays a crucial role in the process of plant infection, yet little is known about the fate of zoospores failing to target their hosts. Here, we describe new stages in the life cycle of P. ramorum concerning the in vitro development of monomorphic diplanetism and microcyclic sporulation in free water. Papillate cysts were formed after zoospore suspensions of isolates of the EU1 and NA1 clonal lineages were vortexed. Cysts usually germinated directly forming an emerging tube, or indirectly by releasing a secondary zoospore, which leaves behind an empty cyst with a short evacuation tube. Germinate cysts frequently developed either an appressorium or a microsporangium both terminally. We also observed microcyclic sporulation, i.e. sporangia indirectly germinated by forming a microsporangium, as in microcyclic conidiation of true fungi. Temporal progress of encysted zoospores in solution showed that percentage of germination varied significantly among and within isolates as well as between experiments, suggesting that germination is partly ruled by internal mechanisms. Diplanetism and microcyclic sporulation in P. ramorum may provide a second opportunity for host infection and may increase the chance of long dispersal in moving water.

}, issn = {1439-0329}, doi = {10.1111/j.1439-0329.2010.00674.x}, url = {http://dx.doi.org/10.1111/j.1439-0329.2010.00674.x}, author = {Moralejo, E. and Descals, E.} } @article {4635, title = {Multiple alien Phytophthora taxa discovered on diseased ornamental plants in Spain}, journal = {Plant Pathology}, volume = {58}, year = {2009}, month = {Jan-02-2009}, pages = {100 - 110}, abstract = {

The plant trade is unwittingly accelerating the worldwide spread of well-known and new or undescribed Phytophthora species and creating novel niches for emerging pathogens. The results of a survey carried out from 2001 to 2006 in garden centres and nurseries of the Balearic Islands and eastern Spain combined with the analysis of samples received from ornamental nurseries from northern Spain reflected the extent of this global issue at the local scale. A total of 125 Phytophthora isolates were obtained from 37 different host species and 17 putative species identified on morphological features and direct sequencing of the internal transcribed spacer and four mitochondrial and nuclear genes. Five species, P. ramorum, P. hedraiandra, P. {\textquoteleft}niederhauserii{\textquoteright}, P. {\textquoteleft}kelmania{\textquoteright} and P. {\textquoteleft}taxon Pgchlamydo{\textquoteright} were formally unknown to science prior to 2001. In addition, 37 new host/pathogen combinations were first records for Spain, highlighting the risk of non-coevolved organisms from different biogeographic origins coming into contact under managed environments. The problem generated by new or rare taxa of Phytophthora found in nurseries for which no prior information on natural habitat and ecology is available for pest risk analysis is discussed.

}, issn = {00320862}, doi = {10.1111/j.1365-3059.2008.01930.x}, url = {http://doi.wiley.com/10.1111/j.1365-3059.2008.01930.x}, author = {Moralejo, E. and P{\'e}rez-Sierra, A. M. and {\'A}lvarez, L. A. and Belbahri, L. and Lefort, F. and Descals, E.} } @article {Moralejo20061323, title = {Stromata, sporangiomata and chlamydosori of Phytophthora ramorum on inoculated Mediterranean woody plants}, journal = {Mycological Research}, volume = {110}, number = {11}, year = {2006}, pages = {1323 - 1332}, abstract = {

Three types of multihyphal structures, stromata, sporangiomata and chlamydosori, are described for the plant pathogen Phytophthora ramorum. Their morphology, morphogenesis and position on the host organ were observed by dissecting, compound and scanning electron microscopy. Stromata were consistently formed one to two weeks after zoospore inoculation of detached leaves and fruits of an assortment of Mediterranean sclerophyll shrubs. Stroma initials appeared subcuticularly or subepidermally and developed as small hyphal aggregates by repeated branching, budding, swelling and interweaving, eventually forming a prosenchyma. They always emerged through the adaxial side of the leaf by rupture of the overlying host tissue. Occasionally sporangia and chlamydosori (packed clusters of chlamydospores) were formed on the stromata. Sporangiomata bore short sporangiophores and clusters of 20-100 sporangia and resembled sporodochia of the mitosporic fungi. The biological significance of these multihyphal structures is discussed. Some epidemiological aspects were also studied: several understorey species of the holm oak (Quercus ilex) woodland were susceptible to in vitro infection with three isolates of P. ramorum originally collected from different ornamental hosts. The risk of spread to this ecosystem is evaluated.

}, keywords = {Sporangial dispersal}, issn = {0953-7562}, doi = {10.1016/j.mycres.2006.09.004}, url = {http://www.sciencedirect.com/science/article/pii/S0953756206002656}, author = {Moralejo, Eduardo and Miquel Puig and Jose A. Garcia and Enrique Descals} } @article {4453, title = {Efficacy of Biofumigation with Brassica carinata Commercial Pellets (BioFence) to Control Vegetative and Reproductive Structures of Phytophthora cinnamomi}, journal = {Plant Disease}, volume = {100}, year = {2016}, month = {Jan-02-2016}, pages = {324 - 330}, abstract = {

The efficacy of biofumigation with Brassica carinata pellets (BioFence) to control vegetative and reproductive structures of Phytophthora cinnamomi was investigated in vitro at different doses and temperatures. Biofumigation was effective in inhibiting mycelial growth (culture diameter) and chlamydospore and zoospore germination, and was lethal at 24 mg of pellet per plate (approximately 0.4 mg/liter). The 50\% effective concentration values showed that efficacy of B. carinata pellets in inhibiting or killing the vegetative and reproductive structures of P. cinnamomi was maximum at 15{\textdegree}C and decreased as temperature rose to 25{\textdegree}C. However, the fungicide effect was independent of the temperature. In vivo biofumigation of Quercus cerris seedlings with BioFence confirmed efficacy by reducing the inoculum density (CFU/g) of P. cinnamomi, thus protecting the host from root infection. The use of BioFence provides an alternative to synthetic pesticides to control P. cinnamomi within disease management programs in agroforestry systems.

}, issn = {0191-2917}, doi = {10.1094/PDIS-03-15-0245-RE}, url = {http://apsjournals.apsnet.org/doi/10.1094/PDIS-03-15-0245-RE}, author = {Morales-Rodr{\'\i}guez, C. and Vettraino, A. M. and Vannini, {\'A}.} } @article {EFP:EFP397, title = {Influence of site factors on the impact of Phytophthora cinnamomi in cork oak stands in Portugal}, journal = {Forest Pathology}, volume = {35}, number = {3}, year = {2005}, pages = {145{\textendash}162}, publisher = {Blackwell Verlag GmbH}, abstract = {

Although decline of cork (Quercus suber) and holm oak trees (Quercus rotundifolia) has been described in Portugal in the late years of the 19th century, its development has become a motive of high concern during the last two decades. The presence of Phytophthora cinnamomi in cork and holm oak stands was surveyed in four different regions of the country (Tr{\'a}s-os-Montes, Alentejo, Ribatejo and Algarve) during 1995{\textendash}98. Tree decline severity, sudden death and site characteristics were assessed in 56 sites representing varied conditions. The pathogen was isolated from oak roots and rhizosphere samples in 27 of those places. Other plant species from natural vegetation were sampled in three active disease centres. This survey showed that 56\% of the surveyed species of shrub flora were infected with P. cinnamomi, which was detected mainly on species belonging to the families Ericaceae, Cistaceae and Leguminosae. Recovery of P. cinnamomi was more frequent in shallow soils (Leptosols and complex Leptosols and Luvisols). These soils are more common in the south (Algarve), where decline has a high impact. Soils with low fertility and low mineral nutrient levels, particularly phosphorus, seemed to favour infection. Site aspect and topographic tree situation were also evaluated. Sites facing south showed higher occurrence of P. cinnamomi, which was also more frequent in slopes and valleys than on hilltops. In Algarve, a relationship could be established between the crown status and the presence of P. cinnamomi in roots and rhizosphere. Different morphotypes of P. cinnamomi could be distinguished in vitro, and their occurrence in the field was correlated with particular site characteristics. Further research needs and management strategies to limit the extension of the disease are discussed.

}, author = {Moreira, A. C. and Martins, J. M. S.} } @article {4489, title = {Endemic and Emerging Pathogens Threatening Cork Oak Trees: Management Options for Conserving a Unique Forest Ecosystem}, journal = {Plant Disease}, volume = {100}, year = {2016}, month = {Jan-11-2016}, pages = {2184 - 2193}, abstract = {

Cork oak (Quercus suber) forests are economically and culturally intertwined with the inhabitants of the Mediterranean basin and characterize its rural landscape. These forests cover over two million hectares in the western Mediterranean basin and sustain a rich biodiversity of endemisms as well as representing an important source of income derived from cork production. Currently cork oak forests are threatened by several factors including human-mediated disturbances such as poor or inappropriate management practices, adverse environmental conditions (irregular water regime with prolonged drought periods), and attacks of pathogens and pests. All these adverse factors can interact, causing a complex disease commonly known as {\textquotedblleft}oak decline.{\textquotedblright} Despite the numerous investigations carried out so far, decline continues to be the main pathological problem of cork oak forests because of its complex etiology and the resulting difficulties in defining suitable control strategies. An overview of the literature indicates that several pathogenic fungi and oomycota can play a primary role in the etiology of this syndrome. Therefore, the aim of this review is to analyze the recent advances achieved regarding the bio-ecology of the endemic and emerging pathogens that threaten cork oak trees with particular emphasis on the species more directly involved in oak decline. Moreover, the effect of climate change on the host-pathogen interactions, a task fundamental for making useful decisions and managing cork oak forests properly, is considered.

}, issn = {0191-2917}, doi = {10.1094/PDIS-03-16-0408-FE}, url = {http://apsjournals.apsnet.org/doi/10.1094/PDIS-03-16-0408-FE}, author = {Moricca, Salvatore and Linaldeddu, Benedetto T. and Ginetti, Beatrice and Scanu, Bruno and Franceschini, Antonio and Ragazzi, Alessandro} } @article {4020, title = {Development of a quantitative real-time PCR assay for the detection of Phytophthora austrocedrae, an emerging pathogen in Britain}, journal = {Forest Pathology}, year = {2013}, month = {05/2013}, pages = {Early view}, abstract = {

A TaqMan real-time PCR assay was developed for Phytophthora austrocedrae, an emerging pathogen causing severe damage to juniper in Britain. The primers amplified DNA of the target pathogen down to 1\ pg of extracted DNA, in both the presence and absence of host DNA, but did not amplify any of the non-target Phytophthora and fungal species tested. The assay provides a useful tool for screening juniper populations for the disease.

}, doi = {10.1111/efp.12058}, url = {http://onlinelibrary.wiley.com/doi/10.1111/efp.12058/abstract}, author = {Mulholland, V. and Schlenzig, A. and MacAskill, G. A. and Green, S.} } @article {doi:10.1094/PDIS.1997.81.12.1400, title = {Susceptibility of Pacific Yew to Phytophthora lateralis}, journal = {Plant Disease}, volume = {81}, number = {12}, year = {1997}, pages = {1400-1404}, doi = {10.1094/PDIS.1997.81.12.1400}, url = {http://apsjournals.apsnet.org/doi/abs/10.1094/PDIS.1997.81.12.1400}, author = {Murray, Marion S. and Hansen, Everett M.} } @article {4636, title = {Characterization of Phytophthora hybrids from ITS clade 6 associated with riparian ecosystems in South Africa and Australia}, journal = {Fungal Biology}, volume = {117}, year = {2013}, month = {Jan-05-2013}, pages = {329 - 347}, abstract = {

Surveys of Australian and South African rivers revealed numerous Phytophthora isolates residing in clade 6 of the genus, with internal transcribed spacer (ITS) gene regions that were either highly polymorphic or unsequenceable. These isolates were suspected to be hybrids. Three nuclear loci, the ITS region, two single copy loci (antisilencing factor (ASF) and G protein alpha subunit (GPA)), and one mitochondrial locus (cytochrome oxidase c subunit I (coxI)) were amplified and sequenced to test this hypothesis. Abundant recombination within the ITS region was observed. This, combined with phylogenetic comparisons of the other three loci, confirmed the presence of four different hybrid types involving the three described parent species Phytophthora amnicola, Phytophthora thermophila, and Phytophthora taxon PgChlamydo. In all cases, only a single coxI allele was detected, suggesting that hybrids arose from sexual recombination. All the hybrid isolates were sterile in culture and all their physiological traits tended to resemble those of the maternal parents. Nothing is known regarding their host range or pathogenicity. Nonetheless, as several isolates from Western Australia were obtained from the rhizosphere soil of dying plants, they should be regarded as potential threats to plant health. The frequent occurrence of the hybrids and their parent species in Australia strongly suggests an Australian origin and a subsequent introduction into South Africa.

}, issn = {18786146}, doi = {10.1016/j.funbio.2013.03.004}, url = {https://doi.org/10.1016/j.funbio.2013.03.004}, author = {Nagel, Jan H. and Gryzenhout, Marieka and Slippers, Bernard and Wingfield, Michael J. and Hardy, Giles E.St.J. and Stukely, Michael J.C. and Burgess, Treena I.} } @article {EFP:EFP703, title = {Relationship between field resistance to Phytophthora ramorum and constitutive phenolic chemistry of coast live oak}, journal = {Forest Pathology}, volume = {41}, number = {6}, year = {2011}, pages = {464{\textendash}469}, publisher = {Blackwell Publishing Ltd}, abstract = {

Sudden oak death, caused by Phytophthora ramorum, has resulted in high levels of coast live oak (CLO) mortality. However, some CLO survive in areas with high disease pressure and may thus be resistant. We tested the hypothesis that such field-resistant trees contain constitutively higher levels of phenolics than susceptible trees. Phloem was sampled from the trunks of two groups of trees (one previously inoculated, one naturally infected with P. ramorum) categorized over the course of several years as putatively resistant (PR, no symptoms), in remission (IR, showed symptoms but then recovered) and symptomatic (S). Individual and total soluble phenolics from these trees were quantified. There were no significant differences in individual or total soluble phenolics between groups of naturally infected trees. However, inoculated PR and IR trees were characterized by higher constitutive levels of ellagic acid, a tyrosol derivative, and an unidentified phenolic than S trees. Ellagic acid and tyrosol-like compounds in CLO phloem are promising resistance biomarker candidates.

}, issn = {1439-0329}, doi = {10.1111/j.1439-0329.2010.00703.x}, url = {http://dx.doi.org/10.1111/j.1439-0329.2010.00703.x}, author = {Nagle, A. M. and Mcpherson, B. A. and Wood, D. L. and Garbelotto, M. and Bonello, P.} } @article {385, title = {Phytophthora alni (Brasier et al.) update on alder Phytophthora and potential new hosts}, journal = {NAPPO Phytosanitary Alert}, number = {04/05/2006}, year = {2006}, publisher = {North American Plant Protection Organization, NSF Center for Integrated Pest Management}, edition = {04/05/2006}, url = {http://www.pestalert.org/viewNewsAlert.cfm?naid=15}, author = {NAPPO} } @article {4443, title = {Pathogenicity to alder of Phytophthora species from riparian ecosystems in western Oregon}, journal = {Forest Pathology}, volume = {45}, year = {2015}, month = {Jan-10-2015}, pages = {358 - 366}, abstract = {

Described as one of the most destructive pathogens of agricultural crops and forest trees, Phytophthora is a genus of microorganisms containing over 100 known species. Phytophthora alni has caused collar and root disease in alders throughout Europe, and a subspecies has recently been isolated in North America. Reports of canopy dieback in red alder, Alnus rubra, prompted a survey of their overall health and to determine whether P.\ alni was present in western Oregon riparian ecosystems. Over 1100 Phytophthora isolates were recovered, representing 20 species and 2 taxa. Phytophthora-type cankers were observed in many trees, and their incidence was positively correlated with canopy dieback. High levels of mortality for red alder were not observed, which suggests these Phytophthora species are not aggressive pathogens. To test this hypothesis, three stem wound inoculations and one root dip were conducted on red alder seedlings using 13 Phytophthora species recovered from the riparian survey. Ten of the 13 Phytophthora species produced significant lesions in at least one pathogenicity test. Phytophthora siskiyouensis produced the largest lesions on red alder from the two stem wound inoculation tests conducted under summer conditions, while P.\ taxon Pgchlamydo caused the largest lesions during the winter stem wound inoculation test. Phytophthora gonapodyides, P.\ taxon Pgchlamydo and P.\ siskiyouensis have previously been found associated with necrotic alder roots and bole cankers in the field, and with the pathogenicity results reported here, we have established these species as causes of Phytophthora root disease and Phytophthora bole canker of alder in Oregon. While none of the Phytophthora species were especially aggressive towards red alder in the pathogenicity tests, they did cause localized disease symptoms. By weakening the root systems or boles of alders, the Phytophthoras could be leaving alders more susceptible to other insects and pathogens.

}, doi = {10.1111/efp.2015.45.issue-510.1111/efp.12175}, url = {http://doi.wiley.com/10.1111/efp.2015.45.issue-5http://doi.wiley.com/10.1111/efp.12175http://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111\%2Fefp.12175}, author = {Navarro, S. and Sims, L. and Hansen, E. and Vannini, {\'A}.} } @article {4124, title = {Impact of removing diseased pods on cocoa black pod caused by Phytophthora megakarya and on cocoa production in Cameroon}, journal = {Crop Protection}, volume = {23}, year = {2004}, month = {5/2004}, pages = {415 - 424}, abstract = {

Black pod rot, caused by Phytophthora megakarya, is the main cause of cocoa harvest losses in Cameroon. Field experiments were carried out over two successive years in two smallholders{\textquoteright} plots of cocoa trees, in order to assess the impact of diseased pod removal (phytosanitary pod removal) on disease progress, total production and final harvest. The generalized linear mixed model proved to be the most appropriate for comparing the two treatments (without and with pod removal) set up in a randomized complete block design. Removing diseased pods helped to reduce the black pod rate by 22\% and 31\% in the two sites in the first year, and by 9\% and 11\% in the second year, compared to a plot in which no preventive control measures were taken. The rate of cherelle (very young pod) appearance was also higher when pod removal was carried out. Total production was higher in the plots with pod removal, but the difference between the two treatments was not significant. This study allowed an evaluation of the respective roles of primary and secondary inoculum in the spread of the disease. The cultural practice of phytosanitary pod removal was found to be a potentially efficient control method. However, it would need to be associated with other control methods to establish an integrated management system for cocoa farmers.

}, issn = {02612194}, doi = {10.1016/j.cropro.2003.09.010}, url = {http://www.sciencedirect.com/science/article/pii/S0261219403002370}, author = {Ndoumbe-Nkeng, M. and Cilas, C. and Nyemb, E. and Nyasse, S. and Bieysse, D. and Flori, A. and Sache, I.} } @article {3978, title = {A combination of baiting and PCR techniques for the detection of Phytophthora quercina and P. citricola in soil samples from oak stands}, journal = {Forest Pathology}, volume = {31}, year = {2001}, pages = {85-97}, abstract = {

Es wird der spezifische Nachweis von Phytophthora quercina und P. citricola in Bodenproben von absterbenden Eichen mit Hilfe einer Kombination von PCR- Reaktionen mit artspezifischen Primern erlaubten den Nachweis von P. quercina und P. citricola in den infizierten Eichenblaettern aus diesen Tests und im jeweiligen {\textquoteright}Baiting-Wasser{\textquoteright}. Der PCR- und Baiting-Methoden beschrieben. Die Bodenproben wurden mit Wasser geflutet und Baiting-Tests unterzogen, bei denen junge Blaettchen von Quercus robur als Koeder zum Einsatz kamen. Einfache oder nested PCR-Nachweis beider Erreger war auch moeglich, wenn Bodenproben gruendlich mit Wasser gemischt wurden, das aufgeschwemmte organische Material abgesammelt und das Wasser abgenommen wurde. P. quercina und P. citricola wurden dabei in nahezu allen Faellen im Wasser, jedoch weniger regelmaessig im organischen Material nachgewiesen. Die Identitaet der betreffenden Arten wurde zusaetzlich durch Restriktions-Analysen der entsprechenden Amplicons bestaetigt. Ausserdem wurde die Anwesenheit beider Arten in den untersuchten Bodenproben durch klassische Baiting-Methoden nachgewiesen. Nested PCR mit den verwendeten Primaerpaaren erlaubte den Nachweis von nur 5 Zoosporen von P. citricola und 300 Zoosporen von P. quercina in einem Gesamt-Volumen von 100 My l. Die beschriebenen Methoden ermoeglichen Nachweis und Identifizierung von Phytophthora-Arten in Bodenproben, ohne die Notwendigkeit einer direkten Extraktion des Bodens und ohne weitreichende Kenntnis der morphologischen Merkmale der Arten dieser Gattung.

}, issn = {1437-4781}, author = {Nechwatal, J. and Schlenzig, A. and T. Jung and Cooke, D. E. L. and Duncan, J. M. and W. O{\ss}wald} } @article {PPA:PPA2638, title = {The morphology, behaviour and molecular phylogeny of Phytophthora taxon Salixsoil and its redesignation as Phytophthora lacustris sp. nov.}, journal = {Plant Pathology}, year = {2012}, month = {04/2013}, pages = {355{\textendash}369}, publisher = {Blackwell Publishing Ltd}, abstract = {

Since its first isolation from Salix roots in 1972, isolates of a sexually sterile Phytophthora species have been obtained frequently from wet or riparian habitats worldwide and have also been isolated from roots of Alnus and Prunus spp. Although originally assigned to Phytophthora gonapodyides on morphological grounds, it was recognized that these isolates, informally named P.\ taxon Salixsoil, might represent a separate lineage within ITS Clade 6. Based on phylogenetic analyses and comparisons of morphology, growth-temperature relationships and pathogenicity, this taxon is formally described here as Phytophthora lacustris sp. nov. Isolates of P.\ lacustris form a clearly resolved cluster in both ITS and mitochondrial cox1 phylogenies, basal to most other Clade 6 taxa. Phytophthora lacustris shares several unusual behavioural properties with other aquatic Clade 6 species, such as sexual sterility and tolerance of high temperatures, that have been suggested as adaptations to riparian conditions. It appears to be widespread in Europe and has also been detected in Australia, New Zealand and the USA. It was shown to be weakly or moderately aggressive on inoculation to Alnus, Prunus and Salix. The extent of P.\ lacustris{\textquoteright} activity as a saprotroph in plant debris in water and as an opportunistic pathogen in riparian habitats needs further investigation. Its pathogenic potential to cultivated fruit trees also deserves attention because P.\ lacustris has apparently been introduced into the nursery trade.

}, keywords = {Alnus, phylogeny, Phytophthora ITS Clade 6, Prunus, riparian habitat, tree pathogen}, issn = {1365-3059}, doi = {10.1111/j.1365-3059.2012.02638.x}, url = {http://dx.doi.org/10.1111/j.1365-3059.2012.02638.x}, author = {Nechwatal, J. and Bakonyi, J. and Cacciola, S. O. and Cooke, D. E. L. and T. Jung and Nagy, Z. {\'A}. and Vannini, {\'A}. and A.M. Vettraino and C.M. Brasier} } @article {EFP:EFP711, title = {A twig blight of understorey European beech (Fagus sylvatica) caused by soilborne Phytophthora spp.}, journal = {Forest Pathology}, volume = {41}, number = {6}, year = {2011}, pages = {493{\textendash}500}, publisher = {Blackwell Publishing Ltd}, abstract = {

During and after prolonged periods of rainfall in late spring, blighted young twigs of European beech (Fagus sylvatica) were frequently observed in several beech stands in south-western and southern Germany. Long and short shoots of young understorey trees or lower branches up to 1.5 m above the soil level were affected. Symptoms also occurred regularly on twigs in heights up to 2 m and more above the ground. Necroses usually expanded within the current year{\textquoteright}s tissue and often also reached into the previous year{\textquoteright}s wood. Ponding rain water in the stands or along forest roads or open soil seemed to promote the disease. Of a total of 54 symptomatic twigs collected in four stands, 37 revealed Phytophthora isolates, of which 33 were P. plurivora and four were P. cambivora. Both species caused extensive lesions on beech twigs in laboratory pathogenicity tests. Patterns of the disease indicated that these pathogens, generally considered soilborne species, in most cases are transmitted from the soil to above-ground parts of the trees via rain splash. In larger heights, however, other vectors such as snails might be responsible for transmission. Although Phytophthora spp. are well known as causal agents of seedling blight as well as root and cambium rot and aerial bleeding cankers of mature beech, to our knowledge this is the first report of a twig blight in beech associated with soilborne Phytophthora spp. In particular in periods of high precipitation, this disease might pose an additional threat to Central European beech forests, especially endangering the success of artificial and natural regeneration of beech in affected stands.

}, issn = {1439-0329}, doi = {10.1111/j.1439-0329.2011.00711.x}, url = {http://dx.doi.org/10.1111/j.1439-0329.2011.00711.x}, author = {Nechwatal, J. and Hahn, J. and Schönborn, A. and Schmitz, G.} } @article {nelson2010prevalence, title = {Prevalence, distribution and identification of Phytophthora species from bleeding canker on European beech}, journal = {Phytopathology}, volume = {28}, number = {3}, year = {2010}, pages = {150{\textendash}158}, author = {Nelson, A. and Weiland, G. and Hudler, G.} } @article {4180, title = {A summary of North American hardwood tree diseases with bleeding canker symptoms}, journal = {Arboriculture and Urban Forestry }, volume = {33(2)}, year = {2007}, pages = {122-131}, url = {http://www.google.com/url?sa=t\&rct=j\&q=\&esrc=s\&source=web\&cd=57\&ved=0CE4QFjAGODI\&url=http\%3A\%2F\%2Fjoa.isa-arbor.com\%2Frequest.asp\%3FJournalID\%3D1\%26ArticleID\%3D2985\%26Type\%3D2\&ei=pKOvUpvjGcv7oASXoYDYDA\&usg=AFQjCNHxNzEH7As_NfGpUf1LVGxbCXIeXA}, author = {Nelson, A.H. and G. W. Hudler} } @article {611, title = {Non-lethal pathological infection of roots}, journal = {Nature}, volume = {191}, year = {1961}, pages = {615-616}, doi = {10.1038/191615a0}, url = {http://dx.doi.org/10.1038/191615a0}, author = {Newhook, F. J.} } @article {PPA:PPA2476, title = {Potential for eradication of the exotic plant pathogens Phytophthora kernoviae and Phytophthora ramorum during composting}, journal = {Plant Pathology}, volume = {60}, number = {6}, year = {2011}, pages = {1077{\textendash}1085}, publisher = {Blackwell Publishing Ltd}, abstract = {

Temperature and exposure time effects on Phytophthora kernoviae and Phytophthora ramorum viability were examined in flasks of compost and in a large-scale composting system containing plant waste. Cellophane, rhododendron leaf and peat-based inoculum of P. kernoviae and P. ramorum isolates were used in flasks; naturally infected leaves were inserted into a large-scale system. Exposures of 5 and 10 days respectively at a mean temperature of 35{\textdegree}C in flask and large-scale composts reduced P. kernoviae and P. ramorum inocula to below detection limits using semi-selective culturing. Although P. ramorum was undetectable after a 1-day exposure of inoculum to compost at 40{\textdegree}C in flasks, it survived on leaves exposed to a mean temperature of 40{\textperiodcentered}9{\textdegree}C for 5 days in a large-scale composting system. No survival of P. ramorum was detected after exposure of infected leaves for 5 days to a mean temperature of \>=41{\textperiodcentered}9{\textdegree}C (32{\textperiodcentered}8{\textdegree}C for P. kernoviae) or for 10 days at \>=31{\textperiodcentered}8{\textdegree}C (25{\textperiodcentered}9{\textdegree}C for Phytophthora pseudosyringae on infected bilberry stems) in large-scale systems. Fitted survival probabilities of P. ramorum on infected leaves exposed in a large-scale system for 5 days at 45{\textdegree}C or for 10 days at 35{\textdegree}C were \<3\%, for an average initial infection level of leaves of 59{\textperiodcentered}2\%. RNA quantification to measure viability was shown to be unreliable in environments that favour RNA preservation: high levels of ITS1 RNA were recovered from P. kernoviae- and P. ramorum-infected leaves exposed to composting plant wastes at \>53{\textdegree}C, when all culture results were negative.

}, keywords = {Phytophthora pseudosyringae, Rhododendron ponticum, temperature, Vaccinium myrtillus}, issn = {1365-3059}, doi = {10.1111/j.1365-3059.2011.02476.x}, url = {http://dx.doi.org/10.1111/j.1365-3059.2011.02476.x}, author = {Noble, R. and Blackburn, J. and Thorp, G. and Dobrovin-Pennington, A. and Pietravalle, S. and Kerins, G. and Allnutt, T. R. and Henry, C. M.} } @article {4491, title = {Rapid diagnosis of pathogenic Phytophthora species in soil by real-time PCR}, journal = {Forest Pathology}, year = {2016}, month = {Jan-07-2016}, abstract = {

Real-time PCR assays based on the TaqMan system and using ITS sequences were developed for the identification of Phytophthora species, including P.\ cactorum, P.\ megasperma, P.\ plurivora, P.\ pseudosyringae and P.\ quercina, all of which are currently causing significant damage to roots of forest trees in both managed stands and natural ecosystems. Total genomic DNA was extracted from mycelia of aforementioned Phytophthora isolates. Species-specific primers for P.\ cactorum, P.\ megasperma, P.\ plurivora, P.\ pseudosyringae and P.\ quercina were designed based on ITS sequences of rDNA. The amplification efficiency of target DNA varied from 93.1\% (P.\ pseudosyringae) to 106.8\% (P.\ quercina). The limit of the detection was calculated as 100 {\textendash} 1,000\ fg DNA, depending on the Phytophthora species. In mixed soil samples, all Phytophthora species were detected for Ct values shifted by 0.7 {\textendash} 2.1 cycles. Based on these real-time PCR assays we were able to identify the five Phytophthora species. These techniques will be of value in the identification of these pathogens, which may cause up to 80 {\textendash} 90\% fine root loss in oak stands.

}, doi = {10.1111/efp.12303}, url = {http://dx.doi.org/10.1111/efp.12303}, author = {Nowakowska, J. A. and Malewski, T. and Tereba, A. and Oszako, T.}, editor = {Belbahri, L.} } @article {4125, title = {Diversity of Phytophthora megakarya in Central and West Africa revealed by isozyme and RAPD markers}, journal = {Mycological Research}, volume = {103}, year = {1999}, month = {10/1999}, pages = {1225 - 1234}, abstract = {

Phytophthora megakarya is an important pathogen of cocoa in Africa. We used isozyme and RAPD markers to estimate the genetic diversity and structuring among 161 isolates, from the known distribution area of the fungus which corresponds to the cocoa belt in Ghana, Togo, Nigeria, Cameroon, Gabon and Sao Tome. Thirty six and 44 multilocus patterns were identified with isozymes and RAPDs, respectively. Patterns were separated into two highly differentiated genetic groups with both types of markers, one located in Central Africa and the other in West Africa. This distribution coincides with two major biogeographical domains which may reflect an ancient evolution of P. megakarya in this part of Africa. The genotypic diversity was lower in West Africa as compared to Central Africa. Inside Central Africa, isolates from Gabon and Sao Tome were highly differentiated based on RAPDs. Four intermediate marker patterns corresponding to isolates sampled near the border between Nigeria and Cameroon were putatively derived from genetic exchanges between the two major groups. The mating type determination permitted to confirm the high prevalence of A1 over A2. Although clonal multiplication seems to be the rule, indices of other reproduction means have been detected.

}, issn = {09537562}, doi = {10.1017/S0953756299008369}, url = {http://www.sciencedirect.com/science/article/pii/S0953756208606711}, author = {Nyass{\'E}, S. and Grivet, L. and Risterucci, A.M. and Blaha, G. and Berry, D. and Lanaud, C. and Despr{\'E}Aux, D.} } @article {702, title = {First report of chestnut ink disease by Phytophthora katsurae on chestnut in Korea}, journal = {Plant Disease}, volume = {92}, year = {2008}, pages = {p. 312}, doi = {10.1094/PDIS-92-2-0312A}, url = {http://apsjournals.apsnet.org/doi/abs/10.1094/PDIS-92-2-0312A}, author = {E. Oh and Lee, S. H. and Kim, K. H. and Lee, J. K. and Shin, K. C.} } @mastersthesis {188, title = {Resistance mechanisms of Port-Orford-cedar to Phytophthora lateralis}, year = {2004}, school = {Oregon State University}, type = {masters}, address = {Corvallis}, author = {Oh, Eunsung} } @article {oh_port-orford-cedar_2006, title = {Port-Orford-cedar resistant to Phytophthora lateralis.}, journal = {Forest pathology }, volume = {36}, number = {6}, year = {2006}, pages = {385{\textendash}394}, issn = {14374781}, doi = {10.1111/j.1439-0329.2006.00474.x}, url = {http://onlinelibrary.wiley.com/doi/10.1111/j.1439-0329.2006.00474.x/full}, author = {E. Oh and R. A. Sniezko and Hansen, E.M.} } @article {4233, title = {Surveys of soil and water reveal a goldmine of Phytophthora diversity in South African natural ecosystems}, journal = {IMA Fungus}, volume = {4}, year = {2013}, month = {Jun-06-2015}, pages = {123 - 131}, abstract = {

Phytophthora species are well-known as destructive plant pathogens, especially in natural ecosystems. It is ironic, therefore, how little is known regarding the Phytophthora diversity in South African natural woody ecosystems. In this study, Phytophthora species were isolated using standard baiting techniques from 182 soil and water samples and these were identified based on ITS and coxI sequence data. The 171 resulting Phytophthora isolates resided in 14 taxa including six known species (P. multivora, P. capensis, P. cryptogea, P. frigida, P. cinnamomi, P. cinnamomi var. parvispora), the known but as yet unnamed Phytophthora sp. PgChlamydo, P. sp. emzansi, and P. sp. Kununurra and five novel taxa referred to as P. sp. stellaris, P. sp. Umtamvuna P. sp. canthium, P. sp. xWS, P. sp. xHennops. Four of the new taxa were found exclusively in water and two of these are hybrids. The most commonly isolated species from soil was P. multivora, a species recently described from Western Australia. Phytophthora frigida was isolated for the first time from stream water. With the exception of P. cinnamomi, very little is known regarding the biology, epidemiology or origin of Phytophthora in South Africa.

}, issn = {22106340}, doi = {10.5598/imafungus.2013.04.01.12}, url = {http://www.imafungus.org/Issue/41/22.pdf}, author = {Oh, Eunsung and Gryzenhout, Marieka and Wingfield, Brenda D. and Wingfield, Michael J. and Burgess, Treena I.} } @article {oh_histopathology_2007, title = {Histopathology of infection and colonization of susceptible and resistant Port-Orford-cedar by Phytophthora lateralis.}, journal = {Phytopathology}, volume = {97}, number = {6}, year = {2007}, pages = {684{\textendash}693}, keywords = {Chamaecyparis lawsoniana, developmental stages, forest trees, fungal anatomy, fungal diseases of plants, histopathology, infection, North America, ornamental plants, pathogenicity, Phytophthora lateralis, plant morphology, plant pathogenic fungi, roots, signs and symptoms (plants), stems}, issn = {0031949X}, doi = {http://dx.doi.org/10.1094/PHYTO-97-6-0684}, url = {http://apsjournals.apsnet.org/doi/abs/10.1094/PHYTO-97-6-0684}, author = {E. Oh and Hansen, E.M.} } @article {4126, title = {Assessment of sanitation and fungicide application directed at cocoa tree trunks for the control of Phytophthora black pod infections in pods growing in the canopy}, journal = {European Journal of Plant Pathology}, volume = {117}, year = {2007}, month = {1/2007}, pages = {167 - 175}, abstract = {

Studies were conducted in two cocoa-growing areas of Ghana, one solely affected by Phytophthora palmivora and the other predominantly by Phytophthora megakarya, to determine the effectiveness of sanitation practices and fungicide application on tree trunks for the control of black pod disease in the canopy. Sanitation practices including weeding, pruning, thinning, shade reduction and removal of mummified pods were carried out prior to fungicide applications, and diseased pods were routinely removed at monthly intervals during harvesting. Three types of fungicides were used: systemic (Foli-R-Fos 400) applied as injection into the main trunks, semi-systemic (Ridomil 72 plus) and contact (Nordox 75, Kocide 101, Kocide DF, Blue Shield and Funguran-OH) applied as sprays onto pods on the main trunk. Sanitation combined with fungicide application on the trunk significantly reduced black pod disease incidence in the tree canopy. For fungicides applied as a spray, Ridomil 72 plus at 3.3\ g\ l-1 and Kocide DF at 10\ g\ l-1 and as injection, 40\ ml Foli-R-Fos 400 injected twice a year, performed better than the other fungicide treatments. The position of pods significantly influenced the incidence of canopy black pod infection in the P. megakarya predominantly affected area but to a lesser extent in the P. palmivora solely affected area. However, no significant interactions were found between fungicide treatments and the position of pods on the tree in both disease areas. The determined trunk-canopy relationship in the development of black pod disease on cocoa can be used in disease control programmes to maximise the impact of sanitation practices, achieve judicious application of fungicides, thereby reducing the environmental impact of fungicides on the cocoa ecosystem, and ultimately increase the economic returns.

}, issn = {0929-1873}, doi = {10.1007/s10658-006-9082-8}, url = {http://link.springer.com/article/10.1007\%2Fs10658-006-9082-8}, author = {Opoku, Isaac Y. and Akrofi, Andrews Y. and Appiah, Alex A.} } @article {4137, title = {Management of black pod disease of cocoa with reduced number of fungicide application and crop sanitation}, journal = {African Journal of Agricultural Research }, volume = {2}, year = {2007}, pages = {601{\textendash}604}, abstract = {

Black pod disease caused by Phytophthora megakarya is the most important fungal disease on cocoa in Ghana. The current recommended control method of combining sanitation practices with 6 - 8 fungicide applications in a year is considered unfriendly to the environment, too expensive and time consuming. Consequently, fungicide adoption rate by farmers is extremely low. Studies were therefore conducted to determine the effectiveness of combining 1 - 3 fungicide application in June and/or September/October with crop sanitation for the control of cocoa black pod disease caused by P. megakarya. Sanitation practices were common to all the treatments and the fungicide application(s) superimposed. A semi-systemic fungicide, Ridomil 72 plus (12\% metalaxyl + 60\% copper-1-oxide), was used as the test fungicide. Fungicide application combined with crop sanitation practices were effective in the management of the severe form of black pod disease caused by P. megakarya, resulting in 25\% to 48\% disease reduction and 10.9\% to 51.8\% yield increase. Combining the sanitation practices with three fungicide applications gave significantly better results, in terms of disease control and yields than either sanitation practices alone or combining them with one or two fungicide applications. However, the combination of sanitation practices and three fungicide applications was significantly less effective than the standard fungicide application of six times a year. All the fungicide applications and/or crop sanitation practices were profitable with a Benefit Cost Ratio (BCR) ranging from 1.8 - 2.1.

}, url = {http://www.academicjournals.org/article/article1380898856_Opoku\%20et\%20al.pdf}, author = {OpokuI, Y and Assuah, MK and Aneani, F} } @article {EFP:EFP714, title = {Phytophthora root and collar rot of mature Fraxinus excelsior in forest stands in Poland and Denmark}, journal = {Forest Pathology}, volume = {41}, number = {6}, year = {2011}, pages = {510{\textendash}519}, publisher = {Blackwell Publishing Ltd}, abstract = {

In recent years, Common ash (Fraxinus excelsior) throughout Europe has been severely impacted by a leaf and twig dieback caused by the hyphomycete Chalara fraxinea. The reasons for its current devastating outbreak, however, still remain unclear. Here, we report the presence of four Phytophthora taxa in declining ash stands in Poland and Denmark. Phytophthora cactorum, Phytophthora plurivora, Phytophthora taxon salixsoil and Phytophthora gonapodyides were isolated from rhizosphere soil samples and necrotic bark lesions on stems and roots of mature declining ash trees in four stands. The first three species proved to be aggressive to abscised roots, twigs and leaves of F. excelsior in inoculation experiments. Soil infestation tests also confirmed their pathogenicity towards fine and feeder roots of ash seedlings. Our results provide first evidence for an involvement of Phytophthora species as a contributing factor in current decline phenomena of F. excelsior across Europe. Specifically, they may act as a predisposing factor for trees subsequently infected by C. fraxinea. Phytophthora species from ash stands also proved to be aggressive towards a wide range of tree and shrub species commonly associated with F. excelsior in mixed stands. Although damage varied considerably depending on the Phytophthora species/isolate-host plant combination, these results show that many woody species may be a potential source for survival and inoculum build-up of soilborne Phytophthora spp. in ash stands and forest ecosystems in general.

}, issn = {1439-0329}, doi = {10.1111/j.1439-0329.2011.00714.x}, url = {http://dx.doi.org/10.1111/j.1439-0329.2011.00714.x}, author = {Orlikowski, L.B. and Ptaszek, M. and Rodziewicz, A. and Nechwatal, J. and Thinggaard, K. and T. Jung} } @article {757, title = {First record on Phytophthora spp. associated with the decline of European beech stand in south-west Poland}, journal = {Phytopatologia Polonica}, volume = {42}, year = {2006}, pages = {37-46}, abstract = {

Phytophthora citricola was detected in Siewierz Forest District in soil samples and diseased bark taken from declined 88-111-year-old European beech trees growing in three compartments of Trzebyczka Forest. Phytophthora cambivora was isolated only from diseased fine roots, bleeding cankers near trunk base and aerial canker spots. Both species colonised leaves and young stem parts as well as five-year-old beech branches. Necrosis spread about 1 mm/24 h.

}, keywords = {Beech, bleeding canker, pathogenicity, root rot, soil}, author = {Orlikowski, L.B. and Oszako, T. and Szkuta, G} } @article {956, title = {Surveying for and eradicating Phytophthora ramorum in agricultural commodities}, journal = {Plant Health Progress}, year = {2004}, abstract = {

Since 2001, Oregon nurseries, Christmas tree plantations, and other sites have been surveyed for the federally regulated pathogen Phytophthora ramorum. Host plants at each site were visually surveyed for disease symptoms and symptomatic tissues tested in the laboratory by isolation onto a selective medium and by a polymerase chain reaction (PCR) assay. In 2002 and 2003, we detected PCR-positive plants that later proved to be infected with another Phytophthora, suggesting there are limitations to the PCR assay tested. In 2003, P. ramorum was detected for the first time in Viburnum, Pieris, Rhododendron, and Camellia plants in six nurseries. All infected and neighboring plant materials were destroyed by incineration and the nurseries and surrounding environs subsequently surveyed for the pathogen. Phytophthora ramorum was not detected, indicating the pathogen was successfully eradicated.

}, doi = {doi:10.1094/PHP-2004-0309-02-RS}, author = {Osterbauer, N. K. and Griesbach, J. A. and Hedberg, J.} } @article {ostrofsky_detection_1977, title = {Detection of Phytophthora lateralis in soil organic matter and factors that affect its survival.}, journal = {Phytopathology}, volume = {67}, year = {1977}, pages = {79{\textendash}84}, keywords = {Chamaecyparis lawsoniana}, author = {W.D. Ostrofsky and L.F. Roth and R.G. Pratt} } @article {3977, title = {Significance of Phytophthoras and Pythium for oak, alder and spruce decline.}, journal = {Journal of Forest Science}, volume = {47}, year = {2001}, pages = {96-103 }, type = {Journal article; Conference paper}, abstract = {

The results of a survey of soil borne Phytophthoras in 35 oak (Quercus) stands on geologically different sites in Bavaria clearly showed that the most widespread species were identified as Phytophthora citricola, P. cambivora and P. quercina. These three species were only isolated from rhizosphere soil of stands with mean soil pH-values (CaCl2) of 3.5 and higher on loamy, clayey or sandy-loamy soil texture. At these Phytophthora stands, all root parameters of declining oaks were significantly reduced as compared to healthy looking trees. It is concluded that the above mentioned Phytophthora species are involved in oak decline as primary root rot pathogens on clay or sandy-loamy stands with soil pH-values higher than 3.5. A new Phytophthora hybrid, called {\textquoteright}alder Phytophthora{\textquoteright}, was isolated frequently from bark sections of declining alders along several Bavarian rivers and from nursery plants. PCR-RFLP analysis proved that the Bavarian isolates belonged to the same hybrid variants found in Great Britain, Sweden, France or Denmark. Spruce decline was studied in the Bavarian Alps on stands representing various site conditions. Most root parameters were negatively correlated with crown transparency. In addition, the total number of lateral roots was significantly lower for declining compared to healthy trees. Remarkably, only Pythium species were isolated from rhizosphere soil, which were divided into several groups after PCR-RFLP analysis. In soil infestation tests, most of the isolates caused severe root damage on spruce similar to root rot seen on declining trees in the field.

}, author = {W. O{\ss}wald and T. Jung and Nechwatal, J. and Schlenzig, A. and F. Fleischmann} } @article {4204, title = {Strategies of attack and defence in woody plant- Phytophthora interactions}, journal = {Forest Pathology}, volume = {44}, year = {2014}, month = {June 2014}, pages = {169{\textendash}190}, abstract = {

This review comprises both well-known and recently described Phytophthora species and concentrates on Phytophthora{\textendash}woody plant interactions. First, comprehensive data on infection strategies are presented which were the basis for three models that explain invasion and spread of Phytophthora pathogens in different woody host plants. The first model describes infection of roots, the second concentrates on invasion of the trunk, and the last one summarizes infection and invasion of host plants via leaves. On the basis of morphological, physiological, biochemical and molecular data, scenarios are suggested which explain the sequences of reactions that occur in susceptible and tolerant plants following infections of roots or of stem bark. Particular emphasis is paid to the significance of Phytophthora elicitins for such host{\textendash}pathogen interactions. The overall goal is to shed light on the sequences of pathogenesis to better understand how Phytophthora pathogens harm their host plants.

}, doi = {10.1111/efp.12096}, url = {http://doi.wiley.com/10.1111/efp.12096}, author = {O{\ss}wald, W. and Fleischmann, F. and Rigling, D. and Coelho, A. C. and Cravador, A. and Diez, J. and Dalio, R. J. and Horta Jung, M. and Pfanz, H. and Robin, C. and Sipos, G. and Solla, A. and Cech, T. and Chambery, A. and Diamandis, S. and Hansen, E. and Jung, T. and Orlikowski, L. B. and Parke, J. and Prospero, S. and Werres, S.} } @article {4255, title = {A revised systematics of twelve papillate Phytophthora species based on isozyme analysis}, journal = {Mycological Research}, volume = {95}, year = {1991}, month = {Jan-09-1991}, pages = {1025 - 1046}, abstract = {

Isoenzyme analysis was used to examine intraspecific diversity and interspecific relatedness of P. cactorum (group I) and 12 papillate species of Phytophthora within group II of Waterhouse{\textquoteright}s (1963) taxonomic scheme. Isolates of 6 species, specifically P. botryosa, P. heveae, P. katsurae, P. meadii, P. palmivora and P. parasitica (P. nicotianae var. parasitica), contained low levels of genetic diversity and were judged to be valid species. Based upon isoenzyme analysis, all isolates of P. arecae were found to be identical with some isolates of P. palmivora. Thus, it is proposed that these 2 species are synonymous. For P. nicotianae var. parasitica, differences in oospore size or host plant were contrasted with the isoenzyme data using single locus coefficients and no evidence was found to support the existence of distinct varieties. In contrast, several other species, particularly P. capsici, P. citrophthora and P. megakarya, demonstrated much higher levels of variation in isoenzyme pattern and subgroups were readily identified. Isolates of P. capsici, including those previously identified as P. palmivora {\textquoteright}MF4{\textquoteright} separated into 3 subgroups CAP1, CAP2 and CAP3. Those in CAP1 were from widely distributed geographical locations on a range of hosts including Capsicum sp., tomato, cucurbits, as well as cocoa and black pepper and it contained the greatest amount of intraspecific diversity. A single representative of P. mexicana also clustered with this subgroup and as such is considered conspecific to P. capsici. CAP2 isolates were found primarily on black pepper and from Hawaii on Macadamia integrifolia as well as other hosts. In some instances, specifically with isolates from India and Indonesia on black pepper both CAP1 and CAP2 were found. However, the evidence from isoenzymes suggests that the 2 groups are genetically isolated from one another. All representatives of CAP3 were derived from diseased cocoa in Brazil and this subgroup was monomorphic for all loci examined. P. citrophthora was divided into 2 subgroups. Isolates of CTR1 were derived from a large range of hosts including citrus and kiwi fruit. CTR2 was composed of only Brazilian isolates from cocoa. P. megakarya, which has only been reported on cocoa from West Africa, was also divided into 2 subgroups which were separated geographically. Isolates of MGK1 originated from either Nigeria or Guinea and isolates of MGK2 were from Cameroon. P. boehmeriae was the most genetically diverse species examined with 4 isoenzymatically diverse ETs representing only 11 isolates. Interspecific comparisons revealed relationships which would not have been predicted based on morphological comparisons alone. For example, P. meadii and P. botryosa clustered together indicating a very close genetic relatedness. P. katsurae and P. heveae also formed a single cluster. However, comparison of oospores of these 2 species showed that the oogonial stalk length of P. katsurae was consistently much longer. Unexpectedly, P. capsici and P. citrophthora also formed a cluster indicating that they were genetically related. Finally, the results of this isoenzyme analysis suggest that the papillate species of Group II of Waterhouse{\textquoteright}s (1963) scheme may form at least 6 distinct evolutionary lines.

}, issn = {09537562}, doi = {10.1016/S0953-7562(09)80543-1}, url = {http://linkinghub.elsevier.com/retrieve/pii/S0953756209805431}, author = {Oudemans, Peter and Coffey, Michael D.} } @article {618, title = {Sudden oak death and ramorum blight.}, journal = {The Plant Health Instructor}, year = {2008}, doi = {10.1094/PHI-I-2008-0227-01.}, url = {http://www.apsnet.org/edcenter/intropp/lessons/fungi/Oomycetes/Pages/SuddenOakDeath.aspx}, author = {Parke, J. L. and Lucas, S.} } @proceedings {958, title = {The Phytophthora online course: Training for nursery growers}, volume = {Gen. Tech. Rep. PSW-GTR-229}, year = {2010}, pages = {355}, publisher = {U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station}, address = {Santa Cruz, California}, url = {http://www.fs.fed.us/psw/publications/documents/psw_gtr229/}, author = {Parke, J. L. and J. Pscheidt and R. Regan and Hedberg, J. and N. J. Gr{\"u}nwald}, editor = {Frankel, S.J. and J.T. Kliejunas and K. M. Palmieri} } @article {doi:10.1094/PHYTO-97-12-1558, title = {Phytophthora ramorum colonizes tanoak xylem and is associated with reduced stem water transport}, journal = {Phytopathology}, volume = {97}, number = {12}, year = {2007}, pages = {1558-1567}, doi = {10.1094/PHYTO-97-12-1558}, url = {http://apsjournals.apsnet.org/doi/abs/10.1094/PHYTO-97-12-1558}, author = {Parke, J. L. and E. Oh and Voelker, S. and Hansen, E.M. and Buckles, G. and Lachenbruch, B.} } @proceedings {957, title = {A systems approach for detecting sources of Phytophthora contamination in nurseries}, volume = {Gen. Tech. Rep. PSW-GTR-229}, year = {2010}, pages = {67-68}, address = {Santa Cruz, California}, url = {http://www.fs.fed.us/psw/publications/documents/psw_gtr229/}, author = {Parke, J. L. and N. J. Gr{\"u}nwald and C. Lewis and V. Fieland}, editor = {Frankel, S.J. and J.T. Kliejunas and K. M. Palmieri} } @article {4361, title = {Phytophthora castaneae, the correct name for P. katsurae nom. nov. superfl.}, journal = {Mycotaxon}, volume = {121}, year = {2013}, month = {Sep-01-2013}, pages = {327 - 331}, abstract = {

Phytophthora katsurae was proposed as a nom. nov. for P. castaneaeon the assumption that the replaced name was an illegitimate later homonym. This assumption was based on the invalid nomen nudum publication of {\textquotedblleft}Phytophthora castaneae{\textquotedblright} in a host{\textendash}pathogen index as a synonym of Mycelophagus castaneae, and an erroneous interpretation of Clements \& Shear{\textquoteright}s listing of the type of the genus Mycelophagus. There is no valid earlier homonym. Phytophthora castaneae is the correct legitimate name for the taxon causing trunk rot of Castanea crenata, and P. katsurae is an illegitimate superfluous name.

}, issn = {2154-8889}, doi = {10.5248/121.327}, url = {http://dx.doi.org/10.5248/121.327}, author = {Pennycook, Shaun R.} } @article {PPA:PPA2485, title = {Genetic diversity, sensitivity to phenylamide fungicides and aggressiveness of Phytophthora ramorum on Camellia, Rhododendron and Viburnum plants in Spain}, journal = {Plant Pathology}, volume = {60}, number = {6}, year = {2011}, pages = {1069{\textendash}1076}, publisher = {Blackwell Publishing Ltd}, abstract = {

Phytophthora ramorum has been detected in official plant health surveys on Rhododendron, Viburnum and Camellia in ornamental nurseries in northern Spain since 2003. A collection of 94 isolates of P. ramorum was obtained from 2003 to 2008 from plants with symptoms at different geographical locations. Isolates were identified based on morphology and sequence of the rDNA ITS region. Mating type, genetic variation, sensitivity to phenylamide fungicides and aggressiveness of these isolates were determined. All isolates belonged to the A1 mating type, ruling out the possibility of genetic recombination. Seven microsatellite markers were used to study genetic diversity; three out of the seven microsatellite markers were polymorphic within the Spanish population of P. ramorum. This study confirms that all Spanish isolates of P. ramorum belonged to the EU1 lineage. Twelve intralineage genotypes were detected, five that are unique to Spain (EU1MG38, EU1MG41, EU1MG37, EU1MG39 and EU1MG40) and seven that are also present in at least one other European country (EU1MG1, EU1MG29, EU1MG22, EU1MG13, EU1MG2, EU1MG18 and EU1MG26). Genotypes EU1MG37, EU1MG39 and EU1MG40 were isolated from Rhododendron from one region; EU1MG38 and EU1MG41 were isolated from Camellia from two different regions. Isolates of genotype EU1MG38 were resistant to metalaxyl and mefenoxam. The level of genetic diversity within the Spanish population of P. ramorum is limited and indicates a relatively recent clonal expansion.

}, keywords = {fungicide resistance, host origin, mefenoxam, metalaxyl, multilocus genotype, Sudden oak death}, issn = {1365-3059}, doi = {10.1111/j.1365-3059.2011.02485.x}, url = {http://dx.doi.org/10.1111/j.1365-3059.2011.02485.x}, author = {P{\'e}rez-Sierra, A. and {\'A}lvarez, L. A. and Vercauteren, A. and Heungens, K. and Abad-Campos, P.} } @article {4311, title = {Phytophthora siskiyouensis causing stem lesions and cankers on Alnus incana}, journal = {New Disease Reports}, volume = {31}, year = {2015}, month = {Jun-06-2017}, pages = {17}, abstract = {

In late summer 2013, stem cankers and sparse foliage were reported on European grey alder (Alnus incana) growing on a 500 ha site recently-planted with broadleaf and coniferous trees in south-west England. A site visit showed that approximately 10\% of\  more than 1000 grey alders (thought to have been imported from Europe and planted in the late 1990s) had symptoms including bleeding stem lesions similar to those caused by Phytophthora alni (Gibbs et al., 2003). In November 2013, samples were collected from stem lesions (Fig. 1), roots (internal lesions tracking-down from stem lesions) and rhizosphere soil from symptom-bearing trees. Tissue from root and stem lesion margins was plated onto Phytophthora selective medium (SMA) (amended as per Brasier et al., 2005) and incubated at 20{\textdegree}C for 48 hrs. Green apples were used as baits for soil samples by inserting a few grams of soil under a flap cut in the side of the apple and incubating for 4-7 days at 20{\textdegree}C. Isolation from developing SMA mycelial cultures and incubated apple baits onto potato dextrose agar (PDA) and carrot agar (CA) was then undertaken.

After 14 days on PDA at 20{\textdegree}C in the dark, colonies exhibited a distinctive stellate growth pattern (Fig. 2a). On CA they had a diffuse {\textquoteright}frosty{\textquoteright} appearance (Fig. 2b). On CA, oogonia with predominantly paragynous antheridia and aplerotic oospores were abundant. Partially-caducous sporangia formed when plugs from colonies on CA were submerged in unsterile pond water held at 20{\textdegree}C in the dark. Sporangia (46-51 μm wide) were semi-papillate and were ovoid, reniform, elongated or irregular in shape (Fig. 3). Sporangial morphology and dimensions corresponded to Phytophthora siskiyouensis (Reeser et al., 2007) and sequences of ITS and coxII regions supported this identification (GenBank Accession Nos. KP207601 and KP207602).\ 

One isolate of P. siskiyouensis was obtained from each of three different symptomatic trees; one from a root lesion, one from a stem lesion and one from associated soil. Koch{\textquoteright}s postulates were tested by inoculating two-year-old potted A. incana saplings with the three isolates. A small wound was made on the stem 10 cm above soil level. A CA plug colonised by P. siskiyouensis was inserted and the wound was sealed with Parafilm. Nine saplings were inoculated per isolate and maintained at 20{\textdegree}C with a 12-hr-photoperiod. Three control saplings were inoculated with sterile CA plugs. After 20 days, cankers and bleeding were visible externally on all of the trees inoculated with P. siskiyouensis (Fig. 4). The bark was peeled away to reveal phloem lesions extending approximately 2-4 cm above and below the inoculation point. No lesions developed on control trees. After re-isolation onto SMA, a Phytophthora sp. was recovered from all of the inoculated trees but not from the controls and it was identified as P. siskiyouensis by morphology (Reeser et al., 2007) and sequencing of the ITS region.

Phytophthora siskiyouensis is a recently-described species in the USA, isolated from stem lesions on myrtlewood (Umbellularia californica) and tanoak (Lithocarpus densiflorus; synonym of Nothocarpus densiflorus) and from soil and stream water, in south-west Oregon (Reeser et al., 2007). It has also been reported causing stem lesions on Italian alder (Alnus cordata) in California (Rooney-Latham et al., 2007). This is the first report of P. siskiyouensis in the UK and, to our knowledge, in Europe, and the first report of P. siskiyouensis causing stem cankers on A. incana. Its occurrence within a recently-planted site suggests a possible origin on introduced nursery stock. P. siskiyouensis has the potential to cause further damage to Alnus spp. and other plant species in Europe. Its comparative pathogenicity on various alder species is under investigation.

}, doi = {10.5197/j.2044-0588.2015.03110.5197/j.2044-0588.2015.031.017}, url = {http://www.ndrs.org.uk/contents.php?vol=31http://www.ndrs.org.uk/article.php?id=031017}, author = {P{\'e}rez-Sierra, A. and Kalantarzadeh, M. and Sancisi-Frey, S. and Brasier, C.M.} } @article {4004, title = {Previously unrecorded low-temperature Phytophthora species associated with Quercus decline in a Mediterranean forest in eastern Spain}, journal = {Forest Pathology}, volume = {43}, year = {2013}, month = {08/2013}, pages = {331{\textendash}339}, abstract = {

Oak decline has been a serious problem in Europe since the beginning of the twentieth century. In south-west Spain, Quercus ilex and Q.\ suber are the main affected species, and their decline has been associated with Phytophthora cinnamomi. During the last 10\ years, a severe decline of Q.\ ilex and Q.\ faginea accompanied by a significant decrease in the production of acorns affecting natural regeneration was observed in the eastern part of the Iberian Peninsula. Therefore, the aim of this study was to investigate the possible involvement of Phytophthora spp. in the decline. A forest in the Natural Park {\textquoteleft}Carrascar de la Font Roja{\textquoteright} in Comunidad Valenciana (eastern Spain), which is dominated by Q.\ ilex and Q.\ faginea, was surveyed during 2010{\textendash}2011. Symptomatic trees showed thinning and dieback of the crown, withering of leaves and death. An extensive loss of both lateral small woody roots and fine roots and callusing or open cankers on suberized roots were observed. Soil samples containing fine roots were baited using both Q.\ robur leaves and apple fruits. Six Phytophthora species were isolated: P.\ cryptogea, P.\ gonapodyides, P.\ megasperma, P.\ quercina, P.\ psychrophila and P.\ syringae. These are the first records of P.\ quercina and P.\ psychrophila on Q. faginea, of P.\ quercina in Spain and of P.\ psychrophila in mainland Spain. A soil infestation trial was conducted for 6\ months under controlled conditions with 1-year-old seedlings of Q.\ ilex and Q.\ faginea. Phytophthora cinnamomi was included in the pathogenicity test for comparison. The results showed that Q.\ ilex seedlings were generally more susceptible to infection than Q.\ faginea with P.\ cinnamomi being the most aggressive pathogen to both oak species. The two most commonly isolated Phytophthora species, P.\ quercina and P.\ psychrophila, also proved their pathogenicity towards both Q.\ ilex and Q.\ faginea.

}, issn = {1439-0329}, doi = {10.1111/efp.12037}, url = {http://dx.doi.org/10.1111/efp.12037}, author = {P{\'e}rez-Sierra, A. and L{\'o}pez-Garc{\'\i}a, C. and Le{\'o}n, M. and Garc{\'\i}a-Jim{\'e}nez, J. and Abad-Campos, P. and T. Jung} } @article {4290, title = {Temporal Epidemiology of Sudden Oak Death in Oregon}, journal = {Phytopathology}, year = {2015}, month = {Feb-04-2016}, pages = {150414124631002}, abstract = {

An effort to eradicate Phytophthora ramorum , causal agent of sudden oak death, has been underway since its discovery in Oregon forests. Using an information-theoretical approach we sought to model yearly variation in the size of newly infested areas and dispersal distance. Maximum dispersal distances were best modeled by spring and winter precipitation two years before detection, and infestation size the year prior. Infestation size was best modeled by infestation size and spring precipitation the year prior. In our interpretation, there is a two year delay between the introduction of inoculum and onset of mortality for a majority of sites. The year-long gap in between allows ample time for the production of inoculum contributing to the spread of P. ramorum. This is supported by epidemic development following changes in eradication protocols precipitated by an outbreak in 2011, attributable to a 2009 treatment delay and an uncharacteristically wet spring in 2010. Post-eradication, we have observed an increase in the total area of new outbreaks and increased frequency in dispersal distances greater than 4 km. While the eradication program has not eliminated P. ramorum from Oregon forests it has likely moderated this epidemic, emphasizing the need for prompt treatment of future invasive forest pathogens.

}, issn = {0031-949X}, doi = {10.1094/PHYTO-12-14-0348-FI}, url = {http://apsjournals.apsnet.org/doi/10.1094/PHYTO-12-14-0348-FI}, author = {Peterson, Ebba and Hansen, Everett and Kanaskie, Alan} } @article {4674, title = {Sudden oak death, sudden larch death, and ramorum blight​ }, year = {2019}, month = {2019}, publisher = {The American Phytopathological Society}, address = {St. Paul, MN}, abstract = {

Phytophthora ramorum is a recently emerged pathogen with a host range of more than 150 plant species. This fungus-like organism causes sudden oak death on certain members of the oak family and has killed an estimated 30-45 million trees in coastal forests of California and Oregon. The pathogen additionally causes sudden larch death of Japanese larch, especially in conifer plantations in the United Kingdom. On most hosts, however, P. ramorum causes ramorum leaf blight or shoot blight on native plant species and horticultural nursery crops, plaguing some nurseries in California, Oregon, Washington, British Columbia and Europe.\ 

}, doi = {DOI: 10.1094/PHI-I-2019-0701-02}, url = {https://www.apsnet.org/edcenter/disandpath/oomycete/pdlessons/Pages/SuddenOakDeath.aspx}, author = {Peterson, Ebba K and Parke, Jennifer L.} } @article {4727, title = {First report of the NA2 clonal lineage of the sudden oak death pathogen, Phytophthora ramorum, infecting tanoak in Oregon forests}, journal = {Plant Disease}, year = {2022}, month = {Feb-02-2022}, abstract = {

Phytophthora ramorum Werres, de Cock \& Man in{\textquoteright}t Veld, causal agent of sudden oak death (SOD) and ramorum leaf blight, is comprised of four clonal lineages in its invasive ranges of North America and Europe (Gr{\"u}nwald et al. 2012, Van Poucke et al. 2012). Of these, three {\textendash} the NA1, NA2, and EU1 lineages {\textendash} are found in U.S. nurseries, but only two, the NA1 and EU1 lineages, have been found infecting trees in North American forests (Gr{\"u}nwald et al. 2012, 2016). In the spring of 2021, tanoak (Notholithocarpus densiflorus Manos, Cannon \& Oh) displaying symptoms consistent with SOD were detected north of Port Orford (Curry County, Oregon). Symptoms were canopy dieback and blackened petiole and stem lesions on tanoak sprouts. The pathogen isolated on PAR (CMA plus 200 ml/L ampicillin, 10 mg/L rifamycin, 66.7 mg/L PCNB) selective media was determined to be P. ramorum based on characteristic morphology of hyphae, sporangia, and chlamydospores (Werres et al. 2001). Positive identification as P. ramorum was obtained with a lineage-specific LAMP assay targeting an NA2 orphan gene, indicating the presence of the NA2 lineage. NA2 was confirmed by sequencing a portion of the cellulose binding elicitor lectin (CBEL) gene using CBEL5U and CBEL6L primers (Gagnon et al. 2014). Sequences (GenBank accessions MZ733981 and MZ733982) were aligned against reference sequences for all lineages (Gagnon et al. 2014) confirming the presence of NA2. Lineage determination as NA2 was further confirmed at eleven SSR loci (ILVOPrMS145, PrMS39, PrMS9C3, ILVOPrMS79, KI18, KI64, PrMS45, PrMS6, ILVOPrMS131, KI82ab, and PrMS43) using the methods of Kamvar et al. (2015). We completed Koch{\textquoteright}s postulates using potted tanoaks, wound-inoculated at the midpoint of 1-year old stems with either hyphal plugs or non-colonized agar (n=4 per treatment). Tanoaks were maintained in a growth chamber (20{\textdegree}C-day / 18{\textdegree}C-night temperatures) with regular watering and an 18-photoperiod using F32T8 fluorescent bulbs (Phillips, Eindhoven, The Netherlands). After 7 days, brown to black lesions 1.2 to 2.9 cm in length were observed on the inoculated stems, from which P. ramorum was subsequently re-isolated; no symptoms were observed on the controls, and no pathogens were recovered when plating the wound sites in PAR. This is the first detection of the NA2 lineage causing disease in forests worldwide. The outbreak was found on private and public lands in forests typical to the SOD outbreak in Oregon (mixed conifer and tanoak), and was 33 km north of the closest known P. ramorum infestation. Follow-up ground surveys on adjacent lands have identified over 100 P. ramorum-positive tanoak trees, from which additional NA2 isolates have been recovered from bole cankers. NA2 is thought to be more aggressive than the NA1 lineage (Elliott et al. 2011), which has been present in Curry County since the mid-1990s (Goheen et al. 2017). Eradication of the NA2 lineage is being pursued to slow its further spread and prevent overlap with existing NA1 and EU1 populations. The repeated introductions of novel lineages into the western United States native plant communities highlights the vulnerability of this region to Phytophthora establishment, justifying continued monitoring for P. ramorum in nurseries and forests. References {\textbullet} Elliott, M, et al. 2011. For. Path. 41:7. https://doi.org/10.1111/j.1439-0329.2009.00627.x {\textbullet} Gagnon, M.-C., et al. 2014. Can. J. Plant Pathol. 36:367. https://doi.org/10.1080/07060661.2014.924999 {\textbullet} Goheen, E.M., et al. 2017. For. Phytophthoras 7:45. https://doi: 10.5399/osu/fp.7.1.4030 {\textbullet} Gr{\"u}nwald, N. J., et al. 2012. Trends Microbiol. 20:131. https://doi.org/10.1016/j.tim.2011.12.006 {\textbullet} Gr{\"u}nwald, N. J., et al. 2016. Plant Dis. 100:1024. https://doi.org/10.1094/PDIS-10-15-1169-PDN {\textbullet} Kamvar, Z.N. et al. 2015. Phytopath. 105:982. https://doi.org/10.1094/PHYTO-12-14-0350-FI {\textbullet} Van Poucke, K., et al. 2012. Fungal Biol. 116:1178. https://doi.org/10.1016/j.funbio.2012.09.003 {\textbullet} Werres, S., et al. 2001. Mycol. Res. 105: 1155. https://doi.org/10.1016/S0953-7562(08)61986-3

}, issn = {0191-2917}, doi = {10.1094/PDIS-10-21-2152-PDN}, url = {https://apsjournals.apsnet.org/doi/pdf/10.1094/PDIS-10-21-2152-PDN}, author = {Peterson, Ebba K. and Sondreli, Kelsey Liann and Reeser, Paul and Navarro, Sarah M. and Nichols, Casara and Wiese, Randall and Fieland, Valerie and Gr{\"u}nwald, Niklaus J. and LeBoldus, Jared M.} } @article {4692, title = {Root Rot of Juniperus and Microbiota by Phytophthora lateralis in Oregon Horticultural Nurseries}, journal = {Plant Disease}, volume = {104}, year = {2020}, month = {Jan-05-2020}, pages = {1500 - 1506}, abstract = {

Widespread symptoms of root rot and mortality on Juniperus communis and Microbiota decussata were observed in two horticultural nurseries in Oregon, leading to the isolation of a Phytophthora sp. from diseased roots. Based on morphology and sequencing the internal transcribed spacer ITS1-5.8S-ITS2 region, isolates were identified as the invasive pathogen Phytophthora lateralis, causal agent of Port-Orford-cedar (POC; Chamaecyparis lawsoniana) root disease. Additional sequencing of the cytochrome c oxidase subunit 1 and 2 genes identified all isolates as belonging to the PNW lineage. Utilizing recovered isolates plus a POC-wildlands isolate and susceptible POC as controls, we completed Koch{\textquoteright}s postulates on potted Juniperus and Microbiota plants. Nursery isolates were more aggressive than the forest isolate, which was used in the POC resistance breeding program. Increased aggressiveness was confirmed using a branch stem dip assay with four POC clones that differed in resistance, although no isolate completely overcame major-gene resistance. Isolates were sensitive to mefenoxam, a fungicide commonly used to suppress Phytophthora spp. growth in commercial nurseries. Although POC resistance is durable against these more aggressive nursery isolates, the expanded host range of P. lateralis challenges POC conservation through the continued movement of P. lateralis by the nursery industry.

}, issn = {0191-2917}, doi = {10.1094/PDIS-04-19-0808-RE}, url = {https://apsjournals.apsnet.org/doi/10.1094/PDIS-04-19-0808-RE}, author = {Peterson, Ebba K. and Rupp, Franziska and Eberhart, Joyce and Parke, Jennifer L.} } @article {4232, title = {Source or sink? The role of soil and water borne inoculum in the dispersal of Phytophthora ramorum in Oregon tanoak forests}, journal = {Forest Ecology and Management}, volume = {322}, year = {2014}, month = {Jan-06-2014}, pages = {48 - 57}, abstract = {

Management of invasive species requires confidence in the detection methods used to assess expanding distributions, as well as an understanding of the dominant modes of spread. Lacking this basic biological information, during early stages of invasion management choices are often driven by available resources and the biology of closely related species. Such has been the case for the management of the phytopathogen, Phytophthora ramorum, causal agent of sudden oak death (SOD) of oaks and tanoaks. To detect P. ramorum, The Oregon SOD eradication program has relied upon the aerial observation of dead, overstory tanoak (Notholithocarpus densiflorus), an easily infected host widely distributed throughout the range of P. ramorum in Oregon. At risk is the possibility of misrepresenting the distribution of SOD, particularly if inoculum is predominately moved in soil and water, common dispersal pathways for other Phytophthora spp. To assess this risk, we performed surveys of understory vegetation in areas with a high risk of establishment of understory infection from soil and water sources: along roadsides within heavily trafficked areas with a history of SOD, and along streams known to contain P. ramorum inoculum. Additionally, we tested the alternative hypothesis of aerial dispersal, whereby infection in the understory would be spatially correlated with overstory mortality. Consistent with prior studies into the spatial structure of P. ramorum in Oregon, we found no evidence of understory infection in close proximity to roads in the absence of overstory mortality. Similarly, P. ramorum was only isolated from understory vegetation associated with streams when within close proximity to overstory sources, and more commonly further away from stream edges than within the splash and flood line. Both disease patterns are inconsistent with a dominate soil and water mediated dispersal mechanism. Rather, we found evidence supporting our alternative hypothesis of aerial dispersal whereby recovery of P. ramorum in the understory declined with increasing distance from the only known overstory source. These results support the use of aerial detection in describing the distribution of SOD in Oregon, and give further support to dispersal of inoculum in blowing fog or rain at scales not yet described for other forest Phytophthora species.

}, issn = {03781127}, doi = {10.1016/j.foreco.2014.02.031}, url = {http://linkinghub.elsevier.com/retrieve/pii/S0378112714001261}, author = {Peterson, Ebba and Hansen, Everett and Hulbert, Joseph} } @article {4559, title = {First Report of Phytophthora {\texttimes} multiformis on Alnus glutinosa in Spain}, journal = {Plant Disease}, volume = {101}, year = {2017}, month = {Jan-01-2017}, pages = {261 - 261}, abstract = {

Alder species are threatened by a lethal disease caused by the oomycete Phytophthora alni, one of the most important emergent pathogens of natural ecosystems in Europe during the last 20 years (Aguayo et al. 2014). Phytophthora alder decline has caused substantial economic losses and ecological damage from riparian alder populations. Initially, three different subspecies had been described, P. alni subsp. alni, P. alni subsp. uniformis, and P. alni subsp. multiformis. Recently, they have been raised to species status and renamed P. {\texttimes} alni, P. uniformis, and P. {\texttimes} multiformis, respectively (Husson et al. 2015). P. {\texttimes} alni was reported to be the most aggressive and pathogenic to alders. The other two species appear to be less aggressive, but are also considered pathogenic (Brasier and Kirk 2001). In Spain, P. {\texttimes} alni and P. uniformis has also been detected (Pintos Varela et al. 2012). In April 2014, crown dieback and mortality of Alnus glutinosa were noted across the riparian area along the Mui{\~n}os River in Galicia (northwest Spain). Affected trees, showing abnormally small, yellow, and sparse leaves and necrotic lesions in the inner bark, were surveyed. Samples of bark including the cambium from active lesions, roots, and soil were collected. Phytophthora spp. were baited from saturated rhizosphere soil using carnation petals. Roots and tissue from fresh active inner bark lesions were plated onto selective medium V8-PARPH agar and incubated for 7 days at 22{\textdegree}C in the dark. A Phytophthora sp. isolated from root and bark was transferred to carrot agar (CA) and incubated in the dark. Colonies on CA were irregular with upper temperature limits for growth at 30{\textdegree}C. The isolates were homothallic, with smooth to extremely ornamented oogonia. Oogonial diameters ranging from 42 to 59 {\textmu}m and one or two celled amphigynous antheridia were observed. In soil extract, noncaducous, nonpapillate, ellipsoid to ovoid sporangia were produced. Amplification of DNA was accomplished by using SCAR-PCR primers (Ioos et al. 2005). DNA samples of Phyophthora isolates have amplified using primers pairs PAM-F/R and PA-F/R. No amplicon was obtained using PAU-F/R primers. ITS (DC6-ITS6/ITS4) and nadh1 (NADHF1/NADHR1) mitochondrial gene regions were also amplified and deposited in GenBank (accession nos. KX090045 and KX090044 isolate CECT 20954). Comparison of the sequences showed 100\% homology with P. {\texttimes} multiformis (KJ755099 and FJ696567). Pathogenicity of P. {\texttimes} multiformis isolate CECT 20954 was performed by inoculating 10 3-year-old A. glutinosa plants growing in pots. One shallow cut was made at the root collar level. A colonized 5-mm mycelial agar plug from a 7-day-old culture was inserted in every wound and sealed with Parafilm. Five control plants were inoculated with a sterile agar plug. Plants were maintained in a controlled chamber at 24{\textdegree}C and 80\% humidity for 2 months. After a 5-week incubation period, inoculated plants showed dieback symptoms and necrosis of the inner bark tissue. Lesion lengths ranged from 2 to 10 cm. Control plants remained symptomless. P. {\texttimes} multiformis was recovered from all inoculated plants, but not from controls. To our knowledge, this is the first report of P. {\texttimes} multiformis in Spain. With this report, the detection of the P. alni species complex in Spain has been completed.

}, issn = {0191-2917}, doi = {10.1094/PDIS-08-16-1092-PDN}, url = {http://apsjournals.apsnet.org/doi/10.1094/PDIS-08-16-1092-PDN}, author = {Pintos-Varela, C. and Rial-Mart{\'\i}nez, C. and Agu{\'\i}n-Casal, O. and Mansilla-V{\'a}zquez, J. P.} } @article {3945, title = {Ground verification of Aerial survey for POC root disease}, year = {2002}, pages = {Two page brochure}, publisher = {PNW Research Station, USDA Forest Service, Forestry Sciences Laboratory}, url = {http://www.fs.fed.us/pnw/publications/brochure-misc.shtml}, author = {PNW Research Station, USDA-FS} } @article {pohe1999factors, title = {Factors involved in the development of nutfall [Cocos nucifera nuts] due to Phytophthora katsurae in Ivory Coast}, journal = {Tropicultura (Belgium)}, volume = {16/17 No. 3}, year = {1999}, pages = {150-153}, abstract = {Nut rot on coconut can be spread simply by contact or by spreading agents which maintain isolated infections within a bunch on a given tree and at plot level. The disease generally spreads horizontally from one bunch to another and vertically, particularly vertically downwards, from one nut to another in a given bunch. The positive effect of water and insects in disease spread has been demonstrated.}, author = {Pohe, J.} } @article {pohe2009effectiveness, title = {Effectiveness of aluminum-fosetyl in the control of early nutfall of coconut tree due to Phytophthora katsurae (Pythiaceae)}, journal = {Agronomie africaine}, volume = {15}, number = {3}, year = {2009}, pages = {123{\textendash}133}, abstract = {

Early nut fall and bud rot due to Phytophthora katsurae are the most important diseases of coconut tree observed in recent years at the Assinie plantations of PALMINDUSTRIE Company, C{\^o}te d{\textquoteright}Ivoire. Field investigations conducted in 1983 revealed a high rate of nut fall (50-70\%) during the rainy season. Cutting of coconut stands with rotten buds, as a way to control the spread of Oryctes sp., allowed to assess the number of dead trees over 139 and 89 ha of land for the hybrids and Grand West cultivars, respectively. In addition to those disease control measures proposed by the Company, comparison trials were systematically carried out using 2 fungicides: aluminum-fosetyl [fosetyl] at 3 doses (3.2, 4.8 and 6.4 g of active ingredient/tree) and Ridomil [metalaxyl] at one dose (3.125 g of active ingredient/tree). These fungicide were injected into the stem of the coconut every 3 months starting from December 1984. After 3 years, the efficacy of the 3 doses of aluminium-fosetyl over Ridomil in significantly reducing nut fall, even at low rates (3.2 g of active ingredient/tree), was apparent. However, the technique still remains out of reach of most farmers because of lack of technical know-how. It appears therefore, that an improvement of the technique, so as to make it accessible to the farmers, is a necessity.

}, url = {http://www.ajol.info/index.php/aga/article/view/1633}, author = {Pohe, J. and Dongo, BK and N{\textquoteright}Goran, N.} } @article {4606, title = {First report of alder Phytophthora cosely related to P. uniformis on Alnus glutinosa seedling in Finland}, journal = {Plant Disease}, year = {2017}, month = {Apr-12-2017}, pages = {PDIS-03-17-0322}, abstract = {

The allotriploid Phytophthora {\texttimes} alni (Brasier \& S.A. Kirk) Husson, Ioos \& Marcais and its progenitors, the diploid P. uniformis (Brasier \& S.A. Kirk) Husson, Ioos \& Aguayo and the allotetraploid P. {\texttimes} multiformis (Brasier \& S.A. Kirk) Husson, Ioos \& Frey are the causal agents of alder decline in Europe. In June 2015, a dark, \~{}40 mm stem lesion was found on one out of 100 inspected Alnus glutinosa (L.) Gaertn seedlings in M{\"a}ntyharju, Finland. Surface wood pieces from the lesion edges were plated onto malt agar. Cultures on carrot piece agar (CPA) showed an appressed colony with woolly aerial mycelium. Oogonia ({\O} mean 44.8 {\textmu}m, n = 50) and oospores ({\O} mean 40.0 {\textmu}m, n = 50) developed after 7 days at 20{\textdegree}C in the dark. They were commonly smooth walled, and 49 out of 50 of the amphigynous antheridia were single celled. Sporangia (21.7 {\texttimes} 18.1 {\textmu}m, n = 50) were produced on pea broth, with 2-day flooding with soil extract, and they were commonly unpapillate and obpyriform-ellipsoidal. DNA was extracted, and the internal transcribed spacer (ITS) rDNA was amplified (ITS6 and ITS4; Cooke et al. 2000). The PCR products were then cloned because of double peaks in the sequence. Among 33 clones, four alleles with five polymorphic bases were obtained (A1, 55\%; A2, 6\%; A3, 15\%; and A4, 24\%; these were deposited in GenBank as accession nos. MF356294, MF356295, MF356296, and MF356297, respectively). The closest match to the ITS allele sequences in GenBank was the very closely related species P. cambivora AF087479 (differences, 7 to 9 bases). All other sequenced regions showed single alleles. The mitochondrial cox spacer (MF356298; amplified by FMPhy8 and FMPhy10, Martin et al. 2004) matched 100\% with P. cambivora P1431 (GU221955) and P. alni P16202 (GU221933) in GenBank. A partial beta tubulin gene (MF356299; amplified by 901F and 1401R, Bilodeau et al. 2007) matched 100\% with P. uniformis ALN58 (KU899249). ASF-like, GPA1, RAS-Ypt, and TRP1 genes were amplified with primers by Ioos et al. (2006). GPA1 (MF356301) matched 100\% with P. uniformis PAU84 (DQ092849), and RAS-Ypt (MF356302) had exact matches with four P. uniformis isolates in GenBank (e.g., PANM53 and EU371549). The TRP1 gene (MF356303) differed by 1 base from P. uniformis alleles PAU60 (DQ202480) and PAU89 (DQ202481). The ASF-like gene (MF356300) matched 100\% with PAU84 (DQ092815). Nine 1-year-old seedlings of A. glutinosa and of Betula pendula Roth were inoculated with plugs from 10-day-old mycelial culture on CPA after making a bark incision. Nine control seedlings of each species received a sterile CPA plug. Inoculations were wrapped in damp cotton wool, and the plants were kept outdoors at 10 to 22{\textdegree}C. After 15 days, eight out of nine (89\%) A. glutinosa seedlings had developed lesions (mean length 22 mm), as well as six out of nine (67\%) B. pendula seedlings (mean length 4 mm). No lesions were observed in control seedlings. The pathogen was reisolated from two symptomatic seedlings of both hosts. This is the first report of an alder Phytophthora in Finland. The sequence data suggested the isolate to be closely related but dissimilar to P. uniformis. The morphology corresponded to that previously reported for P. uniformis (Brasier et al. 2004), except for the antheridia, which were almost all single celled. Multiple ITS alleles could also refer to the initially reported P. uniformis karyotype 2n+2 (Brasier et al. 2004). These findings add to our knowledge on the variation among the alder Phytophthora group. Furthermore, they demonstrate the risk that the pathogen could be transported in new hosts.

}, issn = {0191-2917}, doi = {10.1094/PDIS-03-17-0322-PDN}, url = {https://apsjournals.apsnet.org/doi/10.1094/PDIS-03-17-0322-PDN}, author = {Poimala, A. and Werres, S. and Pennanen, T. and Hantula, J.} } @article {1313, title = {Identity and pathogenicity of species of Phytophthora causing root rot of Douglas-fir in the Pacific Northwest}, journal = {Phytopathology}, volume = {66}, year = {1976}, pages = {710-714}, abstract = {

Three species of Phytophthora previously unreported from Douglas-fir were isolated along with P. cinnamomi from diseased trees from forest nurseries, forest outplanting sites, and seedling storage facilities in western Oregon and Washington. Two species were identified as P. cryptogea and P. drechsleri on the basis of sporangial and colony morphology, temperature-growth relations, and by comparisons with isolates of known identity. A third species, designated Phytophthora sp. 1, did not correspond to any previously described species. Phytophthora cinnamomi and P. cryptogea were highly virulent on dormant and growing Douglas-fir seedlings in greenhouse tests. Phytophthora drechsleri and Phytophthora sp. 1 appeared to be less virulent. Phytophthora cryptogea, P. drechsleri and Phytophthora sp. 1 are similar to P. lateralis, a destructive pathogen of Port-Orford-cedar, in growth at low temperatures and should therefore be regarded as potentially dangerous forest pathogens in cool, moist sites.

}, doi = {DOI: 10.1094/Phyto-66-710}, author = {R.G. Pratt and L.F. Roth and Hansen, E.M. and W.D. Ostrofsky} } @article {4696, title = {First Report of the NA2 Clonal Lineage of Phytophthora ramorum in Indiana}, journal = {Plant Disease}, volume = {104}, year = {2020}, month = {Apr-20-2020}, pages = {1875}, abstract = {

The oomycete pathogen Phytophthora ramorum is the causal agent of ramorum leaf blight and sudden oak death (Rizzo et al. 2002). P. ramorum is known to cause leaf blight and stem dieback on nursery hosts including Rhododendron. The disease typically results in dark, brownish lesions on leaves or stems, which can cause wilting and death of the plant (Gr{\"u}nwald et al. 2008; Werres et al. 2001). Since the emergence of the disease, a federal quarantine was established to prevent the spread of the pathogen, and nurseries that export P. ramorum hosts are subject to a federally mandated certification program for interstate export (Gr{\"u}nwald et al. 2012). This disease has had a significant impact on the U.S. nursery industry via quarantine regulations imposed on nurseries infested with the pathogen. The pathogen has been introduced at least three times into the Western United States as clonal lineages NA1, NA2, and EU1 (Gr{\"u}nwald et al. 2009, 2019; Ivors et al. 2006). In the spring and summer of 2019, USDA-APHIS reported that a shipment of potentially P. ramorum-infested plants was delivered to several Eastern and Midwestern states. Rhododendron leaves from numerous counties in Indiana, showing characteristic necrotic leaf blight symptoms, were sampled by Indiana Department of Natural Resources (IDNR) nursery inspectors between April 18 and June 3, 2019. These samples were initially screened for the presence of Phytophthora at the Purdue Plant and Pest Diagnostic Laboratory using an ELISA test (Agdia). Subsamples from tissue producing a positive ELISA result were forwarded to the Michigan State University Plant \& Pest Diagnostics laboratory for P. ramorum-specific PCR testing, which was later confirmed by USDA CPHST. Leaf surfaces of P. ramorum-positive samples were surface disinfested to remove contaminating organisms by washing vigorously in 50 ml of 70\% ethanol for 10 s followed by three rinses in sterile water. Washed leaves were blotted dry on sterile paper towels. From each leaf, 5-mm leaf discs were punched out of the leading edge of leaf lesions, and the resulting leaf discs were submerged in selective V8 medium amended with pimaricin, ampicillin, and rifampicin in Petri dishes. Petri dishes were incubated at 20{\textdegree}C until growth was present. A plug of growth from the leading edge of the resulting colony was transferred to fresh V8 medium containing a 47-mm 0.4-micron polycarbonate filter (Nucleopore) and incubated for approximately 8 days at 20{\textdegree}C. DNA was extracted by the Center for Genome Research and Biocomputing at Oregon State University using the Omega BioTek Plant DNA DS kit (M1130), and part of the cellulose binding elicitor lectin gene (CBEL) was amplified and sequenced with primers CBEL5U and CBEL6L (Gagnon et al. 2014). Sequences were aligned with the CBEL reference sequences of EU1 (KF679685), EU2 (KF679716), NA1 (EU688908), and NA2 (KF679712) (Gagnon et al. 2014). All 26 of the Indiana isolates were unambiguously classified as belonging to the NA2 clonal lineage (GenBank accessions MN601787 to MN601812). This is the first report of the NA2 clonal lineage outside of British Columbia, Washington, and California, indicating that this pathogen was most likely moved West to East. Prior documented lineages detected obtained from P. ramorum-infected plants in Eastern receiving states have only harbored the NA1 clonal lineage (Goss et al. 2009, 2011). As a result of these detections, the IDNR ordered destruction of more than 6,100 Rhododendron plants at retail outlets in Indiana.

}, issn = {0191-2917}, doi = {10.1094/PDIS-12-19-2543-PDN}, url = {https://apsjournals.apsnet.org/doi/10.1094/PDIS-12-19-2543-PDN}, author = {Press, C. M. and Fieland, V. J. and Creswell, T. and Bonkowski, J. and Miles, L. and Gr{\"u}nwald, N. J.} } @article {3995, title = {Phytophthora diversity and the population structure of Phytophthora ramorum in Swiss ornamental nurseries}, journal = {Plant Pathology}, volume = {62}, year = {2013}, month = {10/2013}, pages = {1063{\textendash}1071}, abstract = {

Invasive oomycete pathogens have been causing significant damage to native ecosystems worldwide for over a century. A recent well-known example is Phytophthora ramorum, the causal agent of sudden oak death, which emerged in the 1990s in Europe and North America. In Europe, this pathogen is mainly restricted to woody ornamentals in nurseries and public greens, while severe outbreaks in the wild have only been reported in the UK. This study presents the results of the P.\ ramorum survey conducted in Swiss nurseries between 2003 and 2011. In all 120 nurseries subjected to the plant passport system, the main P.\ ramorum hosts were visually checked for above ground infections. Phytophthora species were isolated from tissue showing symptoms and identified on the basis of the morphological features of the cultures and sequencing of the ribosomal ITS region. Phytophthora was detected on 125 plants (66 Viburnum, 58 Rhododendron and one Pieris). Phytophthora ramorum was the most frequent species (59{\textperiodcentered}2\% of the plants), followed by P.\ plurivora, P.\ cactorum, P.\ citrophthora, P.\ cinnamomi, P.\ cactorum/P.\ hedraiandra, P.\ multivora and P.\ taxon PgChlamydo. The highest incidence of P.\ ramorum was observed on Viburnum\ {\texttimes}\ bodnantense. Microsatellite genotyping showed that the Swiss P.\ ramorum population is highly clonal and consists of seven genotypes (five previously reported in Europe, two new), all belonging to the European EU1 clonal lineage. It can therefore be assumed that P.\ ramorum entered Switzerland through nursery trade. Despite sanitation measures, repeated P.\ ramorum infections have been recorded in seven nurseries, suggesting either reintroduction or unsuccessful eradication efforts.

}, doi = {10.1111/ppa.12027}, url = {https://onlinelibrary.wiley.com/doi/full/10.1111/ppa.12027}, author = {Prospero, S and Vercauteren, A. and Heungens, K. and Belbahri, L. and Rigling, D.} } @article {4623, title = {Survival of Phytophthora cinnamomi and Fusarium verticillioides in commercial potting substrates for ornamental plants}, journal = {Journal of Phytopathology}, volume = {166}, year = {2018}, month = {Jan-08-2018}, pages = {484 - 493}, abstract = {

Live plants, particularly when accompanied by soil or potting substrates, are considered the main pathway for international spread of plant pathogens. Modern, rapid shipping technologies for international plant trade increase the probability of plant pathogen survival during transport and the subsequent chances of disease outbreaks in new locations. The survival of two model pathogens, an Oomycete, Phytophthora cinnamomi, and a filamentous fungus, Fusarium verticillioides, was studied in two different commercial potting substrates (peat and peat-free) under glasshouse conditions in the absence of a plant host. Survival rates were analysed at 2, 7, 12 and 17\ months after substrate inoculation. Fusarium verticillioides had the longest survival rate, and was still present at 17\ months. In contrast, P.\ cinnamomi survived up to 7\ months but was not recovered after 12 or 17\ months. There was no significant difference in the number of colony-forming units (CFUs) of either pathogen in the two substrates, except at 2\ months, when higher numbers were recovered from peat substrates.

}, doi = {https://doi.org/10.1111/jph.12708}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/jph.12708?campaign=woletoc}, author = {Pu{\'e}rtolas, Alexandra and Boa, Eric and Bonants, Peter J. M. and Woodward, Steve} } @article {4014, title = {Challenges in predicting invasive reservoir hosts of emerging pathogens: mapping Rhododendron ponticum as a foliar host for Phytophthora ramorum and Phytophthora kernoviae in the UK}, journal = {Biological Invasions}, volume = {15}, year = {2013}, month = {3/2013}, pages = {529 - 545}, abstract = {

Invasive species can increase the susceptibility of ecosystems to disease by acting as reservoir hosts for pathogens. Invasive hosts are often sparsely recorded and not in equilibrium, so predicting their spatial distributions and overlap with other hosts is problematic. We applied newly developed methods for modelling the distribution of invasive species to the invasive shrub Rhododendron ponticum{\textemdash}a foliar reservoir host for the Phytophthora oomycete plant pathogens, P. ramorum and P. kernoviae, that threaten woodland and heathland habitat in Scotland. We compiled eleven datasets of biological records for R. ponticum (1,691 points, 8,455 polygons) and developed Maximum Entropy (MaxEnt) models incorporating landscape, soil and climate predictors. Our models produced accurate predictions of current suitable R. ponticum habitat (training AUC\ =\ 0.838; test AUC\ =\ 0.838) that corresponded well with population performance (areal cover). Continuous broad-leaved woodland cover, low elevation (\<400\ m a.s.l.) and intermediate levels of soil moisture (or Enhanced Vegetation Index) favoured presence of R. ponticum. The high coincidence of suitable habitat with both core native woodlands (54\ \% of woodlands) and plantations of another sporulation host, Larix kaempferi (64\ \% of plantations) suggests a high potential for spread of Phytophthora infection to woodland mediated by R. ponticum. Incorporating non-equilibrium modelling methods did not improve habitat suitability predictions of this invasive host, possibly because, as a long-standing invader, R. ponticum has filled more of its available habitat at this national scale than previously suspected.

}, issn = {1387-3547}, doi = {10.1007/s10530-012-0305-y}, url = {http://link.springer.com/article/10.1007/s10530-012-0305-y$\#$}, author = {Purse, Bethan V. and Graeser, Philipp and Searle, Kate and Edwards, Colin and Harris, Catriona} } @article {1312, title = {Phytophthora leaf blight - a new disease of California wax-myrtle (Morella californica) in Oregon, USA caused by a Phytophthora species}, journal = {N. Z. J. For. Sci.}, volume = {41 Suppl.}, year = {2011}, pages = {S57-S63}, abstract = {

In spring, 2009, the Oregon State University Plant Clinic received reports of severe defoliation of California wax-myrtle plants (Morella californica (Cham. \& Schlecht.) Wilbur) on the north-central coast of Oregon, in western North America. Isolations from necrotic leaf tissue yielded an organism which, from morphological characteristics and a genus-specific enzyme-linked immunosorbent assay, was identified as a species of the genus Phytophthora. Total DNA was extracted from hyphal tip-derived cultures from leaf or twig tissue and subjected to a polymerase chain reaction process aimed at species identification. Sequencing techniques revealed a 99.7\% match with P. syringae although our isolates differed from published descriptions of this species in some respects. Inoculation of healthy plants with cultured mycelium resulted in symptoms similar to those originally observed in the field, and reisolations produced colonies of the same organism. This is the first report of a species of Phytophthora causing disease in M. californica. Leaf blight of California wax-myrtle is now widespread on the north-central coast of Oregon. This disease is serious and is adversely affecting the health of this native understory species which is frequently used for amenity plantings.

}, author = {Putnam, M. L. and M. Serdani and M. Curtis and S. Angima} } @article {quillec1984phytophthora, title = {Le Phytophthora heveae du cocotier: son r{\^o}le dans la pourriture du c{\o}eur et dans la chute des noix}, journal = {Ol{\'e}agineux}, volume = {39}, number = {10}, year = {1984}, pages = {477{\textendash}485}, publisher = {Soci{\'e}t{\'e} d{\textquoteright}{\'e}ditions techniques continentales}, url = {http://cat.inist.fr/?aModele=afficheN\&cpsidt=8960536}, author = {Quillec, G and Renard, JL and Ghesqui{\`e}re, H.} } @article {865, title = {Phytophthora rot of coconut.}, journal = {Oleagineux}, volume = {39}, year = {1984}, pages = {143{\textendash}147}, author = {Quillec, G and Renard, JL} } @proceedings {353, title = {Phytophthora kernoviae {\textendash} of southern hemisphere origin?}, year = {2007}, month = {August, 2007}, pages = {1 page}, address = {Monterey, Calif. Coll. of Nat. Resourc., Univ. of Calif., Berkeley.}, author = {Tod D. Ramsfield and Margaret A. Dick and Ross E. Beever and Ian J. Horner} } @proceedings {605, title = {Phytophthora kernoviae in New Zealand}, volume = {General Technical Report PSW-GTR-221}, year = {2009}, pages = {47-53}, publisher = {U.S. Department of Agriculture, Forest Service Pacific Southwest Research Station}, address = {Monterey, California}, abstract = {

Phytophthora kernoviae was first recognised in New Zealand in 2005 by DNA sequencing of an isolate that had been recovered from diseased Annona cherimola (cherimoya or custard apple) in an abandoned orchard in Northland in 2002. Subsequent investigation has recovered P. kernoviae from the soil in Northland, Auckland, Bay of Plenty and Taupo regions. Similarity between P. kernoviae and descriptions of an undescribed Phytophthora sp. found previously in New Zealand indicates that the organism has been present here since at least 1953. This, along with the geographic range of P. kernoviae, and a polymorphism in the ITS sequence, suggest that the pathogen has been present in New Zealand for an even longer time. Little is known of the ecological behaviour of the pathogen in New Zealand; disease has only been recorded on A. cherimola.

}, author = {Ramsfield, T.D. and Dick, M.A. and Beever, R.E. and Horner, I.J. and McAlonan, M.J. and Hill, C.F.}, editor = {Goheen, Ellen Michaels and Susan J. Frankel} } @article {PPA:PPA2463, title = {Two novel and potentially endemic species of Phytophthora associated with episodic dieback of Kwongan vegetation in the south-west of Western Australia}, journal = {Plant Pathology}, volume = {60}, year = {2011}, pages = {1055{\textendash}1068}, publisher = {Blackwell Publishing Ltd}, abstract = {

Two novel homothallic species of Phytophthora causing dieback of Kwongan vegetation in south-west Western Australia are described here as Phytophthora arenaria sp. nov. and Phytophthora constricta sp. nov. DNA sequencing of the ITS rDNA and cox1 gene confirmed that P.\ arenaria and P.\ constricta are unique species residing in ITS clades 4 and 9, respectively. Phytophthora arenaria has been isolated from vegetation occurring on the northern sandplains which are warmer and drier than the southern sandplains from which P.\ constricta has been predominantly isolated, and both species appear morphologically and physiologically well adapted to the ecosystems in which they occur. Both species have been associated mainly with dead and dying Banksia species and the pathogenicity of both P.\ arenaria and P.\ constricta to Banksia attenuata was confirmed in this study. The combination of unique DNA sequences, including considerable variation in cox1 sequence data, thick oospore walls and physiological characteristics that appear to be adaptations favouring survival in the harsh Kwongan ecosystem suggest that these species may be endemic to Western Australia.

}, keywords = {Mediterranean climate, natural ecosystems, pathogens, phylogeny, Phytophthora arenaria, Phytophthora constricta}, issn = {1365-3059}, doi = {10.1111/j.1365-3059.2011.02463.x}, url = {http://dx.doi.org/10.1111/j.1365-3059.2011.02463.x}, author = {Rea, A. J. and Burgess, T. I. and Hardy, G. E. St J. and Stukely, M. J. C. and T. Jung} } @article {3961, title = {Phytophthora elongata sp. nov., a novel pathogen from the Eucalyptus marginata forest of Western Australia}, journal = {Australasian Plant Pathology}, volume = {39}, year = {2010}, pages = {477-491}, abstract = {

A novel homothallic species of Phytophthora producing semipapillate sporangia on sympodially branching sporangiophores, thick-walled oospores in smooth-walled oogonia, and paragynous antheridia is described here as Phytophthora elongata sp. nov. DNA sequencing of the internal transcribed spacer (ITS) DNA and coxI gene confirm P. elongata as a distinct species within ITS clade 2. It has been isolated in the northern jarrah forest of Western Australia (WA) from the roots and collars of dead and dying Eucalyptus marginata and occasionally Corymbia calophylla in rehabilitated bauxite mine pits. It has also been associated with dead and dying plants of several mid- and understorey species in the northern and southern jarrah forest{\textemdash}Banksia grandis, Leucopogon propinquus, Dryandra squarrosa and an Andersonia sp., as well as the monocotyledonous Xanthorrhoea preissii, X. gracilis and Patersonia xanthina. P. elongata has also been isolated from sandy soils and loams in Victoria in eastern Australia. The pathogenicity of P. elongata to E. marginata and Banksia spp. has been shown in this and earlier studies. Due to the uniformity of the ITS DNA and cox 1 sequence data in WA, P. elongata may be the result of a recent clonal introduction. More pathogenicity tests on a wider range of native plant species are needed to assess the host range of P. elongata and its invasive potential in WA.

}, keywords = {biosecurity, natural ecosystems, phylogenetics}, issn = {0815-3191}, doi = {10.1071/AP10014}, url = {http://dx.doi.org/10.1071/AP10014}, author = {Rea, Alexander J. and Thomas Jung and Burgess, Treena I. and Stukely, Michael J. C. and Hardy, Giles E. St J.} } @article {4482, title = {First Report of Phytophthora pseudosyringae Causing Stem Canker on Fagus sylvatica in Spain}, journal = {Plant Disease}, volume = {100}, year = {2016}, month = {Jan-07-2016}, pages = {1508 - 1508}, abstract = {

Phytophthora pseudosyringae T. Jung \& Delatour was described in 2003 as a pathogen associated with root and collar rot of several tree species (Fagus sylvatica, Alnus glutinosa, Quercus spp.) (Jung et al. 2003), and as the causal agent of stem lesions on beech in Europe (Scanu and Webber 2016). In August 2015, a beech (Fagus sylvatica L.) tree displaying 25\% crown dieback and a bleeding canker at the base of the stem was observed in a forested area used for recreational purpose in Central Pyrenees (42{\textdegree}36.87' N, 0{\textdegree}46.09' E, 1,546 m above sea level). Coarse sections of wood surrounding the bleeding patches were sampled and kept moist and cold for 5 days until processed. Once in the laboratory, small phloem pieces from the margin of the lesion were plated onto corn meal agar-PARPBH medium (Jeffers and Martin 1986) and incubated at 20{\textdegree}C. Growing hyphae were transferred to V8 agar and incubated at 20{\textdegree}C in darkness. Colony growth on V8 medium averaged 3.4 cm/week and had a distinct stellate pattern. Sporangia were sympodial, semipapillate, and ovoid, with a length/breadth average ratio of 1.41 μm (SE = 0.02). Oogonia were 21.9 μm (SE = 0.49) in diameter, smoothly walled, spherical, and with paraginous antheridia, although some amphiginous antheridia were observed. Morphological features and growth appearance on V8 corresponded to those reported for P. pseudosyringae (Jung et al. 2003). DNA was extracted from mycelium, and the ITS region was amplified using the ITS4 and ITS6 primers (Cooke et al. 2000). A BLAST search of the sequenced isolate (submitted to GenBank, Accession No. KU321521) showed 100\% identity with P. pseudosyringae ITS sequence (AY230190) from Jung et al. (2003). An under-bark inoculation test with mycelia plugs were performed on 16 excised shoots of 1 cm of diameter obtained from four different F. sylvatica trees. After 4 weeks, inoculated shoots displayed longer necrotic lesions than control inoculations with agar (3.55 cm SE: 2.2 versus 0.59 cm SE: 2.8, P \< 0.0001). The P. pseudosyringae inoculated shoots exhibited lesions that were dark red underneath the bark, whereas the control lesions did not. P. pseudosyringae, which was identified morphologically, was reisolated from 40\% of the infected shoots. No reisolation of the pathogen occurred from any of the six control shoots. Although previously detected in nursery stock on sweet chestnut (Castanea sativa) (Pintos Varela et al. 2007), our report represents the first report of P. pseudosyringae naturally affecting trees in Spain, and widens the geographical distribution of this pathogen in southwestern Europe. In Spain, F. sylvatica is the third species in terms of standing volume, where it covers 400,000 ha, mainly in the Pyrenees. Our finding proves the capacity of this pathogen to establish in nature, and it raises concern over the potential impact on beech forests in Spain.

}, issn = {0191-2917}, doi = {10.1094/PDIS-12-15-1497-PDN}, url = {http://apsjournals.apsnet.org/doi/10.1094/PDIS-12-15-1497-PDN}, author = {Redondo, {\'A}. and Oliva, J.} } @article {4321, title = {Winter Conditions Correlate with Phytophthora alni Subspecies Distribution in Southern Sweden}, journal = {Phytopathology}, volume = {105}, year = {2015}, month = {Jan-09-2015}, pages = {1191 - 1197}, abstract = {

During the last century, the number of forest pathogen invasions has increased substantially. Environmental variables can play a crucial role in determining the establishment of invasive species. The objective of the present work was to determine the correlation between winter climatic conditions and distribution of two subspecies of the invasive forest pathogen Phytophthora alni: P. alni subspp. alni and uniformis killing black alder (Alnus glutinosa) in southern Sweden. It is known from laboratory experiments that P. alni subsp. alni is more pathogenic than P. alni subsp. uniformis, and that P. alni subsp. alni is sensitive to low temperatures and long frost periods. By studying the distribution of these two subspecies at the northern limit of the host species, we could investigate whether winter conditions can affect the geographical distribution of P. alni subsp. alni spreading northward. Sixteen major river systems of southern Sweden were systematically surveyed and isolations were performed from active cankers. The distribution of the two studied subspecies was highly correlated with winter temperature and duration of periods with heavy frost. While P. alni subsp. uniformis covered the whole range of temperatures of the host, P. alni subsp. alni was recovered in areas subjected to milder winter temperatures and shorter frost periods. Our observations suggest that winter conditions can play an important role in limiting P. alni subsp. alni establishment in cold locations, thus affecting the distribution of the different subspecies of P. alni in boreal regions.

}, keywords = {Alnus spp., invasiveness, Phytophthora plurivora}, issn = {0031-949X}, doi = {10.1094/PHYTO-01-15-0020-R}, url = {http://apsjournals.apsnet.org/doi/10.1094/PHYTO-01-15-0020-R}, author = {Redondo, Miguel A. and Boberg, Johanna and Olsson, Christer H. B. and Oliva, Jon{\`a}s} } @article {4475, title = {First Report of Phytophthora pseudosyringae Causing Basal Cankers on Horse Chestnut in Sweden}, journal = {Plant Disease}, volume = {100}, year = {2016}, month = {Jan-05-2016}, pages = {1024}, abstract = {

Phytophthora pseudosyringae causes stem necrosis, and root and collar rot of several woody tree species (Fagus sylvatica, Alnus glutinosa, Castanea sativa, Nothofagus spp., and Quercus spp.) across Europe (Jung et al. 2003; Pintos Varela et al. 2007; Scanu and Webber 2015) and severe dieback of heathland plants such as bilberry (Vaccinium myrtillus) in the UK (Beales et al. 2010). In June 2014, a symptomatic horse chestnut tree (Aesculus hippocastanum) was detected in Sankt J{\"o}rgens Park in Gothenburg, southern Sweden (57{\textdegree}45'1.5" N; 11{\textdegree}57'8.1" E; elevation 22 m). The tree displayed 30\% crown dieback and several tongue -shaped necrosis at the base of the stem. The outer bark over the bleeding patches was removed and small pieces of infected phloem from the margin of the necrosis were directly plated onto CMA-PARPBH selective medium (17 g/liter corn meal agar (CMA), 0.125 g/liter sodium ampicillin, 0.02 g/liter benomyl, 0.07 g/liter hymexazol, 0.1 g/liter PCNB, 0.01 g/liter primaricin, and 0.01 g/liter rifamycin) and incubated at 20{\textdegree}C. Growing hyphae were later transferred to V8 agar and incubated at 20{\textdegree}C in darkness. After 7 days, the colony reached 5.4 cm in diameter and displayed a stellate growth pattern with faint aerial mycelium. Sporangia were sympodial, semipapillate, mostly ovoid, less commonly limoniform to ellipsoid, with a length/breadth average ratio of 1.44 μm (SE = 0.03). Oogonia were 28.1 μm (SE = 0.46) in diameter, smoothly walled, spherical, and with paraginous antheridia, although some amphiginous antheridia were observed. Morphological features and growth pattern on V8 agar corresponded to those of P. pseudosyringae. DNA was extracted from mycelia and the ITS region was amplified and sequenced using the ITS4 and ITS6f primers (Cooke et al. 2000) and deposited in GenBank (Accession No. KU257470). BLAST search showed 99 to 100\% identity with reference sequences of P. pseudosyringae deposited in GenBank. Under-bark inoculation with mycelium plugs was performed on 10 one-year-old excised shoots obtained from three different horse chestnut trees. Inoculated shoots were placed over autoclaved and moistened filter paper inside sterile Petri dishes and incubated at 23{\textdegree}C in darkness. After 14 days, the length of the lesion on inoculated shoots was significantly higher than on control shoots (8.53 mm, SE = 0.74 vs. 0.91 mm, SE = 0.93; P \< 0.0001). The pathogen was reisolated from all infected shoots fulfilling Koch postulates. To our knowledge, this is the first report of P. pseudosyringae in Sweden and the first report of P. pseudosyringae causing basal cankers and dieback on horse chestnut worldwide. The number of recent reports of damage caused by P. pseudosyringae raises concerns about the potential impact of this pathogen on horse chestnut trees, widely planted as ornamentals in Sweden, as well as to natural beech and oak forests across the country.

}, issn = {0191-2917}, doi = {10.1094/PDIS-09-15-1000-PDN}, url = {http://apsjournals.apsnet.org/doi/10.1094/PDIS-09-15-1000-PDN}, author = {Redondo, M. {\'A}. and Boberg, J. and Stenlid, J. and Oliva, J.} } @article {4554, title = {First Report of Phytophthora uniformis and P. plurivora Causing Stem Cankers on Alnus glutinosa in Denmark}, journal = {Plant Disease}, year = {2016}, month = {Aug-12-2017}, pages = {PDIS-09-16-1287}, abstract = {

Phytophthora uniformis (Brasier \& S.A. Kirk) Husson, Ioos \& Aguayo, comb. nov. is an aggressive pathogen associated with root and collar rot of alder trees (Alnus spp.) in Europe (Husson et al. 2015). In summer 2016, symptomatic trees were observed in the banks of a backwater lake area of the river Gurre {\r A} (56{\textdegree}1'46.24"N, 12{\textdegree}27'15.30"E, 29 m above sea level). Several trees displayed chlorosis, reduced leaf size, defoliation, and bleeding cankers on the base of the stem. Inspections upstream near Gurre forest failed in finding other trees with similar crown symptoms, whereas a tree with a bleeding canker was observed downstream (56{\textdegree}3'10.97"N, 12{\textdegree}26'4.40"E, 23 m above sea level). Bark from six trees in the first site and from the tree in the second site was removed from the canker area. As described in Redondo et al. (2015), pieces of 1 cm {\texttimes} 0.5 cm {\texttimes} 1 mm of necrotic cambial tissue from the infection front were plated directly into CMA-PARPBH selective medium. Growing hyphae were transferred onto V8 juice agar medium and incubated at 20{\textdegree}C. Isolates from the first site grew 5 mm/day and formed cottony uniform colonies. After 1 week, spherical smooth-walled oogonia often showing two-celled amphigynous antheridia developed profusely ({\O} 39.6 μm; SE = 0.84). Sporangia were ellipsoid and nonpapillate, often with nested proliferation. Colonies from the second site grew 5.5 mm/day, and formed a stellate colony pattern with limited aerial mycelium. Abundant spherical ({\O} 29.8 μm; SE = 0.53) oogonia with paragynous antheridia formed after 1 week. Sporangia were commonly ovoid and semipapillate. DNA was extracted from all isolates and the ITS region was amplified using the ITS4 and ITS6f primers. BLAST searches showed 99\% similarity with P. uniformis sequence no. AF139367.1 for the six isolates from the first site (GenBank accession nos. KX822022 to KX822027), and 99\% similarity with P. plurivora sequence no. FJ665227.1 for the isolate from the second site (KX822028). As morphological characteristics of the first six isolates corresponded to those of the P. alni species complex, primers TRP-PAU-F/-R and RAS-PAM1-F/-R (Ioos et al. 2006) were used to classify them as P. uniformis. ITS patterns from Jung and Burgess (2009) were used to classify the P. plurivora-like isolate as P. plurivora. Pathogenicity of two P. uniformis isolates and the P. plurivora isolate was confirmed by immersing 30 alder seedlings, grown in vermiculite for 3 weeks, in a zoospore suspension of each isolate adjusted to 3 {\texttimes} 104 zoospores ml{\textendash}1 for 3 h. Seedlings were later kept in dark Eppendorf tubes in sterile water, and rewatered daily. After 10 days, mortality was 76.6 and 86.6\% among those inoculated with P. uniformis, and 60\% for those inoculated with P. plurivora. Surviving seedlings after 10 days displayed wilting symptoms, while seedlings immersed in water were symptomless. The roots of the dead seedlings were plated onto CMA-PARPBH selective medium. Growing hyphae were observed in all plated roots, and were transferred to V8 juice agar medium. The reisolated Phytophthora colonies were morphologically similar to P. uniformis and P. plurivora, fulfilling Koch{\textquoteright}s postulates. Our finding raises concern about the future health of alder trees in Denmark, a country from which P. alni has not yet been reported. However, symptoms of Phytophthora disease have been observed on alder since 1995 (Thinggaard 1996). Further monitoring should investigate the extent of the outbreak.

}, issn = {0191-2917}, doi = {10.1094/PDIS-09-16-1287-PDN}, url = {http://apsjournals.apsnet.org/doi/10.1094/PDIS-09-16-1287-PDN}, author = {Redondo, {\'A}. and Thomsen, I. M. and Oliva, J.} } @proceedings {431, title = {Phytophthora species associated with stem cankers on tanoak in southwestern Oregon}, year = {2007}, address = {Santa Rosa CA}, author = {P. Reeser and Sutton, W. and Hansen, E.M.} } @article {PaulW. Reeser09012007, title = {Phytophthora siskiyouensis, a new species from soil, water, myrtlewood (Umbellularia californica) and tanoak (Lithocarpus densiflorus) in southwestern Oregon}, journal = {Mycologia}, volume = {99}, number = {5}, year = {2007}, pages = {639-643}, abstract = {

An unknown Phytophthora species was recovered in southwestern Oregon from rhododendron and tanoak leaf baits used for monitoring streams and soils for the presence of Phytophthora ramorum, from a blighted shoot of myrtlewood and from tanoak bark cankers. Isolates of this species yielded ITS-DNA sequences that differed substantially from other Phytophthora sequences in GenBank. Morphological features also differed from available descriptions of known Phytophthora species. Based on the combination of unique morphology and unique ITS sequences a new species is proposed. The new species, Phytophthora siskiyouensis, is homothallic with globose to subglobose oogonia, which may be terminal, sessile or laterally intercalary. Antheridia are capitate and mostly paragynous but sometimes amphigynous. Oospores are mostly aplerotic. Sporangia are variable but commonly ovoid to reniform, with apical, subapical or lateral semipapillae (occasionally more than one). Sporangia are terminal, subterminal or occasionally intercalary on unbranched sporangiophores, with basal, subbasal or lateral attachment. Sporangia are weakly deciduous, with variable length pedicels. This combination of characters clearly separates Phytophthora siskiyouensis from other known Phytophthora species.

}, doi = {10.3852/mycologia.99.5.639}, url = {http://www.mycologia.org/cgi/content/abstract/99/5/639}, author = {Reeser, Paul W. and Hansen, Everett M. and Sutton, Wendy} } @article {4186, title = {Phytophthora pluvialis, a new species from mixed tanoak-Douglas-fir forests of western Oregon, U.S.A.}, journal = {North American Fungi}, volume = {8(7)}, year = {2013}, month = {May/2013}, pages = {1-8}, abstract = {

A new species, Phytophthora pluvialis is described. P. pluvialis has been recovered from streams, soil and canopy drip in the mixed tanoak-Douglas-fir forest in Curry County, Oregon, and in two additional streams in other areas of western Oregon. It has been found only rarely in association with twig and stem cankers on tanoak but not with any other plant host. The earliest isolate of P. pluvialis was from soil in 2002. P. pluvialis is classified in ITS Clade 3.

}, keywords = {canopy drip, environmental Phytophthora, oomycetes, rainwater, soil, streams}, doi = {10.2509/naf2013.008.007}, url = {http://dx.doi.org/10.2509/naf2013.008.007}, author = {Reeser, P. and Sutton, Wendy and Hansen, Everett} } @article {1318, title = {Phytophthora species causing tanoak stem cankers in southwestern Oregon}, journal = {Plant Disease}, volume = {92}, year = {2008}, month = {08/2008}, pages = {1252}, abstract = {

Tanoak (Lithocarpus densiflorus) is a principal host of Phytophthora ramorum, cause of sudden oak death (SOD), in the western United States (1). In the course of SOD surveys in southwestern Oregon, other Phytophthora species were encountered to be causing stem cankers on tanoak that were indistinguishable from those caused by P. ramorum. In Oregon, SOD is subject to quarantine and eradication. Aerial surveys are flown two or more times a year to locate symptomatic tanoaks, which are then examined from the ground to determine the cause of death. Isolations on selective media were attempted from all trees with stem cankers typical of Phytophthora. Phytophthora species were identified by morphological features and DNA sequencing of either internal transcribed spacer (ITS) or the mitochondrial COX spacer region. ITS sequences were compared with validated GenBank records, and COX spacer sequences were compared with known reference isolates in the OSU collection. From 2001 through 2006, Phytophthora spp. were isolated from 482 of 1,057 tanoak stem cankers sampled. P. ramorum was isolated from 359 cankers, P. nemorosa was isolated from 102 cankers, P. gonapodyides was isolated from six cankers, P. cambivora was isolated from four cankers (all A1 mating type), P. siskiyouensis was isolated from four cankers, P. pseudosyringae was isolated from two cankers, P. cinnamomi was isolated from one canker (mating type A2), and P. taxon {\textquotedblleft}Pgchlamydo{\textquotedblright} was isolated from one canker. Three cankers yielded isolates that were not identified but were closely related to P. pseudosyringae based on ITS sequence. No Phytophthora spp. were cultured from the remaining cankers. One isolate from each species identified (except P. ramorum and P. pseudosyringae) was tested for pathogenicity on tanoak stems (11.4 to 16.0 cm DBH) in the field. A 5-mm-diameter plug from the margin of a V8 agar culture was placed in a hole in the bark, covered with wet cheesecloth, and sealed with aluminum foil and duct tape. Each isolate was inoculated into five different stems. Each stem received three different isolates and an agar control. After 4 weeks, bark was removed to reveal lesion development. Lesions were measured (length by width), and pieces from four points on the lesion margin were plated in selective media to reisolate. P. cambivora, P. cinnamomi, P. gonapodyides, P. nemorosa, P. siskiyouensis and P. taxon {\textquotedblleft}Pgchlamydo{\textquotedblright} all caused substantial lesions in inoculated tanoak trees (average area 11.5 to 18.6 cm2). In all cases, the species used for inoculation was recovered on reisolation from lesion margins. Control inoculations caused necrotic areas averaging 0.2 cm2. Isolations from these areas were clean. Prior to the recent SOD epidemic, no species of Phytophthora were known as pathogens of tanoak. The discovery of P. ramorum as a pathogen of tanoak in California was quickly followed by the discovery that P. nemorosa and P. pseudosyringae were also associated with tanoak cankers (2). Six years of diagnostic support for survey and detection of P. ramorum in tanoak forests of southwest Oregon has revealed the occurrence, at very low frequency, of at least five additional species of Phytophthora causing stem cankers in tanoak.

}, url = {http://dx.doi.org/10.1094/PDIS-92-8-1252B}, author = {Reeser, Paul W. and Sutton, W. and Hansen, E.M.} } @proceedings {225, title = {Phytophthora species in tanoak trees, canopy drip, soil, and streams in the sudden oak death epidemic area in southwestern Oregon.}, year = {2010}, publisher = {N. Z. J. Forestry}, address = {Auckland and Rotorua, New Zealand}, author = {Reeser, Paul and Sutton, Wendy and Everett Hansen} } @article {4315, title = {First Report of Phytophthora occultans Causing Root and Collar Rot on Ceanothus, Boxwood, Rhododendron, and Other Hosts in Horticultural Nurseries in Oregon, USA}, journal = {Plant Disease}, volume = {99}, year = {2015}, month = {Jan-09-2015}, pages = {1282}, abstract = {

Dead and dying Ceanothus sanguineus, C. velutinus, and C. integerrimus plants grown in a native plant nursery in Oregon for landscape restoration were reported in 2011. Plants were wilted with stem lesions above necrotic roots. Using selective media (Hansen et al. 2012), twelve similar Phytophthora isolates were obtained. DNA sequences of the cox 1, β tubulin, and the rDNA ITS regions were generated (Hansen et al. 2012). All isolates had identical ITS sequences (GenBank KP742989), and were identical to Phytophthora occultans (Man in{\textquoteright}t Veld et al. 2014) (JX978155) and 99\% similar to P. himalsilva (HM752784) in a BLAST analysis. They were also identical to P. occultans in cox 1 and β tubulin (KR028484 and KR028483). Isolates were homothallic, with smooth 30-{\textmu}m-diameter oogonia, and slightly aplerotic oospores. Antheridia were mostly paragynous. Colonies were stellate on carrot agar, growing 6 to 7 mm/d at optimum temperature (25{\textdegree}C). Sporangia were ovoid to irregular and papillate. Morphology and growth were consistent with P. occultans. Collections of unidentified Phytophthora spp. from the OSU Plant Clinic and from other Oregon nurseries (J. Parke et al. 2014) revealed additional isolates with similar morphology and identical DNA sequences. P. occultans was identified from boxwood (Buxus spp.), rhododendron, Gaultheria shallon, Arctostaphylos uva-ursi, and Mahonia nervosa in addition to Ceanothus spp. Two inoculation trials were conducted: (i) Healthy 1-year-old plants of C. sanguineus and C. velutinus were stem wound inoculated with two isolates of P. occultans from Ceanothus, or with sterile agar. There were 3 to 5 replications for each host and the control. The test was repeated with addition of two isolates from boxwood. (ii) Boxwood (B. sempervirens) and rhododendron (R. catawbiense Alba) were stem wound inoculated with two isolates each of P. occultans from Ceanothus and boxwood. There were four replications of each host for each isolate. All plants were incubated at 20 to 22{\textdegree}C. In test 1, all isolates induced stem lesions and wilting on all inoculated plants of both Ceanothus species. Wilting began in 14 days and lesions, measured at 19 days, averaged about 150 mm. There were no symptoms on control plants. In test 2, lesions developed on rhododendron stems, often girdling the stem within 12 days. Most boxwood showed no foliar symptoms or only mild yellowing, although stem lesions averaging 3.5 cm in 7 weeks were present on all plants. P. occultans was reisolated from all hosts in both tests. P. occultans was recently described from Buxus nursery stock in The Netherlands (Man in{\textquoteright}t Veld et al. 2014), and isolates with identical DNA sequences were reported from Germany and Romania (Nechwatal et al. 2014). This is the first report from North America. It appears that a single clone of P. occultans recently has been spread widely in the nursery trade. P. occultans is similar to P. himalsilva (Vettraino et al. 2011) and to other members of the poorly defined P. citrophthora clade. Phylogenetic analysis may revise species definitions. Nursery plants grown for wildland restoration are at high risk to carry exotic Phytophthora species into vulnerable landscapes. Forest restoration specialists must demand healthy stock from nurseries.

}, issn = {0191-2917}, doi = {10.1094/PDIS-02-15-0156-PDN}, url = {http://apsjournals.apsnet.org/doi/10.1094/PDIS-02-15-0156-PDN}, author = {Reeser, P. W. and Sutton, W. and Hansen, E. M. and Goheen, E. M. and Fieland, V. J. and Gr{\"u}nwald, N. J.} } @proceedings {reeser2010phytophthora, title = {Phytophthora siskiyouensis, a new species from soil and water in southwest Oregon}, volume = {General Technical Report PSW-GTR-214}, year = {2010}, month = {03/2008}, pages = {439{\textendash}441}, publisher = {U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station, Albany, CA}, address = {Santa Rosa, CA}, keywords = {coast live oak, invasive species, Phytophthora ramorum, Sudden oak death, tanoak}, url = {http://www.fs.fed.us/psw/publications/documents/psw_gtr214/}, author = {P. Reeser and E. Hansen and Sutton, W.}, editor = {Susan J. Frankel and John T. Kliejunas and Katharine M. Palmieri} } @article {4659, title = {Phytophthora species in forest streams in Oregon and Alaska}, journal = {Mycologia}, volume = {103}, year = {2011}, month = {Aug-01-2012}, pages = {22 - 35}, abstract = {

Eighteen Phytophthora species and one species of Halophytophthora were identified in 113 forest streams in Alaska, western Oregon and southwestern Oregon that were sampled by baiting or filtration of stream water with isolation on selective media. Species were identified by morphology and DNA characterization with single strand conformational polymorphism, COX spacer sequence and ITS sequence. ITS Clade 6 species were most abundant overall, but only four species, P. gonapodyides (37\% of all isolates), P. taxon Salixsoil, P. taxon Oaksoil and P. pseudosyringae, were found in all three regions. The species assemblages were similar in the two Oregon regions, but P. taxon Pgchlamydo was absent in Alaska and one new species present in Alaska was absent in Oregon streams. The number of Phytophthora propagules in Oregon streams varied by season and in SW Oregon, where sampling continued year round, P. taxon Salixsoil, P. nemorosa and P. siskiyouensis were recovered only in some seasons.

}, issn = {0027-5514}, doi = {10.3852/10-013}, url = {https://www.tandfonline.com/doi/pdf/10.3852/10-013}, author = {Reeser, Paul W. and Sutton, Wendy and Hansen, Everett M. and Remigi, Philippe and Adams, Gerry C.} } @article {PaulW.Reeser01012011, title = {Phytophthora species in forest streams in Oregon and Alaska}, journal = {Mycologia}, volume = {103}, number = {1}, year = {2011}, pages = {22-35}, abstract = {

Eighteen Phytophthora species and one species of Halophytophthora were identified in 113 forest streams in Alaska, western Oregon and southwestern Oregon that were sampled by baiting or filtration of stream water with isolation on selective media. Species were identified by morphology and DNA characterization with single strand conformational polymorphism, COX spacer sequence and ITS sequence. ITS Clade 6 species were most abundant overall, but only four species, P. gonapodyides (37\% of all isolates), P. taxon Salixsoil, P. taxon Oaksoil and P. pseudosyringae, were found in all three regions. The species assemblages were similar in the two Oregon regions, but P. taxon Pgchlamydo was absent in Alaska and one new species present in Alaska was absent in Oregon streams. The number of Phytophthora propagules in Oregon streams varied by season and in SW Oregon, where sampling continued year round, P. taxon Salixsoil, P. nemorosa and P. siskiyouensis were recovered only in some seasons.

}, doi = {10.3852/10-013}, url = {http://www.mycologia.org/cgi/content/abstract/103/1/22}, author = {Reeser, Paul W. and Sutton, Wendy and Hansen, Everett M. and Remigi, Philippe and Adams, Gerry C.} } @article {4256, title = {Comparative study of Phytophthora faberi on coconut and cacao in the Philippine Islands}, journal = {Journal of Agricultural Research }, volume = {25}, year = {1923}, pages = {267-284}, url = {http://worldcocoafoundation.org/wp-content/files_mf/reinking1923.pdf}, author = {Reinking, OA} } @article {4695, title = {Detection and spread of Phytophthora austrocedri within infected Juniperus communis woodland and diversity of co-associated Phytophthoras as revealed by metabarcoding}, journal = {Forest Pathology}, volume = {50}, year = {2020}, month = {May-17-2020}, pages = {e12602}, abstract = {

Phytophthora austrocedri is a recently invasive soilborne pathogen which is causing widespread mortality of Juniperus communis in northern Britain. The pathways by which a single genotype of P. austrocedri has spread to infect such a geographically dispersed range of woodland sites within a relatively short timeframe are unknown. This study examined the detectability of P. austrocedri in soil and water within infected J. communis woodland using qPCR to gain a better understanding of the pathogen{\textquoteright}s key mechanisms of spread. A Phytophthora metabarcoding method was also applied to investigate the wider diversity of Phytophthora species present in water at one of the sites. qPCR analyses of P. austrocedri in soil samples at a J. communis woodland exhibiting low-to-moderate levels of disease suggested a slow natural spread of the pathogen in soil, requiring high moisture conditions. However, the ubiquity of P. austrocedri DNA in soil samples collected across a heavily infected J. communis site suggests that once established at a site the pathogen can be spread readily in soil locally, most likely vectored by animal movements and/or human activities. The hypothesis that P. austrocedri is aerially transmitted in rainwater was not adequately proven, and an alternative hypothesis for the widespread distribution of the pathogen on J. communis in northern Britain is presented. Metabarcoding identified DNA from a diverse range of Phytophthora species in river and rainwater samples although the main target pathogen, P. austrocedri, was not amplified which disagreed with some of the qPCR findings. Possible reasons for this are discussed.

}, doi = {10.1111/efp.v50.310.1111/efp.12602}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/efp.12602}, author = {Riddell, Carolyn E. and Dun, Heather F. and Elliot, Matt and Armstrong, April C. and Clark, Mhairi and Forster, Jack and Hedley, Pete E. and Green, Sarah} } @article {4203, title = {In Situ Production of Zoospores by Five Species of Phytophthora in Aqueous Environments for Use as Inocula}, journal = {Plant Disease}, volume = {98}, year = {2014}, month = {Jan-04-2014}, pages = {551 - 558}, abstract = {

The goal of this study was to develop a procedure that could be used to evaluate the potential susceptibility of aquatic plants used in constructed wetlands to species of Phytophthora commonly found in nurseries. V8 agar plugs from actively growing cultures of three or four isolates of Phytophthora cinnamomi, P. citrophthora, P. cryptogea, P. nicotianae, and P. palmivora were used to produce inocula. In a laboratory experiment, plugs were placed in plastic cups and covered with 1.5\% nonsterile soil extract solution (SES) for 29 days, and zoospore presence and activity in the solution were monitored at 2- or 3-day intervals with a rhododendron leaf disk baiting bioassay. In a greenhouse experiment, plugs of each species of Phytophthora were placed in plastic pots and covered with either SES or Milli-Q water for 13 days during both summer and winter months, and zoospore presence in the solutions were monitored at 3-day intervals with the baiting bioassay and by filtration. Zoospores were present in solutions throughout the 29-day and 13-day experimental periods but consistency of zoospore release varied by species. In the laboratory experiment, colonization of leaf baits decreased over time for some species and often varied among isolates within a species. In the greenhouse experiment, bait colonization decreased over time in both summer and winter, varied among species of Phytophthora in the winter, and was better in Milli-Q water. Zoospore densities in solutions were greater in the summer than in the winter. Decreased zoospore activities for some species of Phytophthora were associated with prolonged temperatures below 13 or above 30{\textdegree}C in the greenhouse. Zoospores from plugs were released consistently in aqueous solutions for at least 13 days. This procedure can be used to provide in situ inocula for the five species of Phytophthora used in this study so that aquatic plant species can be evaluated for potential susceptibility.

}, issn = {0191-2917}, doi = {10.1094/PDIS-06-13-0591-RE}, url = {http://apsjournals.apsnet.org/doi/abs/10.1094/PDIS-06-13-0591-RE}, author = {Ridge, G. A. and Jeffers, S. N. and Bridges, W. C. and White, S. A.} } @article {727, title = {First Report of Phytophthora ramorum infecting grand fir in California}, journal = {Plant Health Progress}, volume = {2011}, year = {2011}, month = {1 April 2011}, publisher = {Plant Management Network}, abstract = {

Phytophthora ramorum was detected on grand fir in 2003 and 2005 in a Christmas tree plantation near Los Gatos, CA, in association with infected California bay laurel. Isolates derived from stem lesions were used to inoculate grand fir seedlings in two tests. Isolations from lesions on inoculated plants were positive for P. ramorum in both tests. This work provides the completion of Koch{\textquoteright}s postulates to establish grand fir as a host of P. ramorum. The potential for grand fir to be infected within its native range is unknown.

}, doi = {10.1094/PHP-2011-0401-01-BR}, url = {http://www.plantmanagementnetwork.org/sub/php/brief/2011/grand/}, author = {Kathleen L. Riley and Chastagner, Gary A. and Cheryl Blomquist} } @article {4479, title = {Screening brassicaceous plants as biofumigants for management of Phytophthora cinnamomi oak disease}, journal = {Forest Pathology}, year = {2016}, month = {Jan-06-2016}, abstract = {

Brassicaceous plants rich in glucosinolates have been used as biofumigants for the management of soilborne pathogens. Efficacy of Brassica plant tissue has mainly been attributed to toxic isothiocyanates released upon the hydrolysis of glucosinolates. Management of Phytophthora cinnamomi, the causal agent of oak root rot in rangeland ecosystems using biofumigation, is promising, but requires further validation. The biofumigation activity of 14 brassicaceous plants was evaluated under experimental conditions. All evaluated plants rich in sinigrin suppressed (100\%) the mycelial growth of P.\ cinnamomi, while plants rich in aromatic or other aliphatic glucosinolates had little or no suppressive effect. Simulating soil amendment in field conditions, the effects on natural soil artificially infested with P.\ cinnamomi chlamydospores were examined with Brassica juncea, Eruca vesicaria and Lepidium sativum, three species with different glucosinolate profiles. Only B.\ juncea decreased the viability of chlamydospores significantly in comparison with untreated soil only 1\ day after biofumigation, whereas E. vesicaria needed 8\ days to reach significance and L.\ sativum had no effect at all. Despite the decreases in soil inoculum, biofumigation with B.\ juncea did not prevent the root infections in a highly susceptible host (Lupinus luteus). However, biofumigation with plants rich in sinigrin, such as B.\ juncea, decreased P.\ cinnamomi soil inoculum under the experimental minimum threshold for oak disease expression. Although biofumigation should be considered as an effective measure to be incorporated in integrated control of the oak disease, biofumigation by itself would not be effective enough for the substantial suppression of P.\ cinnamomi inoculum.

}, doi = {10.1111/efp.12287}, url = {http://doi.wiley.com/10.1111/efp.12287http://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111\%2Fefp.12287}, author = {R{\'\i}os, P. and Obreg{\'o}n, S. and Gonz{\'a}lez, M. and de Haro, A. and Sanchez, M. E.}, editor = {Woodward, S.} } @article {4478, title = {Effect of Brassica Biofumigant Amendments on Different Stages of the Life Cycle of Phytophthora cinnamomi}, journal = {Journal of Phytopathology}, year = {2016}, month = {Jan-05-2016}, abstract = {

The oomycete plant pathogen Phytophthora cinnamomi causes a highly destructive root rot that affects numerous hosts. Integrated management strategies are needed to control P.\ cinnamomi in seminatural oak rangelands. We tested how biofumigation affects crucial stages of the pathogen{\textquoteright}s life cycle in\ vitro, in infested soils under laboratory conditions and in planta. Different genotypes of three potential biofumigant plant species (Brassica carinata, Brassica juncea, Brassica napus) were collected at different phenological stages, analysed for their glucosinolate contents, and subsequently tested. The most effective genotypes against mycelial growth and sporangial production were further tested on the viability of chlamydospores in artificially infested natural soils and in planta on Lupinus luteus, a host highly susceptible to P.cinnamomi. Brassica carinata and B.\ juncea genotypes inhibited mycelial growth, decreased sporangial production, and effectively inhibited the viability of chlamydospores in soil, but only B.\ carinata decreased disease symptoms in plants. Effective genotypes of Brassica had high levels of the glucosinolate sinigrin. Biofumigation with Brassica plants rich in sinigrin has potential to be a suitable tool for control of oak root disease caused by P.\ cinnamomi in Spanish oak rangeland ecosystems.

}, doi = {10.1111/jph.12482}, url = {http://doi.wiley.com/10.1111/jph.12482http://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111\%2Fjph.12482}, author = {R{\'\i}os, Pedro and Oberg{\'o}n, Sara and de Haro, Antonio and Fern{\'a}ndez-Rebollo, Pilar and Serrano, Mar{\'\i}a-Socorro and S{\'a}nchez, Mar{\'\i}a-Esperanza} } @article {1218, title = {A Lucid key to the common species of Phytophthora}, journal = {Plant Disease}, volume = {96}, year = {2012}, month = {06/2012}, pages = {897-903}, abstract = {

The Key to the Common Phytophthora species (Lucid v 3.4) is a matrix-based computerized identification key and includes important morphological and molecular characters that are useful for identification of 55 common species of Phytophthora. A set of 20 features are used to make a correct species identification. Once a culture is obtained, the user enters responses to known character state options into Lucid Player and the correct species is identified. Illustrations of each character state for a feature are included in the key. The main morphological features included in the key are: asexual structures, sexual structures, and chlamydospore, hyphae and cultural characteristics. The user can read an illustrated {\textquotedblleft}Fact Sheet{\textquotedblright} on each species that includes pictures of morphological characters, disease symptoms, host range and relevant references. A cross-linked glossary of terminology is included in each fact sheet. In addition, a DNA Search function that contains a simple search of ITS and Barcode of Life (BOL, 5{\textquoteright} end of the cox1 gene) sequences for each species can be queried. The key was created to provide teachers, diagnosticians and regulatory personnel with easily accessible tools to distinguish common species in the genus Phytophthora based on a number of important morphological and molecular characteristics. The key is available for purchase from APS Press and should provide another useful tool for the identification of members of this destructive group of Oomycete plant pathogens.

}, issn = {0191-2917}, doi = {10.1094/PDIS-08-11-0636}, url = {http://dx.doi.org/10.1094/PDIS-08-11-0636}, author = {Ristaino, Jean Beagle} } @article {rizzo2005phytophthora, title = {Phytophthora ramorum: integrative research and management of an emerging pathogen in California and Oregon forests}, journal = {Annual Review of Phytopathology}, volume = {43}, number = {1}, year = {2005}, pages = {309}, abstract = {

Phytophthora ramorum, causal agent of sudden oak death, is an emerging plant pathogen first observed in North America associated with mortality of tanoak (Lithocarpus densiflorus) and coast live oak (Quercus agrifolia) in coastal forests of California during the mid-1990s. The pathogen is now known to occur in North America and Europe and have a host range of over 40 plant genera. Sudden oak death has become an example of unintended linkages between the horticultural industry and potential impacts on forest ecosystems. This paper examines the biology and ecology of P. ramorum in California and Oregon forests as well discussing research on the pathogen in a broader management context.

}, doi = {10.1146/annurev.phyto.42.040803.140418}, url = {http://www.annualreviews.org/toc/phyto/43/1}, author = {D. M. Rizzo and Garbelotto, M. and Hansen, E.M.} } @article {doi:10.1094/PDIS.2002.86.3.205, title = {Phytophthora ramorum as the cause of extensive mortality of Quercus spp. and Lithocarpus densiflorus in California}, journal = {Plant Disease}, volume = {86}, number = {3}, year = {2002}, pages = {205-214}, abstract = {

A new canker disease, commonly known as sudden oak death, of Lithocarpus densiflorus, Quercus agrifolia, Q. kelloggii, and Q. parvula var. shrevei in California is shown to be caused by Phytophthora ramorum. The pathogen is a recently described species that previously was known only from Germany and the Netherlands on Rhododendron spp. and a Viburnum sp. This disease has reached epidemic proportions in forests along approximately 300 km of the central coast of California. The most consistent and diagnostic symptoms on trees are cankers that develop before foliage symptoms become evident. Cankers have brown or black discolored outer bark and seep dark red sap. Cankers occur on the trunk at the root crown up to 20 m above the ground, but do not enlarge below the soil line into the roots. Individual cankers are delimited by thin black lines in the inner bark and can be over 2 m in length. In L. densiflorus saplings, P. ramorum was isolated from branches as small as 5 mm in diameter. L. densiflorus and Q. agrifolia were inoculated with P. ramorum in the field and greenhouse, and symptoms similar to those of naturally infected trees developed. The pathogen was reisolated from the inoculated plants, which confirmed pathogenicity.

}, doi = {10.1094/PDIS.2002.86.3.205}, url = {http://apsjournals.apsnet.org/doi/abs/10.1094/PDIS.2002.86.3.205}, author = {D. M. Rizzo and Garbelotto, M. and J. M. Davidson and Slaughter, G. W. and Koike, S. T.} } @article {MEN:MEN3041, title = {DNA barcoding of oomycetes with cytochrome c oxidase subunit I and internal transcribed spacer}, journal = {Molecular Ecology Resources}, volume = {11}, number = {6}, year = {2011}, pages = {1002{\textendash}1011}, publisher = {Blackwell Publishing Ltd}, abstract = {

Oomycete species occupy many different environments and many ecological niches. The genera Phytophthora and Pythium for example, contain many plant pathogens which cause enormous damage to a wide range of plant species. Proper identification to the species level is a critical first step in any investigation of oomycetes, whether it is research driven or compelled by the need for rapid and accurate diagnostics during a pathogen outbreak. The use of DNA for oomycete species identification is well established, but DNA barcoding with cytochrome c oxidase subunit I (COI) is a relatively new approach that has yet to be assessed over a significant sample of oomycete genera. In this study we have sequenced COI, from 1205 isolates representing 23 genera. A comparison to internal transcribed spacer (ITS) sequences from the same isolates showed that COI identification is a practical option; complementary because it uses the mitochondrial genome instead of nuclear DNA. In some cases COI was more discriminative than ITS at the species level. This is in contrast to the large ribosomal subunit, which showed poor species resolution when sequenced from a subset of the isolates used in this study. The results described in this paper indicate that COI sequencing and the dataset generated are a valuable addition to the currently available oomycete taxonomy resources, and that both COI, the default DNA barcode supported by GenBank, and ITS, the de facto barcode accepted by the oomycete and mycology community, are acceptable and complementary DNA barcodes to be used for identification of oomycetes.

}, keywords = {cytochrome c oxidase subunit I, DNA barcoding, internal transcribed spacer, oomycete, species identification}, issn = {1755-0998}, doi = {10.1111/j.1755-0998.2011.03041.x}, url = {http://dx.doi.org/10.1111/j.1755-0998.2011.03041.x}, author = {Robideau, Gregg P. and De Cock, Arthur W. a. M. and Michael D. Coffey and Voglmayr, Hermann and Brouwer, Henk and Bala, Kanak and Chitty, David W. and D{\'e}saulniers, Nicole and Eggertson,Quinn A. and Gachon, Claire M. M. and Hu, Chia-Hui and K{\"u}pper, Frithjof C. and Rintoul, Tara L. and Sarhan, Ehab and Verstappen, Els C. P. and Zhang, Yonghong and Peter J.M. Bonants and Ristaino, Jean B. and Andr{\'e} L{\'e}vesque, C.} } @article {198, title = {Root and aerial infections of Chamaecyparis lawsoniana by Phytophthora lateralis: a new threat for European countries}, journal = {Forest Pathology}, volume = {41}, year = {2010}, month = {10/2011}, pages = {417{\textendash}424}, doi = {10.1111/j.1439-0329.2010.00688.x}, url = {http://dx.doi.org/10.1111/j.1439-0329.2010.00688.x}, author = {Robin, C. and Piou, D. and Feau, N. and Douzon, G. and Schenck, N. and Hansen, E.M.} } @article {doi:10.1139/x92-047, title = {Spatial and temporal enlargement of trunk cankers of Phytophthora cinnamomi in red oak}, journal = {Canadian Journal of Forest Research}, volume = {22}, number = {3}, year = {1992}, pages = {362-366}, abstract = {

Phytophthora cinnamomi Rands is the agent of ink disease on northern red oak (Quercus rubra L.). Cortical cankers on the trunk are the visible symptoms. The fungus causes necrosis of the cambium and phloem, and the tree reacts by forming xylem callus curls. These features can be dated aposteriori on cross sections. The aim of this study was to describe the spatial and temporal development of cankers on cross-sectioned infected oaks. For each lesion, dates of cambium necrosis and formation of callus were recorded at different heights. The following parameters were measured for each lesion: age, height, rate of development, and length and duration of necrosis and canker. Two hundred sixty-three lesions, on 14 trees, were studied. Trees did not exhibit cankers before 9 years of age. All visible trunk cankers could be related to a collar lesion. Phytophthora cinnamomi spreads upwards and can persist for several years, being active seasonally. In this study cambium necrosis occurred preferentially during the first flush. Twenty-nine percent of the lesions were healed over at the collar after 1 year. The collar was less susceptible than the trunk. The other lesions spread rapidly in the cambium of the trunk, which was very vulnerable. They then progressively healed. Therefore, the canker progress curve was bell shaped.

}, doi = {10.1139/x92-047}, url = {http://www.nrcresearchpress.com/doi/abs/10.1139/x92-047}, author = {Robin, C{\'e}cile and Desprez-Loustau, Marie-Laure and Delatour, Claude} } @article {doi:10.1139/x92-048, title = {Factors influencing the enlargement of trunk cankers of Phytophthora cinnamomi in red oak}, journal = {Canadian Journal of Forest Research}, volume = {22}, number = {3}, year = {1992}, pages = {367-374}, abstract = {

Development of cankers on red oak (Quercus rubra L.) caused by Phytophthora cinnamomi Rands was studied with dendrochronological techniques. Factors of variation among lesions were investigated. Lesion parameters proved to vary with the particular tree to which the lesion belonged. A discriminant factorial analysis and principal component analysis showed that this tree susceptibility was made up of two components. The first accounted for root infection and wound healing. The second concerned susceptibility to vertical spread of the pathogen in bark tissues. Relationships between (i) tree susceptibility and (ii) tree age and vigor were studied. From the occurrence of the first lesion at the collar, number and severity of lesions increased with time, following an exponential and logistic curve, respectively. A comparison of ring widths in infected and healthy trees showed that the disease had no detrimental effect on tree growth. However, annual necrosis length was positively correlated with the annual radial tree growth. The observed differences among trees could not be explained by the effects of time and vigor only. Temperature and drought were analyzed to determine their effect on lesion development. No direct effect of drought on this disease could be shown. The low cold hardiness of P. cinnamomi in the trunk was determined.

}, doi = {10.1139/x92-048}, url = {http://www.nrcresearchpress.com/doi/abs/10.1139/x92-048}, author = {Robin, C{\'e}cile and Desprez-Loustau, Marie-Laure and Delatour, Claude} } @article {4238, title = {Pathogenicity of Phytophthora lateralis lineages on resistant and susceptible selections of Chamaecyparis lawsoniana}, journal = {Plant Disease}, year = {2014}, month = {Oct-10-2015}, abstract = {

Phytophthora lateralis, the cause of Chamaecyparis lawsoniana root disease, was introduced in North America about 1950, and has since killed trees along roads and streams throughout the tree{\textquoteright}s range. Recent results suggest an Asian origin for this Oomycete and four genetic lineages were identified. This raised questions for the genetic exapted resistance demonstrated in 1989 within the wild population of C. lawsoniana but with only one P. lateralis lineage. The main goal of the present research was to test the durability of the demonstrated resistance and to compare the pathogenicity of isolates representing the four lineages. No breakdown of resistance was observed in five separate tests using different inoculation techniques, resistant and susceptible C. lawsoniana trees, and seedling families. Differences in mortality and lesion length were observed between the lineages. The higher aggressiveness of isolates of the TWJ and PNW lineages and the lower aggressiveness of the TWK lineage are discussed in view of the hypotheses on the history of spread and evolutionary history of the P. lateralis lineages.

}, issn = {0191-2917}, doi = {10.1094/PDIS-07-14-0720-RE}, url = {http://apsjournals.apsnet.org/doi/abs/10.1094/PDIS-07-14-0720-RE}, author = {Robin, C{\'e}cile and Brasier, Clive and Reeser, Paul W and Sutton, Wendy and Vannini, Andrea and Vettraino, Anna Maria and Hansen, Everett} } @article {EFP:EFP423, title = {Seasonal and spatial mortality patterns of holm oak seedlings in a reforested soil infected with Phytophthora cinnamomi}, journal = {Forest Pathology}, volume = {35}, number = {6}, year = {2005}, pages = {411{\textendash}422}, publisher = {Blackwell Verlag GmbH}, abstract = {

Summary The viability of 1-year-old holm oak (Quercus ilex) seedlings in a soil naturally infected with Phytophthora cinnamomi was studied during 2 consecutive years in a plot located in south-western Spain. In both years, total mortality during autumn and winter was not noticeable (\<2.1\%). In spring, mortality levels were higher (8.3{\textendash}4.6\%), especially the first year. A steep increase in total mortality occurred in summer, both in the first (11.4\%) and second (24.2\%) year, but mortality attributable to P. cinnamomi was 1.9 and 7.6\%, respectively. Thus, 2 years after planting, total cumulative mortality was 43.4\%, and that attributable to P. cinnamomi 9.6\% (i.e. 22.1\% of total mortality). Fungus-derived mortality followed a spatially aggregated pattern in the reforestation plot, suggesting a clustered distribution of the inoculum in the soil. Furthermore, mortality by P. cinnamomi was also associated with nearness of infected adult trees in the plot. Results obtained are discussed in the framework of seasonal water deficit, P. cinnamomi damage, weed competition and sanitation techniques to be used in declined holm oak stands in Spain.

}, issn = {1439-0329}, doi = {10.1111/j.1439-0329.2005.00423.x}, url = {http://dx.doi.org/10.1111/j.1439-0329.2005.00423.x}, author = {Rodr{\'\i}guez-Molina, M. C. and Blanco-Santos, A. and Palo-N{\'u}{\~n}ez, E. J. and Torres-Vila, L. M. and Torres-{\'A}lvarez, E. and Su{\'a}rez-de-la-C{\'a}mara, M. A.} } @article {4231, title = {The use of adjuvants to improve uptake of phosphorous acid applied to Pinus radiata needles for control of foliar Phytophthora diseases}, journal = {New Zealand Journal of Forestry Science}, volume = {44}, year = {2014}, month = {Jan-01-2014}, pages = {8}, abstract = {

Background

Phosphorous acid is being investigated as a fungicide for the management of a needle disease caused by Phytophthora pluvialis in Pinus radiata in New Zealand. However, little is known about the penetration characteristics of this fungicide into Pinus radiata foliage. This study was undertaken to determine: i) the penetration characteristics of a commercial phosphorous acid formulation, applied at 3\ kg\ ha-1 and 12\ kg\ ha-1 in 100\ L water, into Pinus radiata foliage and, ii) the effect of four commercially available adjuvants on phosphorous acid uptake into Pinus radiata foliage. Efficacy of the best treatment was tested in vitro with two Phytophthora species, Phytophthora kernoviae and P. pluvialis.

Methods

Foliar uptake of orthophosphoric acid radio-labelled with [32P] was used to determine penetration characteristics of phosphorous acid as affected by the adjuvants tested. Needles collected from potted Pinus radiata plants sprayed with the best performing treatment were used in a detached needle assay, where treated needles were exposed to the zoospores of the Phytophthora species being tested.

Results

Uptake of the phosphorous acid formulation into Pinus radiata needles applied without adjuvants was low (3.9-6.6\%) at both concentrations tested. An alcohol ethoxylate adjuvant (applied at 0.2\%) and two organosilicone adjuvants (applied at 0.2\%) were found to significantly increase uptake of the fungicide over that applied alone or in combination with pinolene (applied at 0.35\%). Highest uptake of phosphorous acid into Pinus radiata foliage (51.6\%) occurred over a period of 72\ hours when the phosphorous acid was applied at the equivalent of 12\ kg\ ha-1 with an organosilicone blend adjuvant at 0.2\%. A significant reduction in lesion length on infected needles was found relative to the control when the two phosphorous acid treatments were applied with 0.2\% organosilicone blend adjuvant. However, there were no significant differences in lesion length between the two treatments.

Conclusions

These results show that an organosilicone adjuvant significantly enhances uptake of phosphorous acid into Pinus radiata needles and may increase its efficacy against Phytophthora species.

}, issn = {1179-5395}, doi = {10.1186/s40490-014-0008-5}, url = {http://www.nzjforestryscience.com/content/44/1/8}, author = {Rolando, Carol and Gaskin, Robyn and Horgan, David and Williams, Nari and Bader, Martin} } @article {4477, title = {Comparison of Five Detection and Quantification Methods for Phytophthora ramorum in Stream and Irrigation Water}, journal = {Plant Disease}, volume = {100}, year = {2016}, month = {Jan-06-2016}, pages = {1202 - 1211}, abstract = {

Propagules of Phytophthora ramorum, the causal agent of sudden oak death (SOD) and ramorum blight, can be recovered from infested stream and nursery irrigation runoff using baiting and filtration methods. Five detection methods, including pear and rhododendron leaf baits, Bottle O{\textquoteright} Bait, filtration, and quantitative polymerase chain reaction (qPCR) performed on zoospores trapped on a filter were compared simultaneously in laboratory assays using lab or creek water spiked with known quantities of P. ramorum zoospores. The detection threshold for each method was determined and methods that could be used to quantify zoospore inoculum were identified. Filtration and qPCR were the most sensitive at detecting low levels of zoospores, followed by wounded rhododendron leaves, rhododendron leaf disks, and pear baits. Filtration, qPCR, and leaf disks were able to quantify P. ramorum zoospores ranging from 2 to 451 direct-plate CFU/liter while wounded leaves and pear baits appeared to be better at detection rather than quantification. The ability to detect and quantify P. ramorum inoculum in water will assist scientists, regulatory agencies, and nursery personnel in assessing the risk of spreading P. ramorum in nurseries and landscape sites where untreated infested water is used for irrigation.

}, issn = {0191-2917}, doi = {10.1094/PDIS-11-15-1380-RE}, url = {http://apsjournals.apsnet.org/doi/10.1094/PDIS-11-15-1380-RE}, author = {Rollins, Lucy and Coats, Katie and Elliott, Marianne and Chastagner, Gary} } @article {4492, title = {Potential risk of occurrence of Phytophthora alni in forests of the Czech Republic}, journal = {Journal of Maps}, year = {2016}, month = {Jun-06-2018}, pages = {1 - 5}, abstract = {

Phytophthora alni is an invasive organism that causes root and collar rot in alders, which significantly damages the forest and riparian vegetation of alder trees in Central and Western Europe. In the Czech Republic, this pathogen was first confirmed in 2001, and since then it has been gradually spreading from the west to the east. Here, we applied a model of potential distribution that estimates the level and spatial variability of the pathogen occurrence and spread risk for Czech Republic forests to target the early detection and control the further invasion of P. alni in this region. Our predictions are based on a rigorous statistical analysis of data obtained from field survey as well as available geodatabases. We used two sets of predictor variables describing (i) the forest stands and (ii) neighbourhood of the stands, and generalized linear modelling with forward stepwise selection of predictors. The results of statistical analysis showed the significant effect of the area of the forest stand, forest vegetation zone, presence of watercourse and area of alder stands in the neighbourhood on the probability of occurrence of P. alni in the study region. The map derived based on the final model shows the potential risk of occurrence and impact of P. alni in forests of the Czech Republic as classified on a five-point scale ranging from very low risk for alder stands with a low level of likely invasion to very sensitive alder stands with high probability of pathogen occurrence and high levels of damage. This is a unique output not only for the Czech Republic but also throughout Europe.

}, doi = {10.1080/17445647.2016.1198996}, url = {http://www.tandfonline.com/doi/full/10.1080/17445647.2016.1198996}, author = {Romportl, Du{\v s}an and Chumanov{\'a}, Eva and Havrdov{\'a}, Ludmila and Pe{\v s}kov{\'a}, V{\'\i}t{\v e}zslava and {\v C}ern{\'y}, Karel} } @article {213, title = {Collar rot on Italian alder trees in California caused by Phytophthora siskiyouensis}, journal = {Plant Health Progress}, year = {2009}, publisher = {Plant Management Network}, abstract = {

In November 2006, trees of Italian alder (Alnus cordata) were observed declining in association with bleeding trunk cankers in a commercial landscape in Foster City, CA. A species of Phytophthora was isolated on PARP selective medium from the leading edge of the cankers. The Phytophthora species was homothallic with primarily paragynous antheridia and had oospores that were mostly globose and aplerotic. Sporangia were produced from mycelia on plugs of carrot piece agar in soil extraction solution and were semi-papillate and ovoid to ellipsoid in shape. The intergenic transcribed spacer region of rDNA from an alder isolate matched with 100\% identity to isolates in GenBank of Phytophthora siskiyouensis, a recently described species associated with tanoak and found in the soil and waterways of coastal Oregon. Pathogenicity was tested on young alder trees growing in pots. Pathogenicity was confirmed on Italian alder trees and potential pathogenicity was demonstrated on red and white alder trees.

}, doi = {10.1094/PHP-2009-0413-01-RS}, url = {http://www.plantmanagementnetwork.org/sub/php/research/2009/alder/}, author = {Suzanne Rooney-Latham and Cheryl L. Blomquist and Tomas Pastalka and Laurence Costello} } @article {4337, title = {First detection in the US: new plant pathogen, Phytophthora tentaculata, in native plant nurseries and restoration sites in California}, journal = {Native Plants Journal}, volume = {16}, year = {2015}, month = {Jan-03-2015}, pages = {23 - 27}, abstract = {

Phytophthora tentaculata Kr{\"o}ber \& Marwitz (Pythiaceae) has been detected in several native plant nurseries in 4 California counties and in restoration sites on orange sticky monkey flower (Diplacus aurantiacus (W. Curtis) Jeps. subsp. aurantiacus [Scrophulariaceae]), toyon (Heteromeles arbutifolia (Lindl.) M. Roem. [Rosaceae]), coffeeberry (Frangula californica (Eschsch.) A. Gray [Rhamnaceae]), and sage (Salvia spp. L. [Lamiaceae]). These findings are the first detections of P. tentaculata in the US and the first ever on these host plants. Phytophthora species are a known problem in horticultural nurseries, but little attention has been placed on native plant or restoration nurseries. The potential for plant pathogens to be outplanted along with native plant nursery stock is very high, posing a threat to neighboring forests.

}, issn = {1522-8339}, doi = {10.3368/npj.16.1.23}, url = {http://npj.uwpress.org/cgi/doi/10.3368/npj.16.1.23}, author = {Rooney-Latham, S. and Blomquist, C. L. and Swiecki, T. and Bernhardt, E. and Frankel, S. J.} } @proceedings {370, title = {First report of Phytophthora siskiyouensis causing disease on Italian alder in Foster City, California}, volume = {Phytopathology 97: S101.}, year = {2007}, month = {July 28{\textendash}August}, publisher = {APS Press, American Phytopathological Society}, address = {San Diego, California}, abstract = {

Phytophthora species cause cankers on the stems of many forest and landscape trees. In November of 2006, Italian alder trees, Alnus cordata, were reported to be dying with symptoms of bleeding cankers located at the base of the stem. The trees were located in a business development outside of a library in Foster City, California. Several of the trees had already been removed as hazardous. Successful isolations were made at the leading edge of the canker from the wood cambium interface onto PARP selective medium. A homothallic Phytophthora with primarily paragynous antheridia grew out in the media. The sporangia, produced easily on carrot agar plugs in soil water were ovoid to ellipsoid in shape. Oospores were mostly globose and aplerotic. The intergenic transcribed spacer region of rDNA of the oomycete matched with 100\% identity to Phytophthora siskiyouensis, a pathogen associated with tan oak and also found in the soil and water in coastal Oregon. Pathogenicity experiments were conducted on Italian, red and white alder. This Phytophthora may be endemic to California. Foster City shares a marine- influenced climate with coastal Oregon.

}, url = {http://apsjournals.apsnet.org/doi/pdf/10.1094/PHYTO.2007.97.7.S1}, author = {Rooney-Latham, S and C. L. Blomquist and T. Pastalka and L. R. Costello} } @article {4336, title = {First Report of Root and Stem Rot Caused by Phytophthora tentaculata on Mimulus aurantiacus in North America}, journal = {Plant Disease}, volume = {98}, year = {2014}, month = {Jan-07-2014}, pages = {996 - 996}, abstract = {

Sticky monkey flower plant, Mimulus aurantiacus (Phrymaceae), is a small, perennial shrub that is widely distributed throughout California, especially in coastal and disturbed habitats. It is also found in native plantings in parks and landscapes. In October 2012, nearly all the M. aurantiacus plants grown in a Monterey County, CA nursery for a restoration project were stunted and had dull, yellowish leaves. Roots and stem collars had necrotic, sunken lesions with few feeder roots. Thirty percent of the plants had died. Samples of diseased plants were sent to the CDFA-PPDC Lab and tested positive for Phytophthora sp. using the Agdia ELISA Phytophthora kit (Agdia, Elkhart, IN). A Phytophthora sp. was consistently isolated from the tissue on corn meal agar-PARP (CMA-PARP) (2). Sporangia were spherical to ovoid, papillate to bipapillate and 17 to 42.5 (avg. 27.5) {\texttimes} 12 to 35 (avg. 22.9) μm, with a length/breadth ratio of 1.2:1. Chlamydospores, which were spherical, terminal to intercalary, thin walled and 27.5 to 40 μm, and hyphal swellings formed on CMA-PARP. Spherical oospores, 25 to 36 μm, with primarily paragynous antheridia formed readily on V8 juice agar. rDNA sequences of the internal transcribed spacer (ITS) region of the isolates (GenBank KF667505), amplified using primers ITS1 and ITS4, were 100\% identical to Phytophthora tentaculata (CBS 552.96, GenBank AF266775) by a BLAST query (1,3). To assess pathogenicity, exposed root crowns of three 3.78-liter potted M. aurantiacus plants were inoculated with 20 ml of zoospore suspension (2 {\texttimes} 104 ml-1). Plants were maintained in a 23{\textdegree}C growth chamber with a 12-h photoperiod and watered daily. Sterile water was applied to the exposed crowns of three control plants. At 2 weeks, all inoculated plants were wilted with chlorotic foliage. After 3 weeks, the cortical tissue of the crowns and roots was discolored and sloughing and P. tentaculata was recovered on CMA-PARP. P. tentaculata did not grow from the asymptomatic control plants. Inoculations were repeated with similar results. P. tentaculata is a homothallic species in Phytophthora clade 1 that causes crown, root, and stalk rot of nursery plants in Europe and China (1,4). A USDA PERAL analysis lists it as one of the top 5 Phytophthora species of concern to the United States (4). Genera infected with P. tentaculata include Apium, Aucklandia, Chicorium, Chrysanthemum, Delphinium, Gerbera, Lavandula, Santolina, Origanum, and Verbena (4). To our knowledge, this is the first report of P. tentaculata in North America. The source of inoculum of P. tentaculata in California remains unknown. The nursery used seed and cuttings of M. aurantiacus from nearby native areas for propagation, and P. tentaculata was not found in neighboring plant hosts or by baiting soil and water at the nursery. All infected M. aurantiacus material was destroyed. The presence of P. tentaculata in California nurseries could have serious economic impacts on the nursery industry and environmental impacts on susceptible native hosts, if spread into the wildlands.

}, issn = {0191-2917}, doi = {10.1094/PDIS-09-13-1002-PDN}, url = {http://apsjournals.apsnet.org/doi/abs/10.1094/PDIS-09-13-1002-PDN}, author = {Rooney-Latham, S. and Blomquist, C. L.} } @article {4217, title = {Studies of the genus Phytophthora}, journal = {Journal of Agricultural Research }, volume = {8}, year = {1917}, pages = {233-276}, author = {Rosenbaum, J.} } @article {4705, title = {Sporulation potential of Phytophthora ramorum differs among common California plant species in the Big Sur region}, journal = {Plant Disease}, year = {2020}, month = {Nov-17-2020}, abstract = {

Sudden oak death (SOD), caused by the generalist pathogen Phytophthora ramorum, has profoundly impacted California coastal ecosystems. SOD has largely been treated as a two-host system, with Umbellularia californica as the most transmissive host, Notholithocarpus densiflorus less so, and remaining species as epidemiologically unimportant. However, this understanding of transmission potential primarily stems from observational field studies rather than direct measurements on the diverse assemblage of plant species. Here, we formally quantify the sporulation potential of common plant species inhabiting SOD-endemic ecosystems on the California coast in the Big Sur region. This study allows us to better understand the pathogen{\textquoteright}s basic biology, trajectory of SOD in a changing environment, and how the entire host community contributes to disease risk. Leaves were inoculated in a controlled laboratory environment and assessed for production of sporangia and chlamydospores, the infectious and resistant propagules, respectively. P. ramorum was capable of infecting every species in our study and almost all species produced spores to some extent. Sporangia production was greatest in N. densiflorus and U. californica and the difference was insignificant. Even though other species produced much less, quantities were non-zero. Thus, additional species may play a previously unrecognized role in local transmission. Chlamydospore production was highest in Acer macrophyllum and Ceanothus oliganthus, raising questions about the role they play in pathogen persistence. Lesion size did not consistently correlate with the production of either sporangia or chlamydospores. Overall, we achieved an empirical foundation to better understand how community composition affects transmission of P. ramorum.

}, issn = {0191-2917}, doi = {10.1094/PDIS-03-20-0485-RE}, url = {https://apsjournals.apsnet.org/doi/10.1094/PDIS-03-20-0485-RE}, author = {Rosenthal, Lisa Micaela and Fajardo, Sebastian N. and Rizzo, David} } @article {415, title = {Spatial pattern of Austrocedrus chilensis wilting and the scope of autocorrelation analysis in natural forests}, journal = {Forest Ecology and Management}, volume = {67}, year = {1994}, month = {AUG 1994}, pages = {273-279}, issn = {0378-1127}, url = {http://dx.doi.org.proxy.library.oregonstate.edu/10.1016/0378-1127(94)90022-1}, author = {Rosso, P. H. and Baccal{\'a}, N and Havrylenko, M and Fontenla, S} } @article {Roth:1 June 1966:0015-749X:147, title = {Phytophthora cinnamomi, an unlikely threat to Douglas-fir forestry}, journal = {Forest Science}, volume = {12}, year = {1966}, pages = {147-159(13)}, abstract = {

Phytophthora cinnamomi has damaged forests around the world in regions with mild climates. Its pathogenesis on Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) in southern Europe and southeastern United States suggested a potential threat to Douglas-fir forests of the Pacific Coast. Concern increased in 1950 with discovery of P. cinnamomi in nurseries growing ornamentals and in landscape plantings in western Oregon and Washington and research was undertaken to evaluate the threat. A temperature of 60{\textdegree} F was found necessary for infection. While summer soil temperatures on south exposures are above 60{\textdegree} F most of the time from June to October soil moisture is continuously below field capacity and too dry for infection. On north exposures summer soil moisture is adequate but temperatures are too low; 60{\textdegree} F is reached for only a few hours near the first of August. Forest soils of western Oregon are generally too dry for infection during the summer. The fall rains provide necessary moisture but concurrently depress temperatures below the critical 60{\textdegree} F. Adverse soil temperature and moisture influence disease by impeding infection rather than reducing survival of P. cinnamomi. The disease in ornamentals is sustained by summer irrigation of warm locations such as the south side of buildings. The data show that P. cinnamomi is unlikely to become a problem in forests of the Pacific Northwest.

}, url = {http://www.ingentaconnect.com/content/saf/fs/1966/00000012/00000002/art00005}, author = {Roth, Lewis F. and Kuhlman, E. George} } @article {241, title = {Port-Orford-cedar disease}, year = {1987}, publisher = {U.S. Department of Agriculture, Forest Service, Pacific Northwest Region}, issn = {Forest Pest Management Report No. R6 FPM PR 010 91}, url = {http://www.fs.fed.us/r6/nr/fid/fidls/poc.htm}, author = {L.F. Roth and Harvey,R.D. and J.T. Kliejunas} } @article {4515, title = {Survey and virulence of fungi occurring on diseased Acacia mearnsii in South Africa}, journal = {Forest Ecology and Management}, volume = {99}, year = {1997}, month = {Jan-12-1997}, pages = {327 - 336}, abstract = {

Various disease symptoms occur on Acacia mearnsii in South Africa, of which black butt, on older trees, is the most common. Other less commonly reported symptoms include gummosis, cracks, discoloured lesions and die-back. These diseases are of unknown aetiology. During a 2-year period, a survey of diseases on A. mearnsii was conducted in two major commercial wattle-growing areas of South Africa. Samples were collected from all symptomatic tissue on randomly selected trees in each area. A wide range of fungi were isolated, including species of Phytophthora, Seiridium, Sphaeropsis, Fusarium, Diplodia, Ceratocystis and Botryosphaeria. Of these, Phytophthora spp. were isolated only from basal lesions and soil, whereas the Diplodia and Fusarium spp. were the most frequently isolated from diseased tissue on aboveground parts of trees. Phytophthora parasitica and Ceratocystis albofundus, which are well-known pathogens of A. mearnsii, were excluded from the pathogenicity tests. All other fungi isolated, and particularly those belonging to genera that are known plant pathogens, were used in pathogenicity tests to determine their possible role in diseases. For each isolate, 20 saplings were inoculated in the field, and the resultant lesion lengths were measured. Only the Phytophthora spp., Botryosphaeria sp. and Sphaeropsis sp. produced noticeable lesions. From the surveys and pathogenicity tests, it is clear that many fungi are associated with diseases of A. mearnsii, and that these deserve further study.

}, issn = {03781127}, doi = {10.1016/S0378-1127(97)00110-2}, url = {https://doi.org/10.1016/s0378-1127(97)00110-2 }, author = {Roux, Jolanda and Wingfield, Michael J.} } @article {4085, title = {Irrigation water and Phytophthora cactorum in a forest nursery}, journal = {Scandinavian Journal of Forest Research}, volume = {23}, year = {2008}, month = {10/2008}, pages = {404 - 411}, abstract = {

Phytophthora cactorum (Lebert and Cohn) J. Schr{\"o}t is known to cause stem lesions on Betula pendula Roth in Finnish nurseries. It has been suggested that irrigation water may be one source of infection. Therefore, P. cactorum was baited from pond water used for irrigation and direct isolations were made from necrotic stem lesions in a forest nursery during the years 2004{\textendash}2006. Morphological characteristics, as well as sequencing of the β-tubulin gene and ITS1 region, confirmed the isolates as P. cactorum. The pathogen was present in the pond every year, but no diseased seedlings were found in 2005. The cultural and morphological characteristics showed high variation among the isolates, but it was not possible to identify the origins of the isolates according to them. In random amplified microsatellite (RAMS) analysis and DNA sequencing, the isolates from the pond and from the stem lesions were genetically similar, and the tested isolates were pathogenic. The results indicate that irrigation water is one source of stem lesion disease, and the microbe can overwinter in the pond. Two separate forms of the β-tubulin gene were detected in all the studied isolates, suggesting that the P. cactorum here carries two β-tubulin gene loci in its genome.

}, issn = {0282-7581}, doi = {10.1080/02827580802419034}, url = {http://www.tandfonline.com/doi/abs/10.1080/02827580802419034$\#$.UqfxDo25Ibg}, author = {Rytk{\"o}nen, Anna and Lilja, Arja and Pet{\"a}ist{\"o}, Raija-Liisa and Hantula, Jarkko} } @article {2753228920071201, title = {Phytophthora cambivora in Oregon and its pathogenicity to Chrysolepis chrysophylla.}, journal = {Forest Pathology}, volume = {37}, number = {6}, year = {2007}, pages = {409 - 419}, abstract = {

A new canker disease causing mortality of golden chinquapin trees [Chrysolepis chrysophylla (Dougl.) Hjelmqvist], in Oregon was recently observed. Most of the symptomatic or dead trees were located near roads. The cankers on the lower boles of trees are similar to those caused by species of Phytophthora on other trees in western North America. The cankers in the inner bark were reddish-orange in colour and extended upward from necrotic roots. Phytophthora (Petri) Buisman was isolated from the cankers; identity was confirmed by morphological comparison with known isolates and internal transcribed spacer sequence analysis. Pathogenicity was confirmed by inoculation of chinquapin seedlings and mature trees. Seven of nine isolates from chinquapin were A2 mating type; 27 of 28 isolates from other hosts in Oregon and Washington were A1 mating type.

}, keywords = {Biodiversity, Canker (Plant disease), diseases, Forests. forestry, Oregon, Pathogenic microorganisms, pests, PLANT diseases}, issn = {14374781}, doi = {10.1111/j.1439-0329.2007.00515.x}, url = {http://onlinelibrary.wiley.com.proxy.library.oregonstate.edu/doi/10.1111/j.1439-0329.2007.00515.x/abstract}, author = {Saavedra, A. and Hansen, E.M. and Goheen, D. J.} } @article {EFP:EFP261, title = {Phytophthora disease of Quercus ilex in south-western Spain}, journal = {Forest Pathology}, volume = {32}, number = {1}, year = {2002}, pages = {5{\textendash}18}, publisher = {Blackwell Science Ltd.}, abstract = {

Oak decline that was affecting three holm oak sites in the province of Huelva (south-western Spain) was studied during 1998{\textendash}1999. The syndromes of dieback and sudden death have been observed and, in both cases, foliar symptoms were associated with root rot. Characterization of the fungal isolates from necrotic roots led us to identify Phytophthora cinnamomi A2 as consistently associated with the disease. The optimum growth temperatures of these isolates were very high (30{\textdegree}C). Inoculation tests under controlled conditions demonstrated the pathogenicity of the isolates on holm and cork oak seedlings. None of the other biotic factors of Mediterranean oak decline that have been previously described were found in the present study and so, in this case, the forest decline model does not seem to be necessary in order to explain the disease observed. The defoliation and mortality of the oaks was primarily caused by P. cinnamomi, although some abiotic factors such as alternating periods of drought and wet weather in the region may play an important role.

}, issn = {1439-0329}, doi = {10.1046/j.1439-0329.2002.00261.x}, url = {http://dx.doi.org/10.1046/j.1439-0329.2002.00261.x}, author = {Sanchez, M. E. and Caetano, P. and Ferraz, J. and Trapero, A.} } @article {4471, title = {Phytophthora kernoviae isolated from fallen leaves of Drymis winteri in native forest of southern Chile}, journal = {Australasian Plant Disease Notes}, volume = {11}, year = {2016}, month = {Jan-06-2016}, abstract = {

Phytophthora kernoviae is an invasive species first described from Britain and later New Zealand. We conducted surveys for Phytophthora species in forests in southern Chile. Symptomatic fallen leaves of Drimys winteri were encountered in a native forest. P. kernoviae was isolated. This is the first report of P. kernoviae outside of UK and New Zealand.

}, doi = {10.1007/s13314-016-0205-6}, url = {http://link.springer.com/10.1007/s13314-016-0205-6}, author = {Sanfuentes, E. and Fajardo, S. and Sabag, M. and Hansen, E. and Gonz{\'a}lez, M.} } @article {599, title = {Report on the risk of entry, establishment, spread and socio-economic loss and environmental impact and the appropriate level of management for Phytophthora ramorum for the EU.}, volume = {Deliverable Report 28}, year = {2009}, pages = {311 p.}, address = {Sand Hutton, York, UK}, url = {http://rapra.csl.gov.uk/RAPRA-PRA_26feb09.pdf}, author = {Sansford, C.E. and Inman, A..J. and Baker, R. and Brasier, C. and Frankel, S. and de Gruyter, J. and Husson, C. and Kehlenbeck, H. and Kessel, G. and Moralejo, E. and Steeghs, M. and Webber, J. and Werres, S.}, editor = {Forest Research, Central Science Laboratory and EU Sixth Framework Project, RAPRA} } @article {387, title = {Susceptibility of some mesophilic hardwoods to alder Phytophthora}, journal = {Journal of Phytopathology}, volume = {151}, year = {2003}, month = {08/2003}, pages = {406{\textendash}410}, abstract = {

Abstract Inoculation tests were carried out in the greenhouse on seedlings of five hardwoods (Alnus cordata, A. glutinosa, Castanea sativa, Juglans regia and Quercus robur) to determine their susceptibility to an isolate of alder Phytophthora obtained in Italy from A. cordata. A Phytophthora cinnamomi strain was used for comparison. Host susceptibility to infection was determined as the lesion length after stem inoculation and the percentage of necrotized rootlets after soil infestation with inoculated millet seeds. The aggressiveness of the alder Phytophthora isolate was significantly higher in the two Alnus species than in the other hosts. Our results were confirmed with both methods of inoculation. Alnus cordata was consistently the most susceptible host species when compared with the other hardwoods. Damage by P. cinnamomi was severe, particularly after soil infestation tests. The most susceptible species were alders, chestnut and walnut. The test also suggests that alder Phytophthora is able to spread through infected seedlings of different hardwood species.

}, keywords = {Alnus cordata, Alnus glutinosa, Castanea sativa, Hardwoods, inoculation test, Juglans regia, Phytophthora cinnamomi, Phytophthora spp., Quercus robur}, doi = {10.1046/j.1439-0434.2003.00739.x}, url = {http://dx.doi.org/10.1046/j.1439-0434.2003.00739.x}, author = {Santini, Alberto and Barzanti, Gian Paolo and Capretti, Paolo} } @article {doi:10.1094/PDIS.2001.85.5.560A, title = {A new Phytophthora root disease of alder in Italy}, journal = {Plant Disease}, volume = {85}, number = {5}, year = {2001}, pages = {560-560}, doi = {10.1094/PDIS.2001.85.5.560A}, url = {http://apsjournals.apsnet.org/doi/abs/10.1094/PDIS.2001.85.5.560A}, author = {Santini, A. and Barzanti, G. P. and Capretti, P.} } @article {388, title = {Pathogenicity of four Phytophthora species on wild cherry and Italian alder seedlings}, journal = {Journal of Phytopathology}, volume = {154}, year = {2006}, month = {03/2006}, pages = {163{\textendash}167}, abstract = {

Abstract Inoculation tests were carried out in the greenhouse on wild cherry (Prunus avium) and Italian alder (Alnus cordata) seedlings, to determine their susceptibility to certain Phytophthora species (P. citrophthora, P. alni, P. megasperma and P. cinnamomi) that are commonly present in the soil. Host susceptibility was evaluated in accordance with a disease index, with the lesion length after stem inoculation, and with a root system disease index. Wild cherry was found to be highly susceptible to P. citrophthora, and was also found to be susceptible to P. alni, although to a lesser extent. Italian alder was very susceptible to P. alni, but had only low susceptibility to P. citrophthora. The other Phytophthora species caused only modest symptoms. The danger to alder and wild cherry is all the greater because these trees not only share the same pathogens, but also commonly planted together in mixed stands. The results will now have to be confirmed by using a more natural inoculation method.

}, keywords = {Alnus cordata, inoculation test, pathogenicity, Phytophthora, Prunus avium}, doi = {10.1111/j.1439-0434.2006.01077.x}, url = {http://dx.doi.org/10.1111/j.1439-0434.2006.01077.x}, author = {Santini, A. and Biancalani, F. and Barzanti, G. P. and Capretti, P.} } @article {4504, title = {A gomose da ac{\'a}cia-negra no Brasil: a review}, journal = {Summa Phytopathologica}, volume = {33}, year = {2007}, month = {Jan-01-2007}, pages = {113 - 118}, abstract = {

A ac{\'a}cia-negra (Acacia mearnsii) {\'e} cultivada no Brasil, especialmente no Estado do Rio Grande do Sul, visando tanto {\`a} produ{\c c}{\~a}o de tanino, a partir da casca, quanto o uso da madeira para papel, celulose, carv{\~a}o, lenha e chapas de aglomerados. A gomose causada por Phytophthora nicotianae e P. boehmeriae, {\'e} o seu principal problema fitossanit{\'a}rio. Discute-se nesta revis{\~a}o a exist{\^e}ncia de dois padr{\~o}es distintos de sintomatologia da gomose de Phytophthora que t{\^e}m sido observados nas planta{\c c}{\~o}es brasileiras: gomose basal, associada a P. nicotianae, e gomose generalizada, mais associada a P. boehmeriae. S{\~a}o discutidos aspectos relacionados {\`a} etiologia, {\`a} epidemiologia e {\`a}s estrat{\'e}gias de controle.

The black wattle (Acacia mearnsii ) is cultivated in Brazil for bark tannin, paper, cellulose, plywood, charcoal and firewood production. Gummosis of Phytophthora, caused by P. nicotianae and P. boehmeriae is the main disease problem on black wattle. The existence of two distinct symptom patterns observed on plants in the commercial fields are: butt gummosis which is associated with P. nicotianae and general gummosis more related to P. boehmeriae. Etiological, epidemiological and control aspects of this disease are presented and discussed on this review.

}, issn = {0100-5405}, doi = {10.1590/S0100-54052007000200002}, url = {https://doi.org/10.1590/s0100-54052007000200002 }, author = {Santos, A. F. dos and Luz, E. D. M. N.} } @article {4503, title = {First report of Phytophthora boehmeriae on black wattle in Brazil}, journal = {Plant Pathology}, volume = {55}, year = {2006}, month = {Jan-12-2006}, pages = {813 - 813}, abstract = {

Black wattle (Acacia mearnsii) is an Australian tree species cultivated in several countries. In Brazil, particularly in Rio Grande do Sul State (RS), approximately 140\ 000 ha are cultivated for tannin extraction (Dos Santos et\ al., 2005).

The gummosis complex, which has Phytophthora nicotianae as one of the causal agents, is the main disease of black wattle in Brazil and is characterised by lesions at the trunk base with gum exudation (Dos Santos et\ al., 2005). Different symptoms were observed in plantations at the municipality of Piratini, RS (southern Brazil) and were characterised by dark lesions without gum exudation on trunks of 3- to 4-year-old wattle trees up to 10 m height. Isolates of Phytophthora spp. were obtained from the lesions and deposited in the Brazilian collection of Phytophthora species, under accession numbers CBP 307, 308 and 309. Sporangia of all isolates were ovoid to spherical, papillate and caducous, measuring 35 {\textmu}m {\textpm} 1{\textperiodcentered}42 {\texttimes} 30 {\textmu}m {\textpm} 1{\textperiodcentered}37, with a length/width ratio of 1{\textperiodcentered}16:1, mean depth of papillae of 4{\textperiodcentered}83 {\textmu}m {\textpm} 0{\textperiodcentered}04, and pore exit of 4{\textperiodcentered}69 {\textmu}m {\textpm} 0{\textperiodcentered}04. The isolates were homothallic, forming plerotic oospores with smooth walls and amphigynous antheridia. The ITS sequences obtained for isolates CBP 307 (AY428533), CBP 308 (AY428534), and CBP 309 (AY428535) were identical and most closely matched those of two isolates of P. boehmeriae KACC40173 (AY228076) from Korea and SCRP23 (DQ297406) from China. This and the morphological similarity (Erwin \& Ribeiro, 1996) suggest that these isolates are P. boehmeriae. However, seven clear single base pair differences were noted between the Brazilian and other P. boehmeriae isolates. This, combined with isozyme variation (Oudemans \& Coffey, 1991) suggests that further studies are needed to confirm the taxonomic status of P. boehmeriae.

Pathogenicity tests were done by inoculating five 1-year-old wattle plants with 7 mm mycelial discs of 5-day old cultures of the three isolates used in this study. The mycelial discs were placed in 7 mm diameter holes made in the bark with a cork borer, at 5 cm above the soil. Plants were maintained at approximately 25{\textdegree}C and were assessed 45 days after inoculation. All three isolates were pathogenic to black wattle and were re-isolated from the lesions.

Phytophthora boehmeriae was reported as one of the causal agents of the gummosis complex on black wattle in South Africa (TPCP, 2004) and is of quarantine importance for the citrus industry in Brazil. This is the first report of the involvement of P. boehmeriae in the aetiology of the gummosis complex of black wattle in Brazil.

}, issn = {0032-0862}, doi = {10.1111/j.1365-3059.2006.01462.x}, url = {http://onlinelibrary.wiley.com/doi/10.1111/j.1365-3059.2006.01462.x/full}, author = {Santos, A. F. dos and Luz, E. D. M. N. and Souza, J. T.} } @article {SANTOS2004, title = {Primeiro relato da podrida da estipe da pupunheira, causada por Phytophthora palmivora, no estado do Parana{\textquoteleft}}, journal = {Fitopatologia Brasileira}, volume = {29}, year = {2004}, month = {12}, pages = {680 - 682}, publisher = {scielo}, abstract = {

Phytophthora palmivora was isolated from infected peach palm (Bactris gasipaes) plants with stem rot symptoms in Paran{\'a} State, in 2002. Pathogenicity tests and subsequent reisolations of P. palmivora confirmed the hypothesis that this fungus was the causal agent of the disease. This is the first report of P. palmivora causing stem rot on peach palm (Bactris gasipaes) in the southern State of Paran{\'a}. RESUMO Phytophthora palmivora foi isolado de plantas de pupunheira (Bactris gasipaes) com sintomas de podrid{\~a}o da estipe, no Paran{\'a}, em 2002. Testes de patogenicidade e o subseq{\"u}ente reisolamento do fungo confirmaram a hip{\'o}tese de que P. palmivora {\'e} o agente causal da podrid{\~a}o do estipe. Este {\'e} o primeiro relato de P. palmivora causando podrid{\~a}o do estipe na pupunheira no estado do Paran{\'a}.

}, issn = {0100-4158}, url = {http://www.scielo.br/scielo.php?script=sci_arttext\&pid=S0100-41582004000600016\&nrm=iso}, author = {Santos, A. F. dos and Luz, Edna Dora. M. N. and Finato, Priscila D. and Tessmann, Dauri J. and Vida, J. B.} } @article {4524, title = {O complexo gomose da ac{\'a}cia-negra}, journal = {Colombo-PR: Embrapa Florestas}, volume = {Circular T{\'e}cnica, 44}, year = {2001}, pages = {8 pp.}, abstract = {

A ac{\'a}cia-negra {\'e} uma esp{\'e}cie florestal que foi introduzida no Brasil, no Estado do Rio Grande do Sul, na d{\'e}cada de 30. Atualmente, com uma {\'a}rea plantada de aproximadamente 100.000 ha, envolve cerca de 10 mil pequenos produtores rurais (Higa \& Dedecek, 1999), compondo um dos maci{\c c}os florestais daquele Estado, onde desempenha importante papel s{\'o}cio-econ{\^o}mico para as pequenas propriedades rurais (Fleig, 1993).

O r{\'a}pido crescimento da ac{\'a}cia-negra, associado ao aproveitamento integral da madeira, torna essa esp{\'e}cie ideal para reflorestamento e para utiliza{\c c}{\~a}o industrial. Sua contribui{\c c}{\~a}o aos mais variados segmentos econ{\^o}micos e industriais {\'e} ampla, tanto pelo aproveitamento da casca para extra{\c c}{\~a}o do tanino (a casca possui cerca de 28\% de tanino), quanto pelo uso da madeira para diversos fins, tais como a fabrica{\c c}{\~a}o de papel e celulose, chapas de aglomerados, carv{\~a}o e lenha. No Brasil, {\'e} plantada principalmente para produ{\c c}{\~a}o de tanino.

A ac{\'a}cia-negra {\'e} uma planta que exsuda goma na casca do tronco. A goma {\'e} aparentemente produzida pelas {\'a}rvores em resposta a alguma condi{\c c}{\~a}o anormal, como pat{\'o}genos ou inj{\'u}rias provocadas por insetos, danos mec{\^a}nicos ou fatores externos que afetam o seu crescimento (Zeijlemaker, 1968). Quimicamente, a goma da ac{\'a}cia-negra {\'e} uma combina{\c c}{\~a}o de arabinose, galactose, ramnose e {\'a}cido glucur{\^o}nico (Stephen 1951). A quantidade de goma produzida por uma {\'a}rvore depende da caracter{\'\i}stica gen{\'e}tica do material e da influ{\^e}ncia de fatores ambientais, tais como a temperatura e a disponibilidade de umidade.

Como resultado, tem-se pouca goma no per{\'\i}odo seco, enquanto muita goma pode ser exsudada no per{\'\i}odo {\'u}mido (Zeijlemaker, 1968). Um dos principais problemas da ac{\'a}cia-negra {\'e} a doen{\c c}a conhecida como gomose de Phytophthora sp. (Santos et al., 1998). Os sintomas ocorrem no tronco e se caracterizam por les{\~o}es necr{\'o}ticas na casca, chegando a atingir o lenho. A abundante exsuda{\c c}{\~a}o gomosa {\'e} o sintoma mais caracter{\'\i}stico dessa doen{\c c}a, que {\'e} facilmente confundido com outros problemas, uma vez que o tronco da ac{\'a}cia-negra exsuda goma quando lesionado por a{\c c}{\~a}o tanto bi{\'o}tica quanto abi{\'o}tica. Assim sendo, embora a les{\~a}o exsudativa seja o tipo de sintoma mais caracter{\'\i}stico da gomose de Phytophthora, essa n{\~a}o {\'e} uma caracter{\'\i}stica exclusiva como indicadora da associa{\c c}{\~a}o Phytophthora -ac{\'a}cia. Portanto, este trabalho tem o objetivo de discutir aspectos relacionados {\`a} gomose de Phytophthora e aos de outros tipos de problemas associados {\`a} ac{\'a}cia-negra e que tenham a exsuda{\c c}{\~a}o de goma como parte de seu quadro sintomatol{\'o}gico, de maneira que se possam elucid{\'a}-los, para facilitar a sua identifica{\c c}{\~a}o no camp.

}, issn = {1517-5278}, url = {https://core.ac.uk/download/pdf/15427678.pdf}, author = {Santos, A. F. dos and Grigoletti, A. Jr. and Auer, CG} } @article {4528, title = {Comportamento diferenciado da gomose de Phytophthora em diferentes alturas ao longo de troncos de ac{\'a}cia-negra (Acacia mearnsii) em Piratini, RS}, journal = {Boletim de Pesquisa Florestal }, volume = {43}, year = {2001}, pages = {145-149}, abstract = {

The symptoms of gummosis of Phytophthora of black wattle (Acacia mearnsii) occur\  predominantly\  in\  the\  basal\  region of\  the\  trunk.\  The\  highest\  severity\  is usually observed in the basal section (up to 0,50 m from ground level, along the trunk). Black wattle gummosis was observed in trees growing at Piratini, RS, in 1998. In this case, a different kind of symptoms was observed: necrotic lesions occurring severily in heights above the basal section of the trunks. Phytophthora was isolated from diseased bark from differents heights of the trunk up to 10 m. All isolates of Phytophthora showed\  pathogenicity to black wattle.

Os sintomas da gomose de Phytophthora da ac{\'a}cia-negra (Acacia mearnsii) ocorrem predominantemente na regi{\~a}o basal do tronco das {\'a}rvores, com maior severidade na por{\c c}{\~a}o que vai do colo at{\'e} 0,50 m de altura. No ano de 1998, na regi{\~a}o de Piratini-RS, ocorreu um surto de gomose em {\'a}rvores adultas, caracterizando-se pela predomin{\^a}ncia de les{\~o}es necr{\'o}ticas, n{\~a}o exsudativas, atingindo severamente alturas superiores {\`a}quelas normalmente encontradas nos troncos. Procedeu-se a uma coleta sistematizada de amostras de casca de troncos de {\'a}rvores com sintomas, na regi{\~a}o do colo, aos 2 m, aos 4 m, aos 6 m, aos 8 m e aos 10 m de altura. Nos isolamentos e testes de patogencidade feitos, confirmouse a associa{\c c}{\~a}o de Phytophthora {\`a}s les{\~o}es.

}, url = {http://ainfo.cnptia.embrapa.br/digital/bitstream/CNPF-2009-09/30242/1/santos.pdf}, author = {Santos, A. F. dos} } @article {4519, title = {Gomose da ac{\'a}cia-negra: etiologia, an{\'a}lise temporal, perdas e controle gen{\'e}tico.}, journal = {Boletim de Pesquisa e Desenvolvimento, Embrapa Florestas, Minist{\'e}rio da Agricultura}, volume = {31}, year = {2007}, pages = {28 p.}, abstract = {

Gummosis is one of the most serious phytosanitary problems of black wattle (Acacia mearnsii) in the State of Rio Grande do Sul, Brazil. The objectives of this work were: 1) to identify the species of Phytophthora associated with gummosis; 2) to analyze the temporal distribution of the gummosis; 3) to quantify losses caused by this disease; and 4) to rank black wattle lines based on resistance to gummosis. The major results were: Phytophthora nicotianae and P. boehmeriae are the causal agent of gummosis on black-wattle in Brazil. This disease was found in all the surveyed black-wattle plantations and the species P. nicotianae was the major species found in the samples, suggesting that this is the main species causing this disease in Brazil. It was found two kinds of symptoms: 1) gummosis at the base of the trunks, associated to P. nicotianae; e 2) gummosis spread on the trunk, associated to P. boehmeriae. Plants killed by gummosis or other causes showed exponential growth, and started to die after 34 months. Plants showing gummosis had losses ranging from 3,5 to 0,5\% for bark and timber production, respectively. Both, natural and artificial inoculations assays showed variation on the resistance of plants to gummosis.

A gomose {\'e} um dos mais s{\'e}rios problemas fitossanit{\'a}rios da ac{\'a}cia-negra (Acacia mearnsii) no Rio Grande do Sul. Este trabalho teve como objetivos: 1) identificar a(s) esp{\'e}cie(s) de Phytophthora associada(s) {\`a} gomose; 2) analisar a distribui{\c c}{\~a}o temporal da gomose; 3) quantificar as perdas causadas pela doen{\c c}a; e 4) agrupar os materiais gen{\'e}ticos de ac{\'a}cia-negra de acordo com o n{\'\i}vel de resist{\^e}ncia {\`a} gomose. Os principais resultados foram: Phytophthora nicotianae e P.boehmeriae s{\~a}o os agentes causais da gomose da ac{\'a}cia-negra no Brasil. A gomose de Phytophthora foi encontrada em todos os plantios de ac{\'a}cia-negra e, no levantamento, evidenciou-se a predomin{\^a}ncia de P. nicotianae, mostrando que este pat{\'o}geno {\'e} o principal agente da gomose da ac{\'a}cia-negra no Brasil. As avalia{\c c}{\~o}es em plantios comerciais em idade de corte apresentaram at{\'e} 48 \% de indiv{\'\i}duos atacados. Tanto plantas mortas por outras causas quanto plantas mortas por gomose cresceram exponencialmente, e as mortes come{\c c}aram a partir do 34{\textordmasculine} m{\^e}s. Os dados mostraram perdas de produ{\c c}{\~a}o de at{\'e} 3,5 \% para casca e at{\'e} 0,5 \% para madeira nas {\'a}rvores com gomose. Tanto por infec{\c c}{\~a}o natural quanto por inocula{\c c}{\~a}o artificial, ocorreram varia{\c c}{\~o}es entre as proced{\^e}ncias quanto a resist{\^e}ncia {\`a} gomose.

}, issn = { 1980-041X}, url = {http://www.infoteca.cnptia.embrapa.br/infoteca/bitstream/doc/312305/1/BPD31CD.pdf}, author = {Santos, A. F. dos and Luz, E.D.M.N. and Maffia, L.A. and Souza, J.T.} } @article {4514, title = {Phytophthora nicotianae: agente etiol{\'o}gico da gomose da ac{\'a}cia negra no Brasil}, journal = {Fitopatologia Brasileira}, volume = {30}, year = {2005}, pages = {81{\textendash}4}, abstract = {

A gomose, causada por Phytophthora sp., {\'e} a mais importante enfermidade da ac{\'a}cia-negra (Acacia mearnsii) no Rio Grande do Sul, Brasil. A identifica{\c c}{\~a}o espec{\'\i}fica permanecia indeterminada. Procurou-se, ent{\~a}o, identificar a esp{\'e}cie de Phytophthora causadora desta doen{\c c}a no Rio Grande do Sul, usando caracter{\'\i}sticas fisiomorfol{\'o}gicas e estudos moleculares baseados no seq{\"u}enciamento das regi{\~o}es de Internal Transcribed Spacer (ITS). A patogenicidade dos isolados estudados para a ac{\'a}cia-negra foi confirmada. Os estudos confirmaram Phytophthora nicotianae como a correta identidade dos isolados fitopatog{\^e}nicos. Este {\'e} o primeiro relato de P. nicotianae em ac{\'a}cia-negra no Brasil.

Gummosis caused by Phytophthora sp. is the most important disease of black wattle (Acacia mearnsii) in Rio Grande do Sul, Brazil. Isolates of Phytophthora sp. associated with diseased plants were obtained from Rio Grande do Sul and their pathogenicity was confirmed. In order to elucidate the correct identity of the fungus at the species level physiomorphological characteristics were determined and molecular studies were conducted based on sequences of Internal Transcribed Spacer (ITS) region. The fungus was identified as Phytophthora nicotianae. This is the first report of P. nicotianae on black wattle in Brazil.

}, issn = {1982-5676 }, doi = {10.1590/s0100-41582005000100015 }, url = {https://doi.org/10.1590/s0100-41582005000100015 }, author = {Santos, A. F. dos and Luz, EDMN and Souza, J. T.} } @conference {4526, title = {Phytophthora spp: distribui{\c c}{\~a}o e associa{\c c}{\~a}o com esp{\'e}cies florestais}, booktitle = {Congresso Brasileiro de Fitopatologia, 47}, year = {2014}, publisher = {Sociedade Brasileira de Fitopatologia}, organization = {Sociedade Brasileira de Fitopatologia}, address = {Londrina, Brazil}, url = {http://www.alice.cnptia.embrapa.br/handle/doc/993792}, author = {Santos, A. F. dos and Luz, EDMN and Reis, A.} } @article {JPH:JPH1741, title = {Root and crown rot of Brazilian pine (Araucaria angustifolia) caused by Phytophthora cinnamomi}, journal = {Journal of Phytopathology}, volume = {159}, number = {3}, year = {2011}, pages = {194{\textendash}196}, publisher = {Blackwell Publishing Ltd}, abstract = {

In an area reforested with Brazilian pine (Araucaria angustifolia) located in Paran√{\textdegree} State, southern Brazil, 20- to 40-year-old trees representing 0.2\% of the surveyed area had symptoms of root and crown rot, yellowing and browning of leaves from the uppermost branches and death. Three Phytophthora isolates obtained from diseased plant tissue were tested against 1-year-old Brazilian pine seedlings and found to display positive pathogenicity. Based on their morphological and physiological characteristics, the isolates were identified as Phytophthora cinnamomi. A GenBank BLAST search of partial sequences from the β-tubulin and elongation factor-1α genes, as well as the ITS regions and 5.8S gene of rDNA, confirmed the species identification. This is the first report of the involvement of this pathogen on the aetiology of Brazilian pine root and crown rot.

}, keywords = {chromistan fungi, forest pathology, fungal plant pathogen}, issn = {1439-0434}, doi = {10.1111/j.1439-0434.2010.01741.x}, url = {http://dx.doi.org/10.1111/j.1439-0434.2010.01741.x}, author = {Santos, A. F. dos and Tessmann, Dauri J. and Alves, Tatiane C. A. and Vida, Jo{\~a}o B. and Harakava, Ricardo} } @article {4007, title = {Occurrence of Phytophthora cinnamomi in cork oak forests in Italy}, journal = {Forest Pathology}, volume = {43}, year = {2013}, month = {08/2013}, pages = {340{\textendash}343}, abstract = {

An increasing decline and mortality of cork oak trees have been recently observed in central Italy and Sardinia Island. Following surveys conducted in three declining cork oak forests, a Phytophthora species was consistently isolated from soil samples collected from trees displaying different level of decline. Based on morphological features, growth rates at different temperatures and analysis of DNA sequences of the ITS region, all isolates were identified as Phytophthora cinnamomi Rands. This pathogen caused large brownish lesions on inoculated freshly cut branches of cork oak. It was re-isolated from all infected tissues. These findings represent the first report of P.\ cinnamomi on cork oak trees in Italy.

}, doi = {10.1111/efp.12039}, url = {http://onlinelibrary.wiley.com/doi/10.1111/efp.12039/abstract}, author = {Scanu, B. and Linaldeddu, B. T. and Franceschini, A. and Anselmi, N. and A. Vannini and A.M. Vettraino}, editor = {Belbahri, L.} } @article {4033, title = {A taxonomic re-evaluation reveals that Phytophthora cinnamomi and P.~cinnamomi var. parvispora are separate species}, journal = {Forest Pathology}, year = {2013}, month = {07/2013}, pages = {n/a - n/a}, abstract = {

Between 2008 and 2011, severe dieback associated with root and collar rot was reported on Arbutus unedo in several sites in Sardinia, Italy. Isolations from infected tissues and rhizosphere soil samples consistently yielded a Phytophthora species. It was initially identified as Phytophthora cinnamomi var. parvispora Kr{\"o}ber and Marwitz by comparing morphological features with the original description and the internal transcribed spacer (ITS) sequences with those present in GenBank. A multigene phylogeny based on DNA sequence data from two nuclear (ITS and β-tubulin) and two mitochondrial (cox1 and cox2) gene regions combined with extensive morphological and physiological properties of these isolates, including the ex-type culture of P.\ cinnamomi var. parvispora, demonstrates that this taxon is unique and it is redesignated here as Phytophthora parvispora sp. nov. Although morphologically similar to P.\ cinnamomi, P.\ parvispora differs by its smaller-sized sporangia, chlamydospores, oogonia and oospores, higher oospore wall index, single-celled antheridia, higher minimum and maximum temperatures for growth and faster growth at optimum temperature. In the phylogeny, P.\ parvispora falls within Phytophthora ITS clade 7a, grouped in a well-supported clade sister to P.\ cinnamomi. In pathogenicity tests, P.\ parvispora and P.\ cinnamomi were equally aggressive towards A.\ unedo seedlings. The possible geographic origin of P.\ parvispora is also discussed.

}, doi = {10.1111/efp.12064}, url = {http://onlinelibrary.wiley.com/doi/10.1111/efp.12064/abstract}, author = {Scanu, B. and Hunter, G. C. and Linaldeddu, B. T. and Franceschini, A. and Maddau, L. and T. Jung and Denman, S.}, editor = {Andrea, V.} } @article {4448, title = {Dieback and mortality of Nothofagus in Britain: ecology, pathogenicity and sporulation potential of the causal agent Phytophthora pseudosyringae}, journal = {Plant Pathology}, volume = {65}, year = {2016}, month = {Jan-01-2016}, pages = {26 - 36}, abstract = {

Since 2009 extensive dieback and mortality of Nothofagus obliqua, associated with bleeding cankers on stems and branches, has been observed in the UK. The causal agent was identified as Phytophthora pseudosyringae, based on morphological and analysis of the internal transcribed spacer (ITS) sequences. Between 2011 and 2013, a survey assessed the frequency and nature of these P. pseudosyringae infections. Mature trees of Nothofagus with stem lesions caused by P. pseudosyringae were found across England, Scotland and Wales. Additional symptoms such as twig blight and leaf necrosis indicated that aerial infection was occurring. Besides N. obliqua, other hosts regularly encountered included Nothofagus alpina, Fagus sylvatica and Vaccinium myrtillus. In pathogenicity tests involving inoculation of logs, P. pseudosyringae was shown to be an aggressive bark pathogen of N. obliqua and F. sylvatica, but significantly less aggressive on N. alpina. Foliage susceptibility and sporulation tests showed marked differences between the six host species tested. Leaves of N. obliqua and V. myrtillus were highly susceptible. Leaves of N. alpina were moderately susceptible, those of Rhododendron ponticum slightly susceptible and those of F. sylvatica not susceptible at all. High levels of sporulation were observed only on inoculated N. obliqua and V. myrtillus leaves. This suggests that P. pseudosyringae may sporulate heavily on N. obliqua foliage in the field and that this inoculum initiates the aerial lesions observed on the shoots, branches and stems. The results also suggest that P. pseudosyringae has the potential to pose a serious threat to N. obliqua and other Nothofagus species in their Southern Hemisphere native ranges.

}, doi = {10.1111/ppa.12399}, url = {http://doi.wiley.com/10.1111/ppa.12399http://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111\%2Fppa.12399}, author = {Scanu, B. and Webber, J. F.} } @article {EFP:EFP784, title = {Detecting asymptomatic ink-diseased chestnut trees by the composition of the ectomycorrhizal community}, journal = {Forest Pathology}, year = {2012}, pages = {n/a{\textendash}n/a}, abstract = {The research was performed in a new and isolated ink disease outbreak. Nine sweet chestnuts of comparable age, growing under same environmental and site conditions, and belonging to three phytosanitary classes (healthy, infected but asymptomatic and symptomatic) were randomly selected. Their ectomycorrhizal community was monitored during two periods, with regard to species abundance, to verify whether the community composition can be useful as an ink disease bioindicator. From the 216 samples, 29 ectomycorrhizal species were recorded, with abundances that changed with the health status of the tree. The results demonstrated that the mycorrhizal community composition was highly related to the ink disease level, allowing the consideration of the use of this parameter as a tool for the quick detection and control of the early stages of the disease.}, issn = {1439-0329}, doi = {10.1111/j.1439-0329.2012.00784.x}, url = {http://dx.doi.org/10.1111/j.1439-0329.2012.00784.x}, author = {Scattolin, L. and Dal Maso, E. and Mutto Accordi, S. and Sella, L. and Montecchio, L.} } @article {4624, title = {First Report of Phytophthora ramorum Causing Japanese Larch Dieback in France}, journal = {Plant Disease}, year = {2018}, month = {Aug-08-2018}, pages = {PDIS-02-18-0288}, abstract = {

Phytophthora ramorum Werres, De Cock \& Man in{\textquoteright}t Veld, an oomycete known in the United States as the causal agent of sudden oak death, has spread across Europe since the early 2000s. It is responsible for damage and death to a wide range of plant species, including mature trees. In 2009 it was identified on Japanese larch (Larix kaempferi) in southwest England (Webber et al. 2010), and since then it has caused severe damage and losses to Larix spp. in the United Kingdom and the Republic of Ireland. There are two lineages of the oomycete, EU1 and EU2, found in Europe (King et al. 2015), EU2 being the more aggressive. The symptoms on larch include necrosis and loss of needles, wilting of shoots, dieback of branches, and death, often with abundant resin bleeding on trunks and branches. As sporulating hosts, Larix spp. may disperse P. ramorum over long distances. In May 2017, wilting, yellowing/reddening needles, and branch mortality were observed on mature Larix kaempferi (about 50 years old) in the forest of Saint-Cadou, Finist{\`e}re, in the far northwestern part of France (3{\textdegree}59'49.2" W; 48{\textdegree}22'22.4" N). Approximately, 27\% of the trees were affected in May, and 42\% later in September 2017. The presence of P. ramorum was suspected and was first confirmed by testing samples collected from trunks and branches with necrosis and resin bleeds, using the specific conventional polymerase chain reaction (PCR) method developed by Ioos et al. (2006). The oomycete was also isolated in pure culture, using a Phytophthora selective medium (PARB[H]). The features observed, such as a coralloid mycelium, the presence of numerous thin-walled chlamydospores (up to 75 {\textmu}m large), and deciduous, semipapillate sporangia arranged in clusters, matched those reported for P. ramorum. In June 2017, the presence of P. ramorum was confirmed in another larch stand in Hanvec, Finist{\`e}re (4{\textdegree}12'45.0" W; 48{\textdegree}20'10.8" N), using the same identification techniques. In this stand, the prevalence was not precisely estimated but was deemed much lower than in Saint-Cadou. Based on the analysis of Cox1 partial sequence and the PCR restriction fragment length polymorphism pattern described by Van Poucke et al. (2012) on Cox1, the P. ramorum isolates collected in these two forests could be assigned to the EU1 lineage. This is the first report of P. ramorum affecting Japanese larch in France and in mainland Europe. Until now it had only been detected on shrubs in nurseries, green spaces, and in rare circumstances in the natural environment on understory vegetation (rhododendron) in Normandy and Brittany, but not in the vicinity of the infected larch stands. The presence of this pathogen in the natural environment represents a major threat for larch trees, but also for the other potential forest host trees in this region, such as sweet chestnut, and might have a severe impact on both forest and ornamental tree species. Research is in progress to learn more about this outbreak, the possible origin of the inoculum, the extension of the disease, and its progression.

}, issn = {0191-2917}, doi = {10.1094/PDIS-02-18-0288-PDN}, url = {https://apsjournals.apsnet.org/doi/10.1094/PDIS-02-18-0288-PDN}, author = {Schenck, N. and Saurat, C. and Guinet, C. and Fourrier-Jeandel, C. and Roche, L. and Bouvet, A. and Husson, C. and Saintonge, F.-X. and Contal, C. and Ioos, R.} } @article {EPP:EPP2431, title = {A duplex PCR method for the simultaneous identification of Phytophthora ramorum and Phytophthora kernoviae}, journal = {EPPO Bulletin}, volume = {41}, number = {1}, year = {2011}, pages = {27{\textendash}29}, publisher = {Blackwell Publishing Ltd}, abstract = {

Phytophthora ramorum and Phytophthora kernoviae are two fungus-like organisms affecting a wide range of hardy ornamental plants and trees. Emergency measures are implemented in the European Union for P.\ ramorum and aim to eradicate, or at least prevent the further spread of this harmful pathogen. Phytophthora kernoviae has so far been found only in New Zealand, the UK and Ireland, and is regulated on a UK level using the same measures as for P.\ ramorum. Both Phytophthora species have a similar host range and can be diagnosed using similar methods. Therefore a duplex PCR detection, based on the internal transcribed spacer (ITS) regions of the ribosomal DNA, was developed to enable simultaneous testing to reduce diagnostic times. The method was tested for its specificity and sensitivity, and on plant samples, and was shown to be reliable for identification of the two organisms.

}, issn = {1365-2338}, doi = {10.1111/j.1365-2338.2010.02431.x}, url = {http://dx.doi.org/10.1111/j.1365-2338.2010.02431.x}, author = {Schlenzig, A.} } @article {761, title = {Involvement of Phytophthora species in the decline of beech Fagus sylvatica in Wallonia (Belgium)}, journal = {Commun Agric Appl Biol Sci.}, volume = {72}, year = {2007}, pages = {879-85.}, abstract = {

During the last decade, typical symptoms of Phytophthora diseases were observed in beech stands of several European countries. The main symptoms were the presence of bleeding cankers on the stem, a low crown density as well as the yellowing of foliage and the small size of leaves. Several species of Phytophthora, such as Phytophthora citricola, P. cambivora and P. cactorum, were reported as the causal agents. In order to evaluate the implication of the different Phytophthora species in beech decline in the southern part of Belgium (Wallonia), a monitoring was undertaken with the help of managers of public and private forests. Phytophthora strains isolated from beech of different stands as well as from soil were characterized through morphological and molecular analyses (PCR-RFLP of ITS). All the isolated strains were identified as P. cambivora, except for one strain whose identification is ongoing. Molecular analysis was also directly applied to necrosed tissues of bleeding beeches and enabled the detection of additional cases. All positive cases exhibited a profile characteristic of the species P. cambivora, except for one of the sampled trees showing a different Phytophthora profile also corresponding to the unidentified isolated strain. Identification of the Phytophthora species linked to this different RFLP profile is also ongoing. Both complementation types (A1 and A2) of P. cambivora were identified, sometimes in the same sampling site. Ornamented oogonia characteristic of this species were produced by pairing A1 and A2 strains isolated from the same site.

}, author = {Schmitz, S. and Zini, J and Chandelier, A.} } @article {3975, title = {Detection and quantification of Phytophthora species which are associated with root-rot diseases in European deciduous forests by species-specific polymerase chain reaction}, journal = {Forest Pathology}, volume = {29}, year = {1999}, month = {06/1999}, pages = {169 - 188}, abstract = {

Oligonucleotide primers were developed for the polymerase chain reaction (PCR)-based detection of selected Phytophthora species which are known to cause root-rot diseases in European forest trees. The primer pair CITR1/CITR2, complementing both internal transcribed spacer regions of the ribosomal RNA genes, gave a 711 bp amplicon with Phytophthora citricola. The Phytophthora cambivora specific primer pair CAMB3/CAMB4, producing a 1105bp amplicon, as well as the Phytophthora quercina specific primer pair QUERC1/QUERC2, producing a 842 bp amplicon, were derived from randomly amplified polymorphic DNA (RAPD)-fragments presented in this paper. All three primer pairs revealed no undesirable cross-reaction with a diverse test collection of isolates including other Phytophthora species, Pythium, Xerocomus, Hebeloma, Russula, and Armillaria. Under the PCR conditions described the detection of a well discernable amplicon was possible down to 100 pg (P. cambivora), 4pg (P. quercina), and 2pg (P. citricola) target DNA. This diagnostic PCR system was able to detect P. citricola, P. quercina, and P. cambivora in seedlings of pendunculate oak (Quercus robur) and European beech (Fagus sylvatica) which were artificially infected under controlled conditions.

}, issn = {1437-4781}, doi = {10.1046/j.1439-0329.1999.00141.x}, author = {Schubert, R. and Bahnweg, G. and Nechwatal, J. and T. Jung and Cooke, D. E. L. and Duncan, J. M. and Muller-Starck, G. and Langebartels, C. and Sandermann, H. Jr2 and W. Osswald} } @article {4086, title = {Phytophthora species associated with diseased woody ornamentals in Minnesota nurseries}, journal = {Plant Disease}, volume = {91}, year = {2007}, month = {01/2007}, pages = {97 - 102}, abstract = {

Phytophthora species are responsible for causing extensive losses of ornamental plants worldwide. Recent international and national surveys for the detection of P. ramorum have led to the finding of previously undescribed Phytophthora species. Since no previous Phytophthora surveys have been carried out in Minnesota, surveys of ornamental nurseries were performed over 4 years to isolate and identify the Phytophthora species causing diseases of woody plants in Minnesota. Species were identified by direct sequencing of internal transcribed spacer (ITS) rDNA, β-tub, and mitochondrial coxI genes. Species associated with diseased ornamental plants include P. cactorum, P. cambivora, P. citricola, P. citrophthora, P. hedraiandra, P. megasperma, P. nicotianae, and the previously identified but undescribed taxon P. Pgchlamydo. The most common species encountered were P. cactorum, P. citricola, and P. citrophthora. Two additional isolates obtained did not match known species. One was similar to P. alni subsp. alni, and the other appeared to be a new species and is referred to as P. sp. MN1. In addition, species are reported for the first time from several hosts. Results indicated that several Phytophthora species were more widespread in the nursery industry than previously thought, and undescribed species were causing disease in Minnesota ornamental nurseries.

}, issn = {0191-2917}, doi = {10.1094/PD-91-0097}, url = {http://dx.doi.org/10.1094/PD-91-0097 }, author = {Schwingle, B. W. and Smith, J. A. and Blanchette, R. A.} } @article {Scott:30 June 2009:0031-5850:1, title = {Phytophthora multivora sp. nov., a new species recovered from declining Eucalyptus, Banksia, Agonis and other plant species in Western Australia}, journal = {Persoonia - Molecular Phylogeny and Evolution of Fungi}, volume = {22}, year = {2009}, pages = {1-13(13)}, abstract = {

A new Phytophthora species, isolated from rhizosphere soil of declining or dead trees of Eucalyptus gomphocephala, E. marginata, Agonis flexuosa, and another 13 plant species, and from fine roots of E. marginata and collar lesions of Banksia attenuata in Western Australia, is described as Phytophthora multivora sp. nov. It is homothallic and produces semipapillate sporangia, smooth-walled oogonia containing thick-walled oospores, and paragynous antheridia. Although morphologically similar to P. citricola, phylogenetic analyses of the ITS and cox1 gene regions demonstrate that P. multivora is unique. Phytophthora multivora is pathogenic to bark and cambium of E. gomphocephala and E. marginata and is believed to be involved in the decline syndrome of both eucalypt species within the tuart woodland in south-west Western Australia.

}, doi = {10.3767/003158509X415450}, url = {http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2789538/}, author = {P.M. Scott and Burgess, T. I. and P.A. Barber and Shearer, B. L. and Stukely, M. J. C. and G.E.St.J. Hardy and T. Jung} } @article {EFP:EFP753, title = {Pathogenicity of Phytophthora multivora to Eucalyptus gomphocephala and Eucalyptus marginata}, journal = {Forest Pathology}, volume = {42}, year = {2011}, pages = {289{\textendash}298}, publisher = {Blackwell Publishing Ltd}, abstract = {

Phytophthora multivora is associated with the rhizosphere of declining Eucalyptus gomphocephala, Eucalyptus marginata and Agonis flexuosa. Two pathogenicity experiments were conducted. The first experiment examined the pathogenicity of five P. multivora isolates and one Phytophthora cinnamomi isolate on the root systems of E. gomphocephala and one P. multivora isolate on the root system of E. marginata. In the second experiment, the pathogenicity of P. multivora to E. gomphocephala and E. marginata saplings was measured using under-bark stem inoculation. In Experiment 1, the P. cinnamomi isolate was more aggressive than all P. multivora isolates causing significant loss of fine roots and plant death. Two P. multivora isolates and the P. cinnamomi isolate caused significant losses of E. gomphocephala fine roots 0-2 mm in diameter and significantly reduced the surface area of roots 0-1 mm in diameter. One P. multivora and the P. cinnamomi isolate significantly reduced the surface area of roots 1-2 mm in diameter. Two of the P. multivora isolates significantly reduced the number of E. gomphocephala root tips. In E. marginata, the length and surface area of roots 0-1 mm in diameter and number of root tips were significantly reduced by P. multivora infestation. Rhizosphere infestation with the P. multivora isolates and P. cinnamomi isolate on E. gomphocephala, and one P. multivora isolate on E. marginata, did not significantly influence the foliar nutrient concentrations. In Experiment 2, under-bark inoculation with P. multivora caused significant lesion extension in E. gomphocephala and E. marginata saplings, compared to the control. We propose that P. multivora is inciting E. gomphocephala and E. marginata decline by causing fine root loss and subsequently interfering with nutrient cycling throughout the plant. The impact of fine root loss on the physiology of plants in sites infested with P. multivora requires further research.

}, issn = {1439-0329}, doi = {10.1111/j.1439-0329.2011.00753.x}, url = {http://dx.doi.org/10.1111/j.1439-0329.2011.00753.x}, author = {P.M. Scott and T. Jung and Shearer, B. L. and P.A. Barber and Calver, M. and Hardy, G. E. St. J.} } @article {4236, title = {Phytophthora diseases in New Zealand forests}, journal = {New Zealand Journal of Forestry}, volume = {59}, year = {2014}, pages = {14-21}, abstract = {

This article provides a brief overview of the status of Phytophthora diseases in New Zealand forests. Recent outbreaks of Phytophthora diseases internationally and within these forests, including Red Needle Cast of Pinus radiata caused by Phytophthora pluvialis and Agathis australis (kauri) dieback caused by Phytophthora taxon Agathis (PTA), have highlighted the biosecurity threat these species pose to New Zealand. In isolated cases, Red Needle Cast has impacted P. radiata plantations through the premature defoliation of mature needles. Kauri dieback, caused by Phytophthora taxon Agathis, has resulted in devastating disease within some sites. Preliminary research indicates that both these diseases will respond to treatment with phosphite, consistent with current international Phytophthora management. Ongoing research into Red Needle Cast, Phytophthora taxon Agathis induced kauri dieback and other Phytophthora diseases within P. radiata and kauri is focusing on understanding the epidemiology of the diseases, the chemical and genetic mechanisms of resistance, and also screening for durable resistance to multiple Phytophthora species. Many other Phytophthora pathogens have been identified within New Zealand. These have not been found to cause serious disease in native or exotic forest systems, despite some being known to cause diseases of great consequence internationally. Significant examples include P. cinnamomi, P. multivora and P. kernoviae. As a result of increased global movement of plant material, New Zealand{\textquoteright}s and other international forests are vulnerable to new Phytophthora diseases. However, through the world{\textquoteright}s best practice adaptive management the threat and impacts of these diseases can be reduced.

}, url = {http://www.nzjf.org/abstract.php?volume_issue=j59_2\&first_page=14}, author = {Peter Scott and Nari Williams} } @article {4047, title = {Coconut bud rot in Florida}, volume = {Technical Bulletin 199}, year = {1928}, pages = {87 pp.}, publisher = {University of Florida, Agricultural Experiment Station, Gainsville, FL}, url = {http://ufdc.ufl.edu/UF00027165/00001}, author = {JL Seal} } @article {4074, title = {Dieback and Mortality of Pinus radiata Trees in Italy Associated with Phytophthora cryptogea}, journal = {Plant Disease}, volume = {98}, year = {2014}, month = {01/2014}, pages = {159 - 159}, abstract = {

Pinus radiata D. Don is a forest tree species native to the Monterey Baja in California. Due to its rapid growth and desirable lumber and pulp qualities, between 1960 and 1980, about 12,000 ha of P. radiata were planted in Sardinia, Italy. The only disease reported on this conifer species has been Diplodia pinea, which causes tip and branch dieback (3). In January 2012, dieback and mortality of 25-year-old radiata pine trees were observed in a reforestation area of about 20 ha located in northern Sardinia (40{\textdegree}43'N, 9{\textdegree}22'E, 600 m a.s.l.). Symptoms included chlorosis, reddish-brown discoloration of the whole crown or dieback starting in the upper crown and progressing downward through the crown, and necrotic bark tissues at root collar. Approximately 25\% of the trees were affected. In a first attempt, a Phytophthora species was consistently isolated from the rhizosphere of 23 symptomatic trees, which included necrotic fine roots using oak leaves as bait (4). Afterwards, it was also isolated from phloem samples taken from the margins of fresh lesions at the stem base and upper roots of affected trees using synthetic mucor agar medium (1). Isolation from soil samples of six healthy pine trees randomly selected in the site did not yield any Phytophthora isolate. On carrot agar (CA), Phytophthora colonies were stellate to slightly radiate with limited aerial mycelium. Sporangia were obpiryform, non-papillate, and non-caducous, measuring 46.9 to 51.2 {\texttimes} 29.1 to 32.6 μm (l:b ratio 1.9). Hyphal swellings were formed in chains or clusters; chlamydospores were not observed. These isolates had cardinal temperatures of \<5{\textdegree}C, 25{\textdegree}C, and 35{\textdegree}C, respectively. Their morphological and cultural features were typical of Phytophthora cryptogea Pethybridge \& Lafferty. They were heterothallic and produced oogonia with amphyginous antheridia when paired with an A2 mating type tester strain of P. cryptogea. This identity was corroborated by sequence analysis of the internal transcribed spacer (ITS) region of the rDNA. BLAST searches showed 99\% homology with sequences of P. cryptogea available in GenBank (DQ479410 and HQ697245). The ITS sequence of a representative isolate (PH101) was submitted to GenBank (Accession Nos. KC603895). The strain PH101 was stored in the culture collection of the Department of Agriculture at the University of Sassari. Pathogenicity of isolate PH101 was verified by inoculating five freshly cut logs of radiata pine (1 m long and 15 cm diam.) with a 5-mm agar plug taken from the margin of 4-day-old culture grown on CA (4). The plug was inserted in a 5-mm hole made through the bark with a cork borer. Five control logs were inoculated with sterile CA. All logs were incubated in a growth chamber at 20{\textdegree}C. Phloem lesion sizes were assessed after 1 month and measured 9.7 {\textpm} 5.5 cm2 (average {\textpm} standard deviation). Control logs had no lesions. The pathogen was re-isolated from the lesions, thus fulfilling Koch{\textquoteright}s postulates. P. cryptogea has been previously reported in Australia, causing decline of radiata pine trees in wet and flooded soils (2). To our knowledge, this is the first report of P. cryptogea on P. radiata trees in Europe.

}, issn = {0191-2917}, doi = {10.1094/PDIS-05-13-0572-PDN}, url = {http://dx.doi.org/10.1094/PDIS-05-13-0572-PDN}, author = {Sechi, C. and Seddaiu, S. and Linaldeddu, B. T. and Franceschini, A. and Scanu, B.} } @article {4697, title = {First Report of Phytophthora acerina, P. plurivora, and P. pseudocryptogea Associated with Declining Common Alder Trees in Italy}, journal = {Plant Disease}, volume = {104}, year = {2020}, month = {Apr-17-2020}, pages = {1874}, abstract = {

Since the early 1990s, common alder (Alnus glutinosa) trees showing a variety of symptoms such as a partial or complete canopy dieback, reddening of foliage, and bleeding cankers at the collar and lower stem were observed in several torrential mountain streams in Sardinia (Italy). In order to clarify the etiology of the symptoms observed, three riparian alder stands along three streams in northern Sardinia were surveyed in the spring of 2017. In each stand a 100-m-long transect was established, and 10 symptomatic alder trees per transect were sampled for Phytophthora species. Phytophthora isolations from 30 rhizosphere samples (300 g of soil and roots) collected around the selected alder trees and 30 inner bark samples taken from the margin of active lesions at the collar region of the same trees were performed as described by Linaldeddu et al. (2020). Disease incidence among transects ranged from 81 to 97\%. Based on colony growth patterns on carrot agar (CA), morphological features of sporangia and sequence analysis of the internal transcribed spacer region (ITS1-5.8S-ITS2) of rDNA, the 40 Phytophthora isolates obtained were identified as Phytophthora acerina (seven isolates with ovoid sporangia measuring 48.9 {\texttimes} 33.1 μm), P. plurivora (24 isolates with ovoid sporangia measuring 50.1 {\texttimes} 32.9 μm), and P. pseudocryptogea (nine isolates with ellipsoid sporangia measuring 44.8 {\texttimes} 26.9 μm). For all Phytophthora species, BLAST searches in GenBank showed 100\% identity with reference sequences of representative isolates including those of ex-type cultures (JX951285, FJ665225, and KP288376). The ITS sequence of a representative isolate of each species was deposited in GenBank (P. acerina MN589653, P. plurivora MN589655, and P. pseudocryptogea MN589656). The representative isolates were stored at 10{\textdegree}C under water at the Culture Collection of the University of Padova. The pathogenicity of the representative isolate of each Phytophthora species was evaluated by inoculating five 3-year-old common alder seedlings per isolate. For each seedling a plastic beaker was positioned and sealed at the base of the stem, filled with 130 ml of pond water, and inoculated with 10 agar-mycelium plugs (10 mm) cut from the margin of a 5-day-old CA colony. The water of five control plants was inoculated with sterile CA plugs. Plants were kept in a laboratory at 25{\textdegree}C and watered regularly for 4 weeks. At the end of the experiment, all inoculated plants were symptomatic and displayed reddened to browned leaves and dark brown lesions on the inner bark. The three Phytophthora species were successfully reisolated from symptomatic inner bark tissues of the stem of all plants, fulfilling Koch{\textquoteright}s postulates. No disease symptoms were detected on control seedlings, and no Phytophthora species were isolated. The pathogenicity test was conducted twice. P. plurivora was the dominant species and the only species obtained from stem cankers and rhizosphere samples in all sites. This species is regarded as native to Europe and known as an aggressive pathogen of A. glutinosa (Aday Kaya et al. 2018; Haque et al. 2014). P. acerina and P. pseudocryptogea were obtained from both bleeding cankers and rhizosphere samples in two sites. All three Phytophthora species are reported for the first time to be associated with declining common alder trees in Italy, and for the first time the pathogenicity of P. acerina and P. pseudocryptogea has been demonstrated on A. glutinosa. The widespread occurrence and virulence of these Phytophthora species represents a serious threat to riparian alder ecosystems in Sardinia.

}, issn = {0191-2917}, doi = {10.1094/PDIS-01-20-0186-PDN}, url = {https://apsjournals.apsnet.org/doi/10.1094/PDIS-01-20-0186-PDN}, author = {Seddaiu, S. and Linaldeddu, B. T.} } @article {4662, title = {A microsatellite analysis identifies global pathways of movement of Phytophthora cinnamomi and the likely sources of wildland infestations in California and Mexico}, journal = {Phytopathology}, year = {2019}, month = {Jun-05-2019}, abstract = {

The genetic structure of a sample of isolates of the oomycete plant pathogen Phytophthora cinnamomi from natural and agricultural outbreaks, and the long-distance movement of individual genotypes, were studied using four microsatellite markers genotyped for 159 isolates of Californian, Mexican, and worldwide origin. Allelic profiles identified 75 multilocus genotypes; STRUCTURE analysis placed them in three groups characterized by different geographic and host ranges, different genic and genotypic diversity, and different reproductive modes. When relationships among genotypes were visualized on a minimum spanning network (MSN), genotypes belonging to the same STRUCTURE group were contiguous with rare exceptions. A putatively ancestral Group 1 has high genic diversity, includes all A1 mating type isolates and all Papuan isolates in the sample, was rarely isolated from natural settings in California and Mexico, and was positioned at the center of the MSN. Putatively younger Groups 2 and 3 had lower genic diversity, were both neighbors to Group 1 but formed two distinct peripherical sectors of the MSN, and were equally present in agricultural commodities and natural settings in Mexico and California. A few genotypes, especially in Group 2 and 3, were isolated multiple times in different locations and settings. The presence of identical genotypes from the same hosts in different continents indicates that long-distance human-mediated movement of P. cinnamomi has occurred. The presence of identical genotypes at high frequency in neighboring wildlands and agricultural settings suggests that specific commodities may have been the source of recent wild infestations caused by novel invasive genotypes.

}, issn = {0031-949X}, doi = {10.1094/PHYTO-03-19-0102-R}, url = {https://apsjournals.apsnet.org/doi/10.1094/PHYTO-03-19-0102-R}, author = {Serrano, Maria S and Osmundson, Todd and Almaraz-Sanchez, Alejandra and Croucher, Peter JP and Swiecki, Ted and Alvarado, Dionisio and Garbelotto, Matteo} } @article {EFP:EFP758, title = {Susceptibility to Phytophthora cinnamomi of the commonest morphotypes of Holm oak in southern Spain}, journal = {Forest Pathology}, volume = {42}, year = {2012}, pages = {345{\textendash}347}, publisher = {Blackwell Publishing Ltd}, abstract = {

The four main morphotypes of Holm oak (Quercus ilex subsp. ballota) present in Andalusia (expansa, macrocarpa, microcarpa and rotundifolia) were infected with Phytophthora cinnamomi to determine their susceptibility to the root pathogen. No large differences were found among the four morphotypes in the infection of roots, which always showed a high degree of necrosis. However, the different responses of the foliage to infection separated the four morphotypes of Holm oak into three groups: very susceptible (microcarpa), susceptible (expansa) and moderately susceptible (rotundifolia and macrocarpa). The natural hybrid Q.ilex ballota-Q.faginea exhibited a low level of root and foliar symptoms when infected with P.cinnamomi. Quercus faginea could be considered as a source of resistance to P.cinnamomi in future breeding programmes.

}, issn = {1439-0329}, doi = {10.1111/j.1439-0329.2011.00758.x}, url = {http://dx.doi.org/10.1111/j.1439-0329.2011.00758.x}, author = {Serrano, M. S. and De Vita, P. and Carbonero, M. D. and Fern{\'a}ndez, F. and Fern{\'a}ndez-Rebollo, P. and S{\'a}nchez, M. E.} } @article {4621, title = {An Overview of Canadian Research Activities on Diseases Caused by Phytophthora ramorum: Results, Progress, and Challenges}, journal = {Plant Disease}, volume = {102}, year = {2018}, month = {Jan-07-2018}, pages = {1218 - 1233}, abstract = {

International trade and travel are the driving forces behind the spread of invasive plant pathogens around the world, and human-mediated movement of plants and plant products is now generally accepted as the primary mode of their introduction, resulting in huge disturbance to ecosystems and severe socio-economic impact. These problems are exacerbated under the present conditions of rapid climatic change. We report an overview of the Canadian research activities on Phytophthora ramorum. Since the first discovery and subsequent eradication of P. ramorum on infected ornamentals in nurseries in Vancouver, British Columbia, in 2003, a research team of Canadian government scientists representing the Canadian Forest Service, Canadian Food Inspection Agency, and Agriculture and Agri-Food Canada worked together over a 10-year period and have significantly contributed to many aspects of research and risk assessment on this pathogen. The overall objectives of the Canadian research efforts were to gain a better understanding of the molecular diagnostics of P. ramorum, its biology, host-pathogen interactions, and management options. With this information, it was possible to develop pest risk assessments and evaluate the environmental and economic impact and future research needs and challenges relevant to P. ramorum and other emerging forest Phytophthora spp.

}, issn = {0191-2917}, doi = {10.1094/PDIS-11-17-1730-FE}, url = {https://apsjournals.apsnet.org/doi/10.1094/PDIS-11-17-1730-FE}, author = {Shamoun, Simon Francis and Rioux, Danny and Callan, Brenda and James, Delano and Hamelin, Richard C. and Bilodeau, Guillaume J. and Elliott, Marianne and L{\'e}vesque, Andr{\'e} and Becker, Elisa and McKenney, Dan and Pedlar, John and Bailey, Karen and Bri{\`e}re, S. C. and Niquidet, Kurt and Allen, Eric} } @proceedings {3954, title = {Sudden oak death, a science symposium: the state of our knowledge (abstracts)}, year = {2002}, month = {2002}, pages = {98 pp}, publisher = {U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station, University of California, Integrated Hardwood and Range Management Program, Center for Forestry, Division of Agriculture and Natural Resources, Berkeley, California}, address = {Monterey, California}, abstract = {

Conference Purpose A Symposium designed to bring together a broad array of the scientific community from throughout the world working on Phytophthora ramorum and the phenomena known as {\textquotedblleft}Sudden Oak Death{\textquotedblright}

}, url = {http://www.suddenoakdeath.org/?bibliography=a-survey-of-sudden-oak-death-in-native-california-forest-and-woodland-communities-relating-incidence-and-intensity-of-phytophthora-ramorum-to-plant-community-and-site-variables}, author = {Dr. Patrick J. Shea and Dr. Richard B. Standiford and Dr. Patrick J. Shea and Dr. Richard B. Standiford} } @article {899, title = {Quantification of the susceptibility of the native flora of the South-West Botanical Province, Western Australia, to Phytophthora cinnamomi}, journal = {Australian Journal of Botany}, volume = {52 (4)}, year = {2004}, pages = {435 - 443}, abstract = {

This study compares, for the first time, variation in estimates of susceptibility of native flora to Phytophthora cinnamomi Rands among four databases and proposes an estimate of the proportion of the flora of the South-West Botanical Province of Western Australia that is susceptible to the pathogen. Estimates of the susceptibility of south-western native flora to P. cinnamomi infection were obtained from databases for Banksia woodland of the Swan Coastal Plain, jarrah (Eucalyptus marginata Donn. ex Smith) forest, the Stirling Range National Park and Rare and Threatened Flora of Western Australia. For the woodland, forest and national park databases, hosts were naturally infected in uncontrolled diverse natural environments. In contrast, threatened flora were artificially inoculated in a shadehouse environment. Considerable variation occurred within taxonomic units, making occurrence within family and genus poor predictors of species susceptibility. Identification of intra-specific resistance suggests that P. cinnamomi could be having a strong selection pressure on some threatened flora at infested sites and the populations could shift to more resistant types. Similar estimates of the proportion of species susceptible to P. cinnamomi among the databases from the wide range of environments suggests that a realistic estimate of species susceptibility to P. cinnamomi infection in the south-western region has been obtained. The mean of 40\% susceptible and 14\% highly susceptible equates to 2284 and 800 species of the 5710 described plant species in the South-West Botanical Province susceptible and highly susceptible to P. cinnamomi, respectively. Such estimates are important for determining the cost of disease to conservation values and for prioritising disease importance and research priorities. P. cinnamomi in south-western Australia is an unparalleled example of an introduced pathogen with a wide host range causing immense irreversible damage to unique, diverse but mainly susceptible plant communities.

}, doi = {http://dx.doi.org/10.1071/BT03131}, url = {http://www.publish.csiro.au.proxy.library.oregonstate.edu/?paper=BT03131}, author = {Shearer, B. L. and C. E. Crane and A. Cochrane} } @article {4615, title = {Effects of temperature on germination of sporangia, infection and protein secretion by Phytophthora kernoviae}, journal = {Plant Pathology}, volume = {67}, year = {2018}, month = {Jan-04-2018}, pages = {719 - 728}, abstract = {

Phytophthora kernoviae is a pathogen on a wide range of plants, but little is known of optimal infection conditions. Rhododendron ponticum leaves were inoculated with six different isolates of P.\ kernoviae sporangia and incubated at different temperatures from 10 to 28\ {\textdegree}C. After 1\ week, lesion development and pathogen recovery were only observed from all isolates at 15 and 20\ {\textdegree}C and a few isolates at 10\ {\textdegree}C. In an experiment with temperatures ranging from 20 to 25\ {\textdegree}C, lesion development and pathogen recovery on R.\ ponticum, Magnolia stellata and Viburnum tinus occurred consistently at 20 and 21\ {\textdegree}C, was limited at 22\ {\textdegree}C, and did not occur at 23\ {\textdegree}C and above. There was no difference in sporangia and zoospore germination at 20{\textendash}25\ {\textdegree}C. In a temperature fluctuation experiment, the necrotic area of inoculated R.\ ponticum leaves increased with longer incubation at 20\ {\textdegree}C and decreased with longer incubation at 24\ {\textdegree}C. Crude extracts of secreted proteins from P.\ kernoviae cultures grown at 20 and 24\ {\textdegree}C were compared to determine any effects of temperature on pathogenicity. When spot tested on R.\ ponticum leaves, crude protein suspensions from cultures grown at 20\ {\textdegree}C induced necrosis, while proteins from cultures grown at 24\ {\textdegree}C did not. Proteomic analysis confirmed that a 10\ kDa protein secreted at both 20 and 24\ {\textdegree}C shared sequence homology to the conserved domains of known elicitins of other Phytophthora spp. The protein secreted at 20\ {\textdegree}C that was responsible for necrosis has not been identified.

}, doi = {https://doi.org/10.1111/ppa.12782}, url = {https://doi.org/10.1111/ppa.12782}, author = {Shelley, B. A. and Luster, D. G. and Garrett, W. M. and McMahon, M. B. and Widmer, T. L.} } @article {1132, title = {A test system to quantify inoculum in runoff from Phytophthora ramorum-infected plant roots}, journal = {Phytopathology}, volume = {101}, year = {2011}, pages = {1457-1464}, abstract = {

Foliar hosts of Phytophthora ramorum are often susceptible to root infection but the epidemiological significance of such infections is unknown. A standardized test system was developed to quantify inoculum in runoff from root-infected Viburnum tinus {\textquoteleft}Spring Bouquet{\textquoteright} or Rhododendron {\textquoteleft}Cunningham{\textquoteright}s White{\textquoteright} cuttings. Cuttings of both species gave off a maximum amount of inoculum 1 to 3 weeks after inoculation. The greatest amount of inoculum was recovered from Viburnum roots that were 48 to 70 days old at the time of inoculation, or roots incubated at 15 to 20{\textdegree}C rather than 25{\textdegree}C. Inoculum in runoff from inoculated Viburnum roots was similar for four different isolates of P. ramorum representing both the NA1 and EU1 lineages. When Rhododendron cuttings were inoculated with P. ramorum, P. citricola, or P. cactorum, inoculum of all three pathogens was recovered from runoff, with the highest amount recovered from plants inoculated with P. citricola, followed by the other two. Compared with the other two pathogens, P. ramorum colonized root tissue to a smaller extent. The epidemiology of root infection by P. ramorum is important in itself but the assay might lend itself for use in risk analysis for root infection of other plant species and evaluation of control measures, and also shed light on other root-infecting Phytophthora spp.

}, doi = {10.1094/PHYTO-09-10-0260}, url = {http://dx.doi.org/10.1094/PHYTO-09-10-0260}, author = {Shishkoff, Nina} } @article {4318, title = {Action of fosetyl-al and metalaxyl against Phytophthora austrocedri}, journal = {Forest Pathology}, volume = {46}, year = {2015}, month = {Jan 2016}, pages = {54{\textendash}66}, abstract = {

Fosetyl-Al and metalaxyl, the most commonly used systemic fungicides against Phytophthora, were evaluated for their efficacy to control Phytophthora austrocedri, the pathogen that causes a serious disease at the Austrocedrus chilensis forests in Patagonia. The effect of the chemicals on pathogen development in\ vitro and in planta was analysed. Both chemicals were shown to protect plants from the pathogen. In vitro assays showed that asexual reproduction was sensitive to both chemicals. However, mycelial growth and sexual reproduction, which were clearly sensitive to metalaxyl, were sensitive only to high concentrations of fosetyl-Al. Fosetyl-Al and metalaxyl had almost the same efficacy when applied preventively by soil drench to seedlings. This difference between in\ vitro and in planta results can be attributed to the dual action of fosetyl-Al, not only inhibiting the pathogen but also stimulating host defence. In adult trees, preventive and curative treatments were tested, but only the fosetyl-Al preventive treatment was effective in the assayed conditions. Interestingly, seedlings pretreated with both fungicides were less susceptible to the effectors secreted by the pathogen. Our results indicate that fosetyl-Al and metalaxyl provide some resistance to the plant besides the fungistatic direct action on the pathogen. Further studies to elucidate a possible resistance-inducing activity of these chemicals and the mechanisms involved are underway.

}, doi = {10.1111/efp.12216}, url = {http://doi.wiley.com/10.1111/efp.12216}, author = {Silva, P. V. and V{\'e}lez, M. L. and Ota{\~n}o, D. H. and Nu{\~n}ez, C. and Greslebin, A. G.}, editor = {Osswald, W.} } @article {4614, title = {Phytophthora Contamination in a Nursery and Its Potential Dispersal into the Natural Environment}, journal = {Plant Disease}, volume = {102}, year = {2018}, month = {Jan-01-2018}, pages = {132 - 139}, abstract = {

A detailed site investigation of a eucalypt nursery suffering disease losses revealed the causal agent to be Phytophthora boodjera. The pathogen was detected in vegetation surrounding the nursery production area, including the lawn, under the production benches during the growing season, and, most importantly, from plant debris in used trays. However, it was not found in the container substrate, water supplies, or production equipment or on the workers themselves. The sterilization methods used by the nursery were shown to be ineffective, indicating that a more rigorous method was required. Boiling trays for 15 min or steaming at 65{\textdegree}C for 60 min eradicated P. boodjera. This pathogen was more pathogenic to the eucalypts tested in their early seedling stage than P. cinnamomi. Tracing of out-planting to revegetation sites showed that P. boodjera was able to spread into the environment. Dispersal via out-planting to native vegetation may affect seedling recruitment and drive long-term shifts in native plant species. Inadequate nursery hygiene increases the risk of an outbreak and can limit the success of biosecurity efforts as well as damage conservation efforts.

}, issn = {0191-2917}, doi = {10.1094/PDIS-05-17-0689-RE}, url = {https://apsjournals.apsnet.org/doi/abs/10.1094/PDIS-05-17-0689-RE}, author = {Simamora, Agnes V. and Paap, Trudy and Howard, Kay and Stukely, Michael J. C. and Hardy, Giles E. St. J. and Burgess, Treena I.} } @article {4405, title = {Alder Canopy Dieback and Damage in Western Oregon Riparian Ecosystems}, journal = {Northwest Science}, volume = {89}, year = {2015}, month = {Jan-01-2015}, pages = {34 - 46}, abstract = {

We gathered baseline data to assess alder tree damage in western Oregon riparian ecosystems. We sought to determine if Phytophthora-type cankers found in Europe or the pathogen Phytophthora alni subsp. alni, which represent a major threat to alder forests in the Pacific Northwest, were present in the study area. Damage was evaluated in 88 transects; information was recorded on damage type (pathogen, insect or wound) and damage location. We evaluated 1445 red alder (Alnus rubra), 682 white alder (Alnus rhombifolia) and 181 thinleaf alder (Alnus incana spp. tenuifolia) trees. We tested the correlation between canopy dieback and canker symptoms because canopy dieback is an important symptom of Phytophthora disease of alder in Europe. We calculated the odds that alder canopy dieback was associated with Phytophthora-type cankers or other biotic cankers. P. alni subsp. alni (the causal agent of alder disease in Europe) was not identified in western Oregon; however, Phytophthora siskiyouensis was isolated from Phytophthora-type cankers which were present on 2\% of red alder trees and 3\% of white alder trees. The odds of canopy dieback were 5.4 and 4.8 times greater for red and white alder (respectively) with Phytophthora-type canker symptoms than in trees without such cankers. The percentage of trees with canopy dieback was 51\%, 32\%, and 10\% for red, white, and thinleaf alder respectively. Other common damage included wounding, foliar pathogens and insects on red alder. This is the first report of Phytophthora canker of alder in United States forests and first report of P. siskiyouensis isolation from alder in forests anywhere.

}, issn = {0029-344X}, doi = {10.3955/046.089.0103}, url = {http://www.bioone.org/doi/10.3955/046.089.0103}, author = {Sims, Laura and Goheen, Ellen and Kanaskie, Alan and Hansen, Everett} } @article {4619, title = {Susceptibility to the rare Phytophthora tentaculata and to the widespread Phytophthora cactorum is consistent with host ecology and history}, journal = {Forest Pathology}, year = {2018}, month = {Apr-05-2020}, pages = {e12446}, abstract = {

We evaluated the susceptibility of three California endemic plant species Heteromeles arbutifolia, Platanus racemosa and Quercus agrifolia to the two congeneric soilborne pathogen species: Phytophthora tentaculata and Phytophthora cactorum. These pathogens were recently introduced in ecosystems east of the San Francisco Bay, where the three plant species above are dominant. Phytophthora cactorum has a worldwide distribution inclusive of California, and a broad host range. Phytophthora tentaculata, in contrast, is suspected to be a {\textquotedblleft}new{\textquotedblright} exotic to California and has been described on relatively few hosts. By separately challenging the roots and the stems of the three plant species above, we show that: (a) Both were equally pathogenic, but the type of disease differed based on host; (b) disease was consistent with host ecology and with previous disease reports, even if caused by different Phytophthora spp. and; (c) there were intraspecific differences in virulence. This study provides the following significant information regarding the management and early modelling of polyphagous soilborne Phytophthoras: (a) Endemic species can be as problematic as recently introduced exotics. (b) Multiple introductions should be avoided due to varying virulence levels among genotypes. (c) Riparian species like P.\ racemosa may develop disease tolerance in their root systems, but remain susceptible in their aerial portions, and thus, diseases could be facilitated by flooding or splash of infectious structures of soilborne pathogens onto aerial plant portions.

}, doi = {https://doi.org/10.1111/efp.12446}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/efp.12446?campaign=wolearlyview}, author = {Sims, Laura L. and Garbelotto, Matteo} } @article {4342, title = {The Phytophthora species assemblage and diversity in riparian alder ecosystems of western Oregon, USA}, journal = {Mycologia}, volume = {107}, year = {2015}, month = {October 2015}, pages = {889 - 902}, abstract = {

Phytophthora species were systematically sampled, isolated, identified and compared for presence in streams, soil and roots of alder (Alnus species) dominated riparian ecosystems in western Oregon. We describe the species assemblage and evaluate Phytophthora diversity associated with alder. We recovered 1250 isolates of 20 Phytophthora species. Only three species were recovered from all substrates (streams, soil, alder roots): P. gonapodyides, the informally described {\textquotedblleft}P. taxon Pgchlamydo{\textquotedblright}, and P. siskiyouensis. P. alni ssp. uniformis along with five other species not previously recovered in Oregon forests are included in the assemblage: P.citricola s.l., P. gregata, P. gallica, P. nicotianae and P. parsiana. Phytophthora species diversity was greatest in down- stream riparian locations. There was no significant difference in species diversity comparing soil and unwashed roots (the rhizosphere) to stream water. There was a difference between the predominating species from the rhizosphere compared to stream water. The most numerous species was the informally described {\textquotedblleft}P. taxon Oaksoil{\textquotedblright}, which was mainly recovered from, and most predominant in, stream water. The most common species from riparian forest soils and alder root systems was P. gonapodyides.

}, issn = {0027-5514}, doi = {10.3852/14-255}, url = {http://www.mycologia.org/cgi/doi/10.3852/14-255}, author = {Sims, L. L. and Sutton, W. and Reeser, P. and Hansen, E. M.} } @mastersthesis {4649, title = {Phytophthora species and riparian alder tree damage in western Oregon}, volume = {Ph.D.}, year = {2013}, month = {02/2014}, abstract = {

The genus Phytophthora contains some of the most destructive pathogens of forest trees, including the most destructive pathogen of alder in recent times, Phytophthora alni. Alder trees were reported to be suffering from canopy dieback in riparian ecosystems in western Oregon, which prompted a survey of alder health and monitoring for P. alni. In 2010 surveys in western Oregon riparian ecosystems were initiated to gather baseline data on damage and on the Phytophthora species associated with alder. Damage was recorded and analyzed from transects containing alder trees with canopy dieback symptoms according to damage type: (1) pathogen, (2) insect, or (3) wound. Phytophthora species from western Oregon riparian ecosystems were systematically sampled, isolated, identified, stored and compared. Koch{\textquoteright}s Postulates were evaluated for three key Phytophthora species recovered: P. alni, P. siskiyouensis and P. taxon Oaksoil, and alder disease in the western United States was described. Then, the ecological role of the most abundant Phytophthora species from streams was evaluated. The data indicated that many of the same agents reported causing damage to alder trees in the western United States were also damaging alder trees in western Oregon including the alder flea beetle, sawflies, flood debris, Septoria alnifolia, and Mycopappus alni. The most important damage correlated with canopy dieback was incidence of Phytophthora cankers, and isolation of Phytophthora siskiyouensis. In the initial systematic survey of Phytophthora species, 1190 individual Phytophthora isolates were recovered but were of many different species. In the survey of alder roots, P. alni subsp. uniformis was one of the species recovered from necrotic red alder roots, but overall incidence was low; it was isolated four times. From the evaluation of Koch{\textquoteright}s postulates, Phytophthora canker of alder in the western United States was described, and is a bole canker caused by Phytophthora. Phytophthora canker of alder was only found caused by P. siskiyouensis in nature, and it was isolated 74 times. Isolation was mainly from bole cankers and diseased roots on red and white alder, and from water and alder leaf debris floating in the stream. The most abundant Phytophthora species associated with red alder is an informally described species P. taxon Oaksoil, which appears to be a relatively benign aquatic saprotroph of alder leaf debris. Canopy dieback was more prevalent in riparian alder trees from transects with P. siskiyouensis than from transects with P. taxon Oaksoil but without P. siskiyouensis (70\% and 35\%, respectively). The informally described P. taxon Oaksoil from western Oregon is formally described here as P. obrutafolium sp. nov., closely related to P. bilorbang from western Australia, and P. taxon Oaksoil ss from an oak forest in France. In summary, other agents besides Phytophthora can damage alder trees in western Oregon. Many Phytophthora species associate with alder in western Oregon but not all of them are important damaging agents of alder. However, Phytophthora canker of alder is widespread in western Oregon. In the United States, Phytophthora canker of alder has only been found to be caused by P. siskiyouensis.

}, url = {http://hdl.handle.net/1957/46441 }, author = {Sims, Laura} } @proceedings {214, title = {Another new? species of Phytophthora on alder {\textquoteleft}down under{\textquoteright} (Australia).}, volume = {7}, year = {2006}, pages = {Poster 30}, address = {Freising Germany}, author = {Smith, I. W., and J. Cunnington and I Pascoe}, editor = {Brasier, C. and T. Jung and W. Osswald} } @article {3963, title = {Phytophthora alni on Alnus glutinosa reported for the first time in Spain}, journal = {Plant Pathology}, volume = {59}, year = {2010}, month = {08/2010}, pages = {798 - 798}, doi = {10.1111/ppa.2010.59.issue-410.1111/j.1365-3059.2009.02254.x}, author = {Solla, A. and P{\'e}rez-Sierra, A. and Corcobado, T. and Haque, M. M. and Diez, J. J. and T. Jung} } @article {197, title = {Revised tabular key to the species of Phytophthora}, journal = {Mycological papers, CAB International, Wallingford Oxon}, volume = {162}, year = {1990}, pages = {1-28}, issn = {0027-5522 }, url = {http://www.cabdirect.org/abstracts/19902300161.html;jsessionid=1D85C493563BECA35F0E55609ABAF21C}, author = {Stamps, D. J. and Waterhouse, G. M. and Newhook, F. J. and Hall, G. S.} } @article {859, title = {Phytophthora katsurae. [Descriptions of Fungi and Bacteria].
}, journal = {IMI Descriptions of Fungi and Bacteria}, volume = {84}, year = {1985}, pages = {Sheet 837}, abstract = {

A description is provided for Phytophthora katsurae. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Chestnut, coconut. DISEASE: Trunk rot of chestnut. GEOGRAPHICAL DISTRIBUTION: Asia (Japan, Taiwan), Oceania (Hawaii), Africa (Ivory Coast), Australasia (Australia (Queensland), Papua New Guinea). TRANSMISSION: Soil-borne, isolated from forest soils in Taiwan (59, 2349), Queensland and Papua New Guinea and from chestnut orchard soils in Japan (58, 2951).

}, author = {Stamps, D. J.} } @article {4363, title = {A review of New Zealand kauri (Agathis australis (D.Don) Lindl.): its ecology, history, growth and potential for management for timber}, journal = {New Zealand Journal of Forestry Science}, volume = {40}, year = {2010}, pages = {33-59}, abstract = {

Kauri (Agathis australis (D.Don) Lindl.) is endemic to New Zealand, where it is the only indigenous member of the Araucariaceae. It has the most southerly distribution of any species in the genus and is currently confined to the warm temperate areas of the North Island. At the time of European settlement, forests containing kauri covered 1 000 000 ha or more in New Zealand. Following uncontrolled logging, land clearance for alternative land use and destruction by fire, only 7500 ha of virgin or primary forest remain, mainly in conservation reserves. An additional 60 000 ha of scrub/shrubland and secondary forest contain varying amounts of regenerating kauri. Kauri is reputed to produce greater volumes of wood from single stems than any other timber tree in the world. Its timber is regarded as one of the finest due to qualities of decay resistance and dimensional stability under moist conditions. A wide range of products was developed by Maori and European settlers. Kauri timber and gum made a substantial contribution to the physical and economic development of New Zealand between 1830 and 1900. Agathis australis shares a number of biological characteristics with lowland Agathis species found in the tropics and subtropics. These include a juvenile form with narrow tapering crown; mature emergent trees with massive, spreading, dome-shaped crowns and upwardly-arched branches; self-pruning in sapling and pole-stage trees; flaking bark; winddispersed, small-winged seeds formed in cones that disintegrate at time of seed maturity while still on the tree; and only a few months of seed viability after shedding. Juvenile trees with taproots and mature trees with wide-spreading lateral roots and descending peg roots are windfirm, assisting longevity. Although surviving trees of massive dimensions (3-5 m diameter) are usually hollow, their life span may be 1500 years or more. Large kauri have a podsolising effect on some acidic soils, making them less fertile. Efficiency in the use of water and nutrients has enabled the species to become dominant on infertile and drought-prone ridge tops. Observations of growth in natural stands indicate mean annual increment of 2.5-6.0 mm in diameter and 0.3 m in height. Interplanting of kauri in scrub and shrubland developed on former kauri forest sites has produced poor results. Mean annual increments of 6.9 mm in diameter and 0.44 m in height have been recorded in young untended plantations. Greater success has been achieved through attention to site selection, improved establishment techniques and silvicultural tending. The most suitable sites for planting are those with fertile, well-drained, light-textured soils, a warm, humid climate, and a history of previous occupation by broadleaved (angiosperm) plant species. Current research suggests that rotation length can be reduced by best-practice management, and that planted stands could be a continuing source of kauri timber in the future.

}, issn = {1179-5395}, url = {http://www.scionresearch.com/__data/assets/pdf_file/0019/17164/NZJFS40201033-59_STEWARD.pdf}, author = {Steward, G. A. and Beveridge, A. E.} } @article {4362, title = {Growth and productivity of New Zealand kauri (Agathis australis (D.Don) Lindl.) in planted forests}, journal = {New Zealand Journal of Forestry Science}, volume = {44}, year = {2014}, month = {Jan-12-2014}, pages = {13 pp}, abstract = {

Background

The establishment of even-aged planted stands of New Zealand kauri (Agathis australis (D.Don) Lindl.) for timber has been constrained by a lack of quantitative information on productivity and rotation length on which forest management and investment decisions could be made.

Methods

Stand-level models of height and basal area against time were developed (as well as a stand-volume function to calculate volume from height and basal area) based on planted stands that were up to 83-years old and represented planting sites both within and outside the current natural range of the species.

Results

Planted kauri was shown to be slow to establish with little height growth for the first five years after planting. Similar trends were observed for basal area and whole-tree volume development. A Schumacher equation with local slope parameter and asymptote bounded at 45\ m gave the best fit for height, while a von Bertalanffy-Richards equation in difference form with local slope parameter gave the best fit for basal area. For plantations with an average site index (20.4), height was predicted to be 22.3\ m in height at age 60, with a basal area of 78.1\ m2\ ha?1. Whole-tree volume was predicted to be 702\ m3\ ha?1. Predicted volume mean annual increment was 11.7\ m3\ ha?1\ yr?1for all stands at age 60. From age 20-60 years, stands with a higher site index had a volume mean annual increment of 18.6\ m3\ ha?1\ yr?1. The best stand exceeded 20\ m3\ ha?1\ yr?1.

Conclusions

This study indicates an opportunity to grow kauri in plantations on selected good-quality sites over rotations of 60-80 years or less.

}, doi = {10.1186/s40490-014-0027-2}, url = {http://www.nzjforestryscience.com/content/44/1/27http://link.springer.com/content/pdf/10.1186/s40490-014-0027-2}, author = {Steward, Gregory A and Kimberley, Mark O and Mason, Euan G and Dungey, Heidi S} } @article {4447, title = {Variation in Alnus glutinosa susceptibility to Phytophthora~{\texttimes}alni infection and its geographic pattern in the Czech Republic}, journal = {Forest Pathology}, volume = {46}, year = {2016}, month = {Jan-02-2016}, pages = {3 - 10}, abstract = {

Variation in natural susceptibility of the black alder population to Phytophthora\ {\texttimes}alni (PA), the oomycete pathogen causing a devastating disease of alder, and its possible relationship to geographic origin, was studied in\ vitro using branch inoculation tests. Ninety black alder genotypes from different regions of the Czech Republic and two isolates of PA were employed. Host susceptibility varied significantly. After 1\ week of infection, the lesion surface areas ranged from 254 to 2051\ mm2 and from 19 to 970\ mm2 for the two isolates, respectively. The differences were also dependent on the geographical origin and altitude of the sites from which particular host genotypes were taken. These findings have important implications for restoration plantings and for PA resistance breeding programmes, as there is potential to make selections from natural populations.

}, doi = {10.1111/efp.2016.46.issue-110.1111/efp.12205}, url = {http://doi.wiley.com/10.1111/efp.2016.46.issue-1http://doi.wiley.com/10.1111/efp.12205http://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111\%2Fefp.12205}, author = {{\v S}tochlov{\'a}, P. and Novotn{\'a}, K. and Cerny, K.} } @article {EFP:EFP282, title = {Phytophthora disease of alder (Alnus glutinosa) in France: investigations between 1995 and 1999}, journal = {Forest Pathology}, volume = {32}, number = {3}, year = {2002}, pages = {179{\textendash}191}, publisher = {Blackwell Verlag GmbH}, abstract = {

A severe decline of alder associated with an undescribed Phytophthora species was identified for the first time in England in 1993. No generalized decline of alder was reported in France before 1990. The first diebacks and mortalities of common alder were observed at the beginning of the 1990s, but the so-called alder Phytophthora was not isolated in France until 1996. First, a synthesis about alder declines that were known in France before 1995 is presented. Then, a survey was established in north-eastern France; 108 sites were visited and the alder Phytophthora was isolated from 57 of them. All the main rivers were found to be affected and damage levels are significant along some of them. The frequency of the alder Phytophthora and other fungi isolated from declining alders is discussed. Finally, information on other alder declines in France is presented region by region, and a map summarizes the known distribution of the disease. The alder Phytophthora is quite common and widespread in France, with western and north-eastern France being especially affected; however, the number of diseased or dead trees varies greatly from one site to another. All records are from Alnus glutinosa; other Alnus species were seldom seen in the surveys.

}, issn = {1439-0329}, doi = {10.1046/j.1439-0329.2002.00282.x}, url = {http://dx.doi.org/10.1046/j.1439-0329.2002.00282.x}, author = {Streito, J-C. and Legrand, PH. and Tabary, F. and De Villartay, G. Jarnouen} } @article {4672, title = {Genome sequencing of oomycete isolates from Chile supports the New Zealand origin of Phytophthora kernoviae and makes available the first Nothophytophthora sp. genome}, journal = {Molecular Plant Pathology}, volume = {20}, year = {2019}, month = {Jan-03-2019}, pages = {423 - 431}, abstract = {

Genome sequences were generated for six oomycete isolates collected from forests in Valdivia, Chile. Three of the isolates were identified morphologically as Phytophthora kernoviae, whereas two were similar to other clade 10 Phytophthora species. One isolate was tentatively identified as Nothophytophthora valdiviana based on nucleotide sequence similarity in the cytochrome oxidase 1 gene. This is the first genome sequence for this recently described genus. The genome assembly was more fragmented and contained many duplicated genes when compared with the other Phytophthora sequences. Comparative analyses were performed with genomic sequences of the P.\ kernoviae isolates from the UK and New Zealand. Although the potential New Zealand origin of P.\ kernoviae has been suggested, new isolations from Chile had cast doubt on this hypothesis. We present evidence supporting P.\ kernoviae as having originated in New Zealand. However, investigation of the diversity of oomycete species in Chile has been limited and warrants further exploration. We demonstrate the expediency of genomic analyses in determining phylogenetic relationships between isolates within new and often scantly represented taxonomic groups, such as Phytophthora clade 10 and Nothophytophthora. Data are available on GenBank via BioProject accession number PRJNA352331.

}, doi = {10.1111/mpp.2019.20.issue-310.1111/mpp.12765}, url = {https://bsppjournals.onlinelibrary.wiley.com/doi/full/10.1111/mpp.12765}, author = {Studholme, David J. and Panda, Preeti and Sanfuentes von Stowasser, Eugenio and Gonz{\'a}lez, Mariela and Hill, Rowena and Sambles, Christine and Grant, Murray and Williams, Nari M. and McDougal, Rebecca L.} } @article {4340, title = {Genome sequences of six Phytophthora species associated with forests in New Zealand}, journal = {Genomics Data}, volume = {7}, year = {2016}, month = {Jan-03-2016}, pages = {54 - 56}, abstract = {
In New Zealand there has been a long association of Phytophthora diseases in forests, nurseries, remnant plantings and horticultural crops. However, new Phytophthora diseases of trees have recently emerged. Genome sequencing has been performed for 12 Phytophthora isolates, from six species: Phytophthora pluvialis, P. kernoviae, P. cinnamomi, P. agathidicida, P. multivora and P. taxon Totara. These sequences will enable comparative analyses to identify potential virulence strategies and ultimately facilitate better control strategies. This Whole Genome Shotgun data have been deposited in DDBJ/ENA/GenBank under the accession numbers LGTT00000000, LGTU00000000, JPWV00000000, JPWU00000000, LGSK00000000, LGSJ00000000, LGTR00000000, LGTS00000000, LGSM00000000, LGSL00000000, LGSO00000000, and LGSN00000000.
}, issn = {22135960}, doi = {10.1016/j.gdata.2015.11.015}, url = {http://www.sciencedirect.com/science/article/pii/S2213596015300854}, author = {Studholme, D.J. and McDougal, R.L. and Sambles, C. and Hansen, E. and Hardy, G. and Grant, M. and Ganley, R.J. and Williams, N.M.} } @article {1315, title = {Stream monitoring for detection of Phytophthora ramorum in Oregon tanoak forests}, journal = {Plant Disease}, volume = {93}, year = {2009}, pages = {1182{\textendash}1186}, abstract = {

Stream monitoring using leaf baits for early detection of Phytophthora ramorum has been an important part of the Oregon Sudden Oak Death (SOD) program since 2002. Sixty-four streams in and near the Oregon quarantine area in the southwest corner of the state were monitored in 2008. Leaves of rhododendron (Rhododendron macrophyllum) and tanoak (Lithocarpus densiflorus) were placed in mesh bags, and bags were floated in streams. Leaf baits were exchanged every 2 weeks throughout the year. Leaves were assayed by isolation on selective medium and by multiplex rDNA internal transcribed spacer polymerase chain reaction (ITS PCR). The two methods gave comparable results, but multiplex PCR was more sensitive. P. ramorum was regularly recovered at all seasons of the year from streams draining infested sites 5 years after eradication treatment. In streams with lower inoculum densities, recovery was much higher in summer than in winter. P. ramorum was isolated from streams in 23 watersheds. When P. ramorum was detected, intensive ground surveys located infected tanoaks or other host plants an average of 306 m upstream from the bait station. P. ramorum was isolated from stream baits up to 1,091 m from the probable inoculum source.

}, url = {http://dx.doi.org/10.1094/PDIS-93-11-1182}, author = {Sutton, W. and Hansen, E.M. and Reeser, Paul W. and Kanaskie, Alan} } @article {4467, title = {Phytophthora ramorum can survive introduction into finished compost}, journal = {California Agriculture}, volume = {69}, year = {2015}, month = {Jan-10-2015}, pages = {237 - 241}, abstract = {

Composted municipal green waste is a potential vehicle for the transmission of Phytophtora ramorum, the pathogen responsible for the disease known as sudden oak death. To assess the survival rate of the pathogen in compost, we introduced zoospores {\textemdash} a type of infectious propagule {\textemdash} into six composts of varying provenance and maturity. The compost samples represented three production facilities, two production techniques (turned windrow and forced air static pile) and two levels of maturity (fresh, defined as aged for less than 1 week; and mature, aged for more than 4 weeks). Positive re-isolations {\textemdash} indicating survival of the pathogen {\textemdash} were obtained from all composts. The re-isolation rate from the compost from one of the three production facilities was greater than that obtained from an inert substrate (filter paper) inoculated with the pathogen (P \< 0.01), while re-isolation rates from the other two sources were statistically indistinguishable from those obtained from the inert substrate (P \< 0.01). There was no significant difference in re-isolation rate between composts produced by the turned windrow method and composts produced by the forced air static pile technique. Re-isolation rates were greater from mature composts than from fresh composts (P \< 0.01). The results show that P. ramorum may be present and infectious if introduced into finished compost, and that variations in compost characteristics appear to influence survival rates.

}, issn = {0008-0845}, doi = {10.3733/ca.v069n04p237}, url = {http://californiaagriculture.ucanr.edu/landingpage.cfm?articleid=ca.v069n04p237}, author = {Swain, Steven and Garbelotto, Matteo} } @proceedings {959, title = {Increasing distance from California bay reduces the risk and severity of Phytophthora ramorum canker in coast live oak}, volume = {Gen. Tech. Rep. PSW-GTR-214}, year = {2008}, pages = {181-194}, publisher = {U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station}, address = {Santa Rosa, California}, url = {http://www.fs.fed.us/psw/publications/documents/psw_gtr214/}, author = {Swiecki, T. J. and E. Bernhardt}, editor = {Frankel, S.J. and J.T. Kliejunas and K. M. Palmieri} } @article {doi:10.1094/PDIS.2003.87.11.1395B, title = {First report of root and crown rot caused by Phytophthora cinnamomi affecting native stands of Arctostaphylos myrtifolia and A. viscida in California}, journal = {Plant Disease}, volume = {87}, number = {11}, year = {2003}, pages = {1395-1395}, doi = {10.1094/PDIS.2003.87.11.1395B}, url = {http://apsjournals.apsnet.org/doi/abs/10.1094/PDIS.2003.87.11.1395B}, author = {Swiecki, T. J. and Bernhardt, E. A. and Garbelotto, M.} } @article {doi:10.1094/PDIS.2000.84.11.1251A, title = {First report of Phytophthora root and collar rot of alder in Hungary}, journal = {Plant Disease}, volume = {84}, number = {11}, year = {2000}, pages = {1251-1251}, doi = {10.1094/PDIS.2000.84.11.1251A}, url = {http://apsjournals.apsnet.org/doi/abs/10.1094/PDIS.2000.84.11.1251A}, author = {Szab{\'o}, Ilona and Nagy, Z. and Bakonyi, J. and {\'E}rsek, T.} } @article {4668, title = {Variation in Susceptibility of Tanoak to the NA1 and EU1 Lineages of Phytophthora ramorum, the Cause of Sudden Oak Death}, journal = {Plant Disease}, year = {2019}, month = {Feb-09-2021}, pages = {PDIS-04-19-0831}, abstract = {

Phytophthora ramorum, the cause of sudden oak death (SOD), kills tanoak (Notholithocarpus densiflorus) trees in southwestern Oregon and California. Two lineages of P. ramorum are now found in wildland forests of Oregon (NA1 and EU1). In addition to the management of SOD in forest ecosystems, disease resistance could be used as a way to mitigate the impact of P. ramorum. The objectives of this study were to (i) characterize the variability in resistance of N. densiflorus among families using lesion length; (ii) determine whether lineage, isolate, family, or their interactions significantly affect variation in lesion length; and (iii) determine whether there are differences among isolates and among families in terms of lesion length. The parameters isolate nested within lineage (isolate[lineage]) and family {\texttimes} isolate(lineage) interaction explained the majority of the variation in lesion length. There was no significant difference between the NA1 and EU1 lineages in terms of mean lesion length; however, there were differences among the six isolates. Lesions on seedlings collected from surviving trees at infested sites were smaller, on average, than lesions of seedlings collected from trees at noninfested sites (P = 0.0064). The results indicate that there is potential to establish a breeding program for tanoak resistance to SOD and that several isolates of P. ramorum should be used in an artificial inoculation assay.

}, issn = {0191-2917 e-ISSN:1943-7692}, doi = {10.1094/PDIS-04-19-0831-RE}, url = {https://apsjournals.apsnet.org/doi/10.1094/PDIS-04-19-0831-RE}, author = {S{\o}ndreli, Kelsey L. and Kanaskie, Alan and Keri{\"o}, Susanna and LeBoldus, Jared M.} } @article {doi:10.1094/PDIS.2000.84.4.394, title = {Phytophthora cinnamomi as a cause of oak mortality in the state of Colima, Mexico}, journal = {Plant Disease}, volume = {84}, number = {4}, year = {2000}, pages = {394-398}, doi = {10.1094/PDIS.2000.84.4.394}, url = {http://apsjournals.apsnet.org/doi/abs/10.1094/PDIS.2000.84.4.394}, author = {Tainter, F. H. and O{\textquoteright}Brien, J. G. and Hern{\'a}ndez, A. and Orozco, F. and Rebolledo, O.} } @article {doi:10.1094/PD-90-0682B, title = {First report of root rot and stem canker caused by Phytophthora cambivora on noble fir (Abies procera) for bough production in Norway}, journal = {Plant Disease}, volume = {90}, number = {5}, year = {2006}, pages = {682-682}, abstract = {

In 2004, damages resembling those caused by Phytophthora spp. were observed in a 15-year-old bough plantation of noble fir (Abies procera). When removing bark upward from the roots and base of a diseased tree, a reddish brown discoloration with distinct borders to surrounding wood appeared. The discoloration extended approximately 1.5 m above ground, but only on one side of the stem. This resulted in dead basal branches (flagging) on the cankered side of the tree. Other dying trees in the same field did not show flagging symptoms but turned chlorotic to brown after being girdled by the expanding stem canker. Approximately 25\% of the trees were dead or dying. Isolations were carried out from the area between healthy and diseased tissue both from roots and base of the stem of the tree with flagging symptoms. Samples were rinsed in running tap water and plated on the Phytophthora selective medium PARP (17 g of cornmeal agar, 10 mg of pimaricin, 250 mg of ampicillin, 10 mg of rifampicin, and 100 mg of pentachloronitrobenzene (PCNB) in 1 liter of water), with and without hymexazol added (50 mg/l). Morphological characters of the isolated Phytophthora sp. included nonpapillate sporangia (37 to 64 μm), internal proliferation, and characteristic hyphal swellings. The isolate was heterothallic and produced amphigynous antheridia when crossed with tester strains of P. cryptogea. The mating type was A2. The internal transcribed spacer (ITS) rDNA sequences were identical to P. cambivora (GenBank Accession No. AY880985). Thus, both morphological characters and DNA analysis supported the species identification. A pathogenesis test to fulfill Koch{\textquoteright}s postulate was carried out during 2005. Inoculation was done by placing agar with culture in the growth medium close to the roots of noble fir seedlings. Eleven weeks after inoculation, clearly visible stem canker symptoms were observed. The ITS sequences of the reisolated Phytophthora sp. were determined and found identical to P. cambivora. P. cambivora was reported to cause root rot and stem canker in a noble fir Christmas tree plantation in the United States (1). P. citricola and P. citrophthora are known to cause problems on Lawson Falsecypress/Port-Orford-cedar (Chamaecyparis lawsoniana) in Norway, but damages by Phytophthora spp. have never been reported in Abies spp. plantations or forest stands in Norway. Currently, we are also working on Phytophthora problems discovered in two different Christmas tree plantations (A. lasiocarpa and A. nordmanniana).

}, doi = {10.1094/PD-90-0682B}, url = {http://apsjournals.apsnet.org/doi/abs/10.1094/PD-90-0682B}, author = {Talg{\o}, V. and Herrero, M. and Toppe, B. and Klemsdal, S. and Stensvand, A.} } @article {JPH:JPH1888, title = {Growth enhancement, amino acid synthesis and reduction in susceptibility towards Phytophthora megakarya by arbuscular mycorrhizal fungi inoculation in cocoa plants}, journal = {Journal of Phytopathology}, volume = {160}, number = {5}, year = {2012}, pages = {220{\textendash}228}, publisher = {Blackwell Publishing Ltd}, abstract = {

The effects of some selected arbuscular mycorrhizal (AM) fungi, Gigaspora margarita and Glomus mossae on the growth and the role of soluble amino acids of two contrasting cocoa cultivars (ICS84 tolerant and SNK10 sensitive) against black pod disease caused by Phytophthora megakarya were investigated. Root colonization by AM fungi is between 50 and 70\% 18{\textlnot}{\textdagger}weeks after planting. Tested AM fungi significantly increased all the plant growth parameters (height, number of leaves, shoot and root matter) and P uptake as compared to non-inoculated plants in pot experiments. AM fungi inoculated cocoa reduced the disease severity. Compared to the control, the soluble amino acid levels increased with inoculation of the AM fungi strains in the necrotic stems of disease on inoculated cocoa plants. Significant relationships between amino acids and disease severity observed for two cocoa cultivars imply that the induction of specific amino acids synthesized by leaves, such as arginine, cysteine and glutamic acid, may represent potential candidate molecules for adaptation of such cultivars to P. megakarya disease. Inoculating seedlings with AMF in nurseries could enhance the development of cocoa plants protected against P. megakarya.

}, keywords = {amino acids, arbuscular mycorrhizal fungi, cocoa, Phytophthora megakarya, plant disease}, issn = {1439-0434}, doi = {10.1111/j.1439-0434.2012.01888.x}, url = {http://dx.doi.org/10.1111/j.1439-0434.2012.01888.x}, author = {Tchameni, S{\'e}verin Nguemezi and Nwaga, Dieudonn{\'e} and Wakam, Louise Nana and Mangaptche Ngonkeu, Eddy Leonard and Fokom, Raymond and Kuat{\'e}, Jean and Etoa, Francois-Xavier} } @article {4444, title = {Phytophthora cambivora found on beech in Norway}, journal = {Forest Pathology}, volume = {45}, year = {2015}, month = {Jan-10-2015}, pages = {415 - 425}, abstract = {

In 2011, Phytophthora cambivora was isolated for the first time from a European beech (Fagus sylvatica) in the largest beech forest in Norway, in Larvik. This led to a survey of Phytophthora, both in Larvik and in a small beech stand in {\r A}s. Both locations are in urban areas\ in south-eastern Norway. Trees with a circumference above 20\ cm at chest height were examined for bleeding cankers. Samples from the leading edge of canker wounds were collected from selected trees in both locations and isolations were carried out on a Phytophthora-selective medium. Quantification of diseased trees in three areas of the forest in Larvik showed a variation from 1.8 to 22.7\% trees with bleeding cankers. In {\r A}s, 9.2\% of the trees had bleeding cankers. Isolation from diseased beech in both Larvik and {\r A}s yielded P.\ cambivora. Inoculation of healthy trees, subsequent development of disease and re-isolation of the pathogen confirmed the pathogenicity of P.\ cambivora. Description of morphological features of one of the obtained isolates is included.

}, doi = {10.1111/efp.2015.45.issue-510.1111/efp.12215}, url = {http://doi.wiley.com/10.1111/efp.2015.45.issue-5http://doi.wiley.com/10.1111/efp.12215http://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111\%2Fefp.12215}, author = {Telfer, K. H. and Brurberg, M. B. and Herrero, M.-L. and Stensvand, A. and {\o}, V.}, editor = {Desprez-Loustau, M.-L.} } @article {Tellenbach2012, title = {Inhibition of Phytophthora species by secondary metabolites produced by the dark septate endophyte Phialocephala europaea}, journal = {Fungal Ecology}, year = {2012}, pages = {-}, abstract = {

Dark septate fungal root endophytes of the Phialocephala fortinii s.l.{\textendash}Acephala applanata species complex (PAC) are widely distributed throughout the temperate and subtropical regions of the Northern Hemisphere. Previous studies have shown that some PAC members are pathogenic, others suppress oomycete root pathogens and some have no obvious effect on their Norway spruce (Picea abies) host. The activity of 85 PAC isolates against Phytophthora citricola s.l. was investigated by co-culture on plates. We identified a strain of Phialocephala europaea that significantly reduced the growth of P. citricola in\ vitro. Characterization of its extracellular metabolites resulted in the identification of four major compounds, sclerin, sclerolide, sclerotinin A, and sclerotinin B. These compounds are known for their positive as well as negative effects on plant growth. We found that sclerin and sclerotinin inhibited the growth of P. citricola in\ vitro at 150\ μg\ ml-1 (\~{}1\ mM). This is the first report of their production by Phialocephala and of activity of these compounds against an oomycete. Therefore, our data suggest that some PAC might reduce disease resulting from P. citricola by the production of antibiotics and plant growth promoting metabolites.

}, keywords = {Sclerotinin A}, issn = {1754-5048}, doi = {10.1016/j.funeco.2012.10.003}, url = {http://www.sciencedirect.com/science/article/pii/S1754504812001286}, author = {Christoph Tellenbach and Mark W. Sumarah and Christoph R. Gr{\"u}nig and J. David Miller} } @article {4016, title = {A TaqMan real-time PCR assay for the detection of Phytophthora {\textquoteleft}taxon Agathis{\textquoteright} in soil, pathogen of Kauri in New Zealand}, journal = {Forest Pathology}, volume = {43}, year = {2013}, month = {04/2013}, pages = {324{\textendash}330}, abstract = {

Kauri Agathis australis, an iconic tree of New Zealand, is under threat from an introduced disease-causing pathogen provisionally named Phytophthora {\textquoteleft}taxon Agathis{\textquoteright} (referred to as PTA). This soilborne, Pythiaceous species belongs to the Chromista and causes a collar rot resulting in yellowing of the foliage and thinning of the canopy, which eventually causes death of the infected tree. The management and containment of this pathogen requires rapid and reliable detection in the soil. The current method for soil detection utilizes a soil bioassay involving lupin baits and soil flooding in a process that takes between ten and twenty days. We describe a real-time PCR assay based on TaqMan chemistry for the specific detection of PTA, which targets the internal transcribed spacer (ITS) region of the nuclear ribosomal DNA. This TaqMan real-time PCR assay could be used with DNA extracted directly from bulk soil samples to enable rapid quantification of PTA within soil. The detection limit was 2\ fg of PTA DNA from pure culture, or 20\ fg in the presence of DNA extracted from soil. The assay was validated using soil samples taken from a PTA-infested site and soil spiked with a known concentration of oospores. We conclude that the TaqMan real-time PCR assay offers a more time-efficient method for detection of PTA in soil than existing methods.

}, doi = {10.1111/efp.12034}, url = {http://onlinelibrary.wiley.com/doi/10.1111/efp.12034/abstract}, author = {Than, D. J. and Hughes, K. J. D. and Boonhan, N. and Tomlinson, J. A. and Woodhall, J. W. and Bellgard, S.E.}, editor = {Andrea, V.} } @article {doi:10.1094/PHYTO-97-0099, title = {Risk factors for the Phytophthora-induced decline of alder in northeastern France}, journal = {Phytopathology}, volume = {97}, number = {1}, year = {2007}, pages = {99-105}, doi = {10.1094/PHYTO-97-0099}, url = {http://apsjournals.apsnet.org/doi/abs/10.1094/PHYTO-97-0099}, author = {Thoirain, B. and Husson, C. and Mar{\c c}ais, B.} } @article {4483, title = {Phytophthora species isolated from ash stands in Bia{\l}owie{\.z}a Forest nature reserve}, journal = {Forest Pathology}, year = {2016}, month = {Jan-06-2016}, abstract = {

Five Phytophthora species were isolated from the rhizosphere of ash-dominated areas of the Bia{\l}owieza European lowland forest nature reserve area. Morphological and DNA analyses identified Phytophthora fragariaefolia, P.\ plurivora, P.\ cactorum, P.\ lacustris and P.\ pseudosyringae. This is the first record of P.\ fragariaefolia in ash forests and demonstrates that several species in the potentially highly damaging Phytophthora genus are present within a near-pristine ecosystem.

}, doi = {10.1111/efp.12295}, url = {http://doi.wiley.com/10.1111/efp.12295http://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111\%2Fefp.12295}, author = {Tkaczyk, M. and Nowakowska, J. A. and Oszako, T.} } @article {4699, title = {On-Site DNA Extraction and Real-Time PCR for Detection of Phytophthora ramorum in the FieldABSTRACT}, journal = {Applied and Environmental Microbiology}, volume = {71}, year = {2005}, month = {Jan-11-2005}, pages = {6702 - 6710}, abstract = {

Phytophthora ramorum is a recently described pathogen causing oak mortality (sudden oak death) in forests in coastal areas of California and southern Oregon and dieback and leaf blight in a range of tree, shrub, and herbaceous species in the United States and Europe. Due to the threat posed by this organism, stringent quarantine regulations are in place, which restrict the movement of a number of hosts. Fast and accurate diagnostic tests are required in order to characterize the distribution of P. ramorum, prevent its introduction into pathogen-free areas, and minimize its spread within affected areas. However, sending samples to a laboratory for testing can cause a substantial delay between sampling and diagnosis. A rapid and simple DNA extraction method was developed for use at the point of sampling and used to extract DNAs from symptomatic foliage and stems in the field. A sensitive and specific single-round real-time PCR (TaqMan) assay for P. ramorum was performed using a portable real-time PCR platform (Cepheid SmartCycler II), and a cost-effective method for stabilizing PCR reagents was developed to allow their storage and transportation at room temperature. To our knowledge, this is the first description of a method for DNA extraction and molecular testing for a plant pathogen carried out entirely in the field, independent of any laboratory facilities.

}, issn = {0099-2240}, doi = {10.1128/AEM.71.11.6702-6710.2005}, url = {https://pubmed.ncbi.nlm.nih.gov/16269700/}, author = {Tomlinson, J. A. and Boonham, N. and Hughes, K. J. D. and Griffin, R. L. and Barker, I.} } @article {4209, title = {Effects of Inoculum Density and Wounding on Stem Infection of Three Eastern US Forest Species by Phytophthora ramorum}, journal = {Journal of Phytopathology}, volume = {162}, year = {2014}, month = {Jan-03-2014}, pages = {683 - 689}, abstract = {

Seedlings of three Eastern US forest species Quercus rubra (northern red oak), Quercus prinus (chestnut oak) and Acer rubrum (red maple) were inoculated by applying Phytophthora ramorum sporangia to stems at different inoculum densities with and without wounding. Disease occurred in all treatments involving wounds, and no disease was observed in unwounded treatments. Younger seedlings (2{\textendash}3\ years old) did not differ significantly from older seedlings (5{\textendash}6\ years old) in disease incidence, but older seedlings sustained smaller lesions compared with younger seedlings. For both old and young seedlings, disease on wounded stems was observed down to the lowest sporangia concentration utilized (500 sporangia/ml for old seedlings and 100 sporangia/ml for young seedlings). The results show that in the presence of wounding, even very low sporangia concentrations can result in disease, and further suggest that wounding caused by insects and other factors may play an important role in P.\ ramorum epidemiology in forest environments.

}, doi = {10.1111/jph.12251}, url = {http://doi.wiley.com/10.1111/jph.12251}, author = {Tooley, Paul W. and Browning, Marsha and Leighty, Robert M.} } @article {JPH:JPH1810, title = {Enhanced recovery of Phytophthora ramorum from soil following 30 Days of storage at 4{\textdegree}C}, journal = {Journal of Phytopathology}, year = {2011}, pages = {no{\textendash}no}, publisher = {Blackwell Publishing Ltd}, abstract = {

Chlamydospores of Phytophthora ramorum were used to infest field soil at densities ranging from 0.2 to 42 chlamydospores/cm3 soil. Recovery was determined by baiting with rhododendron leaf discs and dilution plating at time 0 and after 30\ days of storage at 4{\textdegree}C, as recommended by USDA-APHIS. Baiting was slightly more sensitive than dilution plating in recovering P.\ ramorum immediately following infestation of soil and allowed detection from samples infested with as little as 0.2\ chlamydospores/cm3 compared with 1 chlamydospore/cm3 for dilution plating. After 30\ days of infested soil storage at 4{\textdegree}C, P.\ ramorum was detected at significantly (P\ =\ 0.05) higher levels than at time 0 with both recovery methods. The results indicate that storage of P.\ ramorum-infested soil at 4{\textdegree}C may allow for pathogen activity, such as sporangia production, which may enhance recovery from soil.

}, keywords = {chlamydospore, ramorum blight}, issn = {1439-0434}, doi = {10.1111/j.1439-0434.2011.01810.x}, url = {http://dx.doi.org/10.1111/j.1439-0434.2011.01810.x}, author = {Tooley, Paul W. and Carras, Marie M.} } @article {4556, title = {The Effect of Exposure to Decreasing Relative Humidity on the Viability of Phytophthora ramorum sporangia}, journal = {Journal of Phytopathology}, volume = {164}, year = {2016}, month = {Aug 2016}, pages = {874 - 881}, abstract = {

Sporangia of three isolates of Phytophthora ramorum representing three different clonal lineages were subjected to relative humidity (RH) levels between 80 and 100\% for exposure periods ranging from 1 to 24\ h at 20{\textdegree}C in darkness. Plastic containers (21.5\ {\texttimes}\ 14.5\ {\texttimes}\ 5\ cm) were used as humidity chambers with 130\ ml of glycerine solution added to each container. Glycerine concentrations corresponded to 100, 95, 90, 85 and 80\% RH based on refractive index measurements. Sporangia suspensions were pipeted onto nitrile mesh squares (1.5\ {\texttimes}\ 1.5\ cm, 15 micron pore size) which were placed in the humidity chambers and incubated at 20{\textdegree}C in darkness. Following exposure periods of 1, 2, 4, 8, 12 and 24\ h, mesh squares were inverted onto Petri dishes of selective medium and sporangia germination assessed after 24 and 48\ h. At 100\% RH, we observed a mean value of 88\% germination after 1\ h exposure declining to 18\% germination following 24\ h incubation. At 95\% RH, a steeper decline in germination was noted, with means ranging from 79\% at 1\ h to less than 1\% at 24\ h exposure. At 90\% RH, no germination was noted after 8 or more h exposure, and values were 57\%, 22\% and 3\% germination for the 1, 2 and 4\ h exposures, respectively. Germination was only observed at 1\ h exposure for both the 85\% RH treatment (52\% germination) and the 80\% RH treatment (38\% germination). The three isolates responded similarly\ over the range of RH values tested. The germination response of P.\ ramorum sporangia to RH values between 80\% and 100\% was comparable to that reported for other Phytophthora species. Knowledge of conditions that affect P.\ ramorum sporangia germination can shed light on pathogenesis and epidemic potential and lead to improved control recommendations.

}, doi = {10.1111/jph.2016.164.issue-11pt1210.1111/jph.12506}, url = {https://doi.org/10.1111/jph.12506 }, author = {Tooley, Paul W. and Browning, Marsha} } @article {4009, title = {Inoculum density relationships for infection of some eastern US forest species by Phytophthora ramorum}, journal = {Journal of Phytopathology}, volume = {161}, year = {2013}, month = {09/2013}, pages = {595{\textendash}603}, abstract = {
Our objectives were to establish inoculum density relationships between P.\ ramorum and selected hosts using detached leaf and whole-plant inoculations. Young plants and detached leaves of Quercus prinus (Chestnut oak), Q.\ rubra (Northern red oak), Acer rubrum (red maple), Kalmia latifolia (mountain laurel) and Rhododendron {\textquoteleft}Cunningham{\textquoteright}s White{\textquoteright} were dip-inoculated with varying numbers of P.\ ramorum sporangia, and the total number of diseased and healthy leaves recorded following incubation at 20{\textdegree}C and 100\% relative humidity. Calibration threshold estimates for obtaining 50\% infected leaves based on linear analysis ranged from 36 to 750 sporangia/ml for the five hosts. Half-life (LD50) estimates (the number of spores for which the per cent of diseased leaves reaches 50\% of its total) from asymptotic regression analysis ranged from 94 to 319 sporangia/ml. Statistically significant differences (P\ =\ 0.0076) were observed among hosts in per cent infection in response to increased inoculum density. Inoculum threshold estimates based on studies with detached leaves were comparable to those obtained using whole plants. The results provide estimates of inoculum levels necessary to cause disease on these five P.\ ramorum hosts and will be useful in disease prediction and for development of pest risk assessments.
}, doi = {10.1111/jph.12107}, url = {http://onlinelibrary.wiley.com/doi/10.1111/jph.12107/abstract}, author = {Tooley, Paul W. and Browning, Marsha and Leighty, Robert M.} } @article {259, title = {Phytophthora root rot diseases of Lawson cypress and other ornamentals}, year = {1954}, pages = {18 p.}, publisher = {Oregon State College. Agricultural Experiment Station}, address = {Corvallis, OR}, keywords = {Diseases and pests, Ornamental trees}, issn = {StationBulletin537}, url = {http://hdl.handle.net/1957/15349}, author = {Torgeson, D. C. and Young, Roy A. and Milbrath, John A.} } @mastersthesis {3957, title = {Epiphytology and etiology of a Phytophthora-induced root rot diseases of Chamaecyparis in Oregon}, volume = {PhD}, year = {1953}, pages = {72}, school = {Oregon State College}, address = {Corvallis, OR}, author = {Torgeson,DC} } @article {196, title = {The pathology of Phytophthora lateralis on native Chamaecyparis lawsoniana}, journal = {Phytopathology}, volume = {49}, year = {1959}, pages = {306{\textendash}310}, author = {Trione, E. J.} } @article {199, title = {Sporulation and germination of Phytophthora lateralis}, journal = {Phytopathology}, volume = {64}, year = {1974}, pages = {1531-1533}, doi = {10.1094/Phyto-64-1531}, url = {http://www.apsnet.org/publications/phytopathology/backissues/Documents/1974Abstracts/Phyto64_1531.htm}, author = {Edward J. Trione} } @article {trzewik2010detection, title = {Detection and identification of Phytophthora alni.}, journal = {Communications in agricultural and applied biological sciences}, volume = {75}, number = {4}, year = {2010}, pages = {655}, abstract = {

In 2004 Brasier et al. described new species{\textendash}Phytophthora alni, which was especially aeggressive to alder. Now, this Phytophthora disease of alder is widely distributed in Europe as well as in Poland. In this research note we report on identification and detection of P. alni from water and soil samples using PCR method with species-specific primers. Dilution series of P. alni zoospore were used to test the potential sensitivity of the PCR detection methods. Zoospores of P. alni were produced by flooding of 1-week-old Frozen Pea Medium (FPM) cultures in Petri dishes with 30 ml distilled water. The dishes were incubated at 20 degrees C. After 5 days, sporangial production was checked using a binocular microscope and plates were placed at 4 degrees C for 1 h to enhance zoospore release. Zoospores were counted under the microscope using Burker{\textquoteright}s cabin. A dilution series of zoospores ranging from 5 to 5000 per 200 microl was prepared in autoclaved distilled water and in 1 g samples of autoclaved soil. DNA was extracted from artificially infected water and soil, and purified using the CleanUp Kit (A\&A Biotechnology). Zoospores of P. alni in the water were detected by PCR in 5 x 10(3), 5 x 10(2), 5 x 10(1) concentrations. In case of detecting spores in the artificially infected soil it succeeded only for two highest concentrations, i.e. 5 x 10(3), 5 x 10(2) and only when the DNA was additionally purified.

}, author = {Trzewik, A. and Orlikowska, T.} } @article {195, title = {Root rot of Chamaecyparis caused by a species of Phytophthora}, journal = {Mycologia}, volume = {34}, year = {1942}, pages = {94-103}, keywords = {Phytophthora lateralis}, url = {http://www.jstor.org/stable/3754945}, author = {Tucker, C. M. and Milbrath, J.A.} } @article {4637, title = {First Report of Phytophthora chlamydospora Causing Root and Crown Rot on Almond (Prunus dulcis) Trees in Turkey}, journal = {Plant Disease}, volume = {100}, year = {2016}, month = {Jan-08-2016}, pages = {1796 - 1796}, abstract = {

In June 2015, \~{}10\% of 10,000 8-year-old almond [Prunus dulcis (Miller) D.A. Webb. cv. Ferragnes] trees grafted on the GF677 rootstock in a commercial almond orchard in Besni of Ad{\i}yaman Province, showed wilting and lack of vigor, with severely infected trees dying from root and crown rot. The incidence of infected trees on soils with poor water drainage was greater than that on well-drained soils. Crowns of symptomatic plants had a reddish brown discoloration in the inner bark with a sharp contrast between infected and healthy tissue. Most fine roots were completely rotted and the inner bark of infected larger roots showed similar discoloration. Tissue samples taken from the margins of crown and root lesions were placed on carrot agar (CA) amended with 5 mg of pimaricin, 250 mg of ampicillin, 10 mg of rifampicin, 100 mg of pentachloronitrobenzene, and 50 mg of hymexazol (P5ARPH) per liter. Plates were incubated for 5 days at 28{\textdegree}C in the dark and Phytophthora chlamydospora was consistently isolated from the tissues. Isolates produced petaloid colonies and abundant spherical, thin-walled, intercalary but lateral and terminal chlamydospores (30 to 46 μm diameter, 38.5 μm average). Colonized agar discs were submerged in sterilized deionized water at 25{\textdegree}C. After incubation on submerged discs for 24 h, all isolates produced hyaline, nonpapillate, noncaducous sporangia of ovoid to obpyriform shape, with internal and external proliferation, 34.0 to 56.5 μm long, 26.5 to 39.5 μm wide, with a length/breadth ratio of 1.4 to 1.7, formed on simple, unbranched, occasionally sympodial sporangiophores. Globose to subglobose hyphal swellings in branched chains also formed in water. The optimum and maximum temperatures for mycelium growth on CA were 27 and 37{\textdegree}C, respectively. All these characteristics were similar to those described for P. chlamydospora Brasier and Hansen sp. nov. (Hansen et al. 2015), previously known as P. taxon Pgchlamydo. Genomic DNA was extracted from two representative isolates. The ITS region of rDNA was amplified using the ITS6/ITS4 primer pair and sequenced (GenBank KU647271 and KU647272). BLAST searches showed 99 to 100\% identity to P. chlamydospora isolates, including the type isolate P236 (99\% identity) (AF541900) (Hansen et al. 2015), deposited in GenBank and Phytophthora-ID databases, which confirmed morphological identification. Primary roots of ten 1-year-old P. dulcis cv. Ferragnes seedlings were wounded with a scalpel, and mycelial disks (3 per plant) of P. chlamydospora grown on CA were placed under the cortical tissue, after removing 10 to 15 cm of soil around the root base. The inoculated and exposed roots were then covered with soil. P. chlamydospora caused severe wilt and browning of leaves within 1 and 2 months and extensive root necrosis and rot after 2 months of incubation in a greenhouse. During this period, soil was kept wet by watering plants daily as required. Koch{\textquoteright}s postulates were satisfied after reisolating P. chlamydospora from symptomatic roots of inoculated plants. No disease occurred in 10 controls, similarly inoculated with sterile CA disks, and the pathogen was not recovered from these plants. P. chlamydospora has only rarely been recovered from several ornamental and woody species (Blomquist et al. 2012; Brasier et al. 2003; Ginetti et al. 2014), but not from fruit trees so far. To our knowledge, this is the first report of P. chlamydospora infection of almond, which represents a new host for this pathogen. This is also the first record of P. chlamydospora in Turkey. Within a month, all naturally infected almond trees in this orchard were collapsed and destroyed and the number of infected trees increased dramatically, indicating that it might be a significant threat to almond plantations and orchards, particularly on sites where excess soil water occurs periodically.

}, issn = {0191-2917}, doi = {10.1094/PDIS-02-16-0155-PDN}, url = {http://apsjournals.apsnet.org/doi/10.1094/PDIS-02-16-0155-PDN}, author = {T{\"u}rk{\"o}lmez, {\c S}. and Dervi{\c s}, S. and {\c C}ift{\c c}i, O. and Ser{\c c}e, {\c C}. U.} } @article {Tyler01092006, title = {Phytophthora genome sequences uncover evolutionary origins and mechanisms of pathogenesis}, journal = {Science}, volume = {313}, number = {5791}, year = {2006}, pages = {1261-1266}, abstract = {

Draft genome sequences have been determined for the soybean pathogen Phytophthora sojae and the sudden oak death pathogen Phytophthora ramorum. Oomycetes such as these Phytophthora species share the kingdom Stramenopila with photosynthetic algae such as diatoms, and the presence of many Phytophthora genes of probable phototroph origin supports a photosynthetic ancestry for the stramenopiles. Comparison of the two species{\textquoteright} genomes reveals a rapid expansion and diversification of many protein families associated with plant infection such as hydrolases, ABC transporters, protein toxins, proteinase inhibitors, and, in particular, a superfamily of 700 proteins with similarity to known oomycete avirulence genes.

}, doi = {10.1126/science.1128796}, url = {http://www.sciencemag.org/content/313/5791/1261.abstract}, author = {Tyler, Brett M. and Tripathy, Sucheta and Zhang, Xuemin and Dehal, Paramvir and Jiang, Rays H. Y. and Aerts, Andrea and Arredondo, Felipe D. and Baxter, Laura and Bensasson, Douda and Beynon, Jim L. and Chapman, Jarrod and Damasceno, Cynthia M. B. and Dorrance, Anne E. and Dou, Daolong and Dickerman, Allan W. and Dubchak, Inna L. and Garbelotto, Matteo and Gijzen, Mark and Gordon, Stuart G. and Govers, Francine and Grunwald, Niklaus J. and Huang, Wayne and Ivors, Kelly L. and Jones, Richard W. and Kamoun, Sophien and Krampis, Konstantinos and Lamour, Kurt H. and Lee, Mi-Kyung and McDonald, W. Hayes and Medina, M√>=nica and Meijer, Harold J. G. and Nordberg, Eric K. and Maclean, Donald J. and Ospina-Giraldo, Manuel D. and Morris, Paul F. and Phuntumart, Vipaporn and Putnam, Nicholas H. and Rash, Sam and Rose, Jocelyn K. C. and Sakihama, Yasuko and Salamov, Asaf A. and Savidor, Alon and Scheuring, Chantel F. and Smith, Brian M. and Sobral, Bruno W. S. and Terry, Astrid and Torto-Alalibo, Trudy A. and Win, Joe and Xu, Zhanyou and Zhang, Hongbin and Grigoriev, Igor V. and Rokhsar, Daniel S. and Boore, Jeffrey L.} } @article {867, title = {Phytophthora disease of chestnut}, journal = {Plant Prot.}, volume = {21}, year = {1967}, pages = {383-387}, author = {Uchida, K.} } @article {706, title = {Phytophthora katsurae}, journal = {Crop Knowledge Master}, year = {2006}, month = {22 June 2006}, publisher = {Extension Entomology \& UH-CTAHR Integrated Pest Management Program, University of Hawaii}, address = {Manoa, Hi}, url = {http://www.extento.hawaii.edu/Kbase/crop/Type/p_katsu.htm}, author = {Uchida, JY} } @article {864, title = {Studies on the trunk rot of Japanese chestnut trees caused by Phytophthora castaneae}, journal = {Bulletin of the Ibaraki-ken Horticultural Experiment Station}, volume = {Special Issue 3}, year = {1976}, pages = {48 pp.}, abstract = {

Since its discovery in 1962 this disease of Castanea crenata has spread throughout the chestnut growing area and causes particularly severe damage in young orchards with bare ground between the trees. The fungus attacks trunks, branches, shoots and exposed roots, producing symptoms of black sap exudation from bark lesions which enlarge to girdle the trunk. A P. sp. isolated from lesion margins and described as P. castaneae [RPP 57, 2024] was shown to be pathogenic to chestnut and oak, and to rot inoculated apple and Japanese pear fruits. The opt. temp. for mycelial growth was 27 deg and for oospore production 20-30 deg C. The pathogen survives as oospores in infested soil and was isolated using young chestnut shoots as bait. The population density of P. castaneae in orchard soils was not correlated with disease severity. Every cv. of C. crenata tested was susceptible and also the European chestnut (C. sativa), but Chinese chestnut (C. mollissima) and American chestnut (C. dentata) were resistant. The disease was controlled by grassing infested orchards and damage was reduced by grass mulches. Sprays of Difolatan [captafol] or Bordeaux on the trunks from early May to early June were effective, especially when combined with insecticide sprays. Fungicide applications to the soil or to the trunks after early June were ineffective.

}, url = {http://www.cabdirect.org/abstracts/19791352311.html}, author = {Uchida, K.} } @article {uchida1992phytophthora, title = {Phytophthora fruit and heart rots of coconut in Hawaii}, journal = {Plant disease}, volume = {76}, number = {9}, year = {1992}, pages = {925{\textendash}927}, publisher = {American Phytopathological Society}, abstract = {

Serious fruit and heart rots of coconut were found on the major Hawaiian islands of Kauai, Oahu, Hawaii and Maui. Early symptoms included dark fruit rots and the premature loss of young nuts. A Phytophthora sp. was consistently associated with fruit rots. There was a high association of fruit rots and subsequent heart rot followed by tree death. Fruit and heart rots were reproduced by inoculations. The causal organism resembled P. katsurae, but its identification remains undetermined.

}, doi = {10.1094/PD-76-0925}, url = {http://www.apsnet.org/publications/PlantDisease/BackIssues/Documents/1992Abstracts/PD_76_925.htm}, author = {Uchida, JY and Aragaki, M. and Ooka, J. and Nagata, NM} } @article {ullian_predictability_2000, title = {Predictability begets optimism: A conservation perspective on Port-Orford-cedar and Phytophthora lateralis}, journal = {PLANT DISEASE}, volume = {84}, number = {1}, year = {2000}, pages = {12{\textendash}13}, issn = {0191-2917}, author = {B. Ullian and E.S. Jules} } @article {3951, title = {New pest response guidelines - Phytophthora species in the environment and nursery settings}, year = {2010}, pages = {253 pp.}, publisher = { USDA{\textendash}APHIS{\textendash}PPQ{\textendash}Emergency and Domestic Programs{\textendash}Emergency Management, Riverdale, Maryland}, url = {http://www.aphis.usda.gov/import_export/plants/manuals/emergency/downloads/nprg-genericphytophthoras.pdf}, author = {USDA-APHIS-PPD} } @article {191, title = {Record of decision and land and resource management plan amendment for management of Port-Orford-cedar in southwest Oregon, Siskiyou National Forest}, year = {2004}, pages = {63 p.}, publisher = {U.S. Department of Agriculture Forest Service, Rogue River-Siskiyou National Forest}, address = {Medford, OR}, keywords = {Chamaecyparis lawsoniana, disease detection, Phytophthora lateralis}, url = {http://www.fs.fed.us/r6/rogue-siskiyou/projects/foresthealth/poc/poc-rod-fs.pdf}, author = {USDA-FS and USDI-BLM} } @article {192, title = {Final supplemental environmental impact statement management of Port-Orford-cedar in southwest Oregon}, year = {2004}, publisher = {U.S. Department of Agriculture - Forest Service, U.S. Department of the Interior - Bureau of Land Management}, address = {Portland, OR}, keywords = {Chamaecyparis lawsoniana, disease detection, Phytophthora lateralis}, url = {http://www.fs.fed.us/r6/rogue-siskiyou/projects/foresthealth/poc-seis.shtml}, author = {USDA-FS and USDI-BLM} } @proceedings {960, title = {Wildland management of Phytophthora ramorum in northern California forests}, volume = {Gen. Tech. Rep. PSW-GTR-214}, year = {2008}, pages = {305-312}, publisher = {U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station}, address = {Santa Rosa, California}, url = {http://www.fs.fed.us/psw/publications/documents/psw_gtr214/}, author = {Valachovic, Y. and C. Lee and J. Marshall and H. Scanlon}, editor = {Frankel, S.J. and J.T. Kliejunas and K. M. Palmieri} } @proceedings {961, title = {Forest treatment strategies for Phytophthora ramorum}, volume = {Gen. Tech. Rep. PSW-GTR-229}, year = {2010}, pages = {239-248}, publisher = {U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station}, address = {Santa Rosa, California}, url = {http://www.fs.fed.us/psw/publications/documents/psw_gtr229/}, author = {Valachovic, Y. and C. Lee, J. Marshall and H. Scanlon}, editor = {Frankel, S.J. and J.T. Kliejunas and K. M. Palmieri} } @article {4234, title = {Discovery of a fourth evolutionary lineage of Phytophthora ramorum: EU2}, journal = {Fungal Biology}, volume = {116}, year = {2012}, month = {Jan-11-2012}, pages = {1178 - 1191}, abstract = {

Phytophthora ramorum is a recently introduced, aggressive Phytophthora species that has caused extensive mortality of oak and tanoak trees in the western USA and Japanese larch trees in the UK. P. ramorum is also present on Rhododendron, Camellia, and Viburnum in the nursery industry, which is thought to have been the pathway for its spread into new geographic regions including forests and natural ecosystems. Three lineages of P. ramorum have been described, informally designated EU1, NA1, and NA2, and each lineage is believed to originate from an as yet unknown exotic centre of origin. Preliminary SSR and sequence analysis of isolates from a UK P. ramorum survey revealed seven isolates with profiles that did not match the previously known lineages. Detailed SSR and multilocus sequence analysis of these isolates are presented, allowing us to assign these isolates to a new P. ramorum lineage, designated EU2. Although the known geographical origin of these isolates is currently limited to Northern Ireland and western Scotland, the EU2 lineage isolates have been obtained from four different host plants, including Japanese larch. All isolates are of A1 compatibility type, which implies that this finding does not increase the risk of outcrossing with the EU1 lineage isolates already present in the UK. The oldest EU2 strain was isolated in 2007 but no SSR-based intraEU2 lineage genotypic diversity was detected. The combination of these elements points to a recent introduction, despite emergency phytosanitary measures to control introduction and spread. A PCR-RFLP method for the rapid identification of EU2 lineage isolates is presented.

}, issn = {18786146}, doi = {10.1016/j.funbio.2012.09.003}, url = {http://linkinghub.elsevier.com/retrieve/pii/S1878614612001572}, author = {Van Poucke, Kris and Franceschini, Selma and Webber, Joan F. and Vercauteren, Annelies and Turner, Judith A. and McCracken, Alistair R. and Heungens, Kurt and Brasier, Clive M.} } @article {EFP:EFP768, title = {Behaviour and survival of Phytophthora cambivora inoculum in soil-like substrate under different water regimes}, journal = {Forest Pathology}, year = {2012}, pages = {no{\textendash}no}, publisher = {Blackwell Publishing Ltd}, abstract = {

Phytophthora cambivora is a soil-borne pathogen responsible for root and collar rot of woody species including Castanea spp., on which it causes Ink disease. P. cambivora does not produce chlamydospores, and the prevalence of a single mating type in nature limits the production of oogonia and oospores. Thus, survival of P. cambivora, in the absence of suitable hosts, relies mainly on sporangia, zoospores and mycelium. However, inoculum survival in soils or substrates represents a major factor in disease epidemics and is probably dependant on environmental factors. The aim of this article was to study the behaviour of P. cambivora in a peat-based substrate (PbS) in the absence of a host, under controlled conditions, and by varying the substrate water regimes. Total inoculum in the substrate was quantified by qPCR, using customized rDNA primer sets, whilst zoospores were quantified after elution, and their vitality was determined by a specific staining procedure. Inoculum infectivity was assessed using chestnut root baits. Results indicated that during the initial 48 h after infestation (matric potential, pF 1.2; 70\% water content), the inoculum level increased producing microsporangia and mycelium before decreasing, regardless of the water regime applied. The number of free zoospores increased over a period of (maximum) 7 days after substrate inoculation. Vitality of zoospores declined to 45\% at day 18, with no statistical differences amongst water regime treatments. Both rDNA and zoospore number increased in flooded samples at day 23, illustrating the vitality of the inoculum. Inoculum was able to infect chestnut root baits up to 45 days at pF 1.2 and 3.5, before and after flooding, but at pF 6.3, only in the absence of flooding. Although based on experiments carried out in microcosms, these results highlight an unexpected resistance of P. cambivora zoospores to environmental constraints. Furthermore, the infectivity ability of the inoculum to survive in PbS over time even in the absence of the host adds relevance to the risk of movement of soil and substrates associated with plant trading worldwide.

}, issn = {1439-0329}, doi = {10.1111/j.1439-0329.2012.00768.x}, url = {http://dx.doi.org/10.1111/j.1439-0329.2012.00768.x}, author = {A. Vannini and Breccia, M. and Bruni, N. and Tomassini, A. and A.M. Vettraino} } @article {vannini2001ink, title = {Ink disease in chestnuts: impact on the European chestnut}, journal = {For. Snow Landsc. Res}, volume = {76}, number = {3}, year = {2001}, pages = {345{\textendash}350}, abstract = {A resurgence of ink disease in chestnuts in Europe has been noted since the end of the last century. This lethal disease is currently limiting the establishment of new groves and is threatening the survival of old ones. This paper discusses the impact of the disease and current knowledge about its aetiology and epidemiology. It gives information on the existing variability in tolerance in selected hybrid clones and in wild populations.}, author = {A. Vannini and A.M. Vettraino} } @article {PPA:PPA2585, title = {Alteration of physiological parameters of Austrocedrus chilensis by the pathogen Phytophthora austrocedrae}, journal = {Plant Pathology}, volume = {61}, year = {2012}, pages = {877{\textendash}888}, publisher = {Blackwell Publishing Ltd}, abstract = {

The effect of the pathogen Phytophthora austrocedrae on tree physiology of Austrocedrus chilensis in Patagonia was studied in a 4-week study. In the first week, stem-inoculated saplings showed a significant decrease in photosynthesis (A) without alteration of stomatal conductance (gs) or stem-specific hydraulic conductivity (Ks). From the second week on, progressive decreases in A, gs and Ks were observed, concomitantly with development of significant stem lesions. Water use efficiency (WUE) increased in the second week and declined progressively from the third week. Hyphae and resinous materials were observed in tracheids and rays below lesions. Necrosis of parenchyma ray cells and blockage of tracheids torus were observed. Healthy xylem showed no resinous materials or tracheid blockage, but abundant starch in rays, which was absent in altered xylem. The culture filtrate (CF) of the pathogen was shown to induce changes in extracellular pH and conductivity, and increased necrosis in tissues of leaves and stem challenged with CF in vitro. Similar results were obtained in leaf tissues of the inoculated saplings in vivo. CF injection into xylem of saplings induced a decline in A and disturbance of leaf tissue integrity, without altering gs, WUE or Ks. The decrease of A correlated with changes in tissue integrity. A possible mechanism of A. chilensis decline induced by P. austrocedrae is discussed.

}, keywords = {cypress root rot, effectors, hydraulic conductivity, mal del cipr√{\textcopyright}s, photosynthesis, xylem colonization}, issn = {1365-3059}, doi = {10.1111/j.1365-3059.2011.02585.x}, url = {http://dx.doi.org/10.1111/j.1365-3059.2011.02585.x}, author = {V{\'e}lez, M. L. and Silva, P. V. and Troncoso, O. A. and Greslebin, A. G.} } @article {PPA:PPA2627, title = {Survival of Phytophthora ramorum in Rhododendron root balls and in rootless substrates}, journal = {Plant Pathology}, volume = {62}, year = {2012}, pages = {166{\textendash}176}, publisher = {Blackwell Publishing Ltd}, abstract = {

This study assesses the survival of Phytophthora ramorum in the root ball of Rhododendron container plants as well as in different rootless forest substrates and a horticultural potting medium. Following inoculation of the root balls, the aboveground plant parts stayed symptomless, whilst the pathogen could be recovered with a novel non-destructive baiting assay from the root balls until at least 8\ months post-inoculation. Plating of surface-sterilized roots and direct microscopic analysis confirmed the presence of P.\ ramorum in the roots. Phytophthora ramorum could also be baited from the root balls of symptomless Rhododendron plants from commercial nurseries, even 2\ years after acquisition. Survival of P.\ ramorum in rootless media was assessed after burying disks of infected leaf material below the soil surface in columns filled with four different undisturbed forest substrates or a potting medium, and incubated at an outdoor quarantine facility. Phytophthora ramorum could be recovered at least 33\ months after burial from all substrates, with a significant increase in recovery after the winter period. These data suggest the possibility for long-term symptomless presence of P.\ ramorum in root balls of commercial Rhododendron plants as well as survival in potting medium and different forest substrates under western European climate conditions. Symptomless presence in root balls can contribute to latent spread of this pathogen between nurseries. The novel baiting test, being non-destructive, simple and applicable to a relatively large number of plants, can offer a valuable tool to test plants for the presence of Phytophthora species in root balls.

}, keywords = {baiting, detection, latent survival, Sudden oak death}, issn = {1365-3059}, doi = {10.1111/j.1365-3059.2012.02627.x}, url = {http://dx.doi.org/10.1111/j.1365-3059.2012.02627.x}, author = {Vercauteren, A. and Riedel, M. and Maes, M. and Werres, S. and Heungens, K.} } @article {PPA:PPA864, title = {Evaluation of root damage to English walnut caused by five Phytophthora species}, journal = {Plant Pathology}, volume = {52}, number = {4}, year = {2003}, pages = {491{\textendash}495}, publisher = {Blackwell Science Ltd}, abstract = {

The pathogenicity of five species of Phytophthora to English walnut was studied in a greenhouse experiment. Phytophthora cinnamomi was the most aggressive species, causing severe root rot and seedling mortality. The other species tested, P. cambivora, P. citricola, P. cactorum and P. cryptogea, did not induce visible crown symptoms on seedlings 2 months after inoculation. Some strains of P. cambivora and P. cactorum also caused taproot damage to seedlings. All except one of the tested isolates caused significant necrosis of fine roots and a significant reduction of root weight compared with noninoculated seedlings. Reduction of above-ground plant development was not statistically significant. While P. cinnamomi is well known as an aggressive primary pathogen of English walnut, the other species of Phytophthora may act as predisposing factors to walnut decline, affecting root system development and increasing host vulnerability to environmental stress.

}, keywords = {English walnut, Juglans regia, pathogenicity, soilborne pathogens, walnut decline}, issn = {1365-3059}, doi = {10.1046/j.1365-3059.2003.00864.x}, url = {http://dx.doi.org/10.1046/j.1365-3059.2003.00864.x}, author = {A.M. Vettraino and Belisario, A. and Maccaroni, M. and A. Vannini} } @article {1324, title = {Phytophthora ramorum infection of coast live oak leaves in Californian forests and its capacity to sporulate in vitro}, journal = {Australasian Plant Pathology}, volume = {37}, year = {2008}, pages = {72-73}, publisher = {Springer Netherlands}, abstract = {

Coast live oak (Quercus agrifolia) is a known host for Phytophthora ramorum, the casual agent of sudden oak death in California, with symptoms expressed as necrotic stem cankers. In the forest, leaves on two saplings in California were found to be infected with P. ramorum and these were associated with infected bay laurel (Umbellularia californica) trees. Coast live oak leaves supported sporulation and produced chlamydospores in vitro. This is the first report to identify foliage of coast live oak as a source of infection of P. ramorum in the forest and its confirmation in in vitro inoculations.

}, issn = {0815-3191}, doi = {10.1071/AP07085}, url = {http://dx.doi.org/10.1071/AP07085}, author = {A.M. Vettraino and H{\"u}berli, D. and Garbelotto, M.} } @article {PPA:PPA839, title = {Scotch broom: a new host of Phytophthora megasperma in Italy}, journal = {Plant Pathology}, volume = {52}, number = {3}, year = {2003}, pages = {417{\textendash}417}, publisher = {Blackwell Science Ltd}, issn = {1365-3059}, doi = {10.1046/j.1365-3059.2003.00839.x}, url = {http://dx.doi.org/10.1046/j.1365-3059.2003.00839.x}, author = {A.M. Vettraino and A. Vannini} } @article {springerlink:10.1007/s10658-004-1882-0, title = {Occurrence and distribution of Phytophthora; species in European chestnut stands, and their association with Ink Disease and crown decline}, journal = {European Journal of Plant Pathology}, volume = {111}, year = {2005}, note = {10.1007/s10658-004-1882-0}, pages = {169-180}, publisher = {Springer Netherlands}, abstract = {

The Phytophthora complex associated with Castanea sativa Mill. was investigated in five European countries in 35 regions and with respect to various domestication levels. Annual precipitation and length of drought season were the main parameters that regulated the presence of Phytophthora species in the chestnut stands. Seven species of Phytophthora were detected; three of these, P. megasperma, P. cryptogea and P. syringae had not been previously reported on sweet chestnut. P. cinnamomi. P. cambivora and P. citricola were most frequently isolated. P. cinnamomi and P. cambivora were the species significantly associated with declining trees with symptoms of Ink Disease. P. cinnamomi required distinct ecological conditions compared to the other species. P. cinnamomi was never detected in sites characterized by minimum temperatures below 1.4 {\textdegree}C, maximum temperature above 28 {\textdegree}C, or soil pH below 5.4. The results obtained provide useful information for modeling the probability of Ink Disease, crown decline and associated Phytophthora species in chestnut groves in global climatic change scenarios.

}, issn = {0929-1873}, url = {http://dx.doi.org/10.1007/s10658-004-1882-0}, author = {Vettraino, A. and Morel, O. and Perlerou, C. and Robin, C. and Diamandis, S. and A. Vannini} } @article {3966, title = {First report of Phytophthora cactorum associated with beech decline in Italy}, journal = {Plant Disease}, volume = {92}, year = {2008}, month = {12/2008}, pages = {1708 - 1708}, abstract = {

During 2006 and 2007, declining mature beech trees (Fagus sylvatica) were recorded in two stands in the Natural Park of Monti Cimini in central Italy. Symptoms included crown thinning and the presence of bleeding lesions on the main roots and lower stem. Incidence of decline was approximately 5\%. Samples of necrotic bark tissue were collected, cut into 5 mm long segments, plated on PARPNH, and incubated at 20{\textdegree}C (1). Phytophthora isolates were obtained from necrotic tissues of 25\% of the sampled declining trees. Colonies were rosaceous on potato dextrose agar (PDA) and homothallic. Papillate, ovoid-to-obpyriform, caducous sporangia (mean 38 {\texttimes} 26.2 μm) were produced in soil extract. Oospores were plerotic (mean diameter of 22 to 32 μm) and antheridia paragynous. Optimum growth temperature was 23 to 25{\textdegree}C, minimum 6 to 8{\textdegree}C and maximum 30 to 33{\textdegree}C. A portion of the internal transcribed spacer sequence has been deposited in the NCBI database (GenBank Accession No. FJ183724). A BLAST search of the NCBI database revealed Phytophthora cactorum, Accession No. EU194384, as the closest match with 100\% sequence similarity. Pathogenicity of two isolates, PFE3 and IFB-CAC 38, collected from distressed beech trees was tested using a soil infestation test (10 beech seedlings per isolate and control) and an under the bark inoculation method (10 twigs per isolate and controls, wounded and noninoculated taken from a declining beech tree) (2). After 2 weeks at 20{\textdegree}C, twigs and seedlings inoculated with each isolate developed extensive necrotic lesions around the inoculation sites and the collar, respectively, and P. cactorum could be reisolated from all lesions. Controls showed no symptoms. P. cactorum is widespread in declining beech forests in central Europe (1). In Italy, P. cactorum occurs in soils of chestnut and oak forests and was isolated from collar and root lesions of declining walnut trees (3). To our knowledge, this is the first report of P. cactorum being associated with declining beech trees in Italy.

}, issn = {0191-2917}, doi = {10.1094/PDIS-92-12-1708A}, author = {A.M. Vettraino and T. Jung and A. Vannini} } @article {EFP:EFP264, title = {Occurrence of Phytophthora species in oak stands in Italy and their association with declining oak trees}, journal = {Forest Pathology}, volume = {32}, number = {1}, year = {2002}, pages = {19{\textendash}28}, publisher = {Blackwell Science Ltd.}, abstract = {

Soil-borne species of Phytophthora were isolated from 19 of 30 examined oak forest areas in Italy. The frequency of isolated Phytophthora spp. (35.2\%) was significantly correlated with soil pH and longitude of the sites. Eleven Phytophthora species were detected. Phytophthora cambivora, P. cinnamomi and P. cactorum were recovered from sites in central and southern Italy whereas P. quercina was isolated in the northern and central part of the country. Phytophthora citricola occurred all over Italy. Phytophthora quercina was the only species significantly associated with declining oak trees.

}, issn = {1439-0329}, doi = {10.1046/j.1439-0329.2002.00264.x}, url = {http://dx.doi.org/10.1046/j.1439-0329.2002.00264.x}, author = {A.M. Vettraino and Barzanti, G. P. and Bianco, M. C. and Ragazzi, A. and Capretti, P. and Paoletti, E. and Luisi, N. and Anselmi, N. and A. Vannini} } @article {4457, title = {Surveillance methods to determine tree health, distribution of kauri dieback disease and associated pathogens}, journal = {New Zealand Plant Protection}, volume = {66}, year = {2013}, pages = {235{\textendash}241}, abstract = {

Kauri dieback is a pest issue that is increasingly affecting kauri forests. A water and soilborne pathogen, Phytophthora taxon Agathis (PTA), has been identified as a causal agent of kauri dieback at multiple locations, particularly within Auckland and Northland. In 2008, a passive surveillance and adaptive management programme was initiated to manage the disease across the natural range of kauri. Surveys were initially undertaken to determine the distribution and rate of spread of kauri dieback on private land in the Auckland region. Methods to evaluate and monitor overall tree health, disease symptoms and other potential contributing factors were developed. Diagnostic sampling was undertaken to isolate and identify pathogens associated with kauri dieback. Along with PTA, other Phytophthora species and environmental stress were frequently associated with symptoms at over 400 properties inspected. Further management is now required to develop control tools and mitigate further spread.

}, issn = {1175-9003 (print), 1179-352X (online)}, url = {http://www.nzpps.org/nzpp_abstract.php?paper=662350}, author = {Waipara, N.W. and Hill, S. and Hill, L.M.W. and Hough, E.G. and Horner, I.J.} } @proceedings {681, title = {Phytophthora ramorum and Phytophthora kernoviae in England and Wales{\textemdash}Public Consultation and New Programme}, volume = {Gen. Tech. Rep. PSW-GTR-229}, year = {2009}, month = {04/2010}, pages = {6-14}, publisher = {U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station.}, address = {Santa Cruz, California}, author = {Keith Walters and Claire Sansford and David Slawson}, editor = {Susan J. Frankel and John T. Kliejunas and Katharine M. Palmieri} } @article {4376, title = {First Report of Phytophthora tentaculata Causing Stem and Root Rot on Celery in China}, journal = {Plant Disease}, volume = {98}, year = {2014}, month = {Jan-03-2014}, pages = {421 - 421}, abstract = {

Celery (Apium graveolens) is an important vegetable in China. In August 2012, about 20 to 70\% declining plants with root and basal stem rot were observed in Bengbu, Anhui Province, China. Typical symptoms included large dark brown to black water-soaked lesions near the soil line of stems. As the disease progressed, lesions girdled the stem, and plants became brown, wilted, and eventually died. A Phytophthora-like organism was consistently isolated from symptomatic tissues on a selective medium, P5ARP. Resultant isolates were identified as Phytophthora tentaculata based on their morphological features and rDNA sequence. Sporangia, chlamydospores, hyphal swellings, and oospores were produced on V8 agar. Sporangia were ovoid to pyriform, 28.5 to 52.5 {\texttimes} 21.5 to 40.6 μm, average 35.3 {\texttimes} 29.8 μm, with one or occasionally two papillae. Chlamydospores were spherical, 21.3 to 30.2 μm in diameter, average 25.7 μm. The isolates were homothallic, and one or occasionally two paragynous antheridia were attached to the global oogonia (24 to 39 μm in diameter, average 29.5 μm). The internal transcribed spacer region of rDNA was amplified with primer pair ITS1/ITS4 for one isolate (1), and the sequence (GenBank Accession No. KF501392) showed \>99\% similarity with those P. tentaculata isolates deposited in GenBank (AJ854302.1). Pathogenicity was confirmed by inoculating Shijihuangqin, a local cultivar of celery, with isolate PT12081. The isolate was cultivated on V8 agar at 25{\textdegree}C for 5 to 7 days to produce sporangia. Five 2-month-old, disease-free celery were drench-inoculated with 10 ml of a suspension of 2 {\texttimes} 104 zoospores/ml, and five control plants per pot were treated with sterile water. There were four pots for each of the inoculated and non-inoculated treatments, and the experiment was repeated twice. All plants were maintained at 25{\textdegree}C for 10 days. Symptoms similar to those observed in the field developed 7 days after inoculation. Ten days later, five plants wilted and two or three died in each pot inoculated with PT12081, but the control plants remained symptomless. P. tentaculata was consistently re-isolated from the symptomatic plants. P. tentaculata has been reported to infect Chrysanthemum spp., Delphinium ajacis, Verbena spp., and Origanum vulgare (2,3). To our knowledge, this is the first report of Phytophthora blight caused by P. tentaculata on celery in China.

}, issn = {0191-2917}, doi = {10.1094/PDIS-06-13-0592-PDN}, url = {http://apsjournals.apsnet.org/doi/abs/10.1094/PDIS-06-13-0592-PDN}, author = {Wang, T. and Zhao, W. and Qi, R.-D.} } @article {4048, title = {Taxonomy in Phytophthora}, journal = {Phytopathology}, volume = {60}, year = {1970}, month = {1970}, pages = {1141}, issn = {0031949X}, doi = {10.1094/Phyto-60-1141}, author = {Waterhouse, Grace M.} } @article {260, title = {Key to the species of Phytophthora de Bary.}, journal = {Mycological Papers}, volume = {92}, year = {1963}, pages = {1-22}, author = {Waterhouse, G. M.} } @article {EFP:EFP729, title = {Isolation of Phytophthora lateralis from Chamaecyparis foliage in Taiwan}, journal = {Forest Pathology}, year = {2011}, pages = {no{\textendash}no}, publisher = {Blackwell Publishing Ltd}, abstract = {

Summary Following the discovery in 2008 of Phytophthora lateralis in forest soil under old-growth yellow cedar (Chamaecyparis obtusa var. formosana) in north-east Taiwan, further sampling was undertaken in the same region. Soil, root and symptomatic foliage samples were collected from five separate sites where C.\ obtusa was the dominant species in cloud forests at ca.\ 1800{\textendash}2500\ m. Soil and fine root samples were baited with cedar needles; both direct isolation and cedar needle baiting were used on foliage samples. Phytophthora lateralis was obtained from soil at three of the sites, but only from three of the 27 soil samples overall. Only one of 25 root samples yielded the pathogen, and this was associated with infested soil. Three foliage samples with symptoms visible as dark brown to black frond tips also yielded P.\ lateralis; these came from two different sites. This is the first record of P.\ lateralis infecting the foliage of C.\ obtusa. Moreover, when some of the symptomatic Chamaecyparis foliage segments were incubated, sporangia of P.\ lateralis formed on the necrotic tissues, sometimes in the axils of needle segments. The study provides evidence that P.\ lateralis has both a soil/root infecting phase and an aerial or foliar infecting phase in Taiwan, which is consistent with its unusual combination of water-dispersed (non-papillate) and aerially dispersed (caducous) sporangia. It also demonstrates the importance of investigating the biology, aetiology and ecological behaviour of Phytophthoras in their native, endemic environments.

}, issn = {1439-0329}, doi = {10.1111/j.1439-0329.2011.00729.x}, url = {http://dx.doi.org/10.1111/j.1439-0329.2011.00729.x}, author = {Webber, JF and A.M. Vettraino and T.T. Chang and Bellgard, S.E. and C.M. Brasier and A. Vannini} } @proceedings {682, title = {Management of P. kernoviae and P. ramorum in southwest England.}, volume = {General Technical Report PSW-GTR-221}, year = {2009}, pages = {177-183}, publisher = {U.S. Department of Agriculture, Forest Service Pacific Southwest Research Station}, address = {Monterey, California}, author = {Webber,Joan}, editor = {Goheen, E. M. and Susan J. Frankel} } @article {webber_dieback_2010, title = {Dieback and mortality of plantation Japanese larch (Larix kaempferi) associated with infection by Phytophthora ramorum}, journal = {New Disease Reports}, volume = {22}, year = {2010}, pages = {19}, abstract = {

The invasive pathogen Phytophthora ramorum is the cause of {\textquoteright}sudden oak death{\textquoteright}, a dieback and mortality of more than one million live-oak and tanoak trees along 1500 km of near-coastal native forest in California and Oregon since 1995 (Rizzo et al., 2002; Frankel, 2008). P. ramorum has also spread across Europe , mainly within the ornamental nursery trade. From 2003 onwards it was found infecting rhododendron and woodland trees outside nurseries in Britain (Brasier et al., 2004) and has recently spread to native Vaccinium swards (P. Beales, personal communication). Until now, tree infections in Britain have been comparatively few (\<100), mostly foliage or stems of Fagaceae (Fagus, Nothofagus, Quercus and Castanea) in the vicinity of infected Rhododendron in south west England (Webber, 2008). In August 2009 extensive dieback and mortality was observed in mature (25-30 m tall) and juvenile plantation Japanese larch, Larix kaempferi,at multiple sites in south west England (Figs. 1, 2). Symptoms included black or purple discoloured needles (Fig. 3), aborted bud flush, wilting and senescence of dwarf shoots and needle loss. Affected trees often had copious resin bleeding on the trunk, branches and side shoots plus dieback of branches and sometimes of the entire crown. Phloem lesions were often present under resinous outer bark. These usually had deep pink to maroon-red margins, older lesion areas being rusty-brown to cinnamon brown.

When symptom-bearing needles were surface-sterilised in 70\% ethanol for 30 seconds or small pieces of older phloem lesion were plated onto Phytophthora selective medium (Brasier et al., 2005), P. ramorum was obtained from 25-40\% of the samples. Identity was confirmed by sequencing of ITS rDNA regions (GenBank Accession No. HQ010359). P. ramorum was not obtained from the pink-maroon lesion margins. Pathogenicity of a P. ramorum isolate from L. kaempferi was tested by dipping 15 cm long L. kaempferi shoots into a zoospore suspension and damp chamber incubating for 12h light/12h dark cycle at 18{\textdegree}C. On half the shoots all needles were wounded by tip cutting. After seven days each needle was categorised as blackened, browned/brown bands, chlorotic or green, surface sterilised and plated onto selective medium. Both unwounded and wounded blackened needles yielded P. ramorum at high frequency (Table 1). When needles were mounted in lactic acid cotton blue and viewed 24 h later, sporangia and occasionally chlamydospores were observed on the surfaces with an exceptional 2685 sporangia counted on one unwounded needle (Fig. 4).

P. ramorum has so far been isolated from L. kaempferi at 68 currently known plantations where symptoms are present in southwest England . In May 2010 larch plantations with similar symptoms were discovered in south Wales and P. ramorum has again been isolated at multiple sites. Overall an estimated 2400 ha or c. 0.6 million mature larch have been affected to date. A large area of juvenile larch is also affected. This is the first widespread and lethal damage caused by P. ramorum to a conifer and the first to a commercial plantation tree. Adjacent to some affected larch sites in southwest England , secondary infection of Fagus sylvatica, Nothofagus obliqua, Castanea sativa, Betula pendula, Rhododendron ponticum, Tsuga heterophylla and Pseudotsuga menziesii is also occurring, apparently as result of the high levels of P. ramorum inoculum produced from larch foliage.\ \ 

}, url = {http://dx.doi.org/10.5197/j.2044-0588.2010.022.019}, author = {Webber, JF and Mullett, M. and C.M. Brasier} } @article {4310, title = {A taxonomic revision of Phytophthora Clade 5 including two new species, Phytophthora agathidicida and P. cocois}, journal = {Phytotaxa}, volume = {205}, year = {2015}, month = {10/2015}, pages = {21}, abstract = {

Phytophthora Clade 5 is a very poorly studied group of species of oomycete chromists, consisting of only two known species P. castaneae (= P. katsurae, nom. illegit.) and P. heveae with most isolates from East Asia and the Pacific Islands. However, isolates of two important disease-causing chromists in Clade 5, one of kauri (Agathis australis) in New Zealand, the other of coconut (Cocos nucifera) in Hawaii, poorly match the current species descriptions. To verify whether these isolates belong to separate species a detailed morphological study and phylogenetic analysis consisting of eight genetic loci was conducted. On the basis of genetic and morphological differences and host specificity, we present the formal description of two new species in Clade 5, Phytophthora agathidicida sp. nov. and Phytophthora cocois sp. nov. To clarify the typification of the other Clade 5 species, an authentic ex-holotype culture of Phytophthora castaneae is designated and P. heveae is lectotypified and epitypified.

}, issn = {1179-3155}, doi = {http://dx.doi.org/10.11646/phytotaxa.205.1.2}, url = {http://biotaxa.org/Phytotaxa/article/view/phytotaxa.205.1.2}, author = {Weir, B. S. and Paderes, E. P. and Anand, N. and Uchida, J. Y. and Pennycook, S. R. and Bellgard, S. E. and Beever, R. E.} } @article {858, title = {The possible origin and relation of Phytophthora katsurae and P. heveae, discovered in a protected natural forest in Taiwan}, journal = {Botanical Studies}, volume = {47}, year = {2006}, pages = {273-277}, abstract = {When a total of 531 soil samples collected from 1976 to 2000 from various locations distributed in every county on the island of Taiwan was assayed, sixteen isolates of Phytophthora katsurae and nine isolates of P. heveae were recovered from three and four counties, respectively. Phytophthora katsurae and P. heveae were isolated from a protected natural forest located atop a hill at Lenhuachih without higher land within the range of vision, suggesting that both species are indigenous to Taiwan. Phytophthora katsurae is distinguished from the similar P. heveae by its verrucose oogonial wall. The number of protrusions produced by the Taiwanese isolates of P. katsurae varied greatly ranging from 2 to 23 per oogonium, indicating the unsteadiness of this taxonomical characteristic. Oogonia produced by isolates of P. katsurae obtained from Hawaii contained very few protrusions. Moreover, most oogonia produced by two of these isolates did not have any protrusions and were indistinguishable from those produced by P. heveae. Results suggest the development of P. heveae directly from P. katsurae by loss of oogonial protrusions. The high level of ITS sequence similarity between P. heveae and P. katsurae in comparison with their relationships to other Phytophthora species tested also support the possibility of the recent development of one species from the other species.}, url = {http://ejournal.sinica.edu.tw/bbas/content/2006/3/Bot473-07/}, author = {Wen-Hsiung, KO and Wang, SY and Ann, PJ} } @article {Werres20011155, title = {Phytophthora ramorum sp. nov., a new pathogen on Rhododendron and Viburnum}, journal = {Mycological Research}, volume = {105}, number = {10}, year = {2001}, pages = {1155 - 1165}, abstract = {

Since 1993, a hitherto unidentified Phytophthora species has been found associated with twig blight disease in Rhododendron and, sporadically, Viburnum. The morphology and growth characteristics of fourteen isolates from Germany and the Netherlands were investigated, together with their breeding system, the internal transcribed spacer (ITS) regions of the ribosomal DNA, amplified fragment length polymorphism (AFLP) fingerprints, and isozyme profiles, which were compared to those of a number of outgroup species. Morphologically the isolates are characterized by abundant production of chlamydospores and elongate, ellipsoid, deciduous sporangia with a short pedicel, in which they resemble P. palmivora. However, sporangia were semi-papillate, chlamydospores were much larger and cardinal temperatures much lower than those of P. palmivora. Oogonia with amphigynous antheridia and plerotic oospores were produced in dual cultures with an A2 mating type strain of P. cryptogea. ITS1 and ITS2 sequences of the unidentified species were closest to those of P. lateralis, but differed in three and eight nucleotides respectively from the latter species. AFLP fingerprints and isozyme patterns of malate dehydrogenase (MDH-2) and malic enzyme (MDHP) showed that the isolates formed a homogeneous group, distinct from all examined outgroup species, including P. lateralis. It was concluded that they represent a new Phytophthora species, described here as P. ramorum sp. nov. In pathogenicity tests all isolates of P. ramorum were pathogenic to Rhododendron.

}, issn = {0953-7562}, doi = {DOI: 10.1016/S0953-7562(08)61986-3}, url = {http://www.sciencedirect.com/science/article/B7XMR-4RS3YCS-4/2/9f9142119aa3952d3dbc8811be4860bb}, author = {Werres, Sabine and Rainer Marwitz and WA Man_In{\textquoteright}t_veld and De Cock, AWAM and Peter J.M. Bonants and De Weerdt, M. and Karin Themann and Elena Ilieva and Robert P. Baayen} } @article {270, title = {Impact of Phytophthora species on native vegetation of Australia and Papua New Guinea.}, journal = {Australasian Plant Pathology}, volume = {23}, year = {1994}, pages = {190-209}, author = {Weste, G.} } @article { ISI:A1987J838700014, title = {The biology of Phytophthora cinnamomi in Australian forests}, journal = {Annual Review of Phytopathology}, volume = {25}, year = {1987}, pages = {207-229}, publisher = {{ANNUAL REVIEWS INC}}, type = {Review}, address = {{4139 EL CAMINO WAY, PO BOX 10139, PALO ALTO, CA 94303-0139}}, issn = {0066-4286}, doi = {10.1146/annurev.py.25.090187.001231}, url = {http://www.annualreviews.org/doi/abs/10.1146/annurev.py.25.090187.001231}, author = {Weste, G. and Marks, CG} } @book {4660, title = {PCR Protocols amplification and direct sequencing of fungal ribosomal RNA genes for phylogenetics}, year = {1990}, pages = {315 - 322}, publisher = {Elsevier}, organization = {Elsevier}, isbn = {9780123721808}, doi = {10.1016/B978-0-12-372180-8.50042-1}, url = {https://linkinghub.elsevier.com/retrieve/pii/B9780123721808500421}, author = {White, T.J. and Bruns, T. and Lee, S. and Taylor, J.} } @article {1295, title = {Infectivity and inoculum production of Phytophthora ramorum on roots of eastern United States oak species}, journal = {Plant Disease}, volume = {96}, year = {2012}, month = {11/2012}, pages = {1675-1682}, abstract = {

Little is known about colonization of roots of trees by Phytophthora ramorum. We examined zoospore concentration and exposure time needed to infect six Quercus (oak) species and the inoculum produced from their roots. Sprouted acorns, exposed to zoospores (3,000/ml) for different times and transplanted to potting soil, were susceptible to infection within 1 h of exposure but root weights were not impacted after 4 weeks (P = 0.952). Roots of Quercus prinus seedlings, inoculated with sporangia, had 0.6 to 3.2\% colonization of the total root mass after 5 months. Neither root lesions nor obvious root sloughing were observed. Inoculum threshold levels were tested by exposing radicles to varying zoospore concentrations for 24 h. Results showed that radicle infection occurred even at 1 zoospore/ml. To test inoculum production, roots were inoculated with sporangia and transplanted into pots. Periodically, samples of runoff were collected and plated on selective medium. Afterward, root segments were plated to calculate percent colonization. After 16 and 35 days, root colonization and inoculum production from oak was lower than that of Viburnum tinus, a positive control. This study shows that P. ramorum is able to infect sprouted oak acorns and produce secondary inoculum, which may be important epidemiologically.

}, url = {http://dx.doi.org/10.1094/PDIS-12-11-1024-RE}, author = {T. L. Widmer and N. Shishkoff and S. C. Dodge} } @article {4314, title = {Bioassay Conditions for Infection of Pinus radiata Seedlings with Phytophthora pinifolia Zoospores}, journal = {Plant Disease}, volume = {99}, year = {2015}, month = {Jan-09-2015}, pages = {1204 - 1209}, abstract = {

Phytophthora pinifolia is known to cause a devastating disease on Monterey pine in Chile. Although this pathogen is not yet present in the United States, there is reason for concern. The main source of Monterey pine genetic material is found in California and there is potential for other important tree species to be hosts. The study presented here was conducted to develop a method to produce zoospores and determine optimal conditions for infection to be used in future host range studies. Abundant zoospores were produced when agar plugs containing P. pinifolia mycelia were ground into suspension prior to transfer in a solution of carrot broth. These zoospores then were used to inoculate Monterey pine seedlings under various conditions. Infected plants displayed necrotic crowns and stems, often resulting in wilting of the seedling. Consistent infection occurred when seedlings were wounded by trimming needles prior to inoculation and exposure of inoculated seedlings to constant dew for 5 days. Dew chamber temperature (15, 20, or 25{\textdegree}C) did not affect the infection rate. Information obtained from this study will be useful in screening other hosts for susceptibility to P. pinifolia infection.

}, issn = {0191-2917}, doi = {10.1094/PDIS-12-14-1306-RE}, url = {http://apsjournals.apsnet.org/doi/10.1094/PDIS-12-14-1306-RE}, author = {Widmer, Timothy L. and Dodge, Stephen C.} } @article {widmer2011survival, title = {Survival of Phytophthora kernoviae oospores, sporangia, and mycelium}, journal = {New Zealand Journal of Forestry Science}, volume = {41S}, year = {2011}, month = {07/2011}, pages = {15-23}, abstract = {

Interpretive Summary: A recently discovered plant pathogen has been found to attack many different hosts including rhododendrons and beech trees in the United Kingdom and New Zealand. Although not currently known to exist in the United States, it is a pathogen of concern due to its destructive nature and threat to valuable hosts in the U.S. This pathogen produces different propagules for spread and survival of which very little is known. This study was done to learn how long these propagules can survive at different temperatures. Results show that one propagule type can survive buried in sand for up to a year at moderate temperatures but declines rapidly when exposed for increased periods of time as temperatures increase. In addition, this pathogen is able to persist and produce survival propagules in sand with very minimal nutrients. These results provide information to regulatory agency personnel and scientists to develop guidelines that help in limiting the spread of this pathogen. Technical Abstract: Phytophthora kernoviae is a pathogen recently found only in the U.K. and New Zealand. Phytophthora kernoviae, not known to produce chlamydospores, is homothallic and produces abundant oospores and sporangia. This study was conducted to examine long-term survival of oospores, sporangia, and mycelium buried in sand at different temperatures. Viability of oospores embedded onto 20-{\textmu}m-mesh screens and buried in sand at 4, 10, 20, and 30C was measured over time by staining with tetrazolium bromide solution. For one isolate, viability was 82, 81, 79, and 58\% and 86, 75, 82, and 78\% for the other isolate at 4, 10, 20, and 30C, respectively, after 1 year. The infection potential of the oospores was checked by removing additional embedded screens and placing on rhododendron leaf disks. No necrosis was observed on leaf disks exposed to oospores buried for 1 year at 30C. However, necrosis was observed on leaf disks at the other temperatures after the same time. Oospores exposed 6 h at 50C and 24 h at 40 and 50C were less viable than controls and did not germinate. To study survival of sporangia and mycelium, sand was infested only with sporangia or mycelium from four isolates, incubated at different temperatures, and plated on Phytophthora-selective medium over time. All isolates reacted in the same manner with populations generally declining within 1 week but then remaining steady over time. Soil extractions of the infested sand showed that over time sporangia and oospores formed at all temperatures except at 30C. This demonstrates that P. kernoviae oospores can persist in sand for long periods of time at different temperatures, which could be a significant factor in spread of this pathogen.

}, url = {http://www.ars.usda.gov/research/publications/publications.htm?seq_no_115=259635}, author = {Widmer, TL} } @article {Widmer2010661, title = {Phytophthora kernoviae oospore maturity, germination, and infection}, journal = {Fungal Biology}, volume = {114}, number = {8}, year = {2010}, pages = {661 - 668}, abstract = {

Limited information is known on the basic biology of the recently described Phytophthora kernoviae that produces homothallic oospores. In this study, different P. kernoviae isolates were used to investigate oospore maturity, germination, and infection. All isolates produced oospores in V8 broth at 20{\textdagger}${\i}nfty$C in the dark by 6{\textdagger}d. Oospores also formed at 10 and 15{\textdagger}${\i}nfty$C, but did not form at 25 and 28{\textdagger}${\i}nfty$C. Continuous light inhibited oospore production of some isolates but had no negative effect on others. Maturation time of the oospores, as noted by germination and staining with tetrazolium bromide, was not much different among the isolates between 2 and 14 weeks. Oospore germination was optimal at 18 and 20{\textdagger}${\i}nfty$C, and did not occur at 5, 25, and 30{\textdagger}${\i}nfty$C. Oospore germination under continuous light was higher than in the dark, but individual isolates showed variable results. Rhododendron leaf disks inoculated with oospores and maintained in the dark at 20{\textdagger}${\i}nfty$C were necrotic after 1 week, while those kept under continuous light did not develop necrosis. The percentage of leaf disks infected with P. kernoviae was lower in the leaves exposed to continuous light (40{\textdagger}\%) compared to those kept in the dark (100{\textdagger}\%).

}, keywords = {Viability stain}, issn = {1878-6146}, doi = {DOI: 10.1016/j.funbio.2010.06.001}, url = {http://www.sciencedirect.com/science/article/B9879-508K88P-1/2/e35155432b3146cdabc05226a599fa75}, author = {Timothy L. Widmer} } @mastersthesis {wing_field_2005, title = {Field validation of laboratory tests used in screening Port-Orford-cedar for resistance to Phytophthora lateralis}, year = {2005}, type = {mastersphd}, author = {Adam B Wing} } @article {518341320011001, title = {Molecular diagnosis of Phytophthora lateralis in trees, water, and foliage baits using multiplex polymerase chain reaction.}, journal = {Forest Pathology}, volume = {31}, number = {5}, year = {2001}, pages = {275 - 283}, abstract = {

A polymerase chain reaction (PCR)-based protocol for detection of Phytophthora lateralis in plant tissues and water is described. Base-pair (bp) deletions in both of the ribosomal DNA internal transcribed spacer (ITS) regions in P. lateralis were used to design complementary PCR primer sequences that amplify a 738 bp fragment only if P. lateralis DNA is present in the sample. Universal control primers based on conserved sequences of the nuclear ribosomal small subunit are included in a multiplexed reaction, providing an internal check on the procedure. The universal primers amplify an approximately 550 bp fragment that is common to plants, protists, and true fungi. The procedure reliably detects P. lateralis in cedar stem tissues and in roots. Positive reactions were obtained with as few as 200 P. lateralis zoospores in water. (English) [ABSTRACT FROM AUTHOR]

}, keywords = {PHYTOPHTHORA diseases, PLANT diseases, polymerase chain reaction}, issn = {14374781}, doi = {10.1046/j.1439-0329.2001.00251.x}, author = {Winton, L. M. and Hansen, E.M.} } @article {3960, title = {COST action FP0801 - established and emerging phytophthora: Increasing threats to woodland and forest ecosystems in Europe}, journal = {New Zealand Journal of Forestry Science}, volume = {41S}, year = {2011}, pages = {7{\textendash}13}, abstract = {

With the rapidly growing international trade in plants and ongoing impacts of climate change, impacts of plant pathogens in the genus Phytophthora are increasing, threatening the biodiversity and sustainability of European forest ecosystems. Through the European Cooperation in Science and Technology (COST) framework Action FP0801, scientists and disease-control experts are working on Phytophthora in forest ecosystems with the overall aim of increasing understanding of the biology and ecology of Phytophthora species with potential to cause damage to European forestry. This knowledge will be used in the development of effective control and management protocols for the problems caused. Outcomes of the Action will be promoted in an effort to increase knowledge and awareness of the problem by disseminating information to end-users and authorities in the forestry sector, and to the general public. Four interrelated working groups have been established to (i) examine the ways in which Phytophthora species spread into and within Europe; (ii) determine how phytophthoras kill woody plants and elucidate mechanisms for host resistance; (iii) disseminate state-of-the-art rapid molecular diagnostic techniques, and (iv) seek sustainable protocols for management and control of the diseases. The project is expected to increase understanding of threats to forest ecosystems by Phytophthora, improve the ability to rapidly detect phytophthora in environmental samples, and provide sustainable management solutions to the diseases caused by these destructive organisms.

}, url = {http://researchrepository.murdoch.edu.au/4375/}, author = {S. Woodward and A. Vannini and Werres, S. and W. O{\ss}wald and Bonants, P. and T. Jung} } @article {Xavier2010369, title = {Oospores progenies from Phytophthora ramorum}, journal = {Fungal Biology}, volume = {114}, number = {4}, year = {2010}, pages = {369 - 378}, abstract = {

Oospores of Phytophthora ramorum were produced from intraspecific pairings between a European A1 and European or American A2 strains. Their viability was evaluated through colouration with tetrazolium bromide. The distribution of oospores in the different classes of colouration was similar to that found in other Phytophthora species (homothallic and heterothallic): most of the oospores stained purple, which corresponds to spores in dormancy. In order to produce single-oospore cultures, a method was developed to separate oospores from mycelium and chlamydospores. Germination of oospores was observed in 110, 250, 350 and 500-d-old cultures at a low proportion. Microsatellite marker analyses on oospore progenies revealed that the oospores resulted from hybridisation. More than 50 oospore progenies were characterised in terms of mating type, aggressiveness on Rhododendron leaves, and growth rate on two different media. The results are discussed in the context of pest risk analysis.

}, keywords = {Sexual reproduction}, issn = {1878-6146}, doi = {10.1016/j.funbio.2010.02.009}, url = {http://www.sciencedirect.com/science/article/pii/S1878614610000383}, author = {Boutet Xavier and Vercauteren Annelies and Heungens Kurt and Laurent Fr{\'e}deric and Chandelier Anne} } @article {4661, title = {Identification and Frequency of Phytophthora Species Associated with Foliar Diseases in California Ornamental Nurseries}, journal = {Plant Disease}, volume = {93}, year = {2009}, month = {Jan-09-2009}, pages = {883 - 890}, abstract = {

Numerous ornamental nurseries in 32 California counties were surveyed for leaf spots as part of the California Department of Food and Agriculture mandated surveys targeting Phytophthora ramorum. Tissue collected during the 2005 and 2006 surveys was initially screened by a Phytophthora-specific enzyme-linked immunosorbent assay. All positives samples were further tested using polymerase chain reaction to determine if P. ramorum was present. P. ramorum was detected in 1\% of the total number of samples taken during the surveys. A total of 377 isolates were identified as species of Phytophthora other than P. ramorum, and their identity was determined by internal transcriber spacer (ITS) sequences. Subsets of the putative ITS-species were further verified using accepted morphological characters. Thirteen species of Phytophthora were found: P. cactorum, P. cambivora, P. citricola, P. citrophthora, P. cryptogea, P. foliorum, P. gonapodyides, P. hibernalis, P. nemorosa, P. {\textquoteleft}Pgchlamydo{\textquoteright}, P. pseudosyringae, P. syringae, and P. tropicalis. P. syringae and P. citricola made up 55\% of the total number of isolates. Species thought to be strictly forest pathogens, P. nemorosa and P. pseudosyringae, each made up less than 4\% of the isolates. To test pathogenicity of acquired isolates, subsets of different species of Phytophthora were inoculated onto leaves of selected host plant genera. Of the 66 pathogen{\textendash}host genera combinations tested, 44 resulted in lesion formation. Disease symptoms appeared as dark, water-soaked lesions with irregular margins and were similar among Phytophthora species.

}, issn = {0191-2917}, doi = {10.1094/PDIS-93-9-0883}, url = {https://apsjournals.apsnet.org/doi/abs/10.1094/PDIS-93-9-0883}, author = {Yakabe, L. E. and Blomquist, C. L. and Thomas, S. L. and MacDonald, J. D.} } @article {doi:10.1094/PDIS-93-9-0883, title = {Identification and frequency of Phytophthora species associated with foliar diseases in California ornamental nurseries}, journal = {Plant Disease}, volume = {93}, number = {9}, year = {2009}, pages = {883-890}, abstract = {

Numerous ornamental nurseries in 32 California counties were surveyed for leaf spots as part of the California Department of Food and Agriculture mandated surveys targeting Phytophthora ramorum. Tissue collected during the 2005 and 2006 surveys was initially screened by a Phytophthora-specific enzyme-linked immunosorbent assay. All positives samples were further tested using polymerase chain reaction to determine if P. ramorum was present. P. ramorum was detected in 1\% of the total number of samples taken during the surveys. A total of 377 isolates were identified as species of Phytophthora other than P. ramorum, and their identity was determined by internal transcriber spacer (ITS) sequences. Subsets of the putative ITS-species were further verified using accepted morphological characters. Thirteen species of Phytophthora were found: P. cactorum, P. cambivora, P. citricola, P. citrophthora, P. cryptogea, P. foliorum, P. gonapodyides, P. hibernalis, P. nemorosa, P. {\textquoteleft}Pgchlamydo{\textquoteright}, P. pseudosyringae, P. syringae, and P. tropicalis. P. syringae and P. citricola made up 55\% of the total number of isolates. Species thought to be strictly forest pathogens, P. nemorosa and P. pseudosyringae, each made up less than 4\% of the isolates. To test pathogenicity of acquired isolates, subsets of different species of Phytophthora were inoculated onto leaves of selected host plant genera. Of the 66 pathogen{\textendash}host genera combinations tested, 44 resulted in lesion formation. Disease symptoms appeared as dark, water-soaked lesions with irregular margins and were similar among Phytophthora species.

}, doi = {10.1094/PDIS-93-9-0883}, url = {http://apsjournals.apsnet.org/doi/abs/10.1094/PDIS-93-9-0883}, author = {Yakabe, L. E. and C. L. Blomquist and Thomas, S. L. and MacDonald, J. D.} } @article {yao2009differential, title = {Differential behaviour in pathogenicity and enzymatic activities of Phytophthora katsurae strains from coconut trees in C{\^o}te d{\textquoteright}Ivoire. [Article in French]}, journal = {Journal of Applied Biosciences}, volume = {21}, year = {2009}, pages = {1246{\textendash}1257}, publisher = {FACT Limited}, abstract = {

An experiment was conducted to study epidemiological variation of Phytophthora katsurae on coconut trees from four farming areas. Isolates of the pathogenic agent were first characterized based on morphology of sporocysts, oospore, chlamydospore and mycelium, and this enabled detection of differences between the aggressiveness of strains. Differences were also detected when measuring the mycelium growth of each strain in vitro on different culture media (V8, Malt and Carotte). A second study was conducted to confirm the observed differences based on inoculation (gentle or rough) of coconut plants cv. Equatoriale Guinea Green Dwarf (NVE), which is susceptible to P. katsurae, with each of four strains. Last, the enzymatic dosages of pectate lyase and laccase in pathogen were analysed. These enzymes degrade the pectin and lignin of the plant cell walls. Gentle inoculation enabled assessment of the level of aggressiveness of each strain. The activity of pectate lyase and laccase varied between the strains and the synthesis of these enzymes was correlated to pathogen aggressiveness on the plant. The results showed that the strains of Marc Delorme and Assinie are less aggressive than the strain of Fresco, which is less aggressive than the strain of Robert Michaux. The zoospores and the mycelia are considered as the primary inoculum of the four strains. The β-sitosterol added to V8 medium had no influence on the mycelium growth of the four strains. However, its use as ingredient added to the media favoured an increased production of sporocysts. The discovery of this intra specific variability should be of considerable help in elaborating control methods against P. katsurae of coconut trees.

}, url = {http://www.m.elewa.org/JABS/2009/21/Abstract4-Yao.html}, author = {Yao, NR and N{\textquoteright}Goran, B. and Allou, K. and Dogbo, DO and Konan, KJL and Kouassi, P.} } @article {4206, title = {Fungi and oomycetes in open irrigation systems: knowledge gaps and biosecurity implications}, journal = {Plant Pathology}, year = {2014}, month = {Jan-03-2014}, pages = {n/a - n/a}, abstract = {

Water used for the irrigation of plants has the potential to harbour and spread plant pathogens yet little research is conducted within this field. This review was undertaken to critically review our understanding of water-borne fungal and oomycete plant pathogens in open irrigation systems, particularly in the context of plant biosecurity. It was determined that very limited data exists on these plant pathogens, with the majority of previous studies only recording pathogen presence. There are significant gaps in our knowledge of pathogen survival and spread, and very limited information on their ability to cause disease when contaminated irrigation water is applied to crops. This review has highlighted the need for new research on the epidemiology and pathogenicity of putative plant pathogens isolated from water, in order to determine their risk to crops. The importance of regular monitoring of irrigation systems for the early detection of plant pathogens is also discussed.

}, doi = {10.1111/ppa.12223}, url = {http://doi.wiley.com/10.1111/ppa.12223}, author = {Zappia, R.E. and Huberli, D. and Hardy, G. E. St.J. and Bayliss, K.L.} } @article {4525, title = {The gummosis of black wattle: a complex of disease}, number = {Report 1967-68}, year = {1968}, pages = {40-43}, institution = {Wattle Research Institute }, address = {Pietermaritzburg, South Africa}, author = {Zeijlemaker, F. C. J.} } @article {4518, title = {Black-Butt Disease of Black Wattle Caused by Phytophthora nicotianae var. parasitica}, journal = {Phytopathology}, volume = {61}, year = {1971}, month = {Jan-01-1971}, pages = {144}, abstract = {

Inoculation experiments show that the black-butt disease of Black Wattle (Acacia mearnsii), cultivated for the high-quality tannins in its bark, appears to be caused by Phytophthora nicotianae var. parasitica. Two syndromes of the disease can be distinguished. The first takes the form of spreading mottled lesions, possibly related to infection by zoospores, and the second of tongues of diseased bark, originating from the penetration of mycelium.

}, issn = {0031949X}, doi = {10.1094/Phyto-61-144}, url = {https://doi.org/10.1094/phyto-61-144 }, author = {J. Zeijlemaker, F. C.} } @article {JPH:JPH1441, title = {A survey of Phytophthora species on Hainan Island of south China}, journal = {Journal of Phytopathology}, volume = {157}, number = {1}, year = {2009}, pages = {33{\textendash}39}, publisher = {Blackwell Publishing Ltd}, abstract = {

Abstract During the period 1997{\textendash}2007, a comprehensive study of the occurrence and distribution of Phytophthora species was conducted on Hainan Island of South China. To date, 14 species of Phytophthora have been recovered and their distribution determined. Phytophthora nicotianae (=P. parasitica) is the most important species attacking a wide variety of crops, followed by Phytophthora capsici and Phytophthora citrophthora. In contrast to Phytophthora colocasiae attacking taro leaves throughout the entire island, Phytophthora cyperi was found only once on Digitaria ciliaris in Danzhou. It is of interest to note that Phytophthora heveae, Phytophthora katsurae and Phytophthora insolita are commonly found in forest soil/water of protected mountains without causing any plant diseases. Although Phytophthora species are usually terrestrial or found in fresh water, one isolate of Phytophthora resembling closely the asexual isolates of P. insolita in Hainan was obtained from decaying Rhizophora leaves submerged in seawater. An unidentified Phytophthora species producing non-papillate; internally proliferating sporangia was isolated from the soil in which Ceriops tagel and Bruguiera serangula were growing in a salt water shrimp farm.

}, keywords = {marine isolates, Phytophthora capsici, Phytophthora cinnamomi, Phytophthora citrophthora, Phytophthora heveae, Phytophthora insolita, Phytophthora katsurae, Phytophthora nicotianae}, issn = {1439-0434}, doi = {10.1111/j.1439-0434.2008.01441.x}, url = {http://dx.doi.org/10.1111/j.1439-0434.2008.01441.x}, author = {Zeng, Hui-cai and Ho, Hon-hing and Zheng, Fuy-Cong} } @book {266, title = {Phytophthora cinnamomi and the diseases it causes}, series = {Amer. Phytopathol. Soc. Monogr}, volume = {10}, year = {1980}, pages = {1-96}, publisher = {American Phytopathological Society}, organization = {American Phytopathological Society}, address = {St. Paul, Minn.}, author = {Zentemeyer, G. A.} } @article {203, title = {Ecology, pathology and management of Port-orford Cedar (Chamaecyparis lawsoniana).}, year = {1985}, pages = {161 pp.}, publisher = {USDA Forest Service, Pacific Northwest Forest and Range Experiment Station, Portland, OR.}, author = {Zobel, D.B. and L.F. Roth and G.M. Hawk} }