@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 {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 {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 {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 {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 {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 {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 {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 {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 {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 {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 {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 {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 {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 {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 {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 {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 {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} } @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 {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} }