01995nas a2200181 4500008004100000022001400041245008200055210006900137260001600206300001600222490000700238520138200245100002001627700003801647700003001685700002301715856007501738 2020 eng d a0032-086200aPotential host range of four Phytophthora interspecific hybrids from Clade 8a0 aPotential host range of four Phytophthora interspecific hybrids  cMay-11-2020 a1281 - 12900 v693 a

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.

1 aJafari, Fatemeh1 aMostowfizadeh‐Ghalamfarsa, Reza1 aSafaiefarahani, Banafsheh1 aBurgess, Treena, I uhttps://bsppjournals.onlinelibrary.wiley.com/doi/abs/10.1111/ppa.1320502188nas a2200145 4500008004100000022001300041245007600054210006900130260000900199300000900208490000700217520168800224100001701912856011301929 1987 eng d a0031949X00aEnhancing detection of Phytophthora cactorum in naturally infested soil0 aEnhancing detection of Phytophthora cactorum in naturally infest c1987 a14750 v773 a

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.

1 aJeffers, S N uhttps://forestphytophthoras.org/references/enhancing-detection-phytophthora-cactorum-naturally-infested-soil01928nas a2200193 4500008004100000022001400041245010300055210006900158260001600227300001200243490000800255520129500263100002501558700002301583700001701606700002501623700002101648856006501669 2016 eng d a0031-949X00aHost Phenology and Leaf Effects on Susceptibility of California Bay Laurel to Phytophthora ramorum0 aHost Phenology and Leaf Effects on Susceptibility of California  cJan-01-2016 a47 - 550 v1063 a

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.

1 aJohnston, Steven, F.1 aCohen, Michael, F.1 aTorok, Tamas1 aMeentemeyer, Ross, K1 aRank, Nathan, E. uhttp://apsjournals.apsnet.org/doi/10.1094/PHYTO-01-15-0016-R02395nas a2200193 4500008004100000022001400041245010300055210006900158260001200227300001400239490000800253520170300261100002101964700001701985700002202002700002102024700002202045856013402067 2003 eng d a0028-646X00aPathogenicity of Swedish isolates of Phytophthora quercina to Quercus robur in two different soils0 aPathogenicity of Swedish isolates of Phytophthora quercina to Qu c05/2003 a355 - 3640 v1583 a
1 aJönsson, Ulrika1 aJung, Thomas1 aRosengren, Ulrika1 aNihlgård, Bengt1 aSonesson, Kerstin uhttps://forestphytophthoras.org/references/pathogenicity-swedish-isolates-phytophthora-quercina-quercus-robur-two-different-soils01628nas a2200181 4500008004100000022001400041245007500055210006900130260001200199300001400211490000700225520104200232100001601274700001601290700001601306700001201322856011201334 2003 eng d a1437-478100aFirst records of soilborne Phytophthora species in Swedish oak forests0 aFirst records of soilborne Phytophthora species in Swedish oak f c06/2003 a175 - 1790 v333 a

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.

1 aJönsson, U1 aLundberg, L1 aSonesson, K1 aJung, T uhttps://forestphytophthoras.org/references/first-records-soilborne-phytophthora-species-swedish-oak-forests02207nas a2200181 4500008004100000022001400041245012500055210006900180260001200249300001400261490000700275520155200282100001501834700001201849700001601861700001701877856013101894 2005 eng d a0032-086200aRelationships between health of Quercus robur, occurrence of Phytophthora species and site conditions in southern Sweden0 aRelationships between health of Quercus robur occurrence of Phyt c08/2005 a502 - 5110 v543 a

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 < 3·5). 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.

1 aJonsson, U1 aJung, T1 aSonesson, K1 aRosengren, U uhttps://forestphytophthoras.org/references/relationships-between-health-quercus-robur-occurrence-phytophthora-species-and-site00596nas a2200157 4500008004100000022001300041245010500054210006900159300001400228490000700242100001900249700002500268700002200293700002400315856009900339 2002 eng d a0012965800aSpread of an invasive pathogen over a variable landscape: a non-native root rot on Port Orford cedar0 aSpread of an invasive pathogen over a variable landscape a nonna a3167-31810 v831 aJules, Erik, S1 aKauffman, Matthew, J1 aRitts, William, D1 aCarroll, Allyson, L uhttp://www.esajournals.org/doi/abs/10.1890/0012-9658%282002%29083%5B3167%3ASOAIPO%5D2.0.CO%3B202186nas a2200157 4500008004100000245015800041210006900199260001200268300001200280520161700292100001801909700002201927700002001949700001601969856004301985 2014 eng d00aUpdate on the 35-year expansion of the invasive root pathogen, Phytophthora lateralis, across a landscape of Port Orford cedar (Chamaecyparis lawsoniana)0 aUpdate on the 35year expansion of the invasive root pathogen Phy c11/2014 a165-1683 a

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.

1 aJules, E., S.1 aSteenbock, C., M.1 aCarroll, A., L.1 aVannini, Á uhttp://doi.wiley.com/10.1111/efp.1215801902nas a2200253 4500008004100000022001400041245007500055210006900130300001600199490000700215520113900222653001401361100001901375700001801394700002101412700002001433700002301453700001901476700002401495700001901519700002001538700001901558856007101577 2011 eng d a0956-566300aDevelopment of a lab-on-a-chip device for diagnosis of plant pathogens0 aDevelopment of a labonachip device for diagnosis of plant pathog a4070 - 40750 v263 a

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).

10adetection1 aJulich, Sandra1 aRiedel, Marko1 aKielpinski, Mark1 aUrban, Matthias1 aKretschmer, Robert1 aWagner, Stefan1 aFritzsche, Wolfgang1 aHenkel, Thomas1 aMöller, Robert1 aWerres, Sabine uhttp://www.sciencedirect.com/science/article/pii/S095656631100191602232nas a2200205 4500008004100000022001400041245010700055210006900162260001600231300001200247490000700259520159000266100001301856700002101869700001401890700001601904700001301920700001301933856008001946 2018 eng d a0031-585000aCanker and decline diseases caused by soil- and airborne Phytophthora species in forests and woodlands0 aCanker and decline diseases caused by soil and airborne Phytopht cJan-01-2018 a182-2200 v403 a

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.

1 aJung, T.1 aPérez-Sierra, A1 aDurán, A1 aJung, Horta1 aBalci, Y1 aScanu, B uhttp://www.ingentaconnect.com/content/nhn/pimj/10.3767/persoonia.2018.40.0802602nas a2200145 4500008004100000022001300041245011600054210006900170260001200239300001200251490000700263520209800270100001202368856007602380 2009 eng d a1437478100aBeech decline in Central Europe driven by the interaction between Phytophthora infections and climatic extremes0 aBeech decline in Central Europe driven by the interaction betwee c04/2009 a73 - 940 v393 a

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 ‘Beech Bark Disease’, (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.

1 aJung, T uhttp://onlinelibrary.wiley.com/doi/10.1111/efp.2009.39.issue-2/issuetoc02560nas a2200169 4500008004100000245015500041210006900196260001200265300001400277490000700291520195700298100001202255700001902267700002202286700001602308856006602324 2013 eng d00aNew insights into the survival strategy of the invasive soilborne pathogen Phytophthora cinnamomi in different natural ecosystems in Western Australia0 aNew insights into the survival strategy of the invasive soilborn c08/2013 a266–2880 v433 a

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–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–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.

1 aJung, T1 aColquhoun, I J1 aHardy, St., G E J1 aWoodward, S uhttp://onlinelibrary.wiley.com/doi/10.1111/efp.12025/abstract03172nas a2200301 4500008004100000245014100041210006900182260001600251300000700267490000700274520220200281100001702483700001702500700002302517700001702540700002202557700002202579700002402601700001902625700002002644700002002664700002002684700001702704700001602721700002302737700002502760856008502785 2020 eng d00aA Survey in Natural Forest Ecosystems of Vietnam Reveals High Diversity of both New and Described Phytophthora Taxa including P. ramorum0 aSurvey in Natural Forest Ecosystems of Vietnam Reveals High Dive cJan-01-2020 a930 v113 a

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. ×heterohybrida from Clade 7; P. drechsleri, P. pseudocryptogea, P. ramorum (Pr) and P. sp. kelmania from Clade 8, P. macrochlamydospora, P. sp. ×insolita-like, P. sp. ×kunnunara-like, P. sp. ×virginiana-like s.l. and three new taxa, P. sp. quininea-like, P. sp. ×Grenada 3-like and P. sp. ×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.

1 aJung, Thomas1 aScanu, Bruno1 aBrasier, Clive, M.1 aWebber, Joan1 aMilenković, Ivan1 aCorcobado, Tamara1 aTomšovský, Michal1 aPánek, Matěj1 aBakonyi, Jozsef1 aMaia, Cristiana1 aBačová, Aneta1 aRaco, Milica1 aRees, Helen1 aPérez-Sierra, Ana1 aJung, Marilia, Horta uhttps://www.mdpi.com/1999-4907/11/1/93https://www.mdpi.com/1999-4907/11/1/93/pdf02811nas a2200289 4500008004100000245010800041210006900149260001600218300001400234490000700248520193800255100001302193700001802206700001502224700001502239700002102254700001302275700001302288700001302301700001502314700001802329700001302347700001902360700001302379700001602392856011302408 2017 eng d00aDiversity of Phytophthora species in natural ecosystems of Taiwan and association with disease symptoms0 aDiversity of Phytophthora species in natural ecosystems of Taiwa cJan-07-2016 a194–2110 v663 a

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. × botryosa-like, P. sp. × 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. × incrassata nom. prov. and P. × 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.

1 aJung, T.1 aChang, T., T.1 aBakonyi, J1 aSeress, D.1 aPérez-Sierra, A1 aYang, X.1 aHong, C.1 aScanu, B1 aFu, C., H.1 aHsueh, K., L.1 aMaia, C.1 aAbad-Campos, P1 aLeón, M1 aJung, Horta uhttp://doi.wiley.com/10.1111/ppa.12564http://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fppa.1256402188nas a2200265 4500008004100000022001300041245016200054210006900216260001200285300001300297490000700310520133800317653001001655653001401665653001201679653001201691653001101703653001401714653001201728653000801740653001401748100001201762700001701774856013101791 2009 eng d a0031585000aRe-evaluation of Phytophthora citricola isolates from multiple woody hosts in Europe and North America reveals a new species, Phytophthora plurivora sp. nov.0 aReevaluation of Phytophthora citricola isolates from multiple wo c06/2009 a95 - 1100 v223 a

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 °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.

10aBeech10acitricola10aDecline10adieback10aforest10amultivora10anursery10aoak10aphylogeny1 aJung, T1 aBurgess, T I uhttps://forestphytophthoras.org/references/re-evaluation-phytophthora-citricola-isolates-multiple-woody-hosts-europe-and-north02554nas a2200193 4500008004100000022001300041245007000054210006700124260001100191300001400202490000800216520198900224100001202213700001702225700001602242700001602258700001502274856007102289 1999 eng d a0953756200aPhytophthora quercina sp. nov., causing root rot of European oaks0 aPhytophthora quercina sp nov causing root rot of European oaks c7/1999 a785 - 7980 v1033 a

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'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.

1 aJung, T1 aCooke, D E L1 aBlaschke, H1 aDuncan, J M1 aOßwald, W uhttp://www.sciencedirect.com/science/article/pii/S095375620860611502366nas a2200217 4500008004100000022001300041245014500054210006900199260001600268300001200284490000700296520164800303100001301951700002001964700002101984700001302005700001202018700001702030700001802047856008302065 2011 eng d a0031585000aMultiple new Phytophthora species from ITS Clade 6 associated with natural ecosystems in Australia: evolutionary and ecological implications0 aMultiple new Phytophthora species from ITS Clade 6 associated wi cJun-06-2013 a13 - 390 v263 a

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.

1 aJung, T.1 aStukely, M.J.C.1 aHardy, G.E.St.J.1 aWhite, D1 aPaap, T1 aDunstan, W A1 aBurgess, T.I. uhttp://www.ingentaconnect.com/content/nhn/pimj/2011/00000026/00000001/art0000203160nas a2200229 4500008004100000022001300041245012000054210006900174260001100243300001400254490000800268520234900276100001702625700001902642700002202661700002202683700002102705700002502726700002102751700002102772856013702793 2003 eng d a0953756200aPhytophthora pseudosyringae sp. nov., a new species causing root and collar rot of deciduous tree species in Europe0 aPhytophthora pseudosyringae sp nov a new species causing root an c7/2003 a772 - 7890 v1073 a

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 °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.

1 aJung, Thomas1 aNechwatal, Jan1 aCooke, David, E L1 aHartmann, ünther1 aBlaschke, Markus1 aOßwald, Wolfgang, F1 aDuncan, James, M1 aDelatour, Claude uhttps://forestphytophthoras.org/references/phytophthora-pseudosyringae-sp-nov-new-species-causing-root-and-collar-rot-deciduous-tree00651nas a2200193 4500008004100000022001400041245009500055210006900150300001400219490000700233653001400240100001200254700001600266700002200282700001900304700001900323700001500342856010000357 2005 eng d a0269-915X00aInvolvement of Phytophthora species in the decline of European beech in Europe and the USA0 aInvolvement of Phytophthora species in the decline of European b a159 - 1660 v1910adetection1 aJung, T1 aHudler, G W1 aJensen-Tracy, S L1 aGriffiths, H M1 aFleischmann, F1 aOsswald, W uhttp://www.sciencedirect.com/science/article/B7XMS-4R10WR2-5/2/37dcb413ca17af3b17f99e6101570c6502230nas a2200169 4500008004100000022001400041245012800055210006900183260001200252300001400264490000700278520159700285100001201882700001601894700001501910856013501925 2000 eng d a0032-086200aInvolvement of soilborne Phytophthora species in Central European oak decline and the effect of site factors on the disease0 aInvolvement of soilborne Phytophthora species in Central Europea c12/2000 a706 - 7180 v493 a

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 ‘oak decline’. On sites with a mean soil pH (CaCl2) 3·5 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 2·1 and 2·8, respectively. In contrast, in stands with sandy to sandy-loamy soils and a mean soil pH  3·9, 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).

1 aJung, T1 aBlaschke, H1 aOßwald, W uhttps://forestphytophthoras.org/references/involvement-soilborne-phytophthora-species-central-european-oak-decline-and-effect-site02233nas a2200157 4500008004100000022001400041245012400055210006900179260001600248300001400264490000700278520170300285100001301988700001602001856005802017 2004 eng d a0032-086200aPhytophthora root and collar rot of alders in Bavaria: distribution, modes of spread and possible management strategies0 aPhytophthora root and collar rot of alders in Bavaria distributi cJan-04-2004 a197 - 2080 v533 a

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 (80·9%) 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 ‘alder Phytophthora’ 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 ‘alder Phytophthora’ infects alders downstream. Baiting tests showed that the ‘alder Phytophthora’ 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 ‘alder Phytophthora’ in soil.

1 aJung, T.1 aBlaschke, M uhttp://doi.wiley.com/10.1111/j.0032-0862.2004.00957.x02540nas a2200277 4500008004100000022001300041245012500054210006900179300001400248490000700262520170100269653003101970653001002001653001202011653001302023653003002036653001202066653001202078653001202090653001702102653001502119653001902134100001202153700001602165856008102181 2004 eng d a0032086200aPhytophthora root and collar rot of alders in Bavaria: distribution, modes of spread and possible management strategies.0 aPhytophthora root and collar rot of alders in Bavaria distributi a197 - 2080 v533 a

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 (80·9%) 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 ‘alder Phytophthora’ 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 ‘alder Phytophthora’ infects alders downstream. Baiting tests showed that the ‘alder Phytophthora’ 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 ‘alder Phytophthora’ in soil.

10aALDER – Diseases & pests10aAlnus10aBavaria10adiseases10afungal diseases of plants10aGERMANY10anursery10apathway10aPhytophthora10aplantation10ariparian areas1 aJung, T1 aBlaschke, M uhttp://onlinelibrary.wiley.com/doi/10.1111/j.0032-0862.2004.00957.x/abstract02337nas a2200193 4500008004100000022001300041245006400054210006400118260001100182300001400193490000800207520172900215100001701944700002301961700001701984700002202001700002102023856009902044 2002 eng d a0953756200aThree new species of Phytophthora from European oak forests0 aThree new species of Phytophthora from European oak forests c4/2002 a397 - 4110 v1063 a

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'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 'alder phytophthora', 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.

1 aJung, Thomas1 aHansen, Everett, M1 aWinton, Lori1 aOßwald, Wolfgang1 aDelatour, Claude uhttps://forestphytophthoras.org/references/three-new-species-phytophthora-european-oak-forests03359nas a2200277 4500008004100000245010800041210006900149300001100218520245100229100001702680700001902697700003902716700002102755700001902776700002302795700002302818700003202841700002002873700001802893700002402911700002202935700002002957700002502977700001703002856006203019 2018 eng d00aDiversity of Phytophthora species in Valdivian rainforests and association with severe dieback symptoms0 aDiversity of Phytophthora species in Valdivian rainforests and a ae124433 a

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 Concepción 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. ×cambivora, P×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.

1 aJung, Thomas1 aDurán, Alvaro1 avon Stowasser, Eugenio, Sanfuentes1 aSchena, Leonardo1 aMosca, Saveria1 aFajardo, Sebastian1 aGonzález, Mariela1 aOrtega, Angella, D. Navarro1 aBakonyi, Jozsef1 aSeress, Diana1 aTomšovský, Michal1 aCravador, Alfredo1 aMaia, Cristiana1 aJung, Marilia, Horta1 aWoodward, S. uhttps://onlinelibrary.wiley.com/doi/abs/10.1111/efp.1244302261nas a2200157 4500008004100000022001300041245012600054210006900180260001200249300001600261490000800277520164800285100001701933700001901950856013401969 2008 eng d a0953756200aPhytophthora gallica sp. nov., a new species from rhizosphere soil of declining oak and reed stands in France and Germany0 aPhytophthora gallica sp nov a new species from rhizosphere soil  c10/2008 a1195 - 12050 v1123 a

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 ‘G’, 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.

1 aJung, Thomas1 aNechwatal, Jan uhttps://forestphytophthoras.org/references/phytophthora-gallica-sp-nov-new-species-rhizosphere-soil-declining-oak-and-reed-stands02308nas a2200193 4500008004100000245014500041210006900186300001000255490000700265520164800272100001201920700001901932700002101951700001301972700001201985700001701997700001702014856008302031 2011 eng d00aMultiple new Phytophthora species from ITS Clade 6 associated with natural ecosystems in Australia: evolutionary and ecological implications0 aMultiple new Phytophthora species from ITS Clade 6 associated wi a13-390 v263 a

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.

1 aJung, T1 aStukely, M J C1 aHardy, G E S t J1 aWhite, D1 aPaap, T1 aDunstan, W A1 aBurgess, T I uhttp://www.ingentaconnect.com/content/nhn/pimj/2011/00000026/00000001/art00002