00355nas a2200109 4500008004100000245004500041210004400086300001000130490000600140100001700146856008200163 1974 eng d00aPhytophthora heveae, a pathogen of kauri0 aPhytophthora heveae a pathogen of kauri a59-630 v41 aGadgil, P.D. uhttps://forestphytophthoras.org/references/phytophthora-heveae-pathogen-kauri02203nas a2200193 4500008004100000022001400041245012600055210006900181260001600250300001400266490000700280520152500287100002501812700002701837700002401864700002601888700002701914856006801941 2014 eng d a0706-066100aReal-time PCR assay to distinguish Phytophthora ramorum lineages using the cellulose binding elicitor lectin (CBEL) locus0 aRealtime PCR assay to distinguish Phytophthora ramorum lineages  cMar-07-2014 a367 - 3760 v363 a

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

1 aGagnon, Marie-Claude1 aBergeron, Marie-Josée1 aHamelin, Richard, C1 aGrünwald, Niklaus, J1 aBilodeau, Guillaume, J uhttp://www.tandfonline.com/doi/abs/10.1080/07060661.2014.92499900901nam a2200145 4500008004100000022002200041245007300063210006900136260006500205300000800270520032800278100001800606700001900624856011200643 2008 eng d a978-0-89054-364-100aPhytophthora: identifying species by morphology and DNA fingerprints0 aPhytophthora identifying species by morphology and DNA fingerpri aSt. Paul, MNbAmerican Phytopathological Society (APS Press) a1583 a

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

1 aGallegly, M E1 aHong, Chuanxue uhttps://forestphytophthoras.org/references/phytophthora-identifying-species-morphology-and-dna-fingerprints01900nas a2200169 4500008004100000022001400041245003700055210003700092260002900129300001200158490000700170520143300177100001701610700002301627700002501650856005501675 1999 eng d a1439-032900aEtiology of oak decline in Spain0 aEtiology of oak decline in Spain bBlackwell Publishing Ltd a17–270 v293 a

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

1 aGallego, F J1 aPerez de Algaba, A1 aFernandez-Escobar, R uhttp://dx.doi.org/10.1046/j.1439-0329.1999.00128.x01555nas a2200205 4500008004100000022004200041245011400083210006900197300001200266490000700278520088900285100001701174700001901191700001801210700001501228700001701243700001601260700001701276856005601293 2014 eng d a1175-9003 (print), 1179-352X (online)00aManagement of red needle cast, caused by Phytophthora pluvialis, a new disease of radiata pine in New Zealand0 aManagement of red needle cast caused by Phytophthora pluvialis a a48–530 v673 a

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

1 aGanley, R.J.1 aWilliams, N.M.1 aRolando, C.A.1 aHood, I.A.1 aDungey, H.S.1 aBeets, P.N.1 aBulman, L.S. uhttp://www.nzpps.org/nzpp_abstract.php?paper=67048001545nas a2200193 4500008004100000245008600041210006900127300001000196490000700206520094700213100001801160700001601178700001301194700001501207700001601222700001301238700001301251856008701264 2003 eng d00aNon-oak native plants are main hosts for sudden oak death pathogen in California.0 aNonoak native plants are main hosts for sudden oak death pathoge a18-230 v573 a

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

1 aGarbelotto, M1 aDavidson, J1 aIvors, K1 aMaloney, P1 aHüberli, D1 aKoike, S1 aRizzo, D uhttp://ucanr.org/repository/cao/landingpage.cfm?article=ca.v057n01p18&abstract=yes01333nas a2200133 4500008004100000245007000041210006900111300001000180490000700190520086400197100002601061700002401087856008801111 2009 eng d00aPhosphonate controls sudden oak death pathogen for up to 2 years.0 aPhosphonate controls sudden oak death pathogen for up to 2 years a10-170 v633 a

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

1 aGarbelotto, Matteo, M1 aSchmidt, Douglas, J uhttp://ucanr.org/repository/cao/landingpage.cfm?article=ca.v063n01p10&fulltext=yes#01930nas a2200229 4500008004100000022001400041245011800055210006900173260002900242300001400271490000700285520118000292653002301472653002701495653002201522653002101544653002901565100001801594700001601612700001701628856005501645 2009 eng d a1365-305900aEfficacy of phosphonic acid, metalaxyl-M and copper hydroxide against Phytophthora ramorum in vitro and in planta0 aEfficacy of phosphonic acid metalaxylM and copper hydroxide agai bBlackwell Publishing Ltd a111–1190 v583 a

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

10adisease management10aphenotypic variability10aQuercus agrifolia10aSudden oak death10aUmbellularia californica1 aGarbelotto, M1 aHarnik, T Y1 aSchmidt, D J uhttp://dx.doi.org/10.1111/j.1365-3059.2008.01894.x01395nas a2200121 4500008004100000245011200041210006900153490001800222520091700240100002301157700002501180856006801205 2012 eng d00aSudden Oak Death: interactions of the exotic oomycete Phytophthora ramorum with naïve North American hosts0 aSudden Oak Death interactions of the exotic oomycete Phytophthor0 vEarly release3 a

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

1 aGarbelotto, Matteo1 aHayden, Katherine, J uhttp://ec.asm.org/content/early/2012/09/18/EC.00195-12.abstract00524nas a2200133 4500008004100000245015400041210006900195300001200264490000700276100001800283700001500301700001200316856006200328 2006 eng d00aFirst report on an infestation of Phytophthora cinnamomi in natural oak woodlands of California and its differential impact on two native oak species0 aFirst report on an infestation of Phytophthora cinnamomi in natu a685-6850 v901 aGarbelotto, M1 aHuberli, D1 aShaw, D uhttp://apsjournals.apsnet.org/doi/abs/10.1094/PD-90-0685C01405nas a2200133 4500008004100000245011200041210006900153300001400222490000700236520092900243100002301172700002601195856005001221 2012 eng d00aSudden Oak Death: Interactions of the Exotic Oomycete Phytophthora ramorum with Naïve North American Hosts0 aSudden Oak Death Interactions of the Exotic Oomycete Phytophthor a1313-13230 v113 a

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

1 aGarbelotto, Matteo1 aHayden, Katherine, J. uhttp://ec.asm.org/content/11/11/1313.abstract02251nas a2200169 4500008004100000022001400041245016600055210006900221260001600290300001400306490000700320520162300327100002301950700001801973700001901991856007102010 2021 eng d a0032-086200aPathogenicity and infectivity of Phytophthora ramorum vary depending on host species, infected plant part, inoculum potential, pathogen genotype, and temperature0 aPathogenicity and infectivity of Phytophthora ramorum vary depen cOct-19-2020 a287 - 3040 v703 a

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

1 aGarbelotto, Matteo1 aSchmidt, Doug1 aPopenuck, Tina uhttps://bsppjournals.onlinelibrary.wiley.com/doi/10.1111/ppa.1329704266nas a2200205 4500008004100000022001400041245013800055210006900193260001600262520354900278100002303827700002203850700002103872700001803893700001503911700002103926700002503947700002103972856006703993 2021 eng d a0191-291700aFirst reports of Phytophthora ramorum clonal lineages NA1 and EU1 causing Sudden Oak Death on tanoaks in Del Norte County, California0 aFirst reports of Phytophthora ramorum clonal lineages NA1 and EU cJan-18-20213 a

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

1 aGarbelotto, Matteo1 aDovana, Francesco1 aSchmidt, Douglas1 aChee, Cameron1 aLee, Chris1 aFieland, Valerie1 aünwald, Niklaus, J.1 aValachovic, Yana uhttps://apsjournals.apsnet.org/doi/10.1094/PDIS-12-20-2633-PDN03184nas a2200145 4500008004100000245010800041210006900149260002100218490000700239520265600246100002702902700002502929700003002954856005402984 2015 eng d00aSusceptibility of New Zealand flora to Phytophthora kernoviae and its seasonal variability in the field0 aSusceptibility of New Zealand flora to Phytophthora kernoviae an c12 November 20150 v453 a

Background

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

Methods

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

Results

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

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

Conclusions

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

1 aGardner, Judy, Frances1 aDick, Margaret, Anne1 aBader, Martin, Karl-Fried uhttp://www.nzjforestryscience.com/content/45/1/2304137nas a2200169 4500008004100000022001400041245012400055210006900179260001600248300001600264490000700280520356000287100001803847700001603865700002003881856006603901 2010 eng d a0191-291700aFirst Report of Collar and Root Rot Caused by Phytophthora tentaculata on Witloof Chicory (Cichorium intybus ) in Italy0 aFirst Report of Collar and Root Rot Caused by Phytophthora tenta cJan-12-2010 a1504 - 15040 v943 a

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

1 aGaribaldi, A.1 aGilardi, G.1 aGullino, M., L. uhttp://apsjournals.apsnet.org/doi/abs/10.1094/PDIS-03-10-020602153nas a2200145 4500008004100000245011700041210006900158300001200227490000700239520165700246100001501903700001901918700001501937856005501952 1999 eng d00aThe impact of Phytophthora disease on riparian populations of common alder (Alnus glutinosa) in southern Britain0 aimpact of Phytophthora disease on riparian populations of common a39–500 v293 a

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

1 aGibbs, J N1 aLipscombe, M A1 aPeace, A J uhttp://dx.doi.org/10.1046/j.1439-0329.1999.00129.x00325nas a2200097 4500008004100000245003700041210003700078300001400115100001500129856008300144 1995 eng d00aRoot disease of alder in Britain0 aRoot disease of alder in Britain a661–6641 aGibbs, J N uhttp://onlinelibrary.wiley.com/doi/10.1111/j.1365-2338.1995.tb01118.x/abstract03912nas a2200169 4500008004100000022001400041245007100055210006900126260001200195300000800207490000700215520340000222100002203622700002403644700002303668856005103691 2013 eng d a0191-291700aFirst Report of Phytophthora Taxon Walnut in Lombardy, North Italy0 aFirst Report of Phytophthora Taxon Walnut in Lombardy North Ital c03/2014 a4240 v983 a

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

1 aGinetti, Beatrice1 aRagazzi, Alessandro1 aMoricca, Salvatore uhttp://dx.doi.org/10.1094/PDIS-07-13-0766-PDN 02603nas a2200277 4500008004100000022001400041245015200055210006900207260001200276300001400288490000700302520177700309653001602086653001202102653001302114653002002127653001402147653002702161100001602188700001602204700002002220700001702240700001502257700001302272856004002285 2013 eng d a1365-305900aPhytophthora acerina sp. nov., a new species causing bleeding cankers and dieback of Acer pseudoplatanus trees in planted forests in northern Italy0 aPhytophthora acerina sp nov a new species causing bleeding canke c08/2014 a858–8760 v633 a

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

10abiosecurity10aClade 210ainvasive10anursery pathway10aphylogeny10aPhytophthora citricola1 aGinetti, B.1 aMoricca, S.1 aSquires, J., N.1 aCooke, D E L1 aRagazzi, A1 aJung, T. uhttp://dx.doi.org/10.1111/ppa.1215304121nas a2200193 4500008004100000022001400041245012900055210006900184260001200253300001400265490000700279520349100286100001603777700001903793700001503812700001403827700001603841856007003857 2014 eng d a0191-291700aFoliar Blight and Shoot Dieback Caused by Phytophthora ramorum on Viburnum tinus in the Pistoia Area, Tuscany, Central Italy0 aFoliar Blight and Shoot Dieback Caused by Phytophthora ramorum o c03/2014 a423 - 4230 v983 a

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

1 aGinetti, B.1 aCarmignani, S.1 aRagazzi, A1 aWerres, S1 aMoricca, S. uhttp://apsjournals.apsnet.org/doi/abs/10.1094/PDIS-07-13-0767-PDN04151nas a2200181 4500008004100000022001400041245011100055210006900166260001600235300001600251490000700267520356300274100001603837700001903853700001503872700001603887856006603903 2014 eng d a0191-291700aPhytophthoraTaxon Pgchlamydo is a Cause of Shoot Blight and Root and Collar Rot of Viburnum tinus in Italy0 aPhytophthoraTaxon Pgchlamydo is a Cause of Shoot Blight and Root cJan-10-2014 a1432 - 14320 v983 a

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

1 aGinetti, B.1 aCarmignani, S.1 aRagazzi, A1 aMoricca, S. uhttp://apsjournals.apsnet.org/doi/10.1094/PDIS-03-14-0282-PDN02226nas a2200181 4500008004100000245006200041210006200103260001200165490000700177520171000184100001601894700001601910700001601926700002001942700001801962700001401980856005001994 2002 eng d00aSudden oak death caused by Phytophthora ramorum in Oregon0 aSudden oak death caused by Phytophthora ramorum in Oregon c04/20020 v863 a

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

1 aGoheen, E M1 aHansen, E M1 aKanaskie, A1 aMcWilliams, M G1 aOsterbauer, N1 aSutton, W uhttp://dx.doi.org/10.1094/PDIS.2002.86.4.441C01284nas a2200169 4500008004100000024003200041245012900073210006900202260010900271300001000380520058500390100001600975700001700991700001601008700001701024856007301041 2007 eng d aGen. Tech. Rep. PSW-GTR-22100aProceedings of the fourth meeting of the International Union of Forest Research Organizations (IUFRO) Working Party 07.02.090 aProceedings of the fourth meeting of the International Union of  aMonterey, CaliforniabU.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station a334 p3 a

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

1 aGoheen, E M1 aFrankel, S J1 aGoheen, E M1 aFrankel, S J uhttp://www.iufro.org/science/divisions/division-7/70000/70200/70209/02000nas a2200157 4500008004100000245010200041210006900143260001200212300001400224520146500238100001901703700002901722700002401751700002401775856004301799 2014 eng d00aHistopathology of infection and colonization of Quercus ilex fine roots by Phytophthora cinnamomi0 aHistopathology of infection and colonization of Quercus ilex fin c11/2014 a605–6163 a

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

1 aGómez, F., J.1 aNavarro-Cerrillo, R., M.1 aSánchez-Cuesta, R.1 aPérez-de-Luque, A. uhttp://doi.wiley.com/10.1111/ppa.1231001881nas a2200145 4500008004100000245010900041210006900150260001300219520139100232100001801623700002101641700001701662700001701679856003901696 2016 eng d00aTwo Phytophthora species causing decline of wild olive (Olea europaea subsp. europaea var. sylvestris )0 aTwo Phytophthora species causing decline of wild olive Olea euro cNov-20163 a

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

1 aGonzález, M.1 aPérez-Sierra, A1 aSerrano, M S1 aSanchez, M E uhttps://doi.org/10.1111/ppa.12649 00588nas a2200169 4500008004100000245009600041210006900137300001200206490000800218100001900226700001600245700002600261700001900287700001900306700002600325856006700351 2011 eng d00aPhytophthora ramorum in Canada: evidence for migration within North America and from Europe0 aPhytophthora ramorum in Canada evidence for migration within Nor a166-1710 v1011 aGoss, Erica, M1 aLarsen, Meg1 aVercauteren, Annelies1 aWerres, Sabine1 aHeungens, Kurt1 aGrünwald, Niklaus, J uhttp://apsjournals.apsnet.org/doi/abs/10.1094/PHYTO-05-10-013301842nas a2200181 4500008004100000245009800041210006900139260003400208300001300242490000600255520123900261100001901500700001601519700002401535700002201559700002601581856005301607 2009 eng d00aPopulation genetic analysis infers migration pathways of Phytophthora ramorum in US nurseries0 aPopulation genetic analysis infers migration pathways of Phytoph bPublic Library of Sciencec09 ae10005830 v53 a

Author Summary

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

1 aGoss, Erica, M1 aLarsen, Meg1 aChastagner, Gary, A1 aGivens, Donald, R1 aGrünwald, Niklaus, J uhttp://dx.doi.org/10.1371%2Fjournal.ppat.100058301952nas a2200205 4500008004100000022001400041245009600055210006900151260001600220300001400236490000800250520129900258100001901557700001601576700002601592700001901618700001901637700002601656856006401682 2011 eng d a0031-949X00aPhytophthora ramorum in Canada: Evidence for Migration Within North America and from Europe0 aPhytophthora ramorum in Canada Evidence for Migration Within Nor cJan-01-2011 a166 - 1710 v1013 a

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

1 aGoss, Erica, M1 aLarsen, Meg1 aVercauteren, Annelies1 aWerres, Sabine1 aHeungens, Kurt1 aGrünwald, Niklaus, J uhttps://apsjournals.apsnet.org/doi/10.1094/PHYTO-05-10-013300504nas a2200145 4500008004100000245006100041210006000102260006400162300001000226490002300236100001500259700001500274700001600289856005300305 2012 eng d00aFlorida Citrus Pest Management Guide: Brown Rot of Fruit0 aFlorida Citrus Pest Management Guide Brown Rot of Fruit bUniversity of Florida, IFAS Extension, Gainesville, Florida a2 pp.0 vPublication PP-1481 aGraham, JH1 aTimmer, LW1 aDewdney, MM uhttp://edis.ifas.ufl.edu/pdffiles/CG/CG02200.pdf02388nas a2200217 4500008004100000022001400041245010900055210006900164260001200233300001200245490000700257520173900264100001302003700001702016700001702033700001702050700001902067700001402086700001502100856005502115 2012 eng d a1439-032900aThe destructive invasive pathogen Phytophthora lateralis found on Chamaecyparis lawsoniana across the UK0 adestructive invasive pathogen Phytophthora lateralis found on Ch c02/2013 a19–280 v433 a

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

1 aGreen, S1 aBrasier, C M1 aSchlenzig, A1 aMcCracken, A1 aMacAskill, G A1 aWilson, M1 aWebber, JF uhttp://dx.doi.org/10.1111/j.1439-0329.2012.00788.x02385nas a2200169 4500008004100000245009900041210006900140260001600209300001400225490000700239520181300246100001302059700001502072700001802087700001902105856009102124 2015 eng d00aPhytophthora austrocedrae emerges as a serious threat to juniper Juniperus communis in Britain0 aPhytophthora austrocedrae emerges as a serious threat to juniper cJan-04-2015 a456 - 4660 v643 a

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

1 aGreen, S1 aElliot, M.1 aArmstrong, A.1 aHendry, S., J. uhttp://doi.wiley.com/10.1111/ppa.2015.64.issue-2http://doi.wiley.com/10.1111/ppa.1225303959nas a2200181 4500008004100000245010100041210006900142260001600211300000600227490000700233520336600240100001303606700001703619700002003636700001503656700001503671856009103686 2012 eng d00aDieback and mortality of Juniperus communis in Britain associated with Phytophthora austrocedrae0 aDieback and mortality of Juniperus communis in Britain associate cJul-12-2014 a20 v263 a

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

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

1 aGreen, S1 aHendry, S.J.1 aMacAskill, G.A.1 aLaue, B.E.1 aSteele, H. uhttp://www.ndrs.org.uk/contents.php?vol=26http://www.ndrs.org.uk/article.php?id=02600200872nas a2200205 4500008004100000020002800041245015000069210006900219260004500288300001300333653002900346653002000375653002300395653001900418653002700437653003300464653002700497100001500524856012700539 1998 eng d a0195075676 (alk. paper)00aManaging Chamaecyparis lawsoniana (Port-Orford-Cedar) to control the root disease caused by Phytophthora lateralis in the Pacific Northwest, USA.0 aManaging Chamaecyparis lawsoniana PortOrfordCedar to control the bNew York : Oxford University Press, 1998 a93–10010aChamaecyparis lawsoniana10adisease control10aliterature reviews10aPacific States10aPhytophthora lateralis10aplant diseases and disorders10aplant pathogenic fungi1 aGreenup, M uhttps://forestphytophthoras.org/references/managing-chamaecyparis-lawsoniana-port-orford-cedar-control-root-disease-caused00398nas a2200133 4500008004100000245004000041210003900081300001100120490000700131100001600138700001700154700001300171856008000184 1984 eng d00aCocoa black pod: a reinterpretation0 aCocoa black pod a reinterpretation a5–220 v351 aGregory, PH1 aMaddison, AC1 aWard, MR uhttps://forestphytophthoras.org/references/cocoa-black-pod-reinterpretation01180nas a2200169 4500008004100000022001400041245012800055210006900183300001400252490000800266520055200274653001900826100002400845700002300869700001800892856010000910 2007 eng d a0953-756200aPhytophthora austrocedrae sp. nov., a new species associated with Austrocedrus chilensis mortality in Patagonia (Argentina)0 aPhytophthora austrocedrae sp nov a new species associated with A a308 - 3160 v1113 a

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

10asoil pathogens1 aGreslebin, Alina, G1 aHansen, Everett, M1 aSutton, Wendy uhttp://www.sciencedirect.com/science/article/B7XMR-4MWPSTC-2/2/cd293441766ba86e83832d81ab837e1a01694nas a2200193 4500008004100000245012400041210006900165260001600234300001400250490000700264520106900271653001201340653002101352653001301373653002401386100001901410700001601429856005501445 2010 eng d00aPathogenicity of Phytophthora austrocedrae on Austrocedrus chilensis and its relation with mal del ciprés in Patagonia0 aPathogenicity of Phytophthora austrocedrae on Austrocedrus chile cAugust 2010 a604–6120 v593 a

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

10acypress10aforest pathology10aroot rot10asoilborne pathogens1 aGreslebin, A G1 aHansen, E M uhttp://dx.doi.org/10.1111/j.1365-3059.2010.02258.x01442nas a2200157 4500008004100000245009500041210006900136300001200205490000700217520090800224100002401132700002301156700002301179700002301202856005901225 2005 eng d00aPhytophthora species from declining Austrocedrus chilensis forests in Patagonia, Argentina0 aPhytophthora species from declining Austrocedrus chilensis fores a218-2280 v973 a

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

1 aGreslebin, Alina, G1 aHansen, Everett, M1 aWinton, Loretta, M1 aRajchenberg, Mario uhttp://www.mycologia.org/cgi/content/abstract/97/1/21803672nas a2200169 4500008004100000245007500041210006900116260001200185300000700197490000700204520317600211100001803387700001803405700001503423700001503438856004903453 2013 eng d00aPhytophthora multivora causing leaf spot on rhododendrons in Argentina0 aPhytophthora multivora causing leaf spot on rhododendrons in Arg c06/2013 a200 v273 a

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

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

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

1 aGrijalba, P E1 aPalmucci, H E1 aGuillin, E1 aHerrera, C uhttp://www.ndrs.org.uk/article.php?id=02702003594nas a2200181 4500008004100000022001400041245014000055210006900195260001600264300001400280490000800294520297500302100001703277700001603294700001703310700002003327856006503347 2015 eng d a0929-187300aRole of salicylic acid in phosphite-induced protection against Oomycetes; a Phytophthora cinnamomi - Lupinus augustifolius model system0 aRole of salicylic acid in phosphiteinduced protection against Oo cJan-03-2015 a559 - 5690 v1413 a

Phosphite is used to control Oomycetes in a wide range of horticultural and native plant species worldwide. However, phosphite can be phytotoxic, and some pathogens have exhibited a reduction in the effectiveness of phosphite due to prolonged use. In this study, salicylic acid (SA) was investigated as an alter- native, or supplementary, treatment to be used to protect plant species. With the use of aeroponics chambers, foliar application of phosphite, SA, and phosphite/SA to Lupinus augustifolius was assessed in relation to root tip damage, in planta phosphite and SA concentration and lesion development. Both phosphite and SA were measurable at the root tip within 24 h of application, and all treatments significantly (P0.05) reduced the lesion length at 7 days. However, while phosphite and SA application increased the in planta SA concentration, phosphite caused significantly more damage to the root tip by reducing root cap layers and length than the SA, or phosphite/SA application. This study supports the notion that phosphite-induced sensitivity may be SA- dependent, as both phosphite and SA were found to control P. cinnamomi and stimulate SA accumulation. A combination of phosphite and SA may be more beneficial to plants if it can reduce phytotoxic effects and reduce the chance of pathogen sensitivity to phosphite.

1 aGroves, Emma1 aHoward, Kay1 aHardy, Giles1 aBurgess, Treena uhttp://link.springer.com/article/10.1007%2Fs10658-014-0562-y02911nas a2200169 4500008004100000022001400041245014400055210006900199260002900268300001400297490000600311520230100317100002602618700001902644700002302663856005502686 2008 eng d a1364-370300aPhytophthora ramorum: a pathogen with a remarkably wide host range causing sudden oak death on oaks and ramorum blight on woody ornamentals0 aPhytophthora ramorum a pathogen with a remarkably wide host rang bBlackwell Publishing Ltd a729–7400 v93 a

Phytophthora ramorum is an oomycete plant pathogen classified in the kingdom Stramenopila. P. ramorum is the causal agent of sudden oak death on coast live oak and tanoak as well as ramorum blight on woody ornamental and forest understorey plants. It causes stem cankers on trees, and leaf blight or stem dieback on ornamentals and understorey forest species. This pathogen is managed in the USA and Europe by eradication where feasible, by containment elsewhere and by quarantine in many parts of the world. Genomic resources provide information on genes of interest to disease management and have improved tremendously since sequencing the genome in 2004. This review provides a current overview of the pathogenicity, population genetics, evolution and genomics of P. ramorum. Taxonomy: Phytophthora ramorum (Werres, De Cock & Man in’t Veld): kingdom Stramenopila; phylum Oomycota; class Peronosporomycetidae; order Pythiales; family Pythiaceae; genus Phytophthora.Host range: The host range is very large and the list of known hosts continues to expand at the time of writing. Coast live oak and tanoak are ecologically, economically and culturally important forest hosts in the USA. Rhododendron, Viburnum, Pieris, Syringa and Camellia are key ornamental hosts on which P. ramorum has been found repeatedly, some of which have been involved in moving the pathogen via nursery shipments. Disease symptoms: P. ramorum causes two different diseases with differing symptoms: sudden oak death (bleeding lesions, stem cankers) on oaks and ramorum blight (twig dieback and/or foliar lesions) on tree and woody ornamental hosts.Useful websites: http://nature.berkeley.edu/comtf/, http://rapra.csl.gov.uk/, http://www.aphis.usda.gov/plant_health/plant_pest_info/pram/index.shtml, http://genome.jgi-psf.org/Phyra1_1/Phyra1_1.home.html, http://pamgo.vbi.vt.edu/, http://pmgn.vbi.vt.edu/, http://vmd.vbi.vt.edu./, http://web.science.oregonstate.edu/bpp/labs/grunwald/resources.htm, http://www.defra.gov.uk/planth/pramorum.htm, http://www.invasive.org/browse/subject.cfm?sub=4603, http://www.forestry.gov.uk/forestry/WCAS-4Z5JLL

1 aGrünwald, Niklaus, J1 aGoss, Erica, M1 aPress, Caroline, M uhttp://dx.doi.org/10.1111/j.1364-3703.2008.00500.x02122nas a2200265 4500008004100000022001400041245008700055210006900142260004000211300001400251490000700265520134700272653002701619653002101646653001301667653001101680653001701691653001301708100001901721700001401740700001401754700001601768700001701784856005501801 2012 eng d a1365-305900aPhytophthora obscura sp. nov., a new species of the novel Phytophthora subclade 8d0 aPhytophthora obscura sp nov a new species of the novel Phytophth bBlackwell Publishing LtdcJune 2012 a610–6220 v613 a

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

10aAesculus hippocastanum10aKalmia latifolia10aoomycete10aPieris10aRhododendron10ataxonomy1 aGrünwald, N J1 aWerres, S1 aGoss, E M1 aTaylor, C R1 aFieland, V J uhttp://dx.doi.org/10.1111/j.1365-3059.2011.02538.x02390nas a2200601 4500008004100000245011000041210006900151300001200220490000700232520059400239100002600833700001900859700001700878700002300895700002100918700002100939700002000960700002400980700002401004700002101028700001901049700002001068700001701088700001701105700002701122700002501149700001901174700002401193700002101217700002601238700001901264700002201283700002201305700002101327700001801348700001901366700001801385700001901403700002701422700002901449700002201478700002501500700001801525700002301543700002801566700002201594700002001616700002001636700002601656700001701682700002301699856006601722 2009 eng d00aStandardizing the nomenclature for clonal lineages of the sudden oak death pathogen, Phytophthora ramorum0 aStandardizing the nomenclature for clonal lineages of the sudden a792-7950 v993 a

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

1 aGrünwald, Niklaus, J1 aGoss, Erica, M1 aIvors, Kelly1 aGarbelotto, Matteo1 aMartin, Frank, N1 aProspero, Simone1 aHansen, Everett1 aBonants, Peter, J M1 aHamelin, Richard, C1 aChastagner, Gary1 aWerres, Sabine1 aRizzo, David, M1 aAbad, Gloria1 aBeales, Paul1 aBilodeau, Guillaume, J1 aBlomquist, Cheryl, L1 aBrasier, Clive1 aBrière, Stephan, C1 aChandelier, Anne1 aDavidson, Jennifer, M1 aDenman, Sandra1 aElliott, Marianne1 aFrankel, Susan, J1 aGoheen, Ellen, M1 aGruyter, Hans1 aHeungens, Kurt1 aJames, Delano1 aKanaskie, Alan1 aMcWilliams, Michael, G1 aMan in ‘t Veld, Willem1 aMoralejo, Eduardo1 aOsterbauer, Nancy, K1 aPalm, Mary, E1 aParke, Jennifer, L1 aSierra, Ana Maria Perez1 aShamoun, Simon, F1 aShishkoff, Nina1 aTooley, Paul, W1 aVettraino, Anna Maria1 aWebber, Joan1 aWidmer, Timothy, L uhttp://apsjournals.apsnet.org/doi/abs/10.1094/PHYTO-99-7-079201294nas a2200181 4500008004100000022001400041245006800055210006800123300001400191490000700205520072100212100002600933700002300959700001900982700001901001700002101020856007101041 2012 eng d a0966-842X00aEmergence of the sudden oak death pathogen Phytophthora ramorum0 aEmergence of the sudden oak death pathogen Phytophthora ramorum a131 - 1380 v203 a

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

1 aGrünwald, Niklaus, J1 aGarbelotto, Matteo1 aGoss, Erica, M1 aHeungens, Kurt1 aProspero, Simone uhttp://www.sciencedirect.com/science/article/pii/S0966842X1100227701467nas a2200121 4500008004100000245010700041210006900148300001000217490000700227520101700234100002601251856006801277 2012 eng d00aGenome sequences of Phytophthora enable translational plant disease management and accelerate research0 aGenome sequences of Phytophthora enable translational plant dise a13-190 v343 a

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

1 aGrünwald, Niklaus, J uhttp://www.tandfonline.com/doi/abs/10.1080/07060661.2012.66456800656nas a2200193 4500008004100000245007500041210006900116300001200185490000700197100002600204700002100230700002400251700002900275700002300304700002300327700002300350700002300373856006600396 2011 eng d00aPhytophthora-ID.org: a sequence-based Phytophthora identification tool0 aPhytophthoraIDorg a sequencebased Phytophthora identification to a337-3420 v951 aGrünwald, Niklaus, J1 aMartin, Frank, N1 aLarsen, Meredith, M1 aSullivan, Christopher, M1 aPress, Caroline, M1 aCoffey, Michael, D1 aHansen, Everett, M1 aParke, Jennifer, L uhttp://apsjournals.apsnet.org/doi/abs/10.1094/PDIS-08-10-060903561nas a2200217 4500008004100000022001400041245009700055210006900152260001600221300001600237490000800253520289300261100002203154700001903176700001903195700001903214700001603233700001403249700001403263856006603277 2016 eng d a0191-291700aFirst Report of the EU1 Clonal Lineage of Phytophthora ramorum on Tanoak in an Oregon Forest0 aFirst Report of the EU1 Clonal Lineage of Phytophthora ramorum o cJan-05-2016 a1024 - 10240 v1003 a

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

1 aGrünwald, N., J.1 aLarsen, M., M.1 aKamvar, Z., N.1 aReeser, P., W.1 aKanaskie, A1 aLaine, J.1 aWiese, R. uhttp://apsjournals.apsnet.org/doi/10.1094/PDIS-10-15-1169-PDN02527nas a2200241 4500008004100000245014600041210006900187260001300256300001100269490000800280520171900288653001302007653002302020653002502043653002002068653001602088100002102104700002502125700002202150700002302172700002802195856006202223 2020 eng d00aThe influence of time, soil moisture and exogenous factors on the survival potential of oospores and chlamydospores of Phytophthora cinnamomi0 ainfluence of time soil moisture and exogenous factors on the sur cNov/2020 ae126370 vn/a3 a

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

10adormancy10along-term survival10aphytophthora dieback10aspore viability10avital stain1 aGyeltshen, Jamba1 aDunstan, William, A.1 aGrigg, Andrew, H.1 aBurgess, Treena, I1 aHardy, Giles, E. St. J. uhttps://onlinelibrary.wiley.com/doi/abs/10.1111/efp.12637