02168nas a2200205 4500008004100000022001400041245012100055210006900176520148900245100001801734700002101752700002001773700001801793700001901811700002101830700002301851700002201874700001701896856004901913 2012 eng d a0031-949X00aStrong genetic differentiation between North American and European populations of Phytophthora alni subsp. uniformis0 aStrong genetic differentiation between North American and Europe3 a

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

1 aAguayo, Jaime1 aAdams, Gerard, C1 aHalkett, Fabien1 aCatal, Mursel1 aHusson, Claude1 aNagy, Zoltán, A1 aHansen, Everett, M1 aMarçais, Benoît1 aFrey, Pascal uhttp://dx.doi.org/10.1094/PHYTO-05-12-0116-R00767nas a2200193 4500008004100000022001400041245009900055210006900154260008000223300001400303490000800317653002700325653001400352653001900366653001600385100002400401700002100425856012700446 2010 eng d a0378-112700aStand development patterns as a consequence of the mortality in Austrocedrus chilensis forests0 aStand development patterns as a consequence of the mortality in  a{PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}b{ELSEVIER SCIENCE BV}cAPR 30 a1981-19920 v25910aAustrocedrus chilensis10amortality10aStand dynamics10aUneven-aged1 aAmoroso, Mariano, M1 aLarson, Bruce, C uhttps://forestphytophthoras.org/references/stand-development-patterns-consequence-mortality-austrocedrus-chilensis-forests00451nas a2200133 4500008004100000022001300041245007700054210006900131260001600200300001200216490000700228100001600235856006600251 1929 eng d a0007153600aStrains and taxonomy of Phytophthora palmivora Butler (P. Faberi Maubl.)0 aStrains and taxonomy of Phytophthora palmivora Butler P Faberi M cJan-03-1929 a18 - 380 v141 aAshby, S.F. uhttp://linkinghub.elsevier.com/retrieve/pii/S000715362980025300471nas a2200145 4500008004100000245007400041210006900115300001400184490000800198100001900206700001900225700001600244700001700260856004800277 2004 eng d00aSudden oak death (Phytophthora ramorum) discovered on trees in Europe0 aSudden oak death Phytophthora ramorum discovered on trees in Eur a1108-11100 v1081 aBrasier, Clive1 aDenman, Sandra1 aBrown, Anna1 aWebber, Joan uhttp://dx.doi.org/10.1017/S095375620422124400385nas a2200109 4500008004100000245007800041210006900119300001200188490000800200100001900208856004800227 2003 eng d00aSudden Oak Death: Phytophthora ramorum exhibits transatlantic differences0 aSudden Oak Death Phytophthora ramorum exhibits transatlantic dif a257-2590 v1071 aBrasier, Clive uhttp://dx.doi.org/10.1017/S095375620322766001305nas a2200445 4500008004100000022001400041245013000055210006900185260003900254300001400293490000700307653001800314653001200332653002800344653001600372653001700388653001600405653001000421653001700431653002400448653001400472653001200486653001800498653001100516653001700527653001700544653001900561653000900580653002500589653001800614653000900632653001900641653001600660653001800676653001500694100002000709700001400729700001500743856010100758 1995 eng d a0191-291700aSymptoms and Phytophthora spp. associated with root rot and stem canker of noble fir Christmas trees in the Pacific Northwest0 aSymptoms and Phytophthora spp associated with root rot and stem  bAmerican Phytopathological Society a290–2930 v7910aAbies procera10aAmerica10aArtificial forest stand10aConiferales10aepidemiology10aField study10aFungi10aGymnospermae10aHost agent relation10ainfection10aMycosis10aNorth America10aOregon10aPhycomycetes10aPhytophthora10aPlant pathogen10aRoot10aSoftwood forest tree10aSpermatophyta10aStem10aSymptomatology10aThallophyta10aUnited States10aWashington1 aChastagner, G A1 aHamm, P B1 aRiley, K L uhttp://www.apsnet.org/publications/PlantDisease/BackIssues/Documents/1995Abstracts/PD_79_290.htm00450nas a2200133 4500008004100000245006900041210006900110300001200179490000700191100001800198700001900216700001500235856006600250 2008 eng d00aSources of inoculum for Phytophthora ramorum in a redwood forest0 aSources of inoculum for Phytophthora ramorum in a redwood forest a860-8660 v981 aDavidson, J M1 aPatterson, H A1 aRizzo, D M uhttp://apsjournals.apsnet.org/doi/abs/10.1094/PHYTO-98-8-086000486nas a2200145 4500008004100000245007700041210006900118260001400187100001800201700001400219700001800233700001600251700001500267856005800282 2003 eng d00aSudden oak death and associated diseases caused by Phytophthora ramorum.0 aSudden oak death and associated diseases caused by Phytophthora  cJuly 20031 aDavidson, J M1 aWerres, S1 aGarbelotto, M1 aHansen, E M1 aRizzo, D M uhttp://www.plantmanagementnetwork.org/php/shared/sod/02812nas a2200217 4500008004100000245010700041210006900148260001700217300001200234490000900246520210600255653002002361653002302381653002502404653001902429653001002448653002002458653002102478100003702499856005802536 2011 eng d00aScientific opinion on the pest risk analysis on Phytophthora ramorum prepared by the FP6 project RAPRA0 aScientific opinion on the pest risk analysis on Phytophthora ram c28 June 2011 a107 pp.0 v9(6)3 a

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

10aLarix kaempferi10amanagement options10aPhytophthora ramorum10aramorum blight10aRAPRA10arisk assessment10aSudden oak death1 aEFSA Panel on Plant Health (PLH) uhttp://www.efsa.europa.eu/en/efsajournal/pub/2186.htm01935nas a2200205 4500008004100000245013700041210006900178300001400247490000800261520121700269653003501486653002201521100002801543700002501571700001801596700001901614700002001633700002901653856004701682 2010 eng d00aA statistical model to detect asymptomatic infectious individuals with an application in the Phytophthora alni-Induced alder decline0 astatistical model to detect asymptomatic infectious individuals  a1262-12690 v1003 a

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

10aspatial point pattern analysis10asurvival analysis1 aElegbede, Chabi Fabrice1 aPierrat, Jean-Claude1 aAguayo, Jaime1 aHusson, Claude1 aHalkett, Fabien1 ac}ais, Beno{\^ıt Mar{\c uhttp://dx.doi.org/10.1094/PHYTO-05-10-014001163nas a2200157 4500008004100000022001400041245011000055210006900165260002500234300001000259490000800269520064400277100001800921700001800939856004800957 2008 eng d a0929-187300aSpecies hybrids in the genus Phytophthora with emphasis on the alder pathogen Phytophthora alni: a review0 aSpecies hybrids in the genus Phytophthora with emphasis on the a bSpringer Netherlands a31-390 v1223 a

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

1 aÉrsek, Tibor1 aNagy, Zoltán uhttp://dx.doi.org/10.1007/s10658-008-9296-z00504nas a2200133 4500008004100000245012700041210006900168300001200237490000700249100001800256700001500274700001500289856006600304 2009 eng d00aSurvival, dispersal, and potential soil-mediated suppression of Phytophthora ramorum in a California redwood-tanoak Forest0 aSurvival dispersal and potential soilmediated suppression of Phy a608-6190 v991 aFichtner, E J1 aLynch, S C1 aRizzo, D M uhttp://apsjournals.apsnet.org/doi/abs/10.1094/PHYTO-99-5-060801256nas a2200121 4500008004100000245008100041210006900122300001200191490000700203520085500210100002201065856004701087 2008 eng d00aSudden oak death and Phytophthora ramorum in the USA: a management challenge0 aSudden oak death and Phytophthora ramorum in the USA a managemen a19–250 v373 a

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

1 aFrankel, Susan, J uhttp://www.publish.csiro.au/?paper=AP0708801395nas 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.abstract01405nas 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.abstract03184nas 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/45/1/2302226nas 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.2002.86.4.441C02390nas 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-99-7-079200578nas a2200145 4500008004100000022001400041245007800055210006900133260006500202300001600267490000700283100001600290700001400306856011200320 1996 eng d a0191-291700aSurvival of Phytophthora lateralis in infected roots of Port Orford cedar0 aSurvival of Phytophthora lateralis in infected roots of Port Orf b[St. Paul, Minn.: American Phytopathological Society], 1980- a1075–10780 v801 aHansen, E M1 aHamm, P B uhttps://forestphytophthoras.org/references/survival-phytophthora-lateralis-infected-roots-port-orford-cedar00415nas a2200145 4500008004100000022001300041245005100054210005100105260002100156300001200177490000700189100001600196700001700212856004000229 1991 eng d a0027551400aSpecies of the Phytophthora megasperma complex0 aSpecies of the Phytophthora megasperma complex cMay - Jun., 1991 a376-3810 v831 aHansen, E M1 aMaxwell, D P uhttp://www.jstor.org/stable/375999901467nas a2200157 4500008004100000245011100041210006900152300001200221490000700233520090400240100001601144700001401160700001401174700001601188856010501204 1980 eng d00aSurvival, spread, and pathogenicity of Phytophthora spp. on Douglas-fir seedlings planted on forest sites.0 aSurvival spread and pathogenicity of Phytophthora spp on Douglas a422-4250 v703 a

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

1 aHansen, E M1 aRoth, L F1 aHamm, P B1 aJulis., A J uhttp://www.apsnet.org/publications/phytopathology/backissues/Documents/1980Abstracts/Phyto70_422.htm02063nas a2200145 4500008004100000245013900041210006900180300001000249490000700259520154500266100001601811700001501827700001401842856006101856 2005 eng d00aSusceptibility of Oregon forest trees and shrubs to Phytophthora ramorum: a comparison of artificial inoculation and natural infection0 aSusceptibility of Oregon forest trees and shrubs to Phytophthora a63-700 v893 a

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

1 aHansen, E M1 aParke, J L1 aSutton, W uhttp://apsjournals.apsnet.org/doi/abs/10.1094/PD-89-006302365nas a2200145 4500008004100000245012400041210006900165260001600234300001600250490000700266520186900273100001902142700001902161856003902180 2016 eng d00aSporulation potential, symptom expression and detection of Phytophthora ramorum on larch needles and other foliar hosts0 aSporulation potential symptom expression and detection of Phytop cJan-12-2016 a1441 - 14510 v653 a

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

1 aHarris, A., R.1 aWebber, J., F. uhttps://doi.org/10.1111/ppa.12538 02560nas a2200145 4500008004100000022001400041245011000055210006900165260001200234300001400246490000700260520199700267100001602264856013402280 1963 eng d a0003-474600aStudies on the chemical control of Phytophthora palmivora (Butl.) Butl. on Theobroma cacao L. in Nigeria.0 aStudies on the chemical control of Phytophthora palmivora Butl B c12/1963 a465 - 4800 v523 a

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

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

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

Weekly applications of 0·15% fentin acetate to seedlings induced no significant damage.

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

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

1 aHislop, E C uhttp://onlinelibrary.wiley.com/doi/10.1111/j.1744-7348.1963.tb03770.x/abstract;jsessionid=FA42764CD24DC2258C2776AF065DAB4F.d01t0100626nas a2200133 4500008004100000245004900041210004900090260003500139300001200174490000700186520024800193100001100441856004000452 1981 eng d00aSynoptic keys to the species of Phytophthora0 aSynoptic keys to the species of Phytophthora bMycological Society of America a705-7140 v733 a

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

1 aHo, HH uhttp://www.jstor.org/stable/375949701806nas a2200181 4500008004100000022001400041245012800055210007100183260002500254300001200279490000800291520120300299100001701502700001901519700002101538700001701559856004801576 2005 eng d a0929-187300aSCAR–based PCR primers to detect the hybrid pathogen Phytophthora alni and its subspecies causing alder disease in Europe0 aSCAR–based PCR primers to detect the hybrid pathogen Phytophthor bSpringer Netherlands a323-3350 v1123 a

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

1 aIoos, Renaud1 aHusson, Claude1 aAndrieux, Axelle1 aFrey, Pascal uhttp://dx.doi.org/10.1007/s10658-005-6233-200596nas 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%3B203172nas 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/pdf00481nas a2200109 4500008004100000245007500041210006900116260010500185300001100290100002300301856004700324 2010 eng d00aSudden oak death and Phytophthora ramorum: a summary of the literature0 aSudden oak death and Phytophthora ramorum a summary of the liter aAlbany, CA, USAbU.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station. a181 p.1 aKliejunas, John, T uhttp://www.treesearch.fs.fed.us/pubs/3659101965nas a2200217 4500008004100000022001400041245014500055210006900200260001200269300001200281490000800293520124400301653003601545653001301581653002201594100001501616700002101631700002101652700001901673856005501692 2012 eng d a1574-696800aSurvival of Phytophthora alni, Phytophthora kernoviae, and Phytophthora ramorum in a simulated aquatic environment at different levels of pH0 aSurvival of Phytophthora alni Phytophthora kernoviae and Phytoph c07/2012 a54–600 v3323 a

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

10aquarantine Phytophthora species10awater pH10azoospore survival1 aKong, Ping1 aLea-Cox, John, D1 aMoorman, Gary, W1 aHong, Chuanxue uhttp://dx.doi.org/10.1111/j.1574-6968.2012.02574.x00564nas a2200133 4500008004100000245011900041210006900160300001200229490000700241100001600248700001700264700001200281856013700293 2008 eng d00aSeedling recruitment of Austrocedrus chilensis in relation to cattle use, microsite environment and forest disease0 aSeedling recruitment of Austrocedrus chilensis in relation to ca a27–410 v181 aLa Manna, L1 aCollantes, M1 aBava, J uhttps://forestphytophthoras.org/references/seedling-recruitment-austrocedrus-chilensis-relation-cattle-use-microsite-environment-and01853nas a2200193 4500008004100000022001400041245008400055210006900139260001200208300001400220490000700234520122100241100002001462700001401482700001201496700001601508700001901524856011601543 2013 eng d a0191-291700aA survey of Phytophthora spp. in midwest nurseries, greenhouses, and landscapes0 asurvey of Phytophthora spp in midwest nurseries greenhouses and  c05/2013 a635 - 6400 v973 a

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

1 aLeonberger, A J1 aSpeers, C1 aRuhl, G1 aCreswell, T1 aBeckerman, J L uhttps://forestphytophthoras.org/references/survey-phytophthora-spp-midwest-nurseries-greenhouses-and-landscapes01979nas a2200181 4500008004100000022001400041245011000055210006900165300001600234490000800250520136300258653002501621100002201646700001701668700002001685700002101705856007101726 2006 eng d a0953-756200aStromata, sporangiomata and chlamydosori of Phytophthora ramorum on inoculated Mediterranean woody plants0 aStromata sporangiomata and chlamydosori of Phytophthora ramorum  a1323 - 13320 v1103 a

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

10aSporangial dispersal1 aMoralejo, Eduardo1 aPuig, Miquel1 aGarcia, Jose, A1 aDescals, Enrique uhttp://www.sciencedirect.com/science/article/pii/S095375620600265600420nas a2200121 4500008004100000245006000041210006000101300001400161490000700175100002200182700002300204856007100227 1997 eng d00aSusceptibility of Pacific Yew to Phytophthora lateralis0 aSusceptibility of Pacific Yew to Phytophthora lateralis a1400-14040 v811 aMurray, Marion, S1 aHansen, Everett, M uhttp://apsjournals.apsnet.org/doi/abs/10.1094/PDIS.1997.81.12.140000616nas a2200121 4500008004100000245008500041210006900126300001200195490001000207100001600217700001600233856024500249 2007 eng d00aA summary of North American hardwood tree diseases with bleeding canker symptoms0 asummary of North American hardwood tree diseases with bleeding c a122-1310 v33(2)1 aNelson, A H1 aHudler, G W uhttp://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=57&ved=0CE4QFjAGODI&url=http%3A%2F%2Fjoa.isa-arbor.com%2Frequest.asp%3FJournalID%3D1%26ArticleID%3D2985%26Type%3D2&ei=pKOvUpvjGcv7oASXoYDYDA&usg=AFQjCNHxNzEH7As_NfGpUf1LVGxbCXIeXA05098nas a2200193 4500008004100000022001300041245011000054210006900164260001600233300001400249490000600263520447400269100001604743700002404759700002604783700002704809700002304836856004504859 2013 eng d a2210634000aSurveys of soil and water reveal a goldmine of Phytophthora diversity in South African natural ecosystems0 aSurveys of soil and water reveal a goldmine of Phytophthora dive cJun-06-2015 a123 - 1310 v43 a

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

1 aOh, Eunsung1 aGryzenhout, Marieka1 aWingfield, Brenda, D.1 aWingfield, Michael, J.1 aBurgess, Treena, I uhttp://www.imafungus.org/Issue/41/22.pdf01452nas a2200121 4500008004100000245008300041210006900124520096400193100002001157700001901177700001501196856011901211 2004 eng d00aSurveying for and eradicating Phytophthora ramorum in agricultural commodities0 aSurveying for and eradicating Phytophthora ramorum in agricultur3 a

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

1 aOsterbauer, N K1 aGriesbach, J A1 aHedberg, J uhttps://forestphytophthoras.org/references/surveying-and-eradicating-phytophthora-ramorum-agricultural-commodities02280nas a2200169 4500008004100000245008100041210006900122300001200191490000700203520170500210100001501915700001201930700001701942700001701959700001901976856011501995 2001 eng d00aSignificance of Phytophthoras and Pythium for oak, alder and spruce decline.0 aSignificance of Phytophthoras and Pythium for oak alder and spru a96-103 0 v473 a

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

1 aOßwald, W1 aJung, T1 aNechwatal, J1 aSchlenzig, A1 aFleischmann, F uhttps://forestphytophthoras.org/references/significance-phytophthoras-and-pythium-oak-alder-and-spruce-decline02026nas a2200373 4500008004100000245007900041210006900120260001400189300001400203490000700217520105400224100001601278700002001294700001501314700001901329700001701348700001301365700001801378700001601396700001401412700001301426700001401439700001301453700001301466700001701479700001701496700001501513700001301528700002301541700001401564700001701578700001401595856004301609 2014 eng d00aStrategies of attack and defence in woody plant- Phytophthora interactions0 aStrategies of attack and defence in woody plant Phytophthora int cJune 2014 a169–1900 v443 a

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

1 aOßwald, W.1 aFleischmann, F.1 aRigling, D1 aCoelho, A., C.1 aCravador, A.1 aDiez, J.1 aDalio, R., J.1 aJung, Horta1 aPfanz, H.1 aRobin, C1 aSipos, G.1 aSolla, A1 aCech, T.1 aChambery, A.1 aDiamandis, S1 aHansen, E.1 aJung, T.1 aOrlikowski, L., B.1 aParke, J.1 aProspero, S.1 aWerres, S uhttp://doi.wiley.com/10.1111/efp.1209600341nas a2200097 4500008004100000245004100041210004000082100001500122700001300137856009300150 2008 eng d00aSudden oak death and ramorum blight.0 aSudden oak death and ramorum blight1 aParke, J L1 aLucas, S uhttp://www.apsnet.org/edcenter/intropp/lessons/fungi/Oomycetes/Pages/SuddenOakDeath.aspx00641nas a2200193 4500008004100000245008800041210006900129260002700198300001000225490003200235100001500267700001900282700001300301700001500314700001700329700001900346700001800365856006400383 2010 eng d00aA systems approach for detecting sources of Phytophthora contamination in nurseries0 asystems approach for detecting sources of Phytophthora contamina aSanta Cruz, California a67-680 vGen. Tech. Rep. PSW-GTR-2291 aParke, J L1 aGrünwald, N J1 aLewis, C1 aFieland, V1 aFrankel, S J1 aKliejunas, J T1 aPalmieri, K M uhttp://www.fs.fed.us/psw/publications/documents/psw_gtr229/03040nas a2200169 4500008004100000022001300041245012800054210006900182260001600251300001200267490000800279520245800287100001902745700002002764700002002784856006602804 2014 eng d a0378112700aSource or sink? The role of soil and water borne inoculum in the dispersal of Phytophthora ramorum in Oregon tanoak forests0 aSource or sink The role of soil and water borne inoculum in the  cJan-06-2014 a48 - 570 v3223 a

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

1 aPeterson, Ebba1 aHansen, Everett1 aHulbert, Joseph uhttp://linkinghub.elsevier.com/retrieve/pii/S037811271400126101195nas a2200121 4500008004100000245006500041210005900106260006300165520070800228100002200936700002300958856009200981 2019 eng d00aSudden oak death, sudden larch death, and ramorum blight​ 0 aSudden oak death sudden larch death and ramorum blight aSt. Paul, MNbThe American Phytopathological Societyc20193 a

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

1 aPeterson, Ebba, K1 aParke, Jennifer, L uhttps://www.apsnet.org/edcenter/disandpath/oomycete/pdlessons/Pages/SuddenOakDeath.aspx01776nas a2200169 4500008004100000245012300041210006900164260001600233300001400249490000800263520117000271100002601441700001401467700002601481700002001507856007901527 2018 eng d00aSurvival of Phytophthora cinnamomi and Fusarium verticillioides in commercial potting substrates for ornamental plants0 aSurvival of Phytophthora cinnamomi and Fusarium verticillioides  cJan-08-2018 a484 - 4930 v1663 a

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

1 aPuértolas, Alexandra1 aBoa, Eric1 aBonants, Peter, J. M.1 aWoodward, Steve uhttps://onlinelibrary.wiley.com/doi/abs/10.1111/jph.12708?campaign=woletoc02584nas a2200169 4500008004100000245010400041210006900145260001600214520197200230100001402202700001702216700001802233700001602251700001702267700001702284856011302301 2016 eng d00aScreening brassicaceous plants as biofumigants for management of Phytophthora cinnamomi oak disease0 aScreening brassicaceous plants as biofumigants for management of cJan-06-20163 a

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

1 aRíos, P.1 aObregón, S.1 aGonzález, M.1 ade Haro, A.1 aSanchez, M E1 aWoodward, S. uhttp://doi.wiley.com/10.1111/efp.12287http://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fefp.1228701872nas a2200145 4500008004100000245009100041210006900132300001200201490000700213520137300220100001901593700003301612700002101645856006001666 1992 eng d00aSpatial and temporal enlargement of trunk cankers of Phytophthora cinnamomi in red oak0 aSpatial and temporal enlargement of trunk cankers of Phytophthor a362-3660 v223 a

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

1 aRobin, Cécile1 aDesprez-Loustau, Marie-Laure1 aDelatour, Claude uhttp://www.nrcresearchpress.com/doi/abs/10.1139/x92-04701923nas a2200205 4500008004100000022001400041245012400055210006900179260002600248300001400274490000700288520122200295100002701517700002101544700002201565700002101587700002301608700003101631856005501662 2005 eng d a1439-032900aSeasonal and spatial mortality patterns of holm oak seedlings in a reforested soil infected with Phytophthora cinnamomi0 aSeasonal and spatial mortality patterns of holm oak seedlings in bBlackwell Verlag GmbH a411–4220 v353 a

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

1 aRodríguez-Molina, M C1 aBlanco-Santos, A1 aPalo-Núñez, E J1 aTorres-Vila, L M1 aTorres-Álvarez, E1 aSuárez-de-la-Cámara, M A uhttp://dx.doi.org/10.1111/j.1439-0329.2005.00423.x00337nas a2200109 4500008004100000245003800041210003800079300001200117490000600129100001800135856007400153 1917 eng d00aStudies of the genus Phytophthora0 aStudies of the genus Phytophthora a233-2760 v81 aRosenbaum, J. uhttps://forestphytophthoras.org/references/studies-genus-phytophthora02442nas a2200145 4500008004100000022001400041245011800055210006900173260001600242520189900258100002902157700002702186700001702213856006602230 2020 eng d a0191-291700aSporulation potential of Phytophthora ramorum differs among common California plant species in the Big Sur region0 aSporulation potential of Phytophthora ramorum differs among comm cNov-17-20203 a

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

1 aRosenthal, Lisa, Micaela1 aFajardo, Sebastian, N.1 aRizzo, David uhttps://apsjournals.apsnet.org/doi/10.1094/PDIS-03-20-0485-RE00587nas a2200169 4500008004100000022001400041245011500055210006900170260001300239300001200252490000700264100001500271700001600286700001800302700001600320856008100336 1994 eng d a0378-112700aSpatial pattern of Austrocedrus chilensis wilting and the scope of autocorrelation analysis in natural forests0 aSpatial pattern of Austrocedrus chilensis wilting and the scope  cAUG 1994 a273-2790 v671 aRosso, P H1 aBaccalá, N1 aHavrylenko, M1 aFontenla, S uhttp://dx.doi.org.proxy.library.oregonstate.edu/10.1016/0378-1127(94)90022-102161nas a2200157 4500008004100000022001300041245008800054210006900142260001600211300001400227490000700241520165900248100001801907700002701925856005101952 1997 eng d a0378112700aSurvey and virulence of fungi occurring on diseased Acacia mearnsii in South Africa0 aSurvey and virulence of fungi occurring on diseased Acacia mearn cJan-12-1997 a327 - 3360 v993 a

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

1 aRoux, Jolanda1 aWingfield, Michael, J. uhttps://doi.org/10.1016/s0378-1127(97)00110-2 01951nas a2200265 4500008004100000245007000041210006900111260001200180300001400192490000800206520117200214653001801386653002001404653002001424653001401444653002101458653001801479653002701497653002201524653001801546100002101564700002501585700002001610856005501630 2003 eng d00aSusceptibility of some mesophilic hardwoods to alder Phytophthora0 aSusceptibility of some mesophilic hardwoods to alder Phytophthor c08/2003 a406–4100 v1513 a

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

10aAlnus cordata10aAlnus glutinosa10aCastanea sativa10aHardwoods10ainoculation test10aJuglans regia10aPhytophthora cinnamomi10aPhytophthora spp.10aQuercus robur1 aSantini, Alberto1 aBarzanti, Gian Paolo1 aCapretti, Paolo uhttp://dx.doi.org/10.1046/j.1439-0434.2003.00739.x01646nas a2200205 4500008004100000022001400041245010400055210006900159260002900228300001400257490000700271520099400278100001701272700001501289700001901304700001801323700002601341700001801367856005501385 2012 eng d a1439-032900aSusceptibility to Phytophthora cinnamomi of the commonest morphotypes of Holm oak in southern Spain0 aSusceptibility to Phytophthora cinnamomi of the commonest morpho bBlackwell Publishing Ltd a345–3470 v423 a

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

1 aSerrano, M S1 aDe Vita, P1 aCarbonero, M D1 aFernández, F1 aFernández-Rebollo, P1 aSánchez, M E uhttp://dx.doi.org/10.1111/j.1439-0329.2011.00758.x01206nas a2200157 4500008004100000245008200041210006900123260028100192300001000473520022800483100002500711700003100736700002500767700003100792856022500823 2002 eng d00aSudden oak death, a science symposium: the state of our knowledge (abstracts)0 aSudden oak death a science symposium the state of our knowledge  aMonterey, CaliforniabU.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station, University of California, Integrated Hardwood and Range Management Program, Center for Forestry, Division of Agriculture and Natural Resources, Berkeley, Californiac2002 a98 pp3 a

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

1 aShea, Dr. Patrick, J1 aStandiford, Dr. Richard, B1 aShea, Dr. Patrick, J1 aStandiford, Dr. Richard, B uhttp://www.suddenoakdeath.org/?bibliography=a-survey-of-sudden-oak-death-in-native-california-forest-and-woodland-communities-relating-incidence-and-intensity-of-phytophthora-ramorum-to-plant-community-and-site-variables02219nas a2200133 4500008004100000245014400041210006900185260001600254300001100270520167700281100002001958700002301978856008402001 2018 eng d00aSusceptibility to the rare Phytophthora tentaculata and to the widespread Phytophthora cactorum is consistent with host ecology and history0 aSusceptibility to the rare Phytophthora tentaculata and to the w cApr-05-2020 ae124463 a

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

1 aSims, Laura, L.1 aGarbelotto, Matteo uhttps://onlinelibrary.wiley.com/doi/abs/10.1111/efp.12446?campaign=wolearlyview01803nas a2200157 4500008004100000245008500041210006900126300001600195490000700211520131200218100001401530700001601544700002001560700001901580856004601599 2009 eng d00aStream monitoring for detection of Phytophthora ramorum in Oregon tanoak forests0 aStream monitoring for detection of Phytophthora ramorum in Orego a1182–11860 v933 a

Stream monitoring using leaf baits for early detection of Phytophthora ramorum has been an important part of the Oregon Sudden Oak Death (SOD) program since 2002. Sixty-four streams in and near the Oregon quarantine area in the southwest corner of the state were monitored in 2008. Leaves of rhododendron (Rhododendron macrophyllum) and tanoak (Lithocarpus densiflorus) were placed in mesh bags, and bags were floated in streams. Leaf baits were exchanged every 2 weeks throughout the year. Leaves were assayed by isolation on selective medium and by multiplex rDNA internal transcribed spacer polymerase chain reaction (ITS PCR). The two methods gave comparable results, but multiplex PCR was more sensitive. P. ramorum was regularly recovered at all seasons of the year from streams draining infested sites 5 years after eradication treatment. In streams with lower inoculum densities, recovery was much higher in summer than in winter. P. ramorum was isolated from streams in 23 watersheds. When P. ramorum was detected, intensive ground surveys located infected tanoaks or other host plants an average of 306 m upstream from the bait station. P. ramorum was isolated from stream baits up to 1,091 m from the probable inoculum source.

1 aSutton, W1 aHansen, E M1 aReeser, Paul, W1 aKanaskie, Alan uhttp://dx.doi.org/10.1094/PDIS-93-11-118200416nas a2200109 4500008004100000245005800041210005800099300001400157490000700171100002200178856010600200 1974 eng d00aSporulation and germination of Phytophthora lateralis0 aSporulation and germination of Phytophthora lateralis a1531-15330 v641 aTrione, Edward, J uhttp://www.apsnet.org/publications/phytopathology/backissues/Documents/1974Abstracts/Phyto64_1531.htm01836nas a2200121 4500008004100000245008900041210006900130300001100199490002000210520141400230100001401644856005601658 1976 eng d00aStudies on the trunk rot of Japanese chestnut trees caused by Phytophthora castaneae0 aStudies on the trunk rot of Japanese chestnut trees caused by Ph a48 pp.0 vSpecial Issue 33 a

Since its discovery in 1962 this disease of Castanea crenata has spread throughout the chestnut growing area and causes particularly severe damage in young orchards with bare ground between the trees. The fungus attacks trunks, branches, shoots and exposed roots, producing symptoms of black sap exudation from bark lesions which enlarge to girdle the trunk. A P. sp. isolated from lesion margins and described as P. castaneae [RPP 57, 2024] was shown to be pathogenic to chestnut and oak, and to rot inoculated apple and Japanese pear fruits. The opt. temp. for mycelial growth was 27 deg and for oospore production 20-30 deg C. The pathogen survives as oospores in infested soil and was isolated using young chestnut shoots as bait. The population density of P. castaneae in orchard soils was not correlated with disease severity. Every cv. of C. crenata tested was susceptible and also the European chestnut (C. sativa), but Chinese chestnut (C. mollissima) and American chestnut (C. dentata) were resistant. The disease was controlled by grassing infested orchards and damage was reduced by grass mulches. Sprays of Difolatan [captafol] or Bordeaux on the trunks from early May to early June were effective, especially when combined with insecticide sprays. Fungicide applications to the soil or to the trunks after early June were ineffective.

1 aUchida, K uhttp://www.cabdirect.org/abstracts/19791352311.html02510nas a2200241 4500008004100000022001400041245009100055210006900146260002900215300001400244490000700258520180600265653001202071653001402083653002002097653002102117100001902138700001402157700001202171700001402183700001602197856005502213 2012 eng d a1365-305900aSurvival of Phytophthora ramorum in Rhododendron root balls and in rootless substrates0 aSurvival of Phytophthora ramorum in Rhododendron root balls and  bBlackwell Publishing Ltd a166–1760 v623 a

This study assesses the survival of Phytophthora ramorum in the root ball of Rhododendron container plants as well as in different rootless forest substrates and a horticultural potting medium. Following inoculation of the root balls, the aboveground plant parts stayed symptomless, whilst the pathogen could be recovered with a novel non-destructive baiting assay from the root balls until at least 8 months post-inoculation. Plating of surface-sterilized roots and direct microscopic analysis confirmed the presence of P. ramorum in the roots. Phytophthora ramorum could also be baited from the root balls of symptomless Rhododendron plants from commercial nurseries, even 2 years after acquisition. Survival of P. ramorum in rootless media was assessed after burying disks of infected leaf material below the soil surface in columns filled with four different undisturbed forest substrates or a potting medium, and incubated at an outdoor quarantine facility. Phytophthora ramorum could be recovered at least 33 months after burial from all substrates, with a significant increase in recovery after the winter period. These data suggest the possibility for long-term symptomless presence of P. ramorum in root balls of commercial Rhododendron plants as well as survival in potting medium and different forest substrates under western European climate conditions. Symptomless presence in root balls can contribute to latent spread of this pathogen between nurseries. The novel baiting test, being non-destructive, simple and applicable to a relatively large number of plants, can offer a valuable tool to test plants for the presence of Phytophthora species in root balls.

10abaiting10adetection10alatent survival10aSudden oak death1 aVercauteren, A1 aRiedel, M1 aMaes, M1 aWerres, S1 aHeungens, K uhttp://dx.doi.org/10.1111/j.1365-3059.2012.02627.x00466nas a2200145 4500008004100000022001400041245006500055210006400120260002600184300001400210490000700224100001900231700001500250856005500265 2003 eng d a1365-305900aScotch broom: a new host of Phytophthora megasperma in Italy0 aScotch broom a new host of Phytophthora megasperma in Italy bBlackwell Science Ltd a417–4170 v521 aVettraino, A M1 aVannini, A uhttp://dx.doi.org/10.1046/j.1365-3059.2003.00839.x01616nas a2200181 4500008004100000022004200041245011400083210006900197300001400266490000700280520101100287100001801298700001301316700001701329700001601346700001601362856005601378 2013 eng d a1175-9003 (print), 1179-352X (online)00aSurveillance methods to determine tree health, distribution of kauri dieback disease and associated pathogens0 aSurveillance methods to determine tree health distribution of ka a235–2410 v663 a

Kauri dieback is a pest issue that is increasingly affecting kauri forests. A water and soilborne pathogen, Phytophthora taxon Agathis (PTA), has been identified as a causal agent of kauri dieback at multiple locations, particularly within Auckland and Northland. In 2008, a passive surveillance and adaptive management programme was initiated to manage the disease across the natural range of kauri. Surveys were initially undertaken to determine the distribution and rate of spread of kauri dieback on private land in the Auckland region. Methods to evaluate and monitor overall tree health, disease symptoms and other potential contributing factors were developed. Diagnostic sampling was undertaken to isolate and identify pathogens associated with kauri dieback. Along with PTA, other Phytophthora species and environmental stress were frequently associated with symptoms at over 400 properties inspected. Further management is now required to develop control tools and mitigate further spread.

1 aWaipara, N.W.1 aHill, S.1 aHill, L.M.W.1 aHough, E.G.1 aHorner, I J uhttp://www.nzpps.org/nzpp_abstract.php?paper=66235003226nas a2200133 4500008004100000245007300041210006900114260001200183300001000195490000800205520277900213100001502992856008503007 2011 eng d00aSurvival of Phytophthora kernoviae oospores, sporangia, and mycelium0 aSurvival of Phytophthora kernoviae oospores sporangia and myceli c07/2011 a15-230 v41S3 a

Interpretive Summary: A recently discovered plant pathogen has been found to attack many different hosts including rhododendrons and beech trees in the United Kingdom and New Zealand. Although not currently known to exist in the United States, it is a pathogen of concern due to its destructive nature and threat to valuable hosts in the U.S. This pathogen produces different propagules for spread and survival of which very little is known. This study was done to learn how long these propagules can survive at different temperatures. Results show that one propagule type can survive buried in sand for up to a year at moderate temperatures but declines rapidly when exposed for increased periods of time as temperatures increase. In addition, this pathogen is able to persist and produce survival propagules in sand with very minimal nutrients. These results provide information to regulatory agency personnel and scientists to develop guidelines that help in limiting the spread of this pathogen. Technical Abstract: Phytophthora kernoviae is a pathogen recently found only in the U.K. and New Zealand. Phytophthora kernoviae, not known to produce chlamydospores, is homothallic and produces abundant oospores and sporangia. This study was conducted to examine long-term survival of oospores, sporangia, and mycelium buried in sand at different temperatures. Viability of oospores embedded onto 20-µm-mesh screens and buried in sand at 4, 10, 20, and 30C was measured over time by staining with tetrazolium bromide solution. For one isolate, viability was 82, 81, 79, and 58% and 86, 75, 82, and 78% for the other isolate at 4, 10, 20, and 30C, respectively, after 1 year. The infection potential of the oospores was checked by removing additional embedded screens and placing on rhododendron leaf disks. No necrosis was observed on leaf disks exposed to oospores buried for 1 year at 30C. However, necrosis was observed on leaf disks at the other temperatures after the same time. Oospores exposed 6 h at 50C and 24 h at 40 and 50C were less viable than controls and did not germinate. To study survival of sporangia and mycelium, sand was infested only with sporangia or mycelium from four isolates, incubated at different temperatures, and plated on Phytophthora-selective medium over time. All isolates reacted in the same manner with populations generally declining within 1 week but then remaining steady over time. Soil extractions of the infested sand showed that over time sporangia and oospores formed at all temperatures except at 30C. This demonstrates that P. kernoviae oospores can persist in sand for long periods of time at different temperatures, which could be a significant factor in spread of this pathogen.

1 aWidmer, TL uhttp://www.ars.usda.gov/research/publications/publications.htm?seq_no_115=25963502232nas a2200265 4500008004100000022001400041245006900055210006700124260002900191300001200220490000800232520141000240653002001650653002501670653002701695653003001722653002401752653002601776653002601802653002801828100001801856700001701874700002001891856005501911 2009 eng d a1439-043400aA survey of Phytophthora species on Hainan Island of south China0 asurvey of Phytophthora species on Hainan Island of south China bBlackwell Publishing Ltd a33–390 v1573 a

Abstract During the period 1997–2007, a comprehensive study of the occurrence and distribution of Phytophthora species was conducted on Hainan Island of South China. To date, 14 species of Phytophthora have been recovered and their distribution determined. Phytophthora nicotianae (=P. parasitica) is the most important species attacking a wide variety of crops, followed by Phytophthora capsici and Phytophthora citrophthora. In contrast to Phytophthora colocasiae attacking taro leaves throughout the entire island, Phytophthora cyperi was found only once on Digitaria ciliaris in Danzhou. It is of interest to note that Phytophthora heveae, Phytophthora katsurae and Phytophthora insolita are commonly found in forest soil/water of protected mountains without causing any plant diseases. Although Phytophthora species are usually terrestrial or found in fresh water, one isolate of Phytophthora resembling closely the asexual isolates of P. insolita in Hainan was obtained from decaying Rhizophora leaves submerged in seawater. An unidentified Phytophthora species producing non-papillate; internally proliferating sporangia was isolated from the soil in which Ceriops tagel and Bruguiera serangula were growing in a salt water shrimp farm.

10amarine isolates10aPhytophthora capsici10aPhytophthora cinnamomi10aPhytophthora citrophthora10aPhytophthora heveae10aPhytophthora insolita10aPhytophthora katsurae10aPhytophthora nicotianae1 aZeng, Hui-cai1 aHo, Hon-hing1 aZheng, Fuy-Cong uhttp://dx.doi.org/10.1111/j.1439-0434.2008.01441.x