00918nas a2200205 4500008004100000245013300041210006900174260012100243300001000364490003200374100002700406700002000433700001700453700002000470700002200490700002200512700002300534700002700557856012800584 2009 eng d00aPersistence of Phytophthora ramorum and Phytophthora kernoviae in U.K. natural areas and implications for North American forests0 aPersistence of Phytophthora ramorum and Phytophthora kernoviae i aSanta Cruz, CaliforniabU.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station.c04/2010 a83-840 vGen. Tech. Rep. PSW-GTR-2291 aFichtner, Elizabeth, J1 aRizzo, David, M1 aWebber, Joan1 aKirk, Susan, A.1 aWhybrow, Alistair1 aFrankel, Susan, J1 aKliejunas, John, T1 aPalmieri, Katharine, M uhttps://forestphytophthoras.org/references/persistence-phytophthora-ramorum-and-phytophthora-kernoviae-uk-natural-areas-and00502nas a2200133 4500008004100000245012200041210006900163300001400232490000700246100001800253700001500271700001500286856006700301 2007 eng d00aDetection, distribution, sporulation, and survival of Phytophthora ramorum in a California redwood-tanoak forest soil0 aDetection distribution sporulation and survival of Phytophthora  a1366-13750 v971 aFichtner, E J1 aLynch, S C1 aRizzo, D M uhttp://apsjournals.apsnet.org/doi/abs/10.1094/PHYTO-97-10-136602518nas a2200229 4500008004100000022001400041245010700055210006900162260003800231300001400269490000700283520178600290653002302076653002402099653002102123653002702144100001802171700001502189700001402204700001502218856005502233 2011 eng d a1365-305900aInfectivity and sporulation potential of Phytophthora kernoviae to select North American native plants0 aInfectivity and sporulation potential of Phytophthora kernoviae  bBlackwell Publishing Ltdc04/2012 a224–2330 v613 a

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

10aforest biosecurity10ahost susceptibility10ainvasive disease10aPhytophthora kernoviae1 aFichtner, E J1 aRizzo, D M1 aKirk, S A1 aWebber, JF uhttp://dx.doi.org/10.1111/j.1365-3059.2011.02506.x00504nas 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-99-5-060802095nas a2200169 4500008004100000022001400041245009300055210006900148300001000217490000700227520156300234100001801797700001501815700001401830700001501844856006601859 2011 eng d a0191-291700aRoot infections may challenge management of invasive Phytophthora spp. in U.K. woodlands0 aRoot infections may challenge management of invasive Phytophthor a13-180 v953 a

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

1 aFichtner, E J1 aRizzo, D M1 aKirk, S A1 aWebber, JF uhttp://apsjournals.apsnet.org/doi/abs/10.1094/PDIS-03-10-023601356nas a2200145 4500008004100000245013600041210007000177260001500247300001200262490000700274520084400281100001501125700001501140856005501155 1999 eng d00aCypress mortality (mal del ciprés) in the Patagonian Andes: comparisons with similar forest diseases and declines in North America0 aCypress mortality mal del ciprés in the Patagonian Andes compari cApril 1999 a89–960 v293 a

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

1 aFilip, G M1 aRosso, P H uhttp://dx.doi.org/10.1046/j.1439-0329.1999.00133.x00679nas a2200121 4500008004100000245011600041210007000157260011500227300001200342100001500354700001900369856016900388 2009 eng d00a‘‘Mal del ciprés’’ disease: analysis of the association between aerial symptoms and vitality of trees.0 aMal del ciprés disease analysis of the association between aeria aAlbany, CA, USAbUSDA Forest Service, Pacific Southwest Research Station: Gen. Tech. Rep. PSW-GTR-221, 282–3 a282–31 aFloria, MP1 aGreslebin, A G uhttps://forestphytophthoras.org/references/%E2%80%98%E2%80%98mal-del-cipr%C3%A9s%E2%80%99%E2%80%99-disease-analysis-association-between-aerial-symptoms-and-vitality00358nas a2200097 4500008004100000245005400041210005400095260002700149100003800176856004600214 2006 eng d00aDistribution of the Phytophthora disease of alder0 aDistribution of the Phytophthora disease of alder bUK Forestry Commission1 aForestry_Commission_Great_Britain uhttp://www.forestry.gov.uk/fr/INFD-737J2S02381nas a2200181 4500008004100000022001400041245014700055210007000202260001200272300001200284490000700296520177500303100002102078700001902099700002102118700002002139856004002159 2013 eng d a1439-032900aGene × environment tests discriminate the new EU2 evolutionary lineage of Phytophthora ramorum and indicate that it is adaptively different0 aGene × environment tests discriminate the new EU2 evolutionary l c06/2014 a219-2320 v443 a

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

1 aFranceschini, S.1 aWebber, J., F.1 aSancisi-Frey, S.1 aBrasier, C., M. uhttp://dx.doi.org/10.1111/efp.1208501256nas 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=AP0708801155nas a2200205 4500008004100000245006600041210006500107260012900172300001200301520040300313653001900716653002100735653002500756653002100781653001100802100002200813700002300835700002700858856006400885 2009 eng d00aProceedings of the sudden oak death fourth science symposium.0 aProceedings of the sudden oak death fourth science symposium aSanta Cruz, CaliforniabAlbany, CA: Pacific Southwest Research Station, Forest Service, U.S. Department of Agriculturec2010 a378 pp.3 a

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

10acoast live oak10ainvasive species10aPhytophthora ramorum10aSudden oak death10atanoak1 aFrankel, Susan, J1 aKliejunas, John, T1 aPalmieri, Katharine, M uhttp://www.fs.fed.us/psw/publications/documents/psw_gtr229/01277nas a2200205 4500008004100000245009300041210006900134260012700203300001200330520049800342653001900840653002100859653002500880653002100905653001100926100002300937700002200960700002500982856006401007 2005 eng d00aProceedings of the sudden oak death second science symposium: the state of our knowledge0 aProceedings of the sudden oak death second science symposium the aMonterey, CaliforniabAlbany, CA: Pacific Southwest Research Station, Forest Service, U.S. Department of Agriculturec2006 a571 pp.3 a

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

10acoast live oak10ainvasive species10aPhytophthora ramorum10aSudden oak death10atanoak1 aFrankel, Susan, J.1 aShea, Patrick, J.1 aHaverty, Michael, I. uhttp://www.fs.fed.us/psw/publications/documents/psw_gtr196/01176nas a2200205 4500008004100000245006400041210006400105260012900169300001200298520042400310653001900734653002100753653002500774653002100799653001100820100002300831700002400854700002800878856006400906 2007 eng d00aProceedings of the sudden oak death third science symposium0 aProceedings of the sudden oak death third science symposium aSanta Rosa, CaliforniabAlbany, CA: Pacific Southwest Research Station, Forest Service, U.S. Department of Agriculturec2008 a491 pp.3 a

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

10acoast live oak10ainvasive species10aPhytophthora ramorum10aSudden oak death10atanoak1 aFrankel, Susan, J.1 aKliejunas, John, T.1 aPalmieri, Katharine, M. uhttp://www.fs.fed.us/psw/publications/documents/psw_gtr214/02045nas a2200157 4500008004100000245004200041210004000083260007500123520150500198100001501703700001501718700001701733700002101750700001701771856009901788 2015 eng d00aPest Alert: Phytophthora tentaculata.0 aPest Alert Phytophthora tentaculata aAlbany, CA . bPacific Southwest Research Station, USDA Forest Service3 a

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

1 aFrankel, S1 aSwiecki, T1 aBernhardt, E1 aRooney-Latham, S1 aBlomquist, C uhttp://www.suddenoakdeath.org/wp-content/uploads/2015/02/P.tentaculata.Pest_.Alert_.022315.pdf02775nas a2200229 4500008004100000245013500041210006900176260001600245300000900261490000700270520202600277100002302303700002202326700002002348700001702368700001602385700001802401700002602419700002502445700002502470856005002495 2020 eng d00aPhytophthora Introductions in Restoration Areas: Responding to Protect California Native Flora from Human-Assisted Pathogen Spread0 aPhytophthora Introductions in Restoration Areas Responding to Pr cNov-30-2020 a12910 v113 a

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

1 aFrankel, Susan, J.1 aConforti, Christa1 aHillman, Janell1 aIngolia, Mia1 aShor, Alisa1 aBenner, Diana1 aAlexander, Janice, M.1 aBernhardt, Elizabeth1 aSwiecki, Tedmund, J. uhttps://www.mdpi.com/1999-4907/11/12/1291/htm02685nas a2200193 4500008004100000245011100041210006900152260001600221300001100237490000700248520204500255100001902300700002602319700001802345700002402363700001902387700002302406856006202429 2020 eng d00aImpact of weather variables and season on sporulation of Phytophthora pluvialis and Phytophthora kernoviae0 aImpact of weather variables and season on sporulation of Phytoph cMar-03-2020 ae125880 v503 a

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

1 aFraser, Stuart1 aGomez-Gallego, Mireia1 aGardner, Judy1 aBulman, Lindsay, S.1 aDenman, Sandra1 aWilliams, Nari, M. uhttps://onlinelibrary.wiley.com/doi/abs/10.1111/efp.1258800374nas a2200109 4500008004100000245005000041210004900091300001100140490000600151100001500157856009200172 1950 eng d00a Las especies de Phytophthora en la Argentina0 aLas especies de Phytophthora en la Argentina a47-1330 v41 aFrezzi, MJ uhttps://forestphytophthoras.org/references/las-especies-de-phytophthora-en-la-argentina01878nas a2200157 4500008004100000022001400041245015100055210006900206260001600275300001400291490000800305520130900313100001801622700001501640856006501655 2016 eng d a0191-291700aEffects of Soil Solarization and Trichoderma asperellum on Soilborne Inoculum of Phytophthora ramorum and Phytophthora pini in Container Nurseries0 aEffects of Soil Solarization and Trichoderma asperellum on Soilb cJan-02-2016 a438 - 4430 v1003 a

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

1 aFunahashi, F.1 aParke, J L uhttp://apsjournals.apsnet.org/doi/10.1094/PDIS-04-15-0453-RE