00504nas 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-99-5-060802518nas 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.x00502nas 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-97-10-136602095nas 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-03-10-0236