07882nas a2200157 4500008004100000245007600041210006900117260001200186300000900198490000700207520741400214100002007628700001407648700001607662856004607678 2008 eng d00aPhytophthora species causing tanoak stem cankers in southwestern Oregon0 aPhytophthora species causing tanoak stem cankers in southwestern c08/2008 a12520 v923 a

Tanoak (Lithocarpus densiflorus) is a principal host of Phytophthora ramorum, cause of sudden oak death (SOD), in the western United States (1). In the course of SOD surveys in southwestern Oregon, other Phytophthora species were encountered to be causing stem cankers on tanoak that were indistinguishable from those caused by P. ramorum. In Oregon, SOD is subject to quarantine and eradication. Aerial surveys are flown two or more times a year to locate symptomatic tanoaks, which are then examined from the ground to determine the cause of death. Isolations on selective media were attempted from all trees with stem cankers typical of Phytophthora. Phytophthora species were identified by morphological features and DNA sequencing of either internal transcribed spacer (ITS) or the mitochondrial COX spacer region. ITS sequences were compared with validated GenBank records, and COX spacer sequences were compared with known reference isolates in the OSU collection. From 2001 through 2006, Phytophthora spp. were isolated from 482 of 1,057 tanoak stem cankers sampled. P. ramorum was isolated from 359 cankers, P. nemorosa was isolated from 102 cankers, P. gonapodyides was isolated from six cankers, P. cambivora was isolated from four cankers (all A1 mating type), P. siskiyouensis was isolated from four cankers, P. pseudosyringae was isolated from two cankers, P. cinnamomi was isolated from one canker (mating type A2), and P. taxon “Pgchlamydo” was isolated from one canker. Three cankers yielded isolates that were not identified but were closely related to P. pseudosyringae based on ITS sequence. No Phytophthora spp. were cultured from the remaining cankers. One isolate from each species identified (except P. ramorum and P. pseudosyringae) was tested for pathogenicity on tanoak stems (11.4 to 16.0 cm DBH) in the field. A 5-mm-diameter plug from the margin of a V8 agar culture was placed in a hole in the bark, covered with wet cheesecloth, and sealed with aluminum foil and duct tape. Each isolate was inoculated into five different stems. Each stem received three different isolates and an agar control. After 4 weeks, bark was removed to reveal lesion development. Lesions were measured (length by width), and pieces from four points on the lesion margin were plated in selective media to reisolate. P. cambivora, P. cinnamomi, P. gonapodyides, P. nemorosa, P. siskiyouensis and P. taxon “Pgchlamydo” all caused substantial lesions in inoculated tanoak trees (average area 11.5 to 18.6 cm2). In all cases, the species used for inoculation was recovered on reisolation from lesion margins. Control inoculations caused necrotic areas averaging 0.2 cm2. Isolations from these areas were clean. Prior to the recent SOD epidemic, no species of Phytophthora were known as pathogens of tanoak. The discovery of P. ramorum as a pathogen of tanoak in California was quickly followed by the discovery that P. nemorosa and P. pseudosyringae were also associated with tanoak cankers (2). Six years of diagnostic support for survey and detection of P. ramorum in tanoak forests of southwest Oregon has revealed the occurrence, at very low frequency, of at least five additional species of Phytophthora causing stem cankers in tanoak.

1 aReeser, Paul, W1 aSutton, W1 aHansen, E M uhttp://dx.doi.org/10.1094/PDIS-92-8-1252B01614nas a2200169 4500008004100000245006400041210006400105300001000169490000800179520109600187100002001283700001801303700002301321700002101344700002001365856005901385 2011 eng d00aPhytophthora species in forest streams in Oregon and Alaska0 aPhytophthora species in forest streams in Oregon and Alaska a22-350 v1033 a

Eighteen Phytophthora species and one species of Halophytophthora were identified in 113 forest streams in Alaska, western Oregon and southwestern Oregon that were sampled by baiting or filtration of stream water with isolation on selective media. Species were identified by morphology and DNA characterization with single strand conformational polymorphism, COX spacer sequence and ITS sequence. ITS Clade 6 species were most abundant overall, but only four species, P. gonapodyides (37% of all isolates), P. taxon Salixsoil, P. taxon Oaksoil and P. pseudosyringae, were found in all three regions. The species assemblages were similar in the two Oregon regions, but P. taxon Pgchlamydo was absent in Alaska and one new species present in Alaska was absent in Oregon streams. The number of Phytophthora propagules in Oregon streams varied by season and in SW Oregon, where sampling continued year round, P. taxon Salixsoil, P. nemorosa and P. siskiyouensis were recovered only in some seasons.

1 aReeser, Paul, W1 aSutton, Wendy1 aHansen, Everett, M1 aRemigi, Philippe1 aAdams, Gerry, C uhttp://www.mycologia.org/cgi/content/abstract/103/1/2201675nas a2200193 4500008004100000022001400041245006400055210006400119260001600183300001200199490000800211520110500219100002001324700001801344700002301362700002101385700002001406856005501426 2011 eng d a0027-551400aPhytophthora species in forest streams in Oregon and Alaska0 aPhytophthora species in forest streams in Oregon and Alaska cAug-01-2012 a22 - 350 v1033 a

Eighteen Phytophthora species and one species of Halophytophthora were identified in 113 forest streams in Alaska, western Oregon and southwestern Oregon that were sampled by baiting or filtration of stream water with isolation on selective media. Species were identified by morphology and DNA characterization with single strand conformational polymorphism, COX spacer sequence and ITS sequence. ITS Clade 6 species were most abundant overall, but only four species, P. gonapodyides (37% of all isolates), P. taxon Salixsoil, P. taxon Oaksoil and P. pseudosyringae, were found in all three regions. The species assemblages were similar in the two Oregon regions, but P. taxon Pgchlamydo was absent in Alaska and one new species present in Alaska was absent in Oregon streams. The number of Phytophthora propagules in Oregon streams varied by season and in SW Oregon, where sampling continued year round, P. taxon Salixsoil, P. nemorosa and P. siskiyouensis were recovered only in some seasons.

1 aReeser, Paul, W1 aSutton, Wendy1 aHansen, Everett, M1 aRemigi, Philippe1 aAdams, Gerry, C uhttps://www.tandfonline.com/doi/pdf/10.3852/10-01301920nas a2200145 4500008004100000245016200041210006900203300001200272490000700284520136300291100002001654700002301674700001801697856005901715 2007 eng d00aPhytophthora siskiyouensis, a new species from soil, water, myrtlewood (Umbellularia californica) and tanoak (Lithocarpus densiflorus) in southwestern Oregon0 aPhytophthora siskiyouensis a new species from soil water myrtlew a639-6430 v993 a

An unknown Phytophthora species was recovered in southwestern Oregon from rhododendron and tanoak leaf baits used for monitoring streams and soils for the presence of Phytophthora ramorum, from a blighted shoot of myrtlewood and from tanoak bark cankers. Isolates of this species yielded ITS-DNA sequences that differed substantially from other Phytophthora sequences in GenBank. Morphological features also differed from available descriptions of known Phytophthora species. Based on the combination of unique morphology and unique ITS sequences a new species is proposed. The new species, Phytophthora siskiyouensis, is homothallic with globose to subglobose oogonia, which may be terminal, sessile or laterally intercalary. Antheridia are capitate and mostly paragynous but sometimes amphigynous. Oospores are mostly aplerotic. Sporangia are variable but commonly ovoid to reniform, with apical, subapical or lateral semipapillae (occasionally more than one). Sporangia are terminal, subterminal or occasionally intercalary on unbranched sporangiophores, with basal, subbasal or lateral attachment. Sporangia are weakly deciduous, with variable length pedicels. This combination of characters clearly separates Phytophthora siskiyouensis from other known Phytophthora species.

1 aReeser, Paul, W1 aHansen, Everett, M1 aSutton, Wendy uhttp://www.mycologia.org/cgi/content/abstract/99/5/639