00578nas 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-cedar02063nas 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-89-006301467nas 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.htm00415nas 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/3759999