01467nas 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.htm