APS Abstracts of Presentations

Sudden oak death surveys in Oregon - 2001. M. G. McWilliams (1), A. Kanaskie (1), N. Osterbauer (2), E. M. Goheen (3), E. M. HANSEN (4), W. Sutton (4), and J. Mair (1). (1) Oregon Dept. Forestry; (2) Oregon Dept. Agriculture; (3) U.S. Forest Service; (4) Oregon State University. Phytopathology 92:S54. Publication no. P-2002-0391-AMA.

Two aerial surveys in SW Oregon, in July and October 2001, detected 33 sites with recently killed tanoak trees. Eight more sites with dead tanoaks were identified during ground checking. Of these 41 sites, 9 were positive for Phytophthora ramorum. The infested sites all are within a 9-square mile area in Curry County, and range in size from 0.5 to 12 acres. They occur on industrial and non-industrial forest land and federal Bureau of Land Management lands. The primary species killed was tanoak, but rhododendron and evergreen huckleberry also are infected and occasionally killed. Other causes of tanoak mortality included Armillaria species (9 sites), herbicide or mechanical damage (7 sites), an unidentified Phytophthora (5 sites), and unknown agents (11 sites). Armillaria sp. was the most frequently encountered pathogen associated with single trees or small clumps of 2 or 3 dead tanoaks, while larger groups of dead tanoak were more likely to be SOD. Ground surveys not associated with the aerial surveys failed to detect Sudden Oak Death.

Copyright 2002 by The American Phytopathological Society. All rights reserved.