Armillaria ostoyae lesions on Douglas-fir. Presentation by Mike Cruikshank: Field Studies Agree and Extend the Results of Greenhouse Trials for Host Resistance of Douglas-fir to Infection by Armillaria ostoyae. 58th Annual Western International Forest Disease Work Conference, held October 4-8, 2010 in Valemount, BC.
Photo credit: USDA Forest Service, Region 6, State and Private Forestry, Forest Health Protection, Westside Forest Insect and Disease Service Center. Source: Kristen Chadwick collection; Sandy, Oregon.