Root diseases were evaluated on the Reuben's Reserve, Nez Perce Indian Reservation, Idaho. Nineteen trees adjacent to two suspected root disease centers were pushed with a D-6 tractor to expose their root systems. Extent of root necrosis and decay was determined and related to level of crown thinning, chlorosis, and dieback. All excavated trees were infected with Phaeolus schweinitzii; some trees with severe root deterioration lacked crown decline symptoms typical of root disease. Evidence of insect activity was often found in the root crown or bole of trees with extensive root necrosis and decay. A black staining organism, Verticicladiella antibiotica, was isolated from roots of two trees. Implications of root diseases in management of Douglas-fir in the Reserve are discussed.
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