Diagnosis of Annosus Root Disease in Mixed Conifer Forests in the Northwestern United States

Abstract

Recognizing annosus root disease affecting conifers in northwestern United States forests is discussed. Field diagnosis can bemade by observing characteristic stand patterns, wood stain and decay, ectotrophic mycelium, and sporophores. Most seriously affected trees include hemlocks, grand fir, white fir and Pacific silver fir. Ponderosa pine and other true firs may also be damaged. Wounded trees, especially hemlocks and true firs, are readily colonized by Heterobasidion annosum and wounds can be used as an indicator of infection. Laboratory analysis can be used to confirm field diagnosis.

Parent Publication

• Proceedings of the symposium on research and management of annosus root disease (Heterobasidion annosum) in western North America; April 18-21, 1989; Monterey, CA.

Citation

Schmitt, Craig L. 1989. Diagnosis of Annosus Root Disease in Mixed Conifer Forests in the Northwestern United States. In: Otrosina, William J.; Scharpf, Robert F., technical coordinators. 1989. Proceedings of the symposium on research and management of annosus root disease (Heterobasidion annosum) in western North America; April 18-21, 1989; Monterey, CA. Gen. Tech. Rep. PSW-GTR-116. Berkeley, CA: Pacific Southwest Forest and Range Experiment Station, Forest Service, U.S. Department of Agriculture; p. 40-42