Conifer Mortality Associated with Root Disease and Insects in Colorado. R. L. James, Plant Pathologist, USDA Forest Service, Forest Insect and Disease Management, Missoula, MT 59801. D. J. Goheen, Plant Pathologist, USDA Forest Service, Forest Insect and Disease Management, Portland, OR 97208. Plant Dis. 65:506-507. . This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1981. DOI: 10.1094/PD-65-506.

Surveys were made of conifer mortality in the San Isabel, Rio Grande, San Juan, and Grand Mesa national forests in Colorado. More than 99% of trees examined in apparent mortality centers had root disease, and more than 80% were infested with bark beetles or wood borers. Fomes annosus and Armillaria mellea were the major root pathogens; both fungi were occasionally found on the same tree. Most root-diseased white fir trees were adjacent to conifer stumps, whereas many affected subalpine fir trees were in uncut stands. A Verticicladiella sp. was associated with black stain on Douglas-fir. Major insects associated with mortality included Scolytus ventralis, Dryocoetes confusus, Dendroctonus pseudotsugae, D. rufipennis, and wood borers (Buprestidae and Cerambycidae).