Disease Note

Dothiora polyspora on Aspen. T. E. Hinds, USDA Forest Service, Rocky Mountain Forest and Range Experiment Station, Fort Collins, CO 80526. W. D. Shepperd, USDA Forest Service, Rocky Mountain Forest and Range Experiment Station, Fort Collins, CO 80526, and T. H. Laurent, formerly USDA Forest Service, Juneau, AK 99801. Plant Dis. 69:1100. Accepted for publication 22 July 1985. Copyright 1985 The American Phytopathological Society. DOI: 10.1094/PD-69-1100b.

Dothiora polyspora Shear & Davidson was described in 1940 from ascocarps occurring on aspen (Populus tremuloides Michx.) and willow (Salix spp.) in the Grand Mesa National Forest of Colorado. Its occurrence and distribution since then has not been reported. During a 1984 survey of Colorado aspen, D. polyspora and its Dothichiza state were commonly found fruiting on aspen sprouts in previously clear-cut areas. The fungus was associated with 1- to 3-yr-old sprout mortality, recently dead terminal leaders of 4- to 6-yr-old sprouts, old dead terminals in the lower crowns of 6- to 16-yr-old sprouts, annual cankers, and perennial cankers associated with stem wounds. The fungus was found in the Arapaho, Gunnison, Pike, Rio Grande, Roosevelt, Routt, San Juan, Uncompahgre, and White River national forests. It has also been collected in Carson National Forest in northern New Mexico and Fishlake National Forest in Utah and 3 mi west of Takeetna, Alaska.