Fomes fraxinophilus on Green Ash in Nebraska Windbreaks. J. W. Riffle, Plant Pathologist, USDA Forest Service, Rocky Mountain Forest and Range Experiment Station, Forestry Sciences Laboratory, University of Nebraska, Lincoln 68583. W. D. Ostrofsky, Forest Pest Specialist, Department of Forestry, Fisheries, and Wildlife, University of Nebraska; and R. L. James, Plant Pathologist, USDA Forest Service, State and Private Forestry, Forest Pest Management, Lakewood, CO 80215. Plant Dis. 65:667-669. Accepted for publication 29 November 1980. 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-65-667.

Visible incidence of Fomes fraxinophilus stem decay on 35- to 42-year-old Fraxinus pennsylvanica trees in Nebraska Prairie States Forestry Project windbreaks was estimated by using a 2.8% random sample of windbreaks (clusters). A total of 55,155 living trees in 173 windbreaks in 41 counties was examined. Based on occurrence of sporocarps, infected trees were found in 40 counties and in 90% of the windbreaks. Mean incidence of infected trees was 5.5 ± 0.4% (0.95 confidence limit). A mean of six sporocarps was found per infected live tree, and more than 98% of the sporocarps were associated with branch stubs on the bole or major lateral branches within 3.6 m of the ground. About 110,000 trees of an estimated 2 million living Fraxinus pennsylvanica in Nebraska have sporocarps; an even greater number are infected with F. fraxinophilus.

Keyword(s): shelterbelts, white mottled rot.