Yield Loss of Lodgepole Pine Stands to Dwarf Mistletoe in Colorado and Wyoming National Forests. David W. Johnson, Supervisory Plant Pathologist, State and Private Forestry, USDA Forest Service, Lakewood, CO 80225. Frank G. Hawksworth, Research Forest Pathologist, USDA Forest Service, Rocky Mountain Forest and Range Experiment Station, Fort Collins, CO 80526; and David B. Drummond, Survey Plant Pathologist, State and Private Forestry, USDA Forest Service, Pineville, LA 71360. Plant Dis. 65:437-438. . 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-65-437.

From 1977 to 1979, a road and plot survey was conducted for Arceuthobium americanum in lodgepole pine (Pinus contorta) stands on nine national forests in Colorado and Wyoming. Infestation levels ranged from 0 to 64.0% and averaged 50.6% for all forests surveyed. Estimates of annual merchantable loss to dwarf mistletoe by forest ranged from 880 to 101,930 m³ (0.40–1.36 m³/ha). The annual loss for these forests is estimated at 270,750 m³ (average, 0.76 m³/ha). This loss is equivalent to the annual harvest of lodgepole pine sawtimber for these national forests or at least 25% of the annual growth.