VIEW ARTICLE

Etiology

Infection of Trembling Aspen by Hypoxylon mammatum Through Cicada Oviposition Wounds. Michael E. Ostry, Plant pathologist, U.S. Department of Agriculture, Forest Service, North Central Forest Experiment Station, St. Paul, MN 55108; Neil A. Anderson, professor, Department of Plant Pathology, University of Minnesota, St. Paul 55108. Phytopathology 73:1092-1096. Accepted for publication 7 March 1983. 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, 1983. DOI: 10.1094/Phyto-73-1092.

An outbreak of the periodical cicada (Magicicada septendecim) in 1976 caused extensive oviposition injury to 1- and 2-yr-old branch wood of trembling aspen (Populus tremuloides) in a plantation established from progeny of controlled crosses. The incidence of Hypoxylon canker significantly increased, beginning in 1978. By 1982, 78% of the new cankers were associated with cicada wounds. Branch infections developed into lethal cankers on the main stems of many trees. Susceptibility to infection appeared to differ among the progeny. Cicada wounds also were associated with cankers on surrounding wild aspen. Periodic high rates of infection in localized areas may be attributed to wounding by this insect.