Susceptibility of Populus Species and Hybrids to Disease in the North Central United States. Michael E. Ostry, Principal Plant Pathologist, North Central Forest Experiment Station, USDA Forest Service, 1992 Folwell Ave., St. Paul, MN 55108. Harold S. McNabb, Jr., Professor of Forest Pathology, Departments of Plant Pathology, Seed and Weed Sciences, and Forestry, Iowa State University, Ames 50011. Plant Dis. 69:755-757. Accepted for publication 17 March 1985. 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, 1985. DOI: 10.1094/PD-69-755.

In test plantings of hybrid poplars in Iowa, Minnesota, and Wisconsin during 1976–1982, three foliar diseases and one canker disease were common and severe enough to be potentially damaging to yield. Disease incidence and severity varied by clone and location. Premature defoliation was caused by Melampsora medusae, Marssonina brunnea, and Septoria musiva. Highly susceptible trees were predisposed to environmental stress and infection by stress-related fungi. Stem breakage at cankers caused by S. musiva may preclude planting several of the tested clones in the north central United States. Successful plantation establishment and high biomass yields will require selecting disease-resistant clones.

Keyword(s): disease resistance, intensive culture.