Sphaeropsis sapinea Cankers on Stressed Red and Jack Pines in Minnesota and Wisconsin. T. H. Nicholls, Principal Plant Pathologists, U.S. Department of Agriculture, North Central Forest Experiment Station, St. Paul, MN 55108. M. E. Ostry, Principal Plant Pathologists, U.S. Department of Agriculture, North Central Forest Experiment Station, St. Paul, MN 55108. Plant Dis. 74:54-56. Accepted for publication 8 August 1989. 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, 1990. DOI: 10.1094/PD-74-0054.

Outbreaks of Sphaeropsis sapinea infections in red and jack pine plantations were studied in Minnesota and Wisconsin. The incidence and impact of the disease was documented on study plots with low site indices. Tree mortality ranged from 2 to 51% on study plots and was consistently associated with S. sapinea. Cankers occurred more frequently on trees exposed to environmental stresses such as poor site conditions, drought, hail, snow, and insect wounds.