Pathotypes of Peronosclerospora sorghi. Jeweus Craig, Research Plant Pathologist, Agricultural Research, Science and Education Administration, U.S. Department of Agriculture, Plant Sciences Department, Texas A&M University, College Station 77843. R. A. Frederiksen, Professor, Plant Sciences Department, Texas A&M University, College Station 77843. Plant Dis. 64:778-779. 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, 1980. DOI: 10.1094/PD-64-778.

Two pathotypes of Peronosclerospora sorghi were identified by differential pathogenicity on seedlings of sorghum lines inoculated with conidia. Differences in pathogenicity were expressed as percentage of inoculated plants that contracted sorghum downy mildew. Pathotype 2 caused higher percentages of mildew in differential sorghum cultivars than did pathotype 1.