Races of Puccinia graminis f. sp. avenae in the United States During 1979. A. P. Roelfs, Research Plant Pathologist, Cereal Rust Laboratory, AR, SEA, USDA, University of Minnesota, St. Paul 55108. D. L. Long, Plant Pathologist, and D. H. Casper, Research Technician, Cereal Rust Laboratory, AR, SEA, USDA, University of Minnesota, St. Paul 55108. Plant Dis. 64:947-949. 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-64-947.

Oat stem rust overwintered in south Texas and produced a large amount of inoculum in 1979. Unfavorable environmental conditions and a lack of virulence for Pg-2 and Pg-4 restricted disease development to the north. From 501 uredial collections, 1,372 isolates were obtained. NA-27 made up 94% of the isolates. No virulence was found for Pg-16 and -a or the “universally” resistant lines Saia, CI 9221, SES Selection No. 52, X-1588-2, Kyto, and CI 9139.