Races of Puccinia graminis f. sp. tritici in the United States and Mexico in 1981. A. P. Roelfs, Research Plant Pathologist, Cereal Rust Laboratory, USDA, ARS, University of Minnesota, St. Paul 55108. D. L. Long, Plant Pathologist, and D. H. Casper, Research Technician, Cereal Rust Laboratory, USDA, ARS, University of Minnesota, St. Paul 55108. Plant Dis. 67:82-84. Accepted for publication 26 May 1982. 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/PD-67-82.

Wheat stem rust was light in 1981. Rust was found overwintering in three locations in the southern United States. Disease spread was retarded by dry weather and advanced crop maturity in the northern winter wheat areas. Resistant cultivars prevented disease development in the spring and durum wheat area. Race 151-QFB comprised 39% of 596 isolates obtained from 230 rust collections; 15-TNM, 36%; 17-HDL, 7%; 11-RCR, 5%; 17-HNL, 3%; 151-QSH, 2%; 15-TDM, 15-TLM, 151-QCB, 113-RKQ, 113-RTQ, 29-HJC, and 56-MBC, 1% or less of the total isolates identified. No virulence was found in bulked uredospore collections for seedlings with Sr genes 13, 22, 24, 25, 26, 27, 29, 30, 31, 32, 33, Gt, Tt-2, and Wld-1.