Abstract
Wheat stem rust was light in 1981. Rust was found overwintering in 3 locations in the southern USA. 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.