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Characteristics of the 1984-1985 Wheat Leaf Rust Epidemic in Central Texas. D. Marshall, Texas Agricultural Experiment Station, Texas A&M University Research and Extension Center, 17360 Coit Road, Dallas 75252. . Plant Dis. 72:239-241. Accepted for publication 23 September 1987. Copyright 1988 The American Phytopathological Society. DOI: 10.1094/PD-72-0239.

Most of the wheat cultivars planted in central Texas in the fall of 1984 were susceptible to leaf rust (Puccinia recondita). The cultivar Northrup King Probrand 812 (NK 812) occupied 63% of the hectarage. Rust severity on flag leaves of NK 812 reached 100% at the beginning of flowering at Beeville and at the milky ripe stage at Dallas. The leaf rust isopath progressed northward at a rate of 24 km per day from 1 April through 25 May. Virulence frequency data indicated that the P. recondita population had high frequencies of virulence toward the leaf rust resistance genes Lr1, 2a, 2c, 3, 10, and 16. Virulence to Lr24 was detected in early spring in south Texas, but not at any other time or location. Fungicide trials at Dallas indicated a 40% or greater loss in yield on NK 812 as a result of leaf rust.