Reduction of Susceptibility of Wheat to Stem Rust (Puccinia graminis f. sp. tritici) by Brome Mosaic Virus. D. S. Erasmus, M. Sc. Graduate, Department of Microbiology, University of Cape Town, Rondebosch 7700, South Africa. M. B. Von Wechmar, Associate Professor, Department of Microbiology, University of Cape Town, Rondebosch 7700, South Africa. Plant Dis. 67:1196-1198. Accepted for publication 22 April 1983. Copyright 1983 American Phytopathological Society. DOI: 10.1094/PD-67-1196.

Wheat plants (Triticum aestivum) cultivar T4 infected with brome mosaic virus (BMV) were found less susceptible to wheat stem rust (Puccinia graminis f. sp. tritici) infection than virus-free plants were. A progressive decrease in susceptibility to stem rust (as gauged by pustule size and spore yield) occurred with increasing virus concentration in infected tissue. The relevance of this finding to BMV epidemiology and to rust resistance studies is discussed.