Differential Reactions to Three Strains of Wheat Powdery Mildew (Erysiphe Graminis Var. Tritici)

Abstract

The pathogenicity of three strains of wheat powdery mildew on certain Triticum species and cultivars is described. One of these strains is characterized by virulence' on the cultivar Asosan, previously resistant in Australian studies. Resistance, apparently genetically different from any already described, is recorded in two Australian cultivars. In view of the variability in pathogenicity revealed by these strains, the need for the establishment of an acceptable international differential set is emphasized.