Pathogenicity Grouping of Isolates ofLeptosphaeria maculansonBrassica napusCultivars and Their Disease Reaction Profiles on Rapid-Cycling Brassicas

The pathogenic variability among isolates of Leptosphaeria maculans from different geographic regions was tested using 39 isolates from North America, Europe, and Australia against Brassica napus cultivars Westar, Quinta, and Glacier. An additional 62 single-ascospore isolates from oilseed rape debris from Saskatchewan and Manitoba, Canada, and from Western Australia and New South Wales, Australia, were also tested to study pathogen variability within locations