Anthracnose is not established in North Dakota or Minnesota, but it is present in southern Manitoba near the international border, says Art Lamey, NDSU Extension Service plant pathologist. Seed from infected areas The most important disease management procedure is to keep the anthracnose pathogen out by avoiding seed produced in infested areas, Lamey says. Bean growers should determine where the seed they purchase was grown and not purchase seed grown in an infected state or province, including Manitoba, Michigan and Ontario. Seed developed in an infected state or province is acceptable if it was grown under furrow irrigation in a western state such as Idaho, Wyoming, eastern Washington or eastern Oregon, he says. In the field, the most characteristic symptoms of anthracnose appear on the undersides of leaves, where small, angular brick red to purple-brown lesions develop.
Older lesions become darker, extend to the upper leaf surface and proceed along veins.
Pod lesions are sunken, circular, chocolate brown to black colored with a raised dark margin surrounded by a thin zone of reddish tissue. On the lesion surface, tan spores dry into dark granular masses. Anthracnose can be blown from field to field in crop refuse and spreads within the field in splashing rain showers, as well as being carried on seed. Moderate chemical control with multiple applications of Benlate or Topsin M is feasible but may not be economic, Lamey says. Grand Forks Herald.