ABSTRACT
Colletotrichum lindemuthianum, causal agent of anthracnose, a serious disease of dry bean, had been prevalent mostly in the eastern United States and Michigan. In 2001, the disease was observed affecting several commercial bean fields in North Dakota. To assess the potential impact of this pathogen on the North Dakota dry bean industry, 30 of the most widely planted cultivars were inoculated with races 7, 73, and 89 of C. lindemuthianum. Race 73 is present in Michigan, and has been detected in recently North Dakota and Manitoba, while races 7 and 89 are currently present in Michigan and Ontario. All cultivars were spray inoculated with a suspension of 106 conidia/ml in the greenhouse and evaluated for disease reaction using a 0-to-9 scale 8 days after inoculation. Most kidney beans were susceptible to race 7, but resistant to races 73 and 89. ‘Isles’ and ‘Drake’ were the only kidney beans resistant to all three races. All pinto beans were susceptible to races 73 and 89 except ‘Topaz’, which was moderately resistant to race 73 but susceptible to race 89. Most pinto beans were resistant or moderately resistant to race 7. Navy bean cvs. Newport and Envoy were resistant to all three races; however, ‘Norstar’, the most widely planted navy bean cultivar, was susceptible to all three races. Research is being conducted to identify germplasm with resistance to these races. To reduce the possibility of spreading this pathogen to new fields in the region, the use of noncertified seed should be discouraged among producers, and fields used for seed production should be monitored very carefully.
