Colletotrichum lindemuthianum Races Prevalent on Dry Beans in North Dakota and Potential Sources of Resistance

Anthracnose caused by Colletotrichum lindemuthianum is one of the most important diseases of dry edible beans in the major production areas worldwide. This pathogen is highly variable, with numerous races. Disease management relies heavily on genetic resistance and use of clean seed. Genetic resistance is controlled by major resistance genes conferring protection against specific races of the pathogen. Therefore, knowledge of the pathogen population in a region is essential for effective screening of germplasm. Surveys were conducted for more than 6 years in North Dakota, the largest dry-bean-growing state in the United States, and seed samples submitted for certification were assessed to identify the C. lindemuthianum races prevalent in the region. A collection of commercial cultivars from different market classes of dry bean was also screened for resistance to these races. Disease incidence was found to be low in most years. However, in addition to the previously reported races of anthracnose 7, 73, and 89, two new races, 1153 and 1161, previously never reported in the United States, were identified and the commercial cvs. Montcalm, Avalanche, Vista, and Sedona where found to possess resistance to these races.