Previous View
 
APSnet Home
 
Plant Disease Home


Disease Note.

Identification of Race 65-Epsilon of Bean Anthracnose {Colletotrichum lindemuthianum) in Michigan. R. S. Balardin, Crop and Soil Sciences Department, Michigan State University, East Lansing 48824 . J. D. Kelly, Crop and Soil Sciences Department, Michigan State University, East Lansing 48824. Plant Dis. 80:712. Accepted for publication 25 March 1996. Copyright 1996 The American Phytopathological Society. DOI: 10.1094/PD-80-0712B.

Forty-four isolates of Colletotrichum lindemuthianum (Sacc. & Magnus) Lams.-Scrib., collected from bean (Phaseolus vulgaris L.) plants in commercial fields in Michigan from 1993 to 1995, were characterized for virulence. Single-conidial cultures from diseased leaves or pods with characteristic anthracnose symptoms were spray inoculated on 7- to 10-day-old plants (primary leaf stage) of the 12 differential cultivars (1) using a suspension adjusted to 1.0 x 106 spores per ml. The inoculations were performed on 6 to 10 seedlings and each isolate was repeated at least once. The seedlings were incubated for 48 h under conditions of high humidity (>95%), then for 5 days under greenhouse conditions at 22 to 25C. Plants were rated for disease reaction 7 days after inoculation based on a 1 to 9 severity scale, and race numbers were assigned using the binary system (1). Thirty percent of isolates were identified as belonging to race 65-Epsilon. These isolates were isolated from cultivars T-39, Midnight, and Norstar. Other races detected were 7 and 73, previously reported by Kelly et al. (1). Races 65-Epsilon and 73 made up 84% of the isolates, suggesting limited variability of C. lindemuthianum in Michigan. A previous report described the occurrence of race Epsilon on common bean in Ontario (2), but this is the first reported occurrence of this race in Michigan.

References: (1) J. D. Kelly et al. Plant Dis. 78:892, 1994. (2) J. C. Tu et al. Plant Dis. 68:69, 1984.