Yield Losses in Soybeans from Anthracnose Caused by Colletotrichum truncatum. P. A. Backman, Department of Botany, Plant Pathology, and Microbiology, Alabama Agricultural Experiment Station, Auburn University, AL 36849. J. C. Williams, and M. A. Crawford, Department of Botany, Plant Pathology, and Microbiology, Alabama Agricultural Experiment Station, Auburn University, AL 36849. Plant Dis. 66:1032-1034. Accepted for publication 23 February 1982. Copyright 1982 American Phytopathological Society. DOI: 10.1094/PD-66-1032.

Three soybean (Glycine max) cultivars, Bragg, Essex, and Hutton, were evaluated for yield losses resulting from anthracnose caused by Colletotrichum truncatum. Field plots of each cultivar were established in an area naturally infested with C. truncatum and were subsequently sprayed with fungicides that differed in efficiency of disease control. The effect of anthracnose severity on seed yield was estimated by quadratic or linear regression. Estimates of maximal reductions in seed yield due to anthracnose ranged from 16 to 26% for the three cultivars and averaged 19.7%. Yields were typically reduced as the soybean pods became infected with C. truncatum.

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