Disease Note

Stem Canker of Soybean in Texas. N. G. Whitney and G. R. Bowers, Jr., Texas A&M University Agricultural Research and Extension Center, Beaumont 77706. Plant Disease 69:361, 1985. Accepted for publication 18 December 1984. Copyright 1985 The American Phytopathological Society. DOI: 10.1094/PD-69-361b.

Stem canker of soybeans (Glycine max (L.) Merr.) caused by Diaporthe phaseolorum (Cke. & Ell.) Sacc. var. caulivora Athow & Caldwell,, was observed in Texas for the first time in 1984.  The fungus, identified by disease symptoms and cultural characteristics, is thought to be a more aggressive southern biotype than that previously found in the northern and midwestern production areas.  The southern form was first found in Mississippi in 1975 and subsequently spread to Alabama, Georgia, Florida, South Carolina, Tennessee, and Louisiana.  In Texas, the disease was found primarily on the cultivar Coker 338 in the Gulf Coast soybean-growing area between Houston and Beaumont.  Disease incidence was highest in the Chambers County area, where approximately 25% of the soybean acreage was devastated and some fields were total losses.  Disease loss in the Gulf Coast area, however, was estimated at less than 5%.

References: Keeling, B. L. Phyopathology 72:807, 1982.  Morgan-Jones, G., and Backman, P. A. Phytopathology 74:815, 1984.