Disease Note

Macrophomina phaseolina Causing Charcoal Rot of Soybean in Ohio. P. E. Lipps and R. M. Riedel, Department of Plant Pathology, Ohio State University and Ohio Agricultural Research & Development Center, Wooster 44691. Plant Dis. 68:536, 1984. Accepted for publication 21 March 1984. Copyright 1984 The American Phytopathological Society. DOI: 10.1094/PD-68-536g.

Soybean (Glycine max (L.) Merr.) plants with severe wilt symptoms were detected in one field each of Sandusky, Wayne, and Wood counties, Ohio, in 1983.  Unusually dry, hot weather prevailed throughout the latter half of the 1983 growing season, and in each case wilt symptoms appeared after flowering.  When the lower stem was split, numerous small, grayish black sclerotia were observed in the pith area.  Identification of Macrophomina phaseolina (Maubl.) Ashby was based on morphological characteristics in culture and on disease symptomatology.  Charcoal rot of soybean was previously detected in Franklin County, Ohio, in 1952, by A. F. Schmitthenner, but that finding was not formally reported.

Reference: Wyllie, T. D., and Calvert, O. H. Phytopathology 59:1243, 1969.