Increased Incidence of Phomopsis sp. in Seeds from Soybeans Infected with Bean Pod Mottle Virus. R. E. Stuckey, Associate Extension Professor, Department of Plant Pathology, University of Kentucky, Lexington 40546. S. A. Ghabrial, Associate Professor, Department of Plant Pathology, University of Kentucky, Lexington 40546, and D. A. Reicosky, Assistant Professor, Department of Crops and Soil Science, Michigan State University, East Lansing 48824. Plant Dis. 66:826-829. Accepted for publication 31 December 1981. Copyright 1982 American Phytopathological Society. DOI: 10.1094/PD-66-826.

The incidence of Phomopsis sp. in soybean (Glycine max) seeds increased as much as fivefold, depending on the cultivar, in plants inoculated with bean pod mottle virus and compared with uninoculated control plants. Soybean mosaic virus and bean yellow mosaic virus had little or no effect on seed infection by Phomopsis sp. Infection with bean pod mottle virus and soybean mosaic virus, regardless of inoculation sequence, increased seed infection by Phomopsis to levels equal to or significantly greater than infection with bean pod mottle virus alone. Seed infection by Cercospora kikuchii was much lower than that by Phomopsis sp. and did not appear to be influenced by virus infection. Yields from plants infected with both bean pod mottle virus and soybean mosaic virus ranged from 35 to 43% of controls in soybean cultivars susceptible to these two viruses. Soybean fields with a high incidence of bean pod mottle virus are more likely to have high levels of Phomopsis sp. seed infection and should not be saved for planting.

Keyword(s): Diaporthe, predisposition, seed germination.