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Disease Control and Pest Management

Antagonism Between Cercospora kikuchii and Other Seedborne Fungi of Soybeans. K. W. Roy, Graduate Research Assistant, Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907; T. S. Abney, Research Plant Pathologist, Agricultural Research Service, U. S. Department of Agriculture, West Lafayette, IN 47907. Phytopathology 67:1062-1066. Accepted for publication 28 February 1977. Copyright © 1977 The American Phytopathological Society, 3340 Pilot Knob Road, St. Paul, MN 55121. All rights reserved.. DOI: 10.1094/Phyto-67-1062.

Incidence of several fungi, primarily Diaporthe phaseolorum var. sojae, was reduced in pods and seeds of soybean plants inoculated at various growth stages with Cercospora kikuchii. Both pods and seeds were implicated as sites of interaction between C. kikuchii and D. phaseolorum var. sojae, but pods were the most likely site. Reductions in percentage pod infection and pod colonization by D. phaseolorum var. sojae suggest that establishment of infection and growth within pods both were inhibited. Variability in frequency and magnitude of reductions in seed infection by Diaporthe was caused primarily by the effect of weather on establishment of C. kikuchii. Increased seed germination from inoculation treatments was an indirect result of the reduction in seed infection by D. phaseolorum var. sojae. In investigations involving C. kikuchii-inoculated plants the effect(s) on other fungi and the consequences should be considered.