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Etiology of Cephalosporium gregatum in Soybean. R. W. Schneider, Graduate Research Assistant, Department of Plant Pathology, University of Illinois, Urbana 61801; J. B. Sinclair(2), and L. E. Gray(3). (2)(3)Professor, Department of Plant Pathology, and Research Plant Pathologist, ARS, USDA, Soybean Investigations, respectively, University of Illinois, Urbana 61801. Phytopathology 62:345-349. Accepted for publication 20 October 1971. DOI: 10.1094/Phyto-62-345.

Cephalosporium gregatum was isolated from taproots of soybeans within 7 weeks after planting in field plots infested with the pathogen. The fungus was detected in the tops (ninth node) of plants at the early pod-filling stage within 1 day after artificial inoculation of hypocotyls, and within 2 days after a fungal suspension was added to the nutrient solution in which the plants were growing. Conidia are apparently the principal means of spread within the plant. In both greenhouse and field experiments, more stem browning developed in plants inoculated at 4-6 weeks than in those inoculated 8-12 weeks after planting. Infected plants exposed to low temperatures (18-24 C) for 4 weeks had significantly less stem browning than those exposed for 10 and 12 weeks.