VIEW ARTICLE

Root Reduction and Stem Lesion Development on Soybeans by Phytophthora megasperma var. sojae. W. A. Meyer, Graduate Fellow, Department of Plant Pathology, University of Illinois, Urbana 61801; J. B. Sinclair, Professor, Department of Plant Pathology, University of Illinois, Urbana 61801. Phytopathology 62:1414-1416. Accepted for publication 20 June 1972. DOI: 10.1094/Phyto-62-1414.

Phytophthora megasperma var. sojae (Pms) reduced the root system of soybean (Glycine max) in the presence and absence of stem lesions. Pms-susceptible cultivars grown in Pms-infested soil in the greenhouse and field had no stem lesions, but plant heights and yields were significantly less than those of similarly treated Pms-resistant cultivars. In the greenhouse, Pms reduced dry weights of roots but not plant heights of 10-day-old resistant plants. Lesions developed on stems of Pms-susceptible plants in the greenhouse when inoculum was placed adjacent to plants at 1 or 4 cm below the soil line, but not at 9 cm. Root and shoot dry weights increased with depth of inoculum placement.