Neocosmospora Stem Rot of Soybeans in Alabama. Fred A. Gray, Extension Plant Pathologist-Nematologist, Alabama Cooperative Extension Service, Auburn University, Auburn, AL 36830. Rodrigo Rodriguez-Kabana, Professor, Department of Botany and Microbiology, Auburn University; and J. Richard Adams, Extension Associate-Plant Pathology, Alabama Cooperative Extension Service, Auburn University, Auburn, AL 36830. Plant Dis. 64:321-322. Accepted for publication 13 November 1979. Copyright 1980 American Phytopathological Society. DOI: 10.1094/PD-64-321.

Neocosmospora vasinfecta was consistently isolated from field-grown soybean plants showing symptoms of premature senescence, defoliation, root and basal stem rot, and vascular and pith discoloration. Stem injection of greenhouse-grown soybean plants with N. vasinfecta produced a reddish-brown discoloration of the pith. Pith lesions ranged in length from 8 to 52 mm, with a mean of 22 mm. Reddish-brown lesions on the outer stem surfaces of several plants did not exceed 20 mm in length. Pith discoloration was the most frequently observed symptom after 4 wk.