Isolation of Gaeumannomyces graminis var. graminis from Soybeans in the Midwest. K. W. Roy, Former Research Assistant, Botany and Plant Pathology Department, Purdue University, West Lafayette, IN 47907. T. S. Abney, Plant Pathologist, USDA, ARS, D. M. Huber, Professor, and R. Keeler, Former Research Assistant, Botany and Plant Pathology Department, Purdue University, West Lafayette, In 47907. Plant Dis. 66:822-825. Accepted for publication 4 December 1981. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1982. DOI: 10.1094/PD-66-822.

Gaeumannomyces graminis (= Ophiobolus graminis), the cause of take-all disease of wheat (Triticum aestivum) and other cereals, was isolated from immature field-grown pods of six soybean (Glycine max) cultivars in Indiana. The soybean isolates produced typical take-all symptoms on wheat roots and culms and were reisolated from soybean roots inoculated in the greenhouse. The soybean isolates produced lobed hyphopodia, perithecia, and ascospores (71.6 × 2.6 µm) on potato-dextrose agar. The presence of lobed hyphopodia and ascospore size indicated that the isolates were G. graminis var. graminis rather than varieties tritici or avenae. Aminopeptidase profiles for the three varieties supported the identification of the soybean isolates as G. graminis var. graminis, as well as the separation of G. graminis into three varieties. G. graminis var. graminis, previously reported only on monocotyledonous plants, may be potentially significant in the epidemiology of the take-all disease in the Midwest.

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