A Selective Medium for Gaeumannomyces graminis var. tritici. M. Elliott Juhnke, Graduate Research Assistant, Department of Plant Pathology, Montana State University, Bozeman 59717. D. E. Mathre, Professor, and D. C. Sands, Associate Professor, Department of Plant Pathology, Montana State University, Bozeman 59717. Plant Dis. 68:233-236. Accepted for publication 9 September 1983. Copyright 1984 The American Phytopathological Society. DOI: 10.1094/PD-68-233.

A selective medium (SM-GGT3) for Gaeumannomyces graminis var. tritici was developed to confirm field diagnosis of take-all. Differentiation of G. graminis var. tritici from other common soil fungi is based on its melanin pigment formation in the presence of L-DOPA. Other ingredients of the medium are potato-dextrose agar, streptomycin sulfate, dicloran, metalaxyl, and Hoe 00703. A 1% silver nitrate solution was used as a surface-sterilant. There was a 32% increase in take-all isolations from irrigated wheat and barley samples using SM-GGT3 compared with using potato-dextrose agar. There was also a 49% decrease in Fusarium spp., Cochliobolus sativus, and isolations of sterile mycelia using SM-GGT3.