A Medium to Enhance Recovery of Aphanomyces from Infected Plant Tissue. W. F. Pfender, Research Associate, Department of Plant Pathology, University of Wisconsin, Madison 53706. P. A. Delwiche, Research Associate, C. R. Grau, Associate Professor, and D. J. Hagedorn, Professor, Department of Plant Pathology, University of Wisconsin, Madison 53706.. Plant Dis. 68:845-847. Accepted for publication 23 May 1984. Copyright 1984 The American Phytopathological Society. DOI: 10.1094/PD-68- 845.

This report describes a selective medium (MBV) that permits growth of Aphanomyces while inhibiting or restricting growth of several root-associated fungi that commonly obscure Aphanomyces on isolation plates. MBV contains the following ingredients per liter of water: 10 g of Difco-Bacto agar, 10 g of Difco cornmeal agar, 30 mg of metalaxyl, 5 mg of benomyl, and 200 mg of Vancocin. MBV inhibits or greatly restricts growth of Fusarium, Rhizoctonia, Phytophthora, and several Pythium species. Some isolates of Pythium were able to grow in the presence of 30 mg of metalaxyl but at rates lower than for Aphanomyces. If Alternaria, Mucor, or Rhizopus interfere with isolation, 0.5 mg of amphotericin B can be used in the medium.

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