Improved Medium for Isolation of Trichoderma spp. from Soil. G. C. Papavizas, Plant Pathologist, Soilborne Diseases Laboratory, Plant Protection Institute, Agricultural Research Service, U.S. Department of Agriculture, Beltsville, MD 20705. R. D. Lumsden, Plant Pathologist, Soilborne Diseases Laboratory, Plant Protection Institute, Agricultural Research Service, U.S. Department of Agriculture, Beltsville, MD 20705. Plant Dis. 66:1019-1020. Accepted for publication 30 January 1982. 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-66-1019.

A semiselective medium, previously developed for the isolation and enumeration of Trichoderma spp. from soils, was not effective with soils containing rapidly spreading Mucorales. The medium was improved and used effectively to recover Trichoderma spp. from soil by the addition of alkylaryl polyether alcohol at 2.0 ml/L alone or in combination with sodium propionate. The basal medium contained (per liter): V-8 juice, 200 ml; water, 800 ml; agar, 20 g; and glucose, 1 g. The improved medium, designated TME-SA, contained the following antimicrobial agents (µg/ml): neomycin sulfate, bacitracin, penicillin G, and chloroneb, 100; chlortetracycline hydrochloride, 25; nystatin, 20; and sodium propionate, 500. Alkylaryl polyether alcohol was added at 2.0 ml/L. For benomyl-tolerant biotypes of Trichoderma spp., the medium was supplemented with benomyl at 10 µg/ml and designated TME-ben 10-SA. Both of the modified media allowed Trichoderma spp. to develop on the surface of the agar and effectively suppressed rapidly growing fungi such as Rhizopus.

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