Selective Medium for Isolation of Pythium spp. from Soil. Kenneth E. Conway, Associate Professor, Department of Plant Pathology, Oklahoma State University, Stillwater 74078. Plant Dis. 69:393-395. Accepted for publication 30 November 1984. Copyright 1985 The American Phytopathological Society. DOI: 10.1094/PD-69-393.

A selective medium for isolation of Pythium spp. from soil and plant tissue was developed by incorporating the broad-spectrum fungicide etaconazole (1.125 EC) into 2% potato-dextrose agar amended with 300 μg/ml of sodium ampicillin. Etaconazole at 17 μg a.i./ml was as effective as a pimaricin-vancomycin-pentachloronitrobenzene medium in recovery of Pythium arrhenomanes from artificially infested soil and Pythium spp. from wheat, turf, forest nursery, and peanut field soil. Higher concentrations of etaconazole in the medium reduced the recovery of P. arrhenomanes and Pythium spp. from soil but allowed for mycelial growth in culture.