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A selective medium was developed for the isolation and enumeration of Verticillium dahliae in senescent infected tomato tissues heavily colonized with various fungi, from which the pathogen could not be isolated by the common ethanolstreptomycin selective medium. Suppression of the accompanying saprophytes, especially Fusarium, was achieved by the combined effects of relatively low incubation temperature (18°C) and supplementation of the medium with ethanol (0.5%), pentachloronitrobenzene (50 ppm) and antibiotics. Addition of sucrose (0.75%) and Czapek's salts improved visualization of V. dahliae colonies which appeared black. V. dahliae populations were estimated in senescent infected tissues from various sources by use of this medium. [ABSTRACT FROM AUTHOR]