VIEW ARTICLE

A Selective Medium for Assay of Colletotrichum coccodes in Soil. J. D. Farley, Assistant Professor, Ohio Agricultural Research and Development Center, Wooster 44691; Phytopathology 62:1288-1293. Accepted for publication 19 May 1972. DOI: 10.1094/Phyto-62-1288.

A selective medium was developed for the isolation and enumeration of Colletotrichum coccodes from soil. The medium consisted of the following ingredients/liter: 10 g polygalacturonic acid; 1.5 g KH₂ PO₄; 4 g K₂ HPO₄; 25 ml soil extract; 17 g Difco agar; and the following antimicrobial agents added after autoclaving: 0.1 g pentachloronitrobenzene; 0.1 g benomyl; 0.1 g streptomycin sulfate; 0.1 g tetracycline HCl, and 0.1 g chloramphenicol. The medium was used to recover C. coccodes from artificially and naturally infested soil and from overwintered tomato skins. Its selectivity is due to the selective inhibition of microorganisms by antimicrobial agents and the development of distinctive, brown-pigmented sclerotial colonies of C. coccodes.