Morphological responses of Canadian and U.S.A. Isolates of Phoma sclerotioides to different growth media, temperatures and light

Abstract

Conclusive identification is provided for a pathogenic Wyoming Phoma sp. isolated from roots of alfalfa (Medicago sativa ssp. sativa). Phoma sclerotioides, a fungal pathogen known in Canada to cause disease and winter injury of Medicago, Melilotus and Trifolium species, is responsible for winter-killed alfalfa in Wyoming. Identification of the Wyoming Phoma sp. included morphological comparisons with a Canadian isolate of P. sclerotioides obtained from the American Type Culture Collection. Fungal colony response characteristics of the Wyoming and Canadian isolates were closely similar after exposure to different light and temperature regimes on two media. Pycnidial and conidial morphologies also were comparable.