The Effects of Temperature, Nutrients, and Spore Concentration on the Germination of Conidia from Dactylomyces thermophilus

Cooney and Emerson (1964) defined thermophilic fungi as those fungi having a minimum temperature for growth at or above 20C and whose maximum temperature for growth is at or above 50C. Thermophiles have been isolated from a wide variety of habitats and contribute to the decomposition of materials such as stored products, municipal wastes, and compost. Recently, Deploey and Gautam (1987), and Deploey (1989) reported results of studies concerning the germination of spores from two thermophilic species of Rhizomucor (R. miehei and R. pusillus). Other studies of the germination of spores from thermophilic and thermotolerant fungi have also been reported (Celerin and Fergus, 1971; Deploey, 1985; Fergus and Delwiche, 1975; Jack and Tansey, 1977; Streets and Ingle, 1972; Sussman, 1976), but of these only one (Jack and Tansey, 1977) concerned the germination of spores from Dactylomyces thermophilus. In their study Jack and Tansey (1977) reported the results of germination studies of D. thermophilus, conidia exposed to sun-heated soil, sun-shaded soil, and at 22–24C and 37C in the laboratory. However, their study of D. thermophilus did not include any other parameters influencing spore germination. Since so little is known concerning the germination of conidia from D. thermophilus, studies were done here to determine the effects of temperature, spore concentration, and nutrients on the germination of these spores.