INFLUENCE OF CULTURE AGE ON RATE OF CONIDIOSPORE GERMINATION IN 4 DEUTEROMYCETOUS ENTOMOGENOUS FUNGI

Conidiospores of the deuteromycetous fungi, Metarhizium anisopliae, Pa ecilomyces fumoso-roseus and Verticillium lecanii harvested from young (2-3 d old) Petri plate cultures germinated more rapidly than those t aken from older cultures, including those still in an exponential phas e of spore production. Also germ tube lengths were proportionately lon ger for conidia taken from younger cultures. In contrast, conidia of B eauveria bassiana all germinated at the same rates, irrespective of cu lture age. Rapid germination of spores from young cultures cannot easi ly be explained by spore maturation processes leading to eventual slow er germination as cultures age. Possible physiological differences bet ween first-formed and subsequent conidia arising on a phialide may acc ount for these observations. Sympodial holoblastic sporulation could e xplain why the phenomenon was not observed in B. bassiana.