Factors affecting the spore form of Entomophthora gammae

Abstract

Factors suspected of influencing the type of spores (conidia or resting spores) formed by Entomophthora gammae in its host Pseudoplusia includens were investigated. As epizootics of E. gammae progressed in field populations, high numbers of the conidial form gave way to high numbers of the resting spore form. Ratios of conidia to resting spores were not significantly altered when infected larvae were exposed to shortened photoperiods or to cooler temperatures. Age or size of infected larvae appeared to influence spore development; conidia were the predominant spore form in small larvae (< 1.5 cm) and resting spores were predominant in large larvae (> 2.5 cm). © 1975, Academic Press, Inc.. All rights reserved.