Potato tuber moth (PTM), Phthorimaea operculella, is a serious pest of stored potato in most countries where potatoes are grown. Entomopathogens offer promise as alternatives to broad spectrum insecticides for management of this pest. The fungus Muscodor albus, which produces a mixture of antimicrobial volatile organic chemicals, was tested for its insecticidal activity against PTM. Adults and neonate larvae were exposed to volatiles generated by 15 or 30 g of M. albus rye grain culture plus water for 72 h in hermetically sealed 28.3 L chambers at 24 degrees C. Mean percent mortalities in adult moths exposed to 0, 15, and 30 g of fungal formulation were 0.9, 84.6, and 90.6%, respectively. Development to the pupal stage of PTM that were exposed as neonate larvae to 15 or 30 of M. albus culture was reduced by 61.8 and 72.8%, respectively, relative to controls.