BACILLUS THURINGIENSIS FOR CONTROLLING THREE SPECIES OF MOTHS IN STORED GRAIN

Abstract

In laboratory studies, an aqueous suspension of a commercial wettable powder formulation of Bacillus thuringiensis var. kurstaki (strain HD-1) containing at least 25 billion viable spores/g and 16000 International Units of Potency (Trichoplusia ni (Hübner))/mg prevented infestations of Indian meal moths, Plodia interpunctella (Hübner), and almond moths, Cadra cautella (Walker), in corn and wheat at a dose of ca. 120 mg of formulation/kg of grain. Treatment of a 100-mm-deep surface layer was more effective than treatments 33 or 67 mm deep and as effective as treatment of the entire grain mass Lack of uniformity in applying B. thuringiensis to the grain kernels caused a small decrease in effectiveness. Dust and bait formulations at about the same doses were as effective as the suspension, but the bait was undesirable because it supported the development of beetle larvae. The formulation was less effective in controlling the Angoumois grain moth, Sitotroga cerealella (Olivier): doses that gave complete control of the Indian meal moth and the almond moth reduced emergence of adult Angoumois grain moths by only about one-third.