Evaluation of Bacillus thuringiensis for Controlling Indianmeal Moths (Lepidoptera: Pyralidae) in Farm Grain Bins and Elevator Silos1

Abstract

Tests were conducted over a five-state area to evaluate the effectiveness of Bacillus thuringiensis for controlling Indianmeal moths, Plodia interpunctella (Hübner), in stored grain. Infestations in wheat were reduced 50–60%; in corn, infestations were reduced >80%. Dust and wettable powder (WP) formulations were equally effective. Treatment of grain in the auger as it was elevated into the bin gave uniform distribution of both formulations. Application by raking the formulations into the surface layer of filled bins gave acceptable distribution of the dust, but poor distribution of the WP. Control was not as good with rake-in application of the WP to wheat. Spray volume had no effect on distribution or efficacy of WP treatments, but a reduced volume of 326 ml/m² was easier to apply than the current label rate of 815 ml/m².