Application of insecticide dusts for the management of Indian meal moth (Lepidoptera: Pyralidae) wandering larvae under laboratory conditions

The Indian meal moth, Plodia interpunctella (Hubner) (Lepidoptera: Pyralidae), is a very common stored-product pest. The mature larvae wander around searching for suitable places to pupate, offering an opportunity to control this pest. We evaluated the efficacy of 5 insecticide dusts: Alpine (0.25% dinotefuran, 95% diatomaceous earth [DE]), CimeXa (92.1% amorphous silica gel), DX13 (100% DE), Tempo (1% cyfluthrin), and Tri-Die (1% pyrethrin, 10% piperonyl butoxide, 40% amorphous silica) against P. interpunctella wandering larvae by allowing larvae to pass 1-inch treated band, expose to treated vinyl tiles for 5 min, and expose to treated harborage (with or without the presence of an untreated harborage). A commercially treated harborage product (Nattaro band) served as a positive control in the exposure to the treated harborage test. Tempo was significantly more effective than other insecticide dusts in the 1-inch band and forced exposure tests but caused only 44% and 54% larvae mortality in the 2 tests. In contrast, CimeXa, Tri-Die, and Tempo caused 84%-89% mortality when the larvae were provided with treated harborages. When both treated and untreated harborages were present, Tempo caused a significantly higher mortality and a lower percentage of emerged adults from larvae than Tri-Die, but not significantly more than CimeXa. Deploying Tempo or CimeXa-treated harborages and/or applying insecticide dust directly into the wall crevices, perimeters of the floor, shipping pallets, and other areas where P. interpunctella larvae hide could be an effective method for the management of the wandering stage of P. interpunctella larvae in storage facilities.