Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/6/2006
Publication Date: 8/1/2006
Citation: Grieshop, M.J., Flinn, P.W., Nechols, J.R. 2006. Biological control of the Indianmeal moth on finished stored-products using egg and larval parasitoids. Journal of Economic Entomology 99:1080-1084. Interpretive Summary: The Indianmeal moth is a serious pest of raw and finished stored products and attacks both packaged and bulk commodities as well as spillage. Indianmeal moth larvae can infest stored products like bags of grain, cereal, or pet food. A combination of packaging and two species of parasitic wasp, Trichogramma deion, and Habrobracon hebetor provided the best moth suppression. Trichogramma goes after the moth eggs before they can develop into damaging larvae, and Habrobracon finishes the job by killing any larvae that develop from eggs that Trichogramma may have missed. This could provide a new tool for the retail organic food industry to manage insect pests. Growers have been using Trichogramma wasps for decades to control outdoor pests plaguing cotton and other crops, so the beneficial insects would be readily available to the pest control industry. Harmless and practically invisible, parasitic wasps are an effective and environmentally friendly way to keep serious food pests in check.
Technical Abstract: Biological control using hymenopteran parasitoids presents an attractive alternative to insecticides for reducing infestations and damage from the Indianmeal moth (Plodia interpunctella) in retail and warehouse environments. We examined the potential for using combinations of the egg parasitoid Trichogramma deion Riley, and the larval parasitoid Habrobracon hebetor (Say), for preventing infestations of P. interpunctella in coarse ground cornmeal, as well as the influence of packaging on parasitoid effectiveness. Treatments included one or both parasitoids, and either cornmeal infested with P. interpunctella eggs or eggs deposited on the surface of plastic bags containing cornmeal. Habrobracon hebetor had a significant impact on P. interpunctella, lowering populations by about the same magnitude in both open and bagged cornmeal. In contrast, T. deion did not suppress P. interpunctella in open cornmeal. However, when released on bagged cornmeal, T. deion significantly increased the level of pest suppression over bagging alone. When H. hebetor was added to bagged cornmeal, there was a significant reduction of live P. interpunctella compared to the control (70.6%) with a further reduction observed when T. deion was added (96.7%). These findings suggest that, in most cases, a combined release of both T. deion and H. hebetor would have the greatest impact because, even though packaging may protect most of the stored products, there are usually areas in the storage landscape where poor sanitation is present.