ECOLOGY, SAMPLING, AND MODELING OF INSECT PESTS OF STORED GRAIN, PROCESSING FACILITIES, AND WAREHOUSES
Location: Stored Product Insect Research Unit
Title: EFFECTS OF SHELF ARCHITECTURE AND PARASITOID RELEASE HEIGHT ON BIOLOGICAL CONTROL OF PLODIA INTERPUNCTELLA (LEPIDOPTERA: PYRALIDAE) EGGS BY TRICHOGRAMMA DEION (HYMENOPTERA: TRICHOGRAMMATIDAE)
Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 29, 2006
Publication Date: June 30, 2007
Citation: Grieshop, M.J., Flinn, P.W., Nechols, J.R., Campbell, J.F. 2007. Effects of shelf architecture and parasitoid release height on biological control of Plodia interpunctella (Lepidoptera: Pyralidae) eggs by Trichogramma deion (Hymenoptera: Trichogrammatidae). Journal of Economic Entomology 99: 2202-2209.
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 harmless parasitoid wasp, Trichogramma deion, was very effective in finding and killing Indianmeal moth eggs on shelves in a simulated retail store environment. Trichogramma deion killed more Indianmeal moth eggs on open-type shelving than on gondola-type shelving. The presence of packages on the shelves did not interfere with the wasp locating and killing the Indianmeal moth eggs. Trichogramma goes after the moth eggs before they can develop into adult moths. 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, Trichogramma wasps are an environmentally-friendly way to keep food pests in check.
The effects of shelving type, packaging, and release height on success of Trichogramma deion parasitizing Plodia interpunctella eggs was studied under laboratory conditions. In trials on multiple-tiered gondola-type or open shelving units, with or without packaging, foraging success was evaluated by comparing parasitism and total mortality rates of sentinel egg disks among shelves after a single point-release of T. deion. Results showed that T. deion parasitized more egg disks and killed more total eggs on open shelves than on gondola shelving. The presence of packaging had no effect on parasitoid foraging on open shelves; however, packaging did interfere with parasitism of P. interpunctella eggs on gondola shelving. Egg parasitism and mortality patterns among shelves were not as evenly distributed on gondola-type shelving as they were on open shelving. On gondola shelves without packages, changing the release point of T. deion from the middle to the lowest shelf shifted the distribution of parasitism towards the floor. Gondola shelving, especially in the presence of packaging, reduces foraging efficiency of T. deion for P. interpunctella eggs. Thus, to attain adequate control of P. interpunctella, it may be necessary to use multiple release points on gondola shelving.