Beneficial Wasp to Protect U.S. Stored Commodities

A key to improving the quality of U.S. stored commodities may be a beneficial parasitic wasp that attacks the larvae of many agriculturally destructive moths. Agricultural Research Service scientists are studying Habrobracon hebetor, an external-feeding parasitic wasp used to control the Indianmeal moth, the most prevalent and damaging insect pest in stored commodities. ARS is the chief scientific research agency of the U.S. Department of Agriculture.

The Indianmeal moth and other agricultural insect pests have developed widespread resistance to Bacillus thuringiensis, or Bt, which means that synthetic pesticides must be applied to control them. But the same pests are also developing resistance to currently used pesticides, and regulatory restrictions are limiting the use of others. That’s why new biocontrol methods are under scrutiny at ARS’ Grain Marketing and Production Research Center in Manhattan, Kan.

The H. hebetor wasp is a good biocontrol agent partly because it feeds rapidly and has gut enzymes that quickly break down two major blood proteins in moth larvae. It is already commercially available for pest management programs, but it would be more economical to produce if artificial diets were available.

ARS entomologist James E. Baker and doctoral student Jeffrey Fabrick have described the digestive processes of these parasitoids when feeding on the blood of paralyzed Indianmeal moth larvae in the laboratory. Their findings were published in Insect Biochemistry and Molecular Biology (October 2000). Baker will present the information at a joint meeting of the Canadian and Quebec Entomological Societies and the Entomological Society of America in Montreal, Dec. 3-6.

Stored-product insects can be a major problem in grocery, health food and pet stores and in home food pantries. Infested products can include birdseed, peanuts, pecans, dog food, candy, macaroni, breakfast cereals, corn meal, bread and dried beans. This research will aid in the development of an artificial diet for economically rearing this promising potential biocontrol.

Scientific contact: James E. Baker, ARS Grain Marketing and Production Research Center, Manhattan, Kan., phone (785) 776-2785, fax (785) 537-5584, baker@usgmrl.ksu.edu.