Study collaborators were with ARS, Connecticut Agricultural Experiment Station, Michigan State University, West Virginia University and USDA's Animal and Plant Health Inspection Service . Meanwhile, a Connecticut researcher is devising an artificial diet for rearing large numbers of Calosoma beetles in the laboratory. Interplanting two or more oilseed crops in alternating strips produced yields similar to conventional one-crop systems . In field tests, ARS researchers strip-cropped canola and soybeans. The strip crops reduced the need for insecticides, helped control weeds without chemicals, used less fertilizer and produced more and better quality oil.
Results indicate intercropping can be as economical and profitable as conventional systems.
The weevils are becoming resistant to the pesticide malathion, the conventional weapon used against them. But the wasps, Anisopteromalus calandrae , can survive malathion applications. Female wasps deposit eggs on weevil larvae, ensuring a future food source for new-born wasps. ARS researchers say the wasps' malathion resistance is the result of a single gene that could be transferred to other species of beneficial insects. That's if ARS scientists can exploit the protein as a new alternative to chemical insecticides.