HIGH-POWER MICROWAVE-RADIATION AS AN ALTERNATIVE INSECT CONTROL METHOD FOR STORE PRODUCTS

Insect mortality studies were performed with a high-power microwave so urce operating at a frequency of 10.6 GHz at power levels of 9-20 kW t o irradiate samples of soft white wheat, Triticum aestivum (L.), infes ted with maize weevil, Sitophilus zeamais Motschulsky, and ground whea t infested with red flour beetle, Tribolium castaneum (Herbst). These pests are common internal and external feeders in stored products, res pectively. Samples at various age intervals from egg to adult were exp osed. The results support the hypothesis that the insect-to-host dissi pation ratio increases at frequencies >2.45 GHz. Mean mortalities grea ter than or equal to 93% occurred for all ages of S. zeamais and great er than or equal to 94% for adults and larvae of T. castaneum for mean specific input energies of greater than or equal to 51 J/g and 53 J/g , respectively, indicating that S. zeamais is more susceptible. Extrap olating the results to the cost of treating the product in bulk volume at a busbar electric energy cost of $0.05 per kW-h (3,600 kJ) indicat es a unit cost for electric energy ranging only from $0.056 per bushel of wheat infested with S. zeamais to $0.139 per hundred weight of gro und wheat infested with T. castaneum.