Author
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HALVERSON, STEVEN - MICRO-GRAIN, INC. |
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Burkholder, Wendell |
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BIGELOW, TIMOTHY - OAK RIDGE NAT. LAB |
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NORDHEIM, ERIC - UNIVERSITY OF WISCONSIN |
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MISENHEIMER, MARK - UNIVERSITY OF WISCONSIN |
Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 5/15/1996 Publication Date: N/A Citation: N/A Interpretive Summary: New and safe methods of controlling stored product insects in grain are needed to replace those undergoing scrutiny as harmful. In studies with high-power microwave energy a hitherto unobserved phenomenon in which significant lethal effects on insects in grain was discovered Selective heating of the insects at the higher microwave frequencies was demonstrated. New microwave application methods are suggested. This new technology may offer a safer yet effective method of insect control for grain and milled grain products. Technical Abstract: Tests were performed using a high-power microwave source operating at a frequency of 10.6 GHz at powers of 9kW to 20kW to irradiate samples of soft white wheat Triticum aestivum (L.), infested with Sitophilus zeamais (Motschulsky) and ground wheat infested with Tribolium castaneum (Herbst). The purpose of the tests was to confirm that the mortality of insects is not a monotonically decreasing function of frequency and to demonstrate that microwave energy at high power levels and at a frequency an order of magnitude higher than the previously concluded maximum of 1 GHz will produce significant lethal effects on insects in stored- products efficiently and economically. Replicated samples at various age intervals from adult to egg were exposed. The overall results of the tests indicated that mortality of both species was superior to that obtained in other historical studies at 2.45 GHz. This supports the hypothesis of enhanced insect-to-host dissipation ratio as frequency increases due to relaxation processes in free water and hemolymph in the insect. Extrapolating the results to the cost of treating the project in bulk volume at an energy cost of $.05 per kW-hr indicates a unit cost ranging from $0.056 per bushel of wheat infested with S. zeamais to $0.139 per hundred weight of ground wheat infested with T. castaneum. |