Lethal Effects of Microwave Exposures on Eggs and Pupae of the Cabbage Maggot and Cabbage Plants

To control the cabbage maggot (Delia radicum) [Diptera: Anthornyiidae], treatments in an industrial microwave oven (f = 2450 MHz; P =0 to 6 kW)were carried out in the laboratory to test two developmental stages of the insect. First, treatments were directed at Delia radicum eggs after the transplanting of cabbage plants. Treatments with 10 sat 2100 W, 20 s at 1600 W, 20 s at 2100 W, 25 s at 1100 W, 25 s at 1600 W and 25 s at 2100 W inhibited egg hatching. However, exposures caused lethal effects in cabbage plants (Brassica oleracea var. Swnehead). Second, treatments were directed at the maggot pupae after harvest. Treatments with 10 s at 3000 Wand 10 s at 4000 W were more promising, inhibiting the emergence of adults while having no impact on the cabbage plant. Post-harvest treatment would be preferable to spring treatment. High energy levels required to penetrate the soil at a depth of 10 cm to attain all pupae preclude commercial development at the present time.