INSECTICIDE TOXICITY AND DEGRADATION IN HOUSEFLIES AS AFFECTED BY NATURALLY OCCURRING FOOD PLANT COMPONENTS

Studies were conducted to investigate the effects of the naturally occurring food plant components myristicin and d-carvone on the toxicity and in vivo degradation of parathion and paraoxon in houseflies. Simultaneous topical application of myristicin and paraoxon, or feeding diets containing myristicin followed by paraoxon application, caused substantial increases in the toxicity of paraoxon. LD50 values indicated a tenfold increase in paraoxon toxicity due to a topical application of myristicin at a sublethal dosage of 2 µg/fly. Degradation of [14C]paraoxon was inhibited in flies fed myristicin, resulting in its increased toxicity. With parathion, simultaneous application of myristicin increased housefly mortalities, while feeding this natural compound to flies followed by application of the insecticide resulted in decreased mortalities. Feeding myristicin inhibited the metabolism of [14C] parathion and presumably the production of its toxic analogue, paraoxon. Contrary to results obtained with myristicin, feeding d-carvone increased the toxicity and metabolism of parathion, but had no apparent effect on paraoxon toxicity or its degradation. Data reported indicate that some compounds occurring naturally in food plants have the ability to alter the toxicity of insecticides as a result of their effects on insecticide degrading systems. © 1979, American Chemical Society. All rights reserved.