Repellency and toxicity of oil from Artemisia annua to certain stored-product beetles

The essential oil of Artemisia annua L. was tested for its toxic repellent and development inhibitory activities against 2 economically important stor ed product insects: Tribolium. castaneum (Herbst) and Callosobruchus macula tus (L.). Adult beetles of T. castaneum were repelled significantly Ly oil of A. annua at 1% concentration (vol:vol) and above in filter paper arena t est. Dose-response relationship of A. annua oil revealed a significant nega tive correlation between lan al survival; pupal survival and adult emergenc e of T, castaneum (i.e., increase in dose caused decrease in survival and a dult emergence). Effective concentration (EC50) to reduce F-1 progeny by 50 % was calculated to be 2.6 and 4.1 mu l/ml solvent against both the insect species, C, maculatus and T. castaneum, respectively. The relationship betw een bioactivity of oil from A. annua and responses of T. castaneum and C. m aculatus is discussed. We found that oil from A. annua was largely responsi ble for both repellent (behavioral) and toxic (physiological) actions on 2 species of insect tested.