Abstract
Three essential oils (EOs) from flowers and leaves of crofton weed, Eupatorium adenophorum Spreng. and aerial parts of Indian wormwood, Artemisia nilagirica (C.B.Clarke) Pamp., were evaluated for antifeedant activity against adults of red palm weevil (RPW), Rhynchophorus ferrugineus Olivier, a major pest of coconut palm, date palm, and Canary Island date palm. The specific bioassay method for evaluating the antifeedant activity of these EOs was used against R. ferrugineus adults and feeding-mark responses were analyzed at every 24 h interval for a period of 96 h. EOs from E. adenophorum flowers and A. nilagirica aerial parts, showed significant antifeedant activity at 96 h against RPW adults at 1000 ppm, as evident from 60.13 +/- 11.31 and 60.13 +/- 7.94 feeding prick-marks, respectively, as compared to 113.75 +/- 13.55 and 104.81 +/- 11.23 feeding prick-marks in their respective controls. However, the EO from E. adenophorum leaves was not found effective as antifeedant. GC-MS studies revealed differences in chemical composition, showing 40.87% oxygenated sesquiterpenes and 64.25% sesquiterpene hydrocarbons as the major constituents in the EOs of E. adenophorum flowers and leaves, respectively, whereas major class of compounds in EO from aerial parts of A. nilagirica comprised 37.02% sesquiterpenes and 32.92% monoterpene hydrocarbons. EOs from E. adenophorum flowers and aerial parts of A. nilagirica, have potential as environment-friendly alternative method for management of the RPW.