Toxicity of essential oils isolated from three Artemisia species and some of their major components to granary weevil,Sitophilus granarius (L.) (Coleoptera: Curculionidae)

The essential oils of aerial parts of three Artemisia species (A. absinthium, A. santonicum and A. spicigera) were isolated by hydrodistillation method and tested for their toxicity against to granary weevil, Sitophilus granarius (L.) (Coleoptera: Curculionidae). All of the essential oils tested were found to be toxic to adults of S. granarius. The oils showed about 80–90% mortality of granary weevil, S. granarius at a dose of 9 μl/l air after 48 h of exposure. The constituents of these oils isolated from Artemisia spp. were also analyzed by GC–MS method. Camphor, 1,8-cineole, chamazulene, nuciferol propionate, nuciferol butanoate, caryophyllene oxide, terpinen-4-ol, borneol and α-terpineol were the predominant components of the oils. Some pure compounds (camphor, 1,8-cineole, terpinen-4-ol, borneol, bornyl acetate and α-terpineol) identified as major component in the oils, at 0.5, 0.75 and 1 μl/l air doses were also tested for their toxicity against S. granarius. While all pure compounds were found to be toxic against S. granarius, 1,8-cineole and terpinen-4-ol were more toxic among the tested pure compounds. 1,8-Cineole and terpinen-4-ol showed 100% mortality at all doses after 12 h of exposure. It can be concluded that essential oils of three Artemisia species and their major components, 1,8-cineole and terpinen-4-ol are potential control agents against S. granarius.