Laboratory evaluation of plant-derived antifeedants against the pine weevil Hylobius abietis (Coleoptera: Curculionidae).
Twelve plant-derived and 1 insect-produced allelochemicals - verbenone, borneol, bornyl acetate, carvone, cucurbitacin, myrcene, limonin, 4-allyanisole, α-pinene, β-pinene, limonene, and coumarin - were studied for inhibition of feeding by the pine weevil, Hylobius abietis. Scots pine (Pinus sylvestris) twigs were treated with these compounds dissolved in ethyl acetate solvent, and adult weevils were fed for 48 h on twigs in both choice and no-choice assays. Coumarin, carvone, verbenone, and limonin were consistently inhibitory to feeding by both male and female H. abietis. Borneol and 4-allyanisole also demonstrated some activity as an antifeedant compound against H. abietis. The remainder of the compounds did not consistently inhibit weevil feeding. Sex of weevils or temperature in cold storage (10 or 5°C) did not consistently affect the amount of bark feeding. A 48-h feeding period gave more distinct effects for active compounds than did a 24-h test.