5 ref. Sum. (En)

Antifeeding activity of some plant extracts on Hypsipyla grandella larvae. The inhibitory effect of some plant extracts on the mahogany shoot borer (Hypsipyla grandella) larval feeding and growth was studied. A general screening with 29 substances was carried out on H. grandella third instar larvae, by exposing them to Cedrela odorata leaf discs impregnated with one concentration of each substance (10 percent). Six substances with possible anti-feeding or inhibitory effects on growth were selected, and treatments were arranged in a completely randomized design. substances were: bitterwood (Quassia amara) wood and leaf extracts, common rue (Ruta graveolens) leaf extract, Sechium pittieri fruit extract, and two commercial products 8Azatin and Nim 80) derived from the neem tree (Azadirachta indica, Meliaceae). In addition, a greenhouse experiment was carried out in which terminal shoots of C. odorata plants were treated with the same concentration (10 percent) of each substance and exposed to three first instar H. grandella larvae. Plants were distributed in a completely randomized design, with a split plot arrangement through time, with 10 plants per treatment. The bitterwood wood extract showed anti-feedant activity and Azatin caused direct larval mortality; a few attacks were observed in plants treated with the common rue extracts. The bitterwood leaf extract, Nim 80 and S. pittieri extract did not show activity as either anti-feedants nor growth regulators. Laboratory bioassays with increasing concentrations (0,1, 0,316, 1,0, 3,162 and 10 percent) of each extract confirmed the antifeeding activity of both bitterwood extracts, as well as that of common rue foliage.