Antifeedant activity of Quassia amara (Simaroubaceae) extracts on Hypsipyla grandella (Lepidoptera: Pyralidae) larvae

The inhibitory effect of methanolic wood and leaf extracts of bitterwood tree (Quassia amara) on mahogany shootborer (Hypsipyla grandella) larval feeding and growth was studied. A randomized complete block design, with four replications, was used. H. grandella third instar larvae were exposed for 24 h to Cedrela odorata leaf discs dipped in several treatment dissolutions of each extract (0.1, 0.316, 1.0, 3.162, and 10 percent); afterwards, each larva was transferred to a flask containing artificial diet, where it was allowed to complete its development. Variables measured included food consumption (foliar area eaten in 24 h), mortality, and developmental effects (developmental time for each larval instar and the pupa, and pupal weight). Both Q. amara extracts showed a clear antifeedant activity against H. grandella larvae, but it was higher for the wood extract; it was detected at a concentration as low as 0.32 percent for the wood extract and as high as 3.16 percent for the leaf extract.