Insecticidal activity of Aglaia odorata extract and the active principle, rocaglamide, to the European corn borer, Ostrinia nubilalis Hübn. (Lep., Pyralidae)

Abstract

Abstract: A standardized twig extract of the Asian shrub, Aglaia odorata Lour. (Meliaceae), and rocaglamide, a purified active principle of the extract, were evaluated for potential to control the European corn borer (Ostrinia nubilalis Hübn.), via incorporation into meridic diet fed to larvae. Life cycle bioassays using the extract revealed that it inhibited larval growth at all concentrations tested (12.5–100 p.p.m./fresh wt.) and delayed mean time to pupation from 24.1 days (control) to 83.8 days (50 ppm). Other effects include reduced pupal and adult weights and an increase in the frequency of deformed pupae. Investigation of consumption rates and dietary utilization in larvae feeding on diet containing the extract suggested that it acts via a combination of antifeedant and postingestive (toxic) actions. Life cycle bioassays using rocaglamide demonstrated that this compound is an extremely potent inhibitor of larval growth, with concentration dependent activity observed at dietary concentrations from 0.05‐0.02 ppm. Effects at these levels include severe reductions in growth and pupal weight, and increases in larval mortality and time to pupation. Rocaglamide appears to be as, or even more active, than the very effective botanical pesticide azadrachtin from the neem tree.