INSECTICIDAL TOXICITIES OF GLUCOSINOLATE-CONTAINING EXTRACTS FROM CRAMBE SEEDS

Glucosinolate components were extracted from defatted crambe (Crambe a byssinica Hochst ex. R. E. Fries) seed meal by using four different ex traction solvents. These extracts containing naturally occurring gluco sinolates were tested in bioassays against some selected agricultural and public health insect pests. The results showed that continuous aqu eous exposure to dilutions of the extracts caused acute mortality to m osquito [Aedes aegypti (L.)] larvae. Crambe seed meal (containing inta ct glucosinolates) showed toxicity against house fly larvae (Musca dom estica L.) when incorporated into the regular fly diet. Neither extrac ts nor seed meal were acutely toxic to the red flour beetle [Tribolium castaneum (Herbst)] or the sawtoothed grain beetle [Oryzeaphilus suri namensis (L.)] within 24 h; however, longer observation demonstrated a high mortality and antifeedant effect toward these insects. The two s pecies of grain beetles began dying 10 d after exposure. The glucosino late extracts also were effective on western corn rootworm [Diabrotica virgifera virgifera (LeConte)] larvae. No observable behavioral chang es were found on German cockroaches [Blattella germanica (L.)]. The re sults showed that crambe glucosinolates have potential as a possible c ontrol agent for certain agricultural and public health insect pests.