ANTIFEEDANT EFFECTS OF IN-VITRO CULTURE EXTRACTS OF THE NEEM TREE, AZADIRACHTA-INDICA AGAINST THE DESERT LOCUST (SCHISTOCERCA-GREGARIA (FORSKAL))

Callus and micropropagated shoots were initiated from leaf explants of the neem tree, Azadirachta indica A. Juss. A variety of whole plant and in vitro cell cultures from neem seedlings of Ghanian origin were tested for insect antifeedant compounds using the desert locust (Schistocerca gregaria (Forskal)). Feeding suppression occurred when whole extracts of seed, leaf, callus, suspension and shoot cultures were tested in no-choice feeding bioassays. Controls of sucrose, carrot callus and the plant growth medium showed no feeding deterrence. Azadirachtin, the main known antifeedant in neem seed kernels, was quantified from a seed extract by HPLC but was not detected in any of the other extracts. Antifeedancy was determined during batch growth of a suspension culture which had been in culture for 5 months; results indicated that antifeedants were still being formed and that levels increased after maximum biomass was attained.