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 a nd in vitro cell cultures from neem seedlings of Ghanian origin were t ested for insect antifeedant compounds using the desert locust (Schist ocerca gregaria (Forskal)). Feeding suppression occurred when whole ex tracts of seed, leaf, callus, suspension and shoot cultures were teste d in no-choice feeding bioassays. Controls of sucrose, carrot callus a nd 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 extrac ts. Antifeedancy was determined during batch growth of a suspension cu lture which had been in culture for 5 months; results indicated that a ntifeedants were still being formed and that levels increased after ma ximum biomass was attained.