INSECT REGULATORY EFFECT OF MARGOSAN A NATURAL AZADIRACHTIN - CONTAINING PREPARATION ON THE DESERT LOCUST, SCHISTOCERCA GREGARIA (FORSK.) ( ORTHOPT., ACRIDIDAE )

The morphogenetic and metabolic effects of neem kernel extract, azadirachtin of the neem tree Azadirachta indica were investigated as in­dicators for its insect regulatory action in Schistocerca gregatia. Three doses of Azadirachtin (10,20 and 40 pg/nymph) were injected into one day old 4th instar nymphs. The injected doses had resulted In prolonga­tion in the duration of the last instars and a positive correlation between failure in ecdysis to 51h instar and adult stage. These morphogenetic fea­tures induced by azadirachtin in 4th and 5111 instar nymphs were consid­ered as Juvenilizing effect of this compound . The same doses were injected into one and 5 day-old 51h instar nymphs to disclose the metabolic effects of azadirachtin on their haemo­lymph main metabolites . This had resulted in high level of proteins and carbohydrates and low levels of lipids and cholesterol this reflecting the juvenilizing action of azadirachtin in S.gregaria . It was concluded that azadirachtin plays the same insect regula­tory role of Juvenile hormone in delaying or prohibiting metamorphosis, increasing levels of proteins and carbohydrates and suppressing lipids and cholesterol in gregarious nymphs of S.gregaria.