THE PROTECTION OF BARLEY SEEDLINGS FROM ATTACK BY SCHISTOCERCA-GREGARIA USING AZADIRACHTIN AND RELATED ANALOGS

Barley seedlings were sprayed with azadirachtin or analogues and the r esulting crop protection against Schistocerca gregaria was examined. A ny change of the parent azadirachtin molecule resulted in less effecti ve insect control and hence more crop damage. Crop protection by azadi rachtin and dihydroaza-dirachtin resulted from both antifeedancy and t oxicity, 3-tigloylazadirachtol was more effective by direct toxicity a fter significant ingestion and bromoethoxyazadirachtin showed extremel y low antifeedant and insecticidal properties. S. gregaria was shown t o be very sensitive to change in the azadirachtin molecule.