EVALUATION OF NEEM (AZADIRACHTA-INDICA JUSS,A) EXTRACTS AGAINST AMERICAN BOLLWORM, HELICOVERPA-ARMIGERA (HUBNER)

Methanol and chloroform:methanol (9:1) extracts of neem (Azadirachta i ndica A. Juss) seed kernels and green leaves were evaluated against Am erican bollworm, Helicoverpa armigera (Hubner). Various concentrations of extracts were used to treat natural foods, viz. leaves and pods/bo lls of chickpea, pigeonpea, and cotton. Treated foods were offered to early stage (neonate) and advanced stage (grown up) larvae of H. armig era for 48 h, and then, untreated food was offered for the rest of lif e. Chloroform:methanol (9:1) extracts of neem seed kernels and leaves showed better insecticidal properties than methanol extracts. However, neem seed kernels extract in chloroform:methanol (9:1) was the most p romising in causing adverse morphogenic effects on various biological parameters of H. armigera. Early stage larvae were more sensitive to t he exposure of neem extracts than advanced stage larvae.