Evaluation of Neem (<i>Azadirachta indica</i>A. Juss) Extracts against American Bollworm,<i>Helicoverpa armigera</i>(Hubner)

Abstract

Methanol and chloroform:methanol (9:1) extracts of neem ( Azadirachta indica A. Juss) seed kernels and green leaves were evaluated against American bollworm, Helicoverpa armigera (Hubner). Various concentrations of extracts were used to treat natural foods, viz . leaves and pods/bolls of chickpea, pigeonpea, and cotton. Treated foods were offered to early stage (neonate) and advanced stage (grown up) larvae of H . armigera for 48 h, and then, untreated food was offered for the rest of life. 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 promising in causing adverse morphogenic effects on various biological parameters of H . armigera . Early stage larvae were more sensitive to the exposure of neem extracts than advanced stage larvae. Keywords: Neem; seed kernels; chloroform:methanol; biology; Helicoverpa armigera