Survival and development of Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) on neem (Azadirachta indica A. Juss) leaves
The survival, development and feeding responses of Helicoverpa armigera (Hübner) on neem (Azadirachta indica A. Juss) leaflets were evaluated under choice and no-choice conditions. Neem leaflets provided to starving fourth-instar larvae were chewed, but larvae expectorated most of the material. The weight of surviving larvae decreased and no fourth instars completed development on neem leaflets alone. Larvae resumed feeding when transferred to cotton leaves after 5 days of feeding on neem leaflets. Fourth instars strongly discriminated between neem leaflets and cotton leaves when offered a choice. Early sixth instars decreased in weight and had delayed development when fed only on neem leaflets. More than one-half lived for more than 2 weeks and some completed development to adults. Neem is an unacceptable non-host plant species for H. armigera.