Neem, Azadirachta indica (A. Juss) Extracts Negatively Influenced Growth and Development of African Bollworm, Helicoverpa armigera (Hubner) (Lepidoptera: Noctuidae)

3 Abstract: The effects of various concentration levels of neem oil (Nimbecidine 0.03% Aza) and water extracts of neem seed and leaf on growth and development of African bollworm, Helicoverpa armigera were studied under laboratory condition. Square dip and larval immersion experiments were conducted in three replications in a Completely Randomized Design. In square dip experiment, all tested concentration levels (2.5%, 5% and 10%) of neem seed and leaf extracts at 3, 6 and 9 days after treatment application resulted in significantly lower larval weight. In larval immersion experiment, only 10% neem seed extract and 10% neem leaf extract resulted in significantly lower larval weight at 3 days after treatment. In the same experiment, all tested concentration levels (2.5%, 5% and 10%) of neem seed extracts significantly reduced the weight of larvae at 6 days after treatment application. However, at 9 days after treatment application, only 5% and 10% neem seed extracts were found effective in reducing the larval weight. Only the two higher concentration levels (5% and 10%) of neem seed extract significantly reduced the weight of pupae. Generally, the result of this study indicated the potential of neem extracts for the integrated management of H. armigera.