Effect of Azadirachtin on Feeding and Development of Callosobruchus chinensis (Coleoptera: Bruchidae)

The neem formulation, Nimbecidine (0.03% azadirachtin) was assayed to find out the effect of azadirachtin on feeding and development of Callosobruchus chinensis L. (Coleoptera: Bruchidae). Larval feeding was drastically reduced by treating with azadirachtin. On application of 60 ppm azadirachtin, the total canal volume up to 4^th instar was reduced to 1.60 mm³ from as high as 26.00 mm³ in the control, whereas, the body weight of 1^st, 2^nd, 3^rd, and 4^th larval instar was reduced from 0.30±0.16, 1.20±0.16, 2.30±0.07 and 5.20±0.10 mg to 0.01±0.00, 0.39±0.01, 0.90±0.07 and 2.00±0.35 mg, respectively. Azadirachtin at 90 ppm appears to have hormonal activity resulting in increased body weight coupled with decreased size of mandibles in 1^st instar (0.02 mm) and 2^nd instar (0.07 mm) larvae.