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 4th instar was reduced to 1.60 mm3 from as high as 26.00 mm3 in the control, whereas, the body weight of 1st, 2nd, 3rd, and 4th 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 1st instar (0.02 mm) and 2nd instar (0.07 mm) larvae.