The toxicity of a neem extract RB-a in comparison with a pyrethroid, Coopex, was studied along with their effects on GPT and GOT activities and oxygen consumption in S. oryzae. The LD 50 value of Coopex was found to be 6.128 mg/cm 2 whereas RB-a was found not to be an acute contact poison. Even at a dose of 1257 mg/cm 2 it could cause 34% mortality of S. oryzae. The oxygen consumption under the effects of Coopex was found to decline less i.e. at 6.12 mg/cm 2 from 0.0005191 to 0.0006589, as compared to RB-a where the rate of respiration declined more i.e. at 1257 mg/cm 2 from 0.0005191 to 0.0002076. Coopex brought about an inhibition of 62.77% in GPt activity and caused almost no inhibition of GOT activity in insects treated with its LD 50 . In th case of neem extract it was noted that GPT was inhibited by about 57.47% and almost no effect on GOT was observed at a dose of 1257 mg/cm 2 .

The toxicity of a neem extract RB-a in comparison with a pyrethroid, Coopex, was studied along with their effects on GPT and GOT activities and oxygen consumption in S. oryzae. The LD 50 value of Coopex was found to be 6.128 mg/cm 2 whereas RB-a was found not to be an acute contact poison. Even at a dose of 1257 mg/cm 2 it could cause 34% mortality of S. oryzae. The oxygen consumption under the effects of Coopex was found to decline less i.e. at 6.12 mg/cm 2 from 0.0005191 to 0.0006589, as compared to RB-a where the rate of respiration declined more i.e. at 1257 mg/cm 2 from 0.0005191 to 0.0002076. Coopex brought about an inhibition of 62.77% in GPt activity and caused almost no inhibition of GOT activity in insects treated with its LD 50 . In th case of neem extract it was noted that GPT was inhibited by about 57.47% and almost no effect on GOT was observed at a dose of 1257 mg/cm 2 .