The
army worm Spodoptera litura
(fabricius) is one of the most damaging pests of ground nut and castor in India. We
determine the susceptibility of S. litura reared on a castor leaves, to
three insecticides (Temephos, Dichlorvos, and lambda-cyhalothrin) under
laboratory conditions,  associated with
the enzyme activities of acetylcholinesterase (AChE), carboxylesterase (CarE),
glutathione S-transferase (GST) and glutathione S- reductase (GSH) in this
larvae. Among treatments Dichlorvos showed high mortality then lambda
cyhalothrin and Temephos in whole body of the insect. The AChE activities of Spodoptera litura treated with lambda
cyhalothrin, Temephos at 10ppm were almost 1.5 fold high. The CarE activity at
10ppm was almost 3 fold high. The GSH and GST activity were low then control
(0.2 ± 0.4, 1.5 µM mg protein^-1 min^-1). The present study
suggests that esterase and acetylcholine esterase may play a role in detoxification
of synthetic pyrethroid and organophosphates in Spodoptera litura from South India.