COMPARATIVE EFFICACY OF SOME TRADITIONAL AND NEWLY INTRODUCED INSECTICIDES AGAINST HELICOVERPA ARMIGERA ON COTTON

,. INTRODUCTION Work done earlier on conventional insecticides against bollworms, reported by Butter et al. (1982), Kaseem et al. (1986) and Shelke et al. (1986) showed the level/mechanism of resistance in Helicoverpa armigera to different conventional insecticides. In the recent past work of similar nature was reported by Ahmad et al. (1995), Whitehead and Treacy (1995), Armes et at. (1996) and Murray and Lloyd (1997). In the present investigation, effort has been made to study the comparative effectiveness of a' newly introduced insecticide tracer (spinosad) and some conventional insecticides. Spinosad is the result of the fermentation process of newly found species of Actinomycete bacterium and Saccharopolyspora spinosa. The fermentation of Saccharopolyspora spinosa produces several metabolites which are called spinosyn A and spinosyn D. Tracer has a novel molecular structure and mode of action affecting nicotinic acetylcholine receptors at the postsynaptic cells. MATERIALS AND METHODS The cotton variety CIM-443 was sown following randomized complete block design of layout at the Tandalianwala, Jamra, Faisalabad during May-October, 1999. Two sprays were applied at an interval of 15 days. The following five treatments including an untreated control were replicated thrice.