Potency of insecticidal combinations against bollworm complex of cotton

Abstract

Effect of newer insecticidal combinations (acetamiprid + cypermethrin, acetamiprid + quinalphos and acetamiprid + chlorpyrifos) along with their sole counterparts on cotton square, boll and locule damage due to bollworm complex, their effect on natural enemies and yield was evaluated at Department of Agricultural Entomology, Vasantrao Naik Marathwada Krishi Vidyapeeth, Parbhani, Maharashtra. An experiment comprised of fourteen treatments was laid out in randomized block design with three replications. Effectiveness of insecticides was judged on the basis of damage instigated by different bollworms to cotton squares, bolls and loculi on randomly selected plants. The per cent damage was worked out at 7th and 14th days after application of insecticides. During the entire period of experimentation, the results were quite promising and the mean results revealed that combination treatments acetamiprid + quinalphos (40+2000) g, acetamiprid + chlorpyrifos (40+2000) g and acetamiprid + cypermethrin (40+200) g a.i./ha were significantly superior in reducing damage due to bollworm in squares, bolls and loculi and increasing seed cotton yield per hectare. The combination product, acetamiprid + quinalphos (40+2000) g a.i./ha significantly reduced square damage due to Helicoverpa armigera (4.58 %) and Earias vittella (2.48 %), boll damage ( 3.76 %) due to bollworm complex at 14 days after second spray and locule damage ( 19.45 %) due to Pectinophora gossypiella. Similarly, acetamiprid + quinalphos (40+2000) g a.i./ha exhibited significantly highest seed cotton yield (14.79 q/ha). The overall result concludes that all the combinations performed better over their individual counterparts. However, the results on safety of combination products to natural enemies evidenced that all combi products along with their sole counterparts proved highly toxic.