Author(s):

VK Bhamare and DW Wadnerkar

Abstract: A field experiment was undertaken to study the efficacy of newer insecticidal combinations (acetamiprid + cypermethrin, acetamiprid + quinalphos and acetamiprid + chlorpyrifos) along with their sole counterparts against the bollworm complex of cotton, their effect on yield and phytotoxicity 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 infestation of different bollworms in shed material (square and boll) on randomly selected plants. The per cent damage was worked out at 7^th and 14^th days after application of insecticides. During both the years, 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 bollworm infestation in shed material (squares and bolls) and increasing the seed cotton yield per hectare. The combination product, acetamiprid + quinalphos (40+2000) g a.i./ha significantly reduced infestation of Helicoverpa armigera (2.64 %) and Earias vittella (1.08 %) in shed squares and bollworm infestation (4.02 %) in shed bolls at 14 days after second spray. Among the treatments, acetamiprid + quinalphos (40+2000) g a.i./ha evidenced significantly highest seed cotton yield (14.79 q/ha). The overall result concludes that all the combinations performed better over their individual counterparts. The result on phytotoxicity symptoms showed that only leaf injury was observed up to 3 days after spraying in higher concentration of combi products, whereas, other phytotoxic symptoms like wilting, vein clearing, necrosis, epinasty and hyponasty did not observed in any of the treatments.

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