Efficacy of Selected Insecticides against Pests of Grapevine

Field experiments were conducted on Thompson Seedless grapes during October-March, 1995–96 and 1996–97 to study the relative efficacy of eight insecticides viz., acephate 0.15, bifenthrin 0.005, dichlorvos 0.1, isoprocarb 0.2, carbaryl 0.15, chlorpyriphos 0.05, monocrotophos 0.05 and quinalphos 0.05 per cent. All the insecticides were sprayed 18 times starting from 3 d after October pruning (DAP) to 122 DAP at weekly intervals. Carbaryl at 0.15% was superior in reducing flea beetle population, whereas acephate at 0.15% effectively checked the thrips and Helicoverpa population. When compared, the efficacy of above insecticides to ffea beetle, thrips and Helicoverpa together, monocrotophos at 0.05% adjudged as the best insecticides contributing high yield (25997 kg ha⁻¹) as well as cost benefit ratio (1:17.46) followed by carbaryl 0.15, acephate 0.15 and chlorpyriphos 0.05%, respectively. The insecticide residues except for monocrotophos were found to be below detectable level at harvest.