Differential sensitivity of insecticides for targeting of multiple pests in grapes (Vitis vinifera)

Thrips, leafhoppers, flea beetle and caterpillars cause significant damage to grapes in two pruning-single cropping system of peninsular India and occur simultaneously. Against this pest complex,differential sensitivity of 12 insecticides was evaluated based on their bio-efficacy in laboratory and field. Thiamethoxam 25 WG, lambda cyhalothrin 5 CS, fipronil 80 WG, methomyl 40 SP and spinosad 45 SC recorded 96.45-100 and 89.34-92.98 per cent mortality of Scelodonta strigicollis adults in laboratory and field, respectively. Against Spodoptera litura 2nd instar larvae,emamectin benzoate 5 SG, fipronil 80 WG and cyantraniliprole 10 OD were able to provide mortality ranging from 79.6-99.0 and 73.65-84.8 percent in laboratory and field, respectively. Spinosad 45 SC, emamectin benzoate 5 SG, fipronil 80 WG and cyantraniliprole 10 OD provided Scirtothrips dorsalis mortality from 85.09-98.02 in laboratory and 65.36-91.5 per cent population reduction over control in field. Thiamethoxam 25 WG, clothianidin 50 WDG and fipronil 80 WG recorded Amrasca biguttula biguttula mortality from 93.06-100 per cent in laboratory and 80-91.3 per cent population reduction over control in field. The insecticides were classified into four categories, viz. not effective, slightly effective, moderately effective and highly effective; on the basis of their bio-efficacy to various insects. This will help the farmers in selection of right insecticide when multiple pests are present in the vineyard than their conventional practice of tank-mixing separate insecticides for different pests, thus, helping in reducing pesticide load in the environment as well as reduction in cost of cultivation.