Efficacy of insecticide seed treatments against sucking pests and natural enemies in cowpea, Vigna unguiculata (Linn.) Walpers

A field experiment was conducted to test the efficacy of seed treatment chemicals against sucking pests viz., thrips, leafhopper and aphids infesting cowpea. In the experiment I and II, imidacloprid 60 FS, thiamethoxam 35 FS and carbosulfan 25 ST had equal population of thrips at 3rd, 4th and 5th weeks after germination. Seed treatment with thiamethoxam 35 FS was found to be the best in reducing the E. kerri population by 47.38 and 55.23 per cent in both the experiments I and II, respectively. The aphid injury grade was the least in the plants raised from imidacloprid 60 FS and thiamethoxam 35 FS treated seeds. Chlorpyriphos 20 EC (0.35) and dimethoate 30 EC (0.29) treated seeds harboured lesser number of coccinellid adults compared to the untreated control (0.62). All the seed treatments had reduced the spider population by more than 50 per cent compared to UTC in both the experiments.