Bio-efficacy of certain insecticides against tobacco caterpillar, Spodoptera litura (Fabricius) infesting soybean in Punjab

The bio-efficacy of seven insecticides viz., quinalphos 25 EC, carbaryl 50 WP, indoxacarb 14.5 SC, acephate 75 SP, endosulfan 35 EC, chlorpyrifos 20 EC and dichlorvos 76 EC was evaluated against tobacco caterpillar, Spodoptera litura (Fab.) on soybean crop in three field experiments during kharif 2005. In all the three experiments, indoxacarb 14.5 SC @ 500 ml/ha proved most effective in controlling the pest at 3 and 7 days after spray (4.84 and 2.14 larvae/m2, respectively), followed by acephate 75 SP @ 2.0 kg/ha (7.36 and 3.69 larvae/m2, respectively). The highest mean grain yield was also recorded in the treatment indoxacarb 14.5 SC (1356 kg/ha), followed by acephate 75 SP (1299 kg/ ha). Other insecticidal treatments were almost on par with each other in terms of larval mortality as well as grain yield, but significantly better than untreated control. The avoidable losses due to S. litura on soybean crop ranged from 2.66 to 38.51% in all the insecticidal treatments as compared to control. The avoidable losses in indoxacarb 14.5 SC and acephate 75 SP were 38.51 and 32.69%, respectively, indicating their superiority over other treatments in managing the pest.