Efficacy of Different Combination of Insecticides against Cowpea Pod Borer in Cowpea [Vigna ungiculata (L.) Walp.]

Different combinations of insecticides were tested on cowpea crop against cowpea pod borer (Helicoverpa armigera) during 2012-2014 at different time intervals and revealed that lowest H. armigera population was recorded in the treatment of imidacloprid 17.8 SL in combination with spinosad 45 SC (0.57 larva/plant). The next effective treatments were acetamiprid 20 SP in combination with spinosad 45 SC (0.65 larva/plant), thiamethoxam 25 WG in combination with spinosad 45 SC (0.66 larva/plant). Imidacloprid 17.8 SL in combination with novaluron 10 EC (0.88 larva/plant), thiamethoxam 25 WG in combination with novaluron 10 EC (0.93 larva/plant) and acetamiprid 20 SP in combination with novaluron 10 EC (0.93 larva/plant) were the next best treatments. The highest H. armigera population was observed in control (3.70 larvae/plant). Maximum reduction of larvae was found in the treatments in which spinosad is present followed by the treatments in which novaluron is present. With respect to BCR, highest BCR (1:8.70) was registered in the treatment imidacloprid 17.8 SL in combination with indoxacarb 14.5 SC which was followed by thiamethoxam 25 WG in combination with indoxacarb 14.5 SC (1:6.52) and acetamiprid 20 SP in combination with indoxacarb 14.5 SC (1:6.43).