Efficacy of different combination of insecticides against spotted pod borer in cowpea [Vigna ungiculata (L.) Walp.]

Different combinations of insecticides were tested on cowpea crop against spotted pod borer (Maruca vitrata) during 2012-2014 at different time intervals and revealed that lowest M. vitrata population was recorded in the treatment of imidacloprid 17.8 SL in combination with spinosad 45 SC (0.90 larva/plant). The next effective treatments were acetamiprid 20 SP in combination with spinosad 45 SC (0.98 larva/plant) and thiamethoxam 25 WG in combination with spinosad 45 SC (0.98 larva/plant). The highest M. vitrata population was observed in control (4.18 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. Imidacloprid 17.8 SL in combination with spinosad 45 SC recorded the lowest spotted pod borer damage with 5.61 per cent damage. 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).