Evaluation of different combinations of insecticides and biopesticides for the management of fruit flies infesting bitter gourd

Abstract

Fruit flies have been a constant threat to agricultural commodities from the distant past and the management of the pest is very difficult. To reduce the pesticide pressure and slow down the development of resistance, different combinations of insecticides and biopesticides were evaluated against the fruit flies. When biopesticides were rotated with insecticides in a three spray schedule (applied at an interval of 10 days) in 12 combinations for their efficacy as well as economic viability for the management of fruit flies in bitter gourd, combination C2 [azadirachtin (0.01%) - spinosad (0.002%) - λ-cyhalothrin (0.004%)] with minimum fruit infestation (17.39% infestation), maximum yield (12.03 kg/plant) and maximum avoidable loss value (58.10%) was found most efficacious but the Incremental Benefit Cost Ratio (IBCR) computed was quite low (2.17:1). The combination C7 [B. bassiana (1×1010 CFU/gm) - λ-cyhalothrin (0.004%) - spinosad (0.002%)] was next in order of effectiveness and was also economically viable with higher IBCR value (13.25:1). The combinations (C1 - C5) in which azadirachtin formulation was applied as the first spray, the IBCR computed was quite low, due to the high price of the biopesticide. All the test combinations were found superior to control (C12), wherein only water was sprayed.