Bioefficacy and economics of newer insecticides against sucking insect pests of cowpea

Abstract

A field experiment was conducted during the summer of 2023 at the Vegetable Research Farm, R.P.C.A.U., Pusa, to evaluate the bioefficacy and economic viability of newer insecticides against major sucking insect pests of cowpea (Vigna unguiculata L.). The study focused on seven insecticidal treatments: Thiamethoxam 25% WDG, Imidacloprid 17.8% SL, Acetamiprid 20% SP, Buprofezin 25% SC, Diafenthiuron 50% EC, Fipronil 5% SC, and Dimethoate 30% EC, with an untreated control as the benchmark. The field layout followed a Randomized Block Design (RBD) with three replications, and the pest population was monitored pre-treatment and at intervals post-application (3, 7, and 10 days). Thiamethoxam 25% WDG emerged as the most effective treatment, significantly reducing the population of aphids (Aphis craccivora) and whiteflies (Bemisia tabaci), with the lowest mean pest population observed across the assessment intervals. Imidacloprid 17.8% SL and Diafenthiuron 50% EC were the next most effective, with moderate pest control achieved by Acetamiprid 20% SP and Buprofezin 25% SC. Dimethoate 30% EC, serving as the standard check, was the least effective among the treatments, yet still outperformed the untreated control. Yield assessments demonstrated that Thiamethoxam 25% WDG-treated plots recorded the highest yield at 97.26 quintals per hectare (q/ha), followed by Imidacloprid 17.8% SL at 92.13 q/ha, and Diafenthiuron 50% EC at 88.20 q/ha. The untreated control plots had the lowest yield of 72.90 q/ha. Economic analysis revealed that Thiamethoxam 25% WDG also provided the highest benefit-cost ratio, indicating its superior cost-effectiveness in managing sucking insect pests in cowpea cultivation. The study concludes that Thiamethoxam 25% WDG is the most potent and economically viable insecticide for controlling sucking pests in cowpea, offering substantial yield improvements and profitability for farmers. This research underlines the importance of selecting appropriate insecticides to manage pest populations effectively while considering economic returns, thereby contributing to sustainable cowpea production.