Bio-efficacy and Economics of Newer Insecticides against Mustard Aphid, Lipaphis erysimi (Kalt.) on Indian Mustard

A field experiment was conducted during the rabi season of 2024–25 at R.B.S. College, Bichpuri, Agra (Uttar Pradesh), to evaluate the bio-efficacy of seven newer insecticides, viz., imidacloprid 17.8 SL, thiamethoxam 25 WG, acephate 75 SP, acetamiprid 20 SP, dimethoate 30 EC, diafenthiuron 50 WP and fipronil 5 SC, against the mustard aphid, Lipaphis erysimi (Kalt.). The experiment was laid out in a randomised block design with three replications. A single foliar spray was applied on 18 January 2025 following sufficient pest population build-up. Among the treatments, imidacloprid 17.8 SL recorded the highest mean population reduction (93.97%), followed by thiamethoxam 25 WG (86.35%) and dimethoate 30 EC (83.71%). Conversely, fipronil 5 SC (61.79%), acephate 75 SP (66.14%) and diafenthiuron 50 WP (69.05%) proved the least effective. In terms of productivity and economics, imidacloprid 17.8 SL recorded the highest seed yield (39.49 q ha⁻¹), zero avoidable yield loss, the highest net returns (₹1,91,448 ha⁻¹), and a benefit–cost (B:C) ratio of 6.04:1, followed closely by thiamethoxam 25 WG and dimethoate 30 EC. In comparison, the untreated control registered the lowest seed yield (25.33 q ha⁻¹) and B:C ratio (3.56:1). Overall, imidacloprid 17.8 SL and thiamethoxam 25 WG emerged as the most effective and economically viable interventions for the management of L. erysimi in mustard under integrated pest management (IPM) programmes.