Preventable yield losses and management of mustard aphid, Lipaphis erysimi (Kaltenbach) in different cultivars of Brassica juncea (L.) Czern & Coss

The mustard aphid, Lipaphis erysimi (Kaltenbach) is a major pest of Brassica spp. and causes significant yield losses. We determined the current status of levels of infestation, yield loss due to aphids, and efficacy of biopesticides as well as neonicotinoids to manage L. erysimi in Brassica juncea. The reduction in the number of aphids after insecticide applications and seed yield differed significantly among treatments (insecticide protected and unprotected), across seasons, and treatment x season interactions in most test cultivars (cv.) viz., BSH 1, NRCDR 02, PDZM 31 and RH 725. The insecticide applications reduced the aphid populations by 51.4-99.6% across cultivars and seasons. Aphid population was significantly higher and seed yield lower under late-sown than early and timely-sown conditions in cv. PM 26. Seed treatment with different insecticides did not result in a significant reduction in the aphid population and protect the potential seed yield of B. juncea. Dimethoate was effective over the biopesticide treatments, and Beauveria bassiana performed best among the test biopesticides. Thiomethoxam and imidacloprid were best among the neonicotinoids for reduction in aphid population, protection of potential seed yield, and incremental benefit-cost ratio in cv. PM 30. The control of aphid populations could prevent 10.2-61.1% yield loss. The alternate use of B. bassiana @ 2 g/l, dimethoate 30 EC @ 1 ml/l, imidacloprid 17.8 SL @ 0.25 ml/l, or thiomethoxam 25 WG @ 0.2 g/l water based on the extent of aphid population effectively manages L. erysimi in B. juncea.