Bio-efficacy of selected insecticides against aphid population in grass pea (Lathyrus sativus L.)

An experiment was conducted at Research Farms, RABL College of Agriculture and Research Station, Chhuikhadan during rabi, 2024. During the study, Most occurring sucking pest aphid (Acyrthosiphon pisum) were evaluate on grass pea (Lathyrus sativus L) under six treatment including control. Six treatment include T1, application of Thiamethoxam 25 WG @ 0.2 g/l of water during vegetative stage and reproductive stage; T2, application of Dimethoate 30% EC @ 1.5 ml/l of water during vegetative stage and reproductive stage; T3, application of Thiamethoxam 25 WG @ 0.2 g/l of water and Dimethoate 30% EC @ 1.5 ml/l of water during vegetative stage and reproductive stage; T4, application of Neem oil (0.5%) @ 5 ml/l of water during vegetative stage and reproductive stage; T5, application of Dimethoate 30% EC @ 1.5 ml/l and Neem oil (0.5%) @ 5 ml/l of water during vegetative stage and reproductive stage, respectively; T6, Crop having manual weeding with untreated for easy access to insect pests throughout the crop season. After successful conduction of all scheduled practices, Pea aphid mean population ranged from 3.07 to 53.94 aphids per plant during whole crop periods. In case of treatment, T3 secured lowest aphid population between 3.07 to11.60 aphids per plant as mean population, followed by T1 with 9.04 to 14.14 aphids per plant as mean population. In case of yield, it reduces with the increase of aphid population due to aphid population influenced to all treatment. In this context, T3 have obtained 1411.54kg/ha of grass pea with 8.02 aphids per plant.