Assessment of the bio-efficacy of new insecticides on sucking pests in chilli

Abstract

A field experiment was conducted during 2023-24 at the Agriculture Farm of Institute of Agriculture (Palli Siksha Bhavana), Visva-Bharati, West Bengal, to assess the bio-efficacy of novel insecticides against major sucking pests viz; aphids, thrips, mites, and whiteflies infesting chilli (Capsicum spp.), using the chilli variety 'Bullet'. Seven insecticidal treatments, namely Diafenthiuron 25% + Pyriproxyfen 5% SE at 562.5, 750, and 937.5 ml/ha respectively; Diafenthiuron 50% WP at 600 gm/ha; Pyriproxyfen 10% EC at 500 ml/ha; Clothianidine 3.5% + Pyriproxyfen 8% SE at 1250 ml/ha; and Beta-Cyfluthrin 8.49% + Imidacloprid 19.81% w/w OD at 200 ml/ha, along with an untreated control, were evaluated in a Randomized Block Design with three replications. All insecticidal treatments significantly reduced pest populations compared to the control. The application of Diafenthiuron 25% + Pyriproxyfen 5% SE @ 937.5 ml/ha was found to be the most effective, recording the lowest populations of thrips, whiteflies, aphids, and mites at 3, 7, and 14 days after both the first and second sprays. This treatment was immediately followed by Diafenthiuron 25% + Pyriproxyfen 5% SE @ 750 ml/ha which was at par with the same at 937.5 ml/ha. This treatment also resulted in the highest green chilli yield (88.37 q/ha), followed by Diafenthiuron 25% + Pyriproxyfen 5% SE @ 750 ml/ha (81.40 q/ha) and Pyriproxyfen 10% EC @ 500 ml/ha (76.30 q/ha), whereas the untreated control recorded the lowest yield (31.83 q/ha). The findings indicate that though Diafenthiuron 25% + Pyriproxyfen 5% SE @ 937.5 ml/ha yielded better results in terms of population reduction of sucking pests, however Diafenthiuron 25% + Pyriproxyfen 5% SE @ 750 ml/ha is a promising option for the effective management of sucking pests, conservation of natural enemies and achieving higher yields in chilli cultivation.