Indian Journal of Entomology Online published Ref. No. e20372 DoI No.: 10.55446/IJE.2021.307 EVALUATION OF INSECTICIDES AGAINST THRIPS IN CHILLI PRAJNA PRAKASH MISHRA 1 , ARUNDHATI SASMAL* 2 AND KAILASH CHANDRA SAMAL 3 1 Department of Entomology; 3 Department of Agricultural Biotechnology College of Agriculture; 2 Regional Research and Technology Transfer Station, Coastal Zone, Odisha University of Agriculture and Technology, Bhubaneswar 751003, Odisha, India *Email: sasmalarundhati@gmail.com (corresponding author) ABSTRACT Field efficacy of some novel insecticides was evaluated against chilli thrips Scirtothrips dorsalis (Hood) . Acetamiprid 20SP, spinosad 45SC, fenpyroximate 5EC, emamectin benzoate 5SG, fipronil 80WG, spiromesifen 22.9SC, diafenthiuron 50WP, acephate 75 SP and dimethoate 30EC were included. Among these, fipronil 80WG and spiromesifen 22.9SC were found superior with least incidence (0.98 and 1.04 thrips/ leaf, respectively) and 75.6 and 74.1% reduction over untreated control, respectively. Spiromesifen 22.9SC led to maximum reduction in leaf curl and fruit curl (84.6 and 83.1%, respectively) with maximum chlorophyll content in leaves and green chilli yield (93.85 q/ ha). Key words: Chilli thrips, Scirtothrips dorsalis (Hood), acetamiprid, spinosad, fenpyroximate, emamectin benzoate, fipronil, spiromesifen, diafenthiuron, acephate, dimethoate, leaf curl, fruit curl, chlorophyll content, yield Chilli (Capsicum annum L.) is one of the important commercial vegetable crops in India. It is used as both green and ripe as spice crop. It has a great export potential. Its cultivation and production is affected by a number of biotic and abiotic factors. Among the insect pests, thrips Scirtothrips dorsalis (Hood) are the most destructive causing a significant yield loss of 11 to 32% (quantitative) and 88% (qualitative) in chilli (Kumar et al., 2015; Jadhao et al., 2016). Nymphs and adults suck the sap from tender foliage and lacerate the leaf tissue, growing shoots, flowers and fruits resulting in upward curling of leaves, drooping of flowers prematurely and scaring on the fruits. The present study was undertaken to evaluate the efficacy of some novel insecticides against S. dorsalis (Hood) under field condition. MATERIALS AND METHODS Field trial to evaluate the efficacy of insecticides was conducted at the Regional Research and Technology Transfer Station, Odisha University of Agriculture and Technology, Bhubaneswar, Odisha in two consecutive kharif seasons 2017 and 2018. Chilli (cv. Utkal Ava) was used. Seed treatment with imidachloprid 600FS @5ml/ kg of seed was included in all the treatments except untreated control. Then seeds were sown in the nursery bed. Another nursery bed was sown with untreated seeds. The seedlings of 25 days old were transplanted in a plot size of 5.0x 4.5 m with row spacing of 50 cm. The seedlings from treated nursery bed were planted in all the treatment plots except untreated control. Seedlings from untreated nursery bed were planted in the plots of untreated control. The recommended package of practices except plant protection was followed. The details of treatments (T 1 -T 10 ) are given in Table 1. The spray solution was freshly prepared every time and sprayed with hand compression knapsack sprayer. Two sprays were given during entire crop season once at 30 days after transplanting (DAT) and repeated at 45 DAT. The observations on nymphs and adults of thrips from 5 randomly selected plants were made. Count of thrips (nymphs and adults) was taken on three tender leaves (One from the top, middle and lower canopy) from each plant one day prior to insecticidal application, as pretreatment count and at 5, 10 and 15 DAT. Number of leaves and curled leaves were observed in five randomly selected plants and % was calculated. Similarly, the weight of curled fruits was recorded at harvesting and % fruit curl was calculated. The yield of marketable green chillies was recorded from each picking, and with all pickings, yield/ ha was calculated. The chlorophyll content was estimated at 5 DAT by preparing homogenate of 0.5g of leaf sample in 50 ml of 80% acetone. Then the content was centrifuged and supernatant was collected and then absorbance was measured at 430, 645 and 663 nm. The quality of pigments was calculated after standard formula (Arnon, 1949). All the data were subjected to statistical analysis using ANOVA. RESULTS AND DISCUSSION Observations on S. dorsalis incidence, leaf curl and fruit curl damage revealed that all the insecticidal