Efficacy of Chlorpyrifos 35% and Fipronil 3.5% EC against Thrips, Scirtothrips dorsalis Hood and Fruit Borer, Helicoverpa armigera (Hubner) in Chilli (Capsicum annuum L.)

Abstract

Aims: To evaluate the bio-efficacy of Chlorpyrifos 35% + Fipronil 3.5% EC against major insect pests viz., thrips, Scirtothrips dorsalis Hood and fruit borer, Helicoverpa armigera (Hubner) in chilli (Capsicum annuum L.) under field conditions. Place and Duration of Study: Field trials were conducted at the University of Agricultural Sciences, GKVK, Bangalore, India, during the Kharif seasons of 2019 and 2020 using a Randomized Block Design (RBD) with nine treatments and three replications. Treatments included varying doses of the test insecticide, standard checks, and an untreated control, with two foliar sprays applied each season. Data on pest populations, shoot and fruit infestation, yield, predator counts, and phytotoxicity were recorded and statistically analysed. Methodology: The experiment consisted of nine treatments (T1-T9) with varying doses of Chlorpyrifos 35% + Fipronil 3.5% EC, standard checks, and an untreated control. Two foliar sprays were applied per season. Observations on thrips and fruit borer population (pre-and post-treatment), number of infested shoots and fruits per 10 plants, yield (kg/ha), coccinellid predator population, and phytotoxicity symptoms were recorded. Data were statistically analysed using ANOVA and percent reduction over control was calculated. Results: Results revealed that treatment T5 (875 + 87.5 g a.i./ha) consistently achieved the highest efficacy, significantly reducing pest incidence and fruit infestation by 80.74% to 84.51%, while delivering the highest yield (16,342 to 17,142 kg/ha). Importantly, coccinellid populations remained unaffected and no phytotoxicity symptoms were observed at any dose. The study confirms that Chlorpyrifos 35% + Fipronil 3.5% EC, particularly at the T5 dose, is highly effective and environmentally safe for chilli pest management.