Field Efficacy of Chlorpyrifos 35% + Fipronil 3.5% EC Against Shoot and Fruit Borer, Earias vitella (Fabricius) in Okra

Abstract

Aims: The present study assess the bio-efficacy of Chlorpyrifos 35% + Fipronil 3.5% EC against shoot and fruit borer, Earias vittella (Fabricius) infestation in okra (Abelmoschus esculentus L. Moench), and to evaluate its influence on infestation intensity and fruit yield. Study Design: Randomized Block Design (RBD) with nine treatments and three replications. Place and Duration of Study: The experiment was conducted at [Institution Name] during the Kharif seasons of 2019 and 2020. Methodology: Different doses of Chlorpyrifos 35% + Fipronil 3.5% EC formulated as nine treatments (T1-T9), including five doses of (T1-T5), along with standard checks (Chlorpyrifos 50% EC, Fipronil 5% SC, Cypermethrin 25% EC) and an untreated control (T9) were tested for efficacy. Two foliar sprays were applied in each season. Data on larval population build-up and the mean number of infested shoots and fruits per 10 plants were recorded at multiple intervals post-application. Green fruit yield and percent reduction over control were also assessed. Data were statistically analysed using ANOVA. Results: In 2019, the lowest shoot infestation (6.30 shoots/10 plants) and highest yield (16,342 kg/ha) were recorded in T5- Chlorpyrifos 35% + Fipronil 3.5% EC @ 875 + 87.5 g a.i./ha, followed by T4- 546.87 + 54.68 g a.i./ha (6.37 shoots; 16,037 kg/ha) and T3- 437.5 + 43.75 g a.i./ha (6.43 shoots; 16,029 kg/ha). Fruit infestation ranged from 6.27 (T5) to 9.17 (T9-Untreated control). Percent reduction over control in fruit infestation reached 82.10% in T5. Whereas, in 2020 similar trends were observed, with T5 again showing the lowest shoot (5.23) and fruit (4.63) infestations and the highest yield (17,142 kg/ha). T9 recorded the lowest yield (9453 kg/ha). The maximum reduction in fruit infestation was 84.51% in T5. Conclusion: Application of combination product at 546.87 + 54.68 to 875 + 87.5 g a.i /ha, was highly effective in controlling Earias vittella and increasing okra yield. It can be recommended as a potent component in okra pest management programs. Additionally, the use of combination insecticides at optimized doses may help reduce overall chemical load and delay resistance development eventually contributing to more ecologically sustainable pest management.