Effect of Biopesticides against Shoot and Fruit Borer (Earias vittella Fab.) on Okra [Abelmoschus esculentus (L.) Moench]

Abstract

A comprehensive field experiment was executed at the Department of Entomology, RVSKVV, College of Agriculture, Gwalior, Madhya Pradesh, during the Kharif seasons of 2018 and 2019 to investigate the comparative efficacy of diverse biopesticidal formulations in the management of shoot and fruit borer (Earias vittella) infestation in okra (Abelmoschus esculentus). The experimental design was a Randomized Block Design composed of eight distinct treatments: Beauveria bassiana at 0.5kg/ha, Verticillium lecanii at 1.0kg/ha, neem oil 5% at 2.5L/ha, neem leaf extract 5% at 25kg/ha, neem seed kernel extract (NSKE) 5% at 25kg/ha, garlic clove extract 5% at 25kg/ha, and Panchgavya 3% at 15L/ha. Empirical data robustly indicated that all biopesticidal interventions were efficacious in mitigating shoot damage relative to untreated controls. Across all treated plots, the proportion of shoots damaged ranged from 0.89–2.62%, which is appreciably lower compared to 2.72% in the untreated controls. The highest reduction in shoot damage was attributed to NSKE 5% (0.89%), closely followed by B. bassiana, whereas Panchgavya 3% exhibited the highest shoot damage among the biopesticidal treatments (2.62%). Analytical computations revealed a percent reduction in shoot damage between 3.7% and 67.3% depending on the biopesticidal intervention. Assessment of fruit damage, evaluated on both weight and numerical basis, mirrored these findings. NSKE 5% conferred minimal fruit damage (3.07% by weight, 3.32% by number), followed sequentially by B. bassiana, V. lecanii and neem oil 5%. Conversely, the maximum fruit damage among all treated plots was associated with Panchgavya 3% (7.03% by weight, 7.38% by number). Untreated plots experienced fruit damage rates substantially higher (10.09% by weight, 10.74% by number). The application of biopesticides led to a reduction in fruit damage by 30.3–69.7% (weight) and 31.3–69.1% (number) across treatments. Yield assessments demonstrated that NSKE 5% augmented fruit yield maximally (119.56q/ha), succeeded by B. bassiana and neem oil 5%. In contrast, the lowest fruit yield was found in plots treated with Panchgavya 3% for both years. Economic analyses highlighted B. bassiana as the most profitable intervention, yielding the highest net profit (₹27,128/ha), followed by NSKE 5% (₹25,938/ha), along with the maximal benefit-cost ratio for B. bassiana (1:14.13), then V. lecanii (1:8.36), NSKE 5% (1:8.11) and garlic clove extract 5% (1:6.78).In summation, the study distinctly substantiates the high efficacy of select biopesticides - particularly NSKE 5%, B. bassiana and neem oil 5% - in curtailing shoot and fruit borer damage, enhancing fruit yield, and improving economic returns. These results highlight the strategic merit and sustainability of integrating these biopesticidal agents into pest management protocols for okra cultivation in Madhya Pradesh, offering an environmentally responsible alternative to conventional chemical pesticides.