Field Evaluation of Botanical and Conventional Insect Pest Management Strategies for Reducing Fruit Damage and Improving Yield of Two Okra Species in Nigeria

Abstract

Insect-induced fruit damage is a major constraint to okra production and marketability in Nigeria, necessitating sustainable pest management strategies. This study combined a market survey with a two-season field experiment to evaluate the effectiveness of neem kernel oil and a conventional insecticide in reducing fruit damage and improving the yield of two okra species (Abelmoschus esculentus and A. caillei) in Makurdi, Nigeria. A structured questionnaire was administered to 90 okra marketers across six major markets to assess perceptions of fruit damage severity. Concurrently, a 2 × 3 factorial experiment arranged in a randomized complete block design with four replications was conducted during the 2023 and 2024 early cropping seasons. Lesion (81.3%) and incision (78.7%) were ranked as the most severe market-quality defects. A. caillei produced significantly higher yield (2.44 t ha⁻¹) than A. esculentus (2.07 t ha⁻¹; P < 0.0001). Cypermethrin and neem kernel oil increased fresh fruit yield to 2.64 and 2.58 t ha⁻¹, respectively, compared with 1.55 t ha⁻¹ in the untreated control. Neem kernel oil reduced overall fruit damage by 82.1%, increased yield by 66.5%, achieved 97.7% of the yield obtained with the conventional insecticide, and produced the highest benefit ratio (26.64). The findings demonstrate that neem kernel oil is an effective, economically viable and environmentally sustainable alternative to conventional insecticides for integrated management of insect pests in okra production.