EFFICACY OF INTERCROPPING AND PLANT DENSITY IN MANAGEMENT OF Earias vittella and Helicoverpa armigera LEPIDOPTERAN INSECT PESTS OF OKRA (Abelmoschus esculentus L. Moench)

Abstract

Field experiment was carried out to evaluate the efficacy of intercropping and plant density in managing of lepidopteran insect pests of Okra (Abelmoschus esculentus L. Moench). The objectives of this study were to determine the effect of intercropping and plant density on the incidence and abundance of lepidopterous insect pests of okra, crop damage caused by these pests; evaluate the relationship between intercropping and plant density on crop damage or fruit yield/loss and determine the cost-benefit of using intercropping and plant density to manage lepidopterous insect pests of okra. The experiment was conducted during the 2023 dry season under irrigation in Monguno, Borno State, Nigeria. The was laid out in a split-plot design, with the main plot consisting of okra variety and the sub-plot consist of nine different crop level of intercrop and a control (okra monocrop). Data were collected on the population of insects, shoot damage, and fruit damage. The results showed that intercropping okra with soybean at a 4:1 ratio significantly reduced the population of E. vitella (13.22 larvae/10 plants) and H. armigera (6.96 larvae/10 plants) compared to other intercrop options and the okra monocrop. Shoot damage and combined fruit damage caused by these pests were also lowest (16.07% and 16.51%, respectively) in the okra-soybean intercropping system. The reduced pest pressure and crop damage in the intercropping system were attributed to the creation of a more diverse and complex agroecosystem, which disrupted the pests' host-finding ability, provided alternative food sources and habitats for natural enemies, and enhanced the plant's defense mechanisms. In conclusion, the adoption of the okra-soybean intercropping system (4:1 ratio) is recommended as an effective and sustainable pest management strategy for okra cultivation. Further research on optimal spatial arrangements and integration with other agroecological practices can contribute to the development of holistic and environmentally-friendly approaches to managing insect pests of okra.