Assessment of Bioefficacy of Chilli Pepper Capsicum frutescens (L.) and its Intercropping on the Performance and Insect Pests Management of Bambara Groundnut (Vigna subterranea L.)

A study was conducted at the Yaba College of Technology Instructional and Research Farm in 2022 and 2023 wet and dry seasons to determine the bio-efficacy of chilli pepper, (Capsicum frutescens (L.)) and its intercropping on the growth, yield and insect pest management of Bambara groundnut (Vigna subterranea (L.)). The experiment was laid out in a 3×4 factorial experiment in Randomized Complete Block Design with 3 treatments (chilli pepper extract at 200l/ha, 250l/ha, and local control) at 3 replications in alternate intercropping, strip cropping, border cropping, and sole cropping arrangement. The chilli pepper aqueous extract at 200 l/ha and 250 l/ha sprayed on the Bambara groundnut plants were sprayed as scheduled from 10 am to 12 noon with the view of protecting it with aqueous extract of chilli pepper on 12 plots of 60 ridges. Data were collected on growth parameters of Bambara groundnut at 2, 4, and 6 weeks after planting, pest population, assessment of thrips and legume pod borer, assessment of both nymph and adult of legume pod borer and pod sucking bugs, pod density, pod damage, grain yield, yield loss and assessment of phytotoxicity signs using Analysis of Variance. Results showed that 250 l/ha aqueous extract treated plots reduced the number of insect pests including thrips (4.67±1.09), legume pod borer (1.76±0.35), legume pod borer nymph (1.08±0.10) adults of pod borers (1.18±0.11) and pod sucking bugs adult (3.33±1.09) in intercropping situation, followed by 200 l/ha respectively as compared to untreated plots (2.69±0.12). There was a significant difference (p < 0.05) between the treated plots (9.08±0.62) and untreated plots (12.44±0.71) in terms of pod damage as well as increased grain yields (343.73±4.71) when compared to the untreated control (322.12±43). However, 250 l/ha causes higher phytotoxicity damage than 200 l/ha although it controlled pest population better than 200 l/ha. Alternate cropping proved to be superior to other cropping system with respect to grain yield (36.78±12.99), reduction in pest infestation (6.33±1.23) and reduction in yield loss (299.58±9.41) when compared to sole cropping of Bambara groundnut with respect to grain yield (100.24±12.99), reduction in pest infestation (15.33±1.23) and reduction in yield loss (395.27±9.41). The bio-pesticidal effect of chilli pepper on Bambara groundnut insects may be due to the presence of active ingredients present in chilli pepper including glycosides, tannin, terpenoides, flavonoids, saponin, reducing sugar, steroids, and resins. This result indicates the potential of using plant extract with insecticidal attributes for the protection of Bambara groundnut in low input agriculture practiced by limited resource farmers in developing countries.