BIOEFFICACY OF CHILLI PEPPER Capsicum frutescens (L.) AND IT’S INTERCROPPING ON THE GROWTH, YIELD AND INSECT PEST MANAGEMENT OF COWPEA Vigna unguiculata (L.) WALP IN THE RAIN FOREST AREA OF NIGERIA

The experiment was laid out in a 3x4 factorial experiment in randomized complete block design with 3 treatments (chilli pepper extract at 200 l/ha, 250 l/ha and local control) at 3 replications arranged as alternate intercropping, strip cropping, border cropping and sole cropping of cowpea with 12 plots and 60 ridges. The chilli pepper aqueous extract at 200 l/ha and 250 l/ha were sprayed on the cowpea plants at a spraying schedule of 10 am to 12 noon after insect sampling with the view of protecting it. Data were collected on growth parameters after planting, pest population and incidence of insects on cowpea, pod density, pod damage, grain yield, yield loss and phytotoxicity signs. Data collected were subjected to Analysis of Variance. The results indicated that 250 l/ha aqueous extract treated plots reduced the number of insect pests thrips (3.79±0.11), legume pod borer (1.76±0.24), legume pod borer nymph (1.17±0.06) and adult (1.07±0.05), and pod sucking bug adults (1.19±0.07) in intercropping situation, than 200 l/ha respectively, compared to untreated plots (1.31±0.09). There was significant difference (p < 0.05) between the treated plots (1.19±0.02) and untreated plots (1.46±0.02) in terms of pod damage as well as increased grain yields (0.12±0.00) when compared to the untreated control (0.07±0.00). In all, 250 l/ha causes higher phytotoxicity damage than 200 l/ha. The bio-pesticidal effect of chilli pepper on cowpea insects might not be unconnected with active ingredients present in it including glycosides, tannin, terpenoides, flavonoids, saponin, reducing sugar, steroids and resins. The study ranks 250 l/ha and alternate intercropping superior than other aqueous extract and cropping system respectively. However, alcoholic extracts of insecticides from C. frutescens may yield a more potent insecticide than ordinary aqueous extract. Extensive work will need to be done on the age of the sample after preparation and storage condition as this could affect the assessment of any plant material as a biopesticide.