COMPARATIVE STUDY OF BOTANICALS AND SYNTHETIC INSECTICIDE ON THE CONTROL OF INSECT PESTS AND DISEASES OF COWPEA

Abstract

The quest to minimize synthetic insecticide use due to their adverse environmental effects and the need to improve yield has led to eco-friendly botanical pesticides use. This study was carried out to demonstrate the efficacy of garlic and lemon liquid botanical extracts in mitigating cowpea insect pests, diseases and increasing yield at Faculty of Agriculture and Veterinary Medicine, University of Buea, Cameroon. The design was a randomized complete block with four treatments, replicated four times. The treatments comprised synthetic insecticide, garlic liquid extract, lemon liquid extract, and control. Data collected were subjected to ANOVA (P<0.05). Cowpea vegetative parameters differed significantly (P<0.05), with garlic liquid extract dominating synthetic insecticide in the number of leaves having 32 highest leaves, but there was no significance between botanical pesticides and synthetic insecticide. Botanical pesticides effectively mitigated pest, significantly different from the control (P<0.05) but similar to the synthetic insecticide. Garlic liquid extract had 11 thrips per 10 flowers, three less than synthetic insecticide, and one pod borer/10 flowers less than synthetic insecticide. Fusarium oxysporium, Curvularia lunata and Botryodiplodia theobromae (BT) were identified to infect cowpea. Least disease incidence was 11.6 % from plants treated with garlic liquid extract. Cowpea treated with garlic liquid extract was least infected with the pathogens (23). The highest weight of pods yield was recorded in garlic liquid extract 10 kg/treatment with the lowest in control 5 kg/treatment and differed significantly (P<0.05) across treatments. Thus garlic and lemon liquid extracts improved cowpea yield while minimizing environmental hazards.