VIGNA UNGUICULATA

Cowpea (Vigna unguiculata) is a widely cultivated leguminous crop known for its high protein content, drought resistance, and economic importance, particularly in Africa, Asia, and Latin America. It serves as a major source of nutrition for millions of people, providing essential proteins, vitamins, and minerals. Cowpea production is significantly challenged by insect pests, including aphids (Aphis craccivora), thrips (Megalurothrips sjostedti), and pod borers (Maruca vitrata), which can cause substantial yield losses if not effectively controlled. To combat these pest infestations, farmers frequently use chemical pesticides to safeguard their crops and enhance productivity. However, excessive or improper pesticide application can lead to the accumulation of harmful residues in harvested cowpea, posing potential risks to both human health and the environment. For this study, cowpea (Vigna unguiculata) from different vendor were chosen to provide a broad analysis of pesticide residues. The cowpeas samples were categorized into eight sets, each consisting of raw samples and their corresponding milled forms. The raw samples were labeled and stored separately from the milled samples to ensure proper identification and traceability. High-Performance Liquid Chromatography (HPLC) was used for detection. The research followed a structured process, including sample collection, preparation, extraction, purification, and analysis using HPLC. The concentrations of the pesticides; Dichlorvos and Cypermethrin in the analyzed samples were calculated and expressed in µg/ml to indicate residue levels in the cowpeas. The concentrations of Dichlorvos in the analyzed cowpea samples varied: Sample E had the highest concentration (125.15 µg/mL), followed by sample F (116.06 µg/mL). Sample I had a moderate concentration (79.52 µg/mL). Sample G had the lowest concentration (52.73 µg/mL). Cypermethrin was only detected in sample I at a concentration of 2.82 µg/mL. The retention time (6.000 min) and peak area (5.33) confirm the presence of Cypermethrin but at a significantly lower concentration compared to Dichlorvos.These findings indicate that pesticide residue levels differ among viiviiisamples, potentially due to varying pesticide application methods, time intervals between pesticide application and sample collection, or environmental degradation. The detected Dichlorvos concentrations (52.73 – 125.15 µg/mL) in this study significantly exceed the maximum residue limits (MRLs) set by international food safety authorities. Cypermethrin was detected in only one sample (2.82 µg/mL), which is significantly below the Codex Alimentarius MRL of 0.05 mg/kg (FAO/WHO, 2021). This study revealed high Dichlorvos concentrations in cowpea samples, exceeding permissible limits, while Cypermethrin levels were minimal. These findings highlight potential health risks and the need for stricter pesticide regulation and better agricultural practices.