Efficacy of Neem Seed Derivatives Against Nematodes Affecting Cowpea

1.1 Introduction Cowpea (Vigna unguiculata) is a vital legume crop cultivated primarily in tropical and subtropical regions. It plays a significant role in food security and income generation for millions of smallholder farmers (Kebede et al;2020) Despite its importance, cowpea cultivation faces substantial challenges, one of the most pressing being infestations by nematodes. Nematodes are microscopic, worm-like organisms that can cause severe damage to plant roots, leading to stunted growth, reduced yield, and in severe cases, complete crop failure. Root-knot nematodes (Meloidogyne spp.) and cyst nematodes (Heterodera spp.) are among the most destructive nematode species affecting cowpeas. These nematodes invade the root system of the plants, causing the formation of galls or cysts, which interfere with nutrient and water uptake. Managing nematode infestations is critical to maintaining healthy cowpea crops and ensuring sustainable agricultural practices (Tapia-Vázquez et al.,2022). Neem (Azadirachta indica) is a tree renowned for its broad-spectrum pesticidal properties. Its seeds contain several bioactive compounds, including azadirachtin, Nimbin, and salannin, which have shown efficacy against a variety of pests and pathogens. Neem seed derivatives, such as neem oil, neem cake, and neem-based formulations, have been studied for their potential use in integrated pest management (IPM) strategies. Compounds in neem can deter nematodes from feeding on plant roots. Neem interferes with the hormonal balance and moulting process of nematodes, leading to their impaired development and reproduction. Direct exposure to neem extracts can be lethal to nematodes (Roychoudhury, 2016). Numerous studies have investigated the efficacy of neem seed derivatives in managing nematode infestations in cowpeas. These studies typically evaluate the impact of neem treatments on nematode population density, root damage, and overall plant health and yield (Baah et al.,2024). The results have generally shown that neem derivatives can significantly reduce nematode populations and improve plant growth parameters. The use of neem seed derivatives presents a promising, eco-friendly approach to managing nematodes in cowpea cultivation. By integrating neem-based treatments into pest management programs, farmers can reduce reliance on synthetic nematicides, which are often costly and environmentally harmful (Mwamula et al.,2022) Further research and extension efforts are needed to optimize application methods and dosages for maximum efficacy and to educate farmers about the benefits and use of neem products in sustainable agriculture. 1.2 Problem Statement Cowpea production is heavily impacted by nematode infestations, particularly root-knot nematodes (Meloidogyne spp.) and cyst nematodes (Heterodera spp.). These pests cause extensive root damage, reducing nutrient uptake and leading to stunted growth and lower yields. Conventional nematode control methods primarily rely on chemical nematicides, which pose environmental and health risks and can be prohibitively expensive for smallholder farmers. There is an urgent need for sustainable, cost-effective, and eco-friendly alternatives to manage nematode populations in cowpea cultivation. Neem (Azadirachta indica) seed derivatives, including neem oil, neem cake, and neem-based formulations, have shown promise as natural nematicides due to their bioactive compounds such as azadirachtin, nimbin, and salannin . These compounds exhibit antifeedant, growth-disrupting, and toxic effects on nematodes, making them a viable option for integrated pest management (IPM) strategies in cowpea farming. Despite the potential of neem seed derivatives, there is limited comprehensive research on their efficacy specifically against nematodes in cowpea crops. Existing studies have shown varying levels of success, and optimal application methods and dosages are not well-established. There is a need to assess the long-term impacts of neem treatments on soil health and overall plant productivity 1.3 SIGNIFICANCE OF STUDY With rising concerns about the environmental and health impacts of chemical pesticides, there is an increasing need to explore sustainable alternatives for pest management. Neem extracts, which are natural plant-based compounds, show potential as nematicides, making them promising for eco-friendly pest control. This study aligns with the principles of integrated pest management (IPM), which emphasizes a holistic approach to pest control and aims to minimize chemical pesticide use. Integrating natural extracts into IPM practices can enhance the sustainability and effectiveness of pest management strategies. Effective nematode management can directly benefit the economy by boosting cowpea yields. Reducing reliance on expensive chemical nematicides can lower production costs and improve the economic viability of cowpea farming. This study aims to provide an eco-friendly and sustainable solution for controlling soil-dwelling nematodes in cowpea production 1.4 Objectives of study The Main objectives of this study are; 1. To determine the impact of neem plant crude extract on the population dynamics of soil-inhabiting nematodes, particularly root-knot nematodes (Meloidogyne spp.) 2. To determine the effects of neem on the growth and yield of cowpeas. 3. To enhance the scientific understanding of the effects of neem extracts.