Prevalence and Severity of Cercospora Leaf Spot Disease on Groundnut (Arachis hypogaea L.) in Ankpa L.G.A., Kogi State, Nigeria

Background and Objective: Cercospora leaf spot (CLS) is a major foliar disease limiting groundnut production worldwide. Despite its significance, information on the distribution, severity, and impact of CLS in Ankpa Local Government Area (LGA), Kogi State, Nigeria, remains limited. This study aimed to assess the prevalence, severity, and impact of CLS and to evaluate farmers’ knowledge and management practices. Materials and Methods: During the 2024 cropping season, 72 farms across six wards in Ankpa LGA were surveyed, assessing 3,600 groundnut plants for CLS symptoms. Causal agents were confirmed via morphological identification and pathogenicity tests. Disease incidence and severity were recorded, and temporal and climatic influences were analyzed. Farmer interviews evaluated awareness and management practices. Data were analyzed using SPSS 26.0, applying ANOVA with Duncan’s Multiple Range Test (p≤0.05) and correlation analysis. Results: Cercospora arachidicola and C. personata were detected in 89% and 67% of farms, with mixed infections in 56%. Overall disease incidence was 76.4% (68.2-84.7% across wards), and mean severity was 4.2 (1-9 scale). Incidence and severity were strongly correlated (r = 0.847, p<0.001). Disease progressed from early (52.8%) to late (76.4%) growth stages. Relative humidity (r = 0.723, p<0.001) and rainfall (r = 0.589, p<0.01) positively influenced disease, while temperature was negatively correlated. Estimated yield losses averaged 28% (15-45%), highest in high-humidity wards. Farmers’ awareness was moderate: 68.1% could identify CLS, though 31.9% misdiagnosed symptoms. Management practices were limited: 31.9% applied no control, 38.9% used fungicides, and 16.7% planted resistant varieties. Conclusion: A CLS is now endemic in Ankpa LGA, significantly threatening groundnut production and farmer livelihoods. Integrated disease management strategies-including resistant cultivars, timely fungicide application, cultural practices, and farmer training-are urgently needed to mitigate the impact and sustain groundnut yields.