Survey and in Vitro Control of Cercospora Leaf Spot of Groundnut from Some Selected Districts of Hong Local Government Area, Nigeria

This study investigates the incidence, severity, management practices, and in vitro control of Cercospora leaf spot (CLS) disease from groundnut (Arachis hypogaea L.) farms in Hong, Adamawa State, Nigeria, focusing on farmers’ knowledge and practices. 60 farmers from six communities within the Hong Local Government Area were surveyed using structured questionnaires to assess their awareness and management strategies for CLS while seed, stem-bark and leaf extracts of A. indica were used at different concentrations (100, 200, 400 and 800 mg/ml) with a positive (Tebuconazole) and negative (5 ml of water) control for in vitro control trials. The results revealed that the majority of farmers lacked adequate knowledge about the disease and its causal agent, Cercospora arachidicola. Chemical control methods were the most commonly used, although not universally accessible or sustainable, while cultural control practices were rarely implemented. Disease incidence varied across locations, with Bangshika showing the highest incidence at 43.16%, while Pella had the lowest. Disease severity ranged from 41-60% in most farms, with some locations like Zhedinyi reporting higher severity (61-80%). In vitro antifungal investigation showed that seed extract of A. indica had the least radial mycelial growth (2.21 mm) compared to the stem-bark (3.47 mm) and the leaf (4.24 mm). These findings highlight the critical need for more effective disease management strategies, as well as farmer education on sustainable disease control measures. This study emphasizes the importance of integrated pest management (IPM) strategies for reducing groundnut yield losses due to CLS, more especially using A. indica as a biocontrol agent with recommendations for further research into identifying the active metabolites present in the botanical.