Comparative Economic Analysis of Botanical and Synthetic Fungicides for the Management of Cocoa Black Pod Disease (Phytophthora spp) in Nigeria
Cocoa production in West Africa continues to suffer significant yield losses due to black pod disease caused by Phytophthora spp. Conventional synthetic fungicides, though widely used, are increasingly constrained by rising costs, environmental risks, and variable field effectiveness. This study evaluates the economic viability of botanical fungicides specifically aqueous and ethanolic extracts of Eucalyptus grandis and Datura stramonium relative to synthetic fungicides using a comprehensive Cost-Benefit Analysis (CBA) and Benefit-Cost Ratio (BCR) approach under weekly and bi-weekly treatment regimes. A Completely Randomized Design with three replications was employed, with seven treatments: (i) 4% aqueous E. grandis, (ii) 4% aqueous D. stramonium, (iii) 3% aqueous mixture of E. grandis + D. stramonium, (iv) 1% ethanol extract of E. grandis, (v) 1% ethanol extract of D. stramonium, (vi) synthetic fungicide (commercial standard), and (vii) control. Spraying costs were included for weekly and bi-weekly schedules. Data were analyzed using ANOVA and means separated with New Duncan Multiple Range Test (p≤0.05). Results show that aqueous botanical treatments provided the highest economic returns, with the mixture of E. grandis + D. stramonium achieving the highest weekly BCR of 180.0 followed by aqueous D. stramonium (158.0). Under bi-weekly schedule, the mixture maintained strong performance (BCR 45.0), while aqueous D. stramonium recorded (BCR 28.0). Aqueous E. grandis, with no extraction cost, was economically dominant, yielding net benefits of ₦89,000 weekly and ₦50,000 bi-weekly. Synthetic fungicides showed the lowest BCR (7.17), confirming economic inefficiency. Conclusively, aqueous botanicals demonstrated superior profitability, cost efficiency, and sustainability, providing strong justification for their integration into cocoa disease management strategies in Nigeria and similar regions.