In vitro Evaluation of the Effectiveness of Commonly Used Fungicides against Phytophthora colocasiae in Ghana

Abstract

In vitro study was conducted to determine the percentage inhibition and radial mycelial growth of Phytophthora colocasiae, the causal agent of taro leaf blight disease, on five selected fungicides including Carbendazim, Mancozeb, Chemoliette (Fosetyl-aluminium), Agro Comet (metalaxyl + copper (1) oxide) and TOPS-M (Methyl thiophanate) at different concentrations (100, 200, 300, 400, and 500 ppm). The aim was to identify the type of fungicide with the rate or concentration that can best be used in the management of the taro leaf blight disease. All the five fungicides showed different effects against the pathogen, Phytophthora colocasiae, but Chemoliette (fosetyl-aluminium) and Agro Comet (metalaxyl + copper (1) oxide) were the most effective at the different concentrations, especially from 300 ppm to 500 ppm. The two fungicides also recorded the highest percentage inhibitions of 63.59% and 53.88%, respectively, and can therefore be combined with other management strategies to manage the disease effectively.