Improvement in the Management of Leaf Blight Disease of Taro (Colocasia esculenta) with Copper and Metalaxyl Fungicides

Abstract

Taro (Colocasia esculenta (L.) Schott) is an important staple food crop for millions of people in developing countries. Taro production is constrained by many diseases of which leaf blight, caused by Phytophthora colocasiae Raciborski, is the most destructive and it accounts for up to 80% yield loss of taro in many countries. In Ghana, the disease accounts for 25 – 50% yield loss. Non-sustainability of cultural control method and the use of resistant varieties have compelled some farmers to abandon their fields while others have converted their farms to dry season vegetable farming. In this study, copper and metalaxyl fungicides were tested for the control of leaf blight disease of taro. In vitro fungicidal activity tests and field evaluation showed that Ridomil Gold Plus 66 WP (6% metalaxyl-M + 60% copper (I) oxide) and Metalm 72 WP (12% metalaxyl + 60% copper (I) oxide) at 50 g in 15 litres of water (3.3g/L) and Nordox 75 WG (86% cuprous oxide) at 75 g in 15 litres of water (5 g/L) are effective for the control of leaf blight disease of taro at 4 weekly intervals for five consecutive months in the wet season.