Officials of the Ministry of Agriculture recently confirmed the presence of the black Sigatoka disease on Dominican farms. As a result extension officers have been visiting farms educating farmers’ island wide on the identification and management of the disease.
Black Sigatoka is a leaf spot disease of banana and plantain plants caused by a fungus. Plants with leaves damaged by the disease may have up to 50 percent lower yield of fruit. The fungal disease causes dark leaf spots that eventually enlarge and coalesce, causing much of the leaf area to turn yellow and brown.
The fungus that causes black Sigatoka, Mycosphaerella fijiensis, is spread from tree to tree by wind, rain, and irrigation water. The name black Sigatoka was given to the disease because it was first discovered in 1963 in the Sigatoka Valley of Fiji.
The first symptoms of the black Sigatoka disease are tiny, chlorotic spots that appear on the bottom surface of the 3rd or 4th open leaf. The spots grow into thin brown streaks that are limited by leaf veins. The color of the streaks becomes darker, sometimes with a purple tinge, and visible on the top surface.
Cultural practices such as removing diseased leaves and pruning branches to improve air circulation are also helpful in reducing the occurrence of the disease.
Farmers have been advised that use of proper procedure is important in the destruction of damaged plants to prevent further contamination of the field. For the plants that are severely affected more immediate action is necessary.