Black sigatoka is a destructive fungal disease that affects all banana varieties. The fungus requires living plant tissue in order to complete its lifecycle but also has the ability to survive on dead plant residues. The fungus penetrates leaf tissue and continues to develop for a few weeks without causing damage to the tree.
Black sigatoka favours periods of heavy rainfall and high humidity. It is spread mainly by winds, splashes of water, and packaging materials that came in contact with infected plant parts. Infected crops may result in more than 50% of yield losses due to crop damages. Black sigatoka symptoms often include small chlorotic spots appearing on the underside of leaves. With time, spots expand and form thin brown streaks in the around the veins. When humidity conditions are high for a significant period of time, the whole leaf can become dry and die, which triggers fruit to ripen early.
*Sanitation: Make an effort to clean and maintain the fields’ close surroundings from weeds as often as possible. Remove and dispose of infected leaves.
Proper soil drainage: Standing water will promote the development and spread black sigatoka.
When conditions for black sigatoka are favorable, apply frequent applications of fungicides in places that are high risk and in intervals of every 7 days. Some areas will require applications for up to 20 days.
The following are generic names of fungicides used in one or more parts of the world: azoxystrobin, propiconazole, tridemorph, bordeaux mixture, and methoxyacrylate.
*Names marked in red are considered to be highly poisonous to beneficial insects.
*Names marked in green are considered to be organic and IPM (integrated pest management) compatible.