FACTSHEETS FOR FARMERS

Created in Grenada, October 2012 www.plantwise.org Black Sigatoka disease management

Recognize the problem symptoms of Black Sigatoka. 2-4 will develop the Black Sigatoka, a leaf spot disease of , plantain, rock fig and other symptoms and they will get worse related species is now widespread throughout the island. This disease, caused as the leaf ages. A heavily diseased by a , has the potential to destroy banana fields and cut production leaf will not help the plant produce fruit needs to be removed. (Photo significantly if sanitation and chemical control is not employed. by Thaddeus Peters)

Early symptoms include small brown spots and streaks on the lower surface of leaves. These become larger, blacken and dry, making the leaves useless to the plant. The result is smaller, lighter bunches and in severe cases underdeveloped bunches that fall off the stalk. Background The fungus is readily spread by the wind and rain water. Spread also takes place by people moving infected plants and old banana leaves. Hot, humid weather conditions are ideal for the growth of the fungus. Management The aim is to maintain at least 6-8 healthy leaves on the plant at bunching so that it can produce a proper bunch. Recently pruned field, the diseased Prune heavily infected and dried leaves then stack them in heaps along the leaves have been removed which rows, keeping the lower leaf surface facing the ground. This will help prevent helps to prevent the disease spreading. (Photo by Thaddeus disease spread. Peters) Keep weeds to a minimum and maintain good drainage to prevent high humidity within the field which will favour development of the fungus. Fertilize - Ensure proper plant nutrition to maintain a good rate of leaf emergence so that the plant will outgrow the disease. In the absence of disease monitoring data (used to guide spray treatments), apply fungicide at 14-21 day application cycle especially during the wet season when disease levels are higher. A well-managed fungicide rotation system is needed to prevent the fungus from becoming resistant to any single one, especially those that are systemic.

Recommended fungicides: Propiconazole, Fenpropimorph, Boscalid applied in Banana spray oil and Manzate applied in water. In organic production, banana spray oil only can be used. NB: It is important to take safety precaution and follow manufacturers’ direction when using fungicides.

One variety of banana and one of plantain that are partially resistant to black sigatoka, have been introduced to Grenada and may be available through the Ministry in 2013. When using a pesticide, always wear protective clothing and follow the instructions on the product label, such as dosage, timing of application, and pre-harvest interval.

Scientific name(s) > fijiensis

The recommendations in this factsheet are relevant to: Grenada

Authors: Thaddeus Peters Ministry of Agriculture Edited by Plantwise tel: (473) 440- 0019 email: [email protected]

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