Sigatoka leaf spot (banana)
Streaks and spots that spread until much of the foliage dries before the bunch matures — a defoliating banana leaf-spot fungus.
- Pathogen
- Fungus (Mycosphaerella / Sigatoka)
- Spreads by
- Air- & rain-splashed spores
- Favoured by
- Warm humid weather; dense, wet plantings
- Main risk
- Foliage dries; small bunches, premature ripening
Overview
Sigatoka leaf spot is a major fungal foliar disease of banana caused by Mycosphaerella fungi (yellow and black Sigatoka). It begins as small pale-yellow or brown streaks running parallel to the veins on the leaf, which enlarge into elongated spots with grey centres and yellow to brown margins. As the spots multiply and merge, large areas of the leaf dry up.
The real damage is loss of functional leaf area: a heavy Sigatoka attack scorches and kills much of the foliage before the bunch matures, so the plant cannot fill the bunch. Bunches are smaller, and the fruit tends to ripen prematurely and unevenly, often while still on the plant, which hurts quality and marketability. It is favoured by warm, humid, wet weather, dense plantings, poor drainage and crowded old leaves. Management combines spacing, drainage and deleafing to open the canopy, plus protective fungicide sprays in the wet season.
How to identify it
- Small pale-yellow or brown streaks running parallel to the veins on the leaf.
- Streaks enlarging into elongated spots with grey centres and yellow-to-brown margins.
- Spots multiplying and merging so large areas of the leaf dry and die.
- Much of the foliage scorched before bunch maturity, with smaller bunches and premature, uneven ripening.
What causes it and when
- Mycosphaerella fungi (yellow and black Sigatoka), spread by air- and rain-splashed spores.
- Favoured by warm, humid, wet weather and by dense plantings, poor drainage and crowded old leaves.
- Builds through the wet season and is worst where the canopy stays wet and closed.
- Carries over on infected leaves and debris on and around the plant.
Cultural & organic control
- Use recommended spacing and good drainage so the canopy is open and dries after rain.
- Remove (deleaf) and destroy severely spotted and dried leaves to cut the spore source.
- Avoid excess nitrogen and overcrowding, and keep the plantation weed-free for airflow.
- Plant clean material and manage the crop for vigorous, healthy foliage.
Chemical control
- Apply protective fungicide sprays in the wet season when the disease is active — CIB&RC-registered products for banana leaf spot, rotated to avoid resistance.
- Adding a recommended spray oil/sticker can improve cover on the waxy banana leaf.
- Cover the foliage well and repeat on the recommended schedule through the wet, humid period.
- Confirm the current product, dose and schedule for your area with your local KVK.
Prevent it coming back
- Make spacing, drainage and regular deleafing the routine to keep an open, drier canopy.
- Remove and destroy spotted old leaves and debris, and avoid overcrowding and excess nitrogen.
- Plan protective sprays for the wet season in plantations with a history of the disease, rotating groups.
Crops most at risk
Where this problem is called out in our crop guides — open a crop for the full package of practices.
Frequently asked questions
My banana leaves have streaks and spots and are drying up before the bunch is ready. What is it?
Those pale streaks along the veins that grow into grey-centred spots and dry large areas of the leaf are Sigatoka leaf spot, a fungal disease. Losing that leaf area before the bunch matures gives smaller bunches and premature, uneven ripening. Open up the canopy with spacing, drainage and deleafing, remove spotted old leaves, and apply protective fungicide sprays through the wet season.
Why does Sigatoka cause premature ripening of the fruit?
Because a banana plant fills and holds its bunch using its leaves, and Sigatoka destroys much of that leaf area before the bunch matures. With the foliage scorched and dying, the plant is stressed and cannot support the bunch normally, so the fruit tends to ripen early and unevenly — often while still on the plant — which lowers quality and marketability. Keeping the foliage healthy through bunch fill is the whole aim of control.
How do I reduce Sigatoka without relying only on sprays?
Focus on the canopy and moisture. Use recommended spacing and good drainage so the canopy is open and dries after rain, deleaf and destroy severely spotted old leaves to cut the spore source, keep weeds down for airflow, and avoid overcrowding and excess nitrogen. These cultural steps reduce how favourable the plantation is to the fungus, so the protective sprays you do use in the wet season work much better.
Symptoms and control measures follow ICAR, KVK and state agricultural-university package-of-practices; any named chemical is a registered use. Always read the product label and confirm the dose for your crop and zone. editorial policy.