Mango Anthracnose: How to Identify, Treat and Prevent It

Anthracnose is the most damaging disease of mango worldwide, and the one our AI is asked about more than any other during flowering and fruit set. It is caused by the fungus Colletotrichum gloeosporioides, thrives in warm, wet weather, and can quietly destroy a flush of blossom or spoil fruit weeks after it looks perfectly healthy on the tree.

This guide walks through how to recognise it, what to do about an active infection, and — most importantly — how to stop it coming back.

How to identify mango anthracnose

The fungus attacks young, soft tissue, so look at the parts of the tree that are actively growing.

Leaves: small, dark brown to black spots that enlarge and merge into irregular dead patches, often along the leaf margin or tip. Badly hit young leaves curl and drop.
Flowers (blossom blight): the flower panicle develops black streaks on its stalk (the rachis), blossoms turn black and die, and the whole panicle can be lost before a single fruit sets. This is the costliest phase.
Fruit: the tell-tale sign is quiescent infection — the fungus infects young fruit but stays dormant until ripening. You harvest clean-looking fruit, and days later sunken, dark, circular spots spread across the skin, sometimes with pinkish spore masses in the centre.

If you are seeing black panicles and dieback together, you are almost certainly dealing with anthracnose rather than a nutrient problem or pest.

What makes it worse

Anthracnose is a weather-driven disease. Spores spread in water, so risk spikes when:

humidity is high and leaves stay wet for long periods;
rain or heavy dew coincides with flowering and new flushes;
the canopy is dense and poorly ventilated, trapping moisture;
infected leaves, mummified fruit and dead panicles are left on or under the tree as a spore reservoir.

Because the trigger is moisture during susceptible growth stages, timing your response to the weather matters as much as the spray you choose.

How to treat an active infection

Prune and remove the source. Cut out blackened panicles, dead twigs and diseased leaves, and clear fallen leaves and mummified fruit from under the tree. Don’t compost them near the orchard.
Improve airflow. Open up a dense canopy so foliage dries quickly after rain or dew — this alone significantly lowers infection pressure.
Apply a protectant fungicide on a schedule. Copper-based fungicides and mancozeb are widely used protectants; during flowering, growers often rotate in a systemic such as a strobilurin or a triazole to protect new blossom. Always follow the label rate and pre-harvest interval for your region, and rotate chemistry to avoid resistance.
Protect the fruit through to storage. Because infection is quiescent, post-harvest hot-water treatment is commonly used to stop spots appearing after picking.

How to prevent it next season

Spray preventively, not reactively. Begin protectant sprays as panicles emerge and continue through fruit set, tightening the interval in wet weather.
Sanitise in the off-season. Remove mummified fruit and prune out dead wood so the fungus has nowhere to overwinter.
Space and prune for light and air. An open canopy that dries fast is your cheapest, most durable defence.
Choose tolerant varieties where anthracnose is a perennial problem in your area.

Diagnose your tree in seconds

Not sure whether those black spots are anthracnose, bacterial black spot or simply sunburn? Snap a photo of the affected leaves, panicle and fruit with VVF CropDoctor and get an instant, weather-aware diagnosis — spoken and written in your language, and reviewable by a real agronomist. It factors in your local rainfall and humidity, which is exactly what anthracnose risk depends on.

This article is general guidance, not a substitute for local extension advice. Always follow product labels and local regulations when applying any fungicide.