Fruit Rot

Symptoms by part

Causes

• Prolonged periods of high humidity
• Frequent rainfall during the fruit development stage
• Poor air circulation within the tree canopy
• Physical damage to the fruit skin from insects or birds
• Overcrowded fruit clusters that trap moisture

Could be confused with

• Sunscald · Sunscald creates bleached or leathery patches on the side of the fruit facing the sun, whereas rot is soft, mushy, and often fuzzy.
• Insect damage · Insect feeding leaves distinct holes or tunnels, while rot presents as spreading, decaying tissue without necessarily having a clear entry point.

Treatment

1. Remove and destroy all infected fruit immediately to stop the spread of spores.
2. Prune away crowded branches to improve airflow through the canopy.
3. Thin out fruit clusters so they do not touch each other.
4. Clean up all fallen debris from the ground beneath the tree.

Without chemicals

• Prune the canopy to increase light and air movement.
• Thin fruit to ensure adequate spacing.
• Sanitize pruning tools with alcohol between cuts to prevent spreading spores.
• Install a rain cover or protective bagging over individual fruits if the tree is small enough.

Chemical options

• Potassium bicarbonate, mix with water and spray on developing fruit to alter the surface pH, follow the label.

Preventing it

• Keep the area under the tree clear of fallen fruit and leaves.
• Maintain a regular pruning schedule to keep the canopy open.
• Manage insect populations that might create entry wounds for the fungus.
• Ensure the tree is planted in well draining soil to reduce overall humidity.

When to act

Act as soon as you notice the first dark, water soaked spots on the fruit. If the infection has spread to the majority of the fruit or the main branches, remove the affected parts immediately to save the rest of the tree.

Questions people ask

Can I eat fruit that has a small spot of rot?

It is best to discard the fruit entirely, as the fungal threads often extend deeper into the flesh than what is visible on the surface.

Will the rot go away if the weather turns dry?

Dry weather will slow the progression of the disease, but it will not cure the existing rot, so you must still remove the infected fruit.

Plants it affects

• Breadfruit
• Jackfruit