Jackfruit fruit rot (Rhizopus soft rot)
A soft, watery, rapidly spreading rot starting from a wound, insect entry point or the stalk end of a ripening fruit — a badly affected jackfruit collapses within days in warm, humid weather.
- Pathogen
- Fungus (Rhizopus stolonifer)
- Enters through
- Wounds, insect entry points, the stalk end
- Favoured by
- Warm, humid, wet weather
- Main risk
- Whole fruit collapsing within days once started
Overview
Jackfruit fruit rot is caused by the fungus Rhizopus stolonifer, a common and fast-acting mould that enters ripening or ripe fruit through any break in the rind — a wound from a fruit borer or fruit fly, a bruise from rough handling, or the natural opening at the stalk end. Once inside, it spreads through the soft flesh extremely quickly in warm, humid weather, turning the tissue soft, watery and discoloured, often with a visible whitish-grey fungal growth on the surface.
This is one of the biggest sources of loss on jackfruit, since the fruit is large, heavy, thin-skinned once ripening starts, and does not keep for more than a few days even when healthy. A single small wound can turn into a fully collapsed, unsellable fruit within days, which is why prevention — prompt harvest at the first ripening signs, careful wound-free handling, and control of the borers and flies that create entry points — matters far more than any treatment once rot has begun.
How to identify it
- A soft, watery, discoloured patch starting at a wound, insect hole or the stalk end of a ripening or ripe fruit.
- Rapid spread through the flesh — a small patch can consume the whole fruit within a few days in warm, humid weather.
- A visible whitish-grey fungal growth on the surface of the rotting area as it develops.
- A sour, fermenting smell from an advanced infection.
What causes it and when
- The fungus Rhizopus stolonifer, present widely in the environment, entering only through a break in the rind rather than through unbroken skin.
- Common entry points are fruit-borer or fruit-fly damage, bruises and punctures from rough handling or dropping, and the natural stalk-end opening on an over-ripe fruit.
- Favoured strongly by warm, humid, wet weather — the same conditions common around the main ripening season in most of jackfruit's growing range.
Cultural & organic control
- Harvest promptly at the first genuine ripening signs rather than letting fruit over-ripen on the tree, where it is more likely to develop entry wounds and rot before it is even picked.
- Control fruit borer and fruit fly, since the wounds they create are common entry points for the rot.
- Handle fruit gently at every stage — cutting, carrying, packing — since even a small bruise or puncture can start an infection.
- Remove and destroy any rotting fruit promptly, rather than leaving it near sound fruit, since spores spread easily in storage or transport.
Chemical control
- There is no practical fungicide cure once rot has set into the flesh of a fruit meant for fresh eating.
- For high-value export or processing operations, a post-harvest fungicide dip or treatment recommended by the local horticulture extension can reduce losses in storage — confirm current-approved products before use.
Prevent it coming back
- Build harvest timing around the fruit's own ripening signals rather than a fixed calendar, so fruit is picked before it becomes vulnerable to wounds and over-ripening.
- Keep the borer and fruit-fly programme running through the fruiting season, since their damage is the main door this fungus uses.
- Train pickers and handlers in gentle handling, padded crates, and prompt sale — speed to market is itself a form of prevention for this fast-acting rot.
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 jackfruit was fine yesterday and today has a soft, collapsing patch. Is this normal?
That is almost certainly Rhizopus soft rot, and its speed is exactly why it catches growers off guard — once the fungus enters through a wound, it can spread through the whole fruit within a couple of days in warm, humid weather. Remove and destroy the affected fruit promptly and check nearby fruit for wounds or early signs.
Is there a spray that prevents this rot on the tree?
There is no practical preventive fungicide spray for fresh-market fruit — the real prevention is controlling the fruit borer and fruit fly that create the entry wounds, harvesting promptly once ripening signs appear rather than letting fruit over-ripen, and handling every fruit gently to avoid bruises and punctures.
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.