Divisi
Oil palm bunch rot
Marasmius palmivorus · Fungal
Photo: T.K. Naliaka · CC BY-SA 4.0
Oil palm bunch rot is a fungus (Marasmius palmivorus, a small toadstool) that rots the fruit bunch right on the palm, before you can harvest it. It spreads as white, cottony threads that creep over the bunch and grow in between the fruitlets, binding and rotting them; on badly-rotted bunches and on dead flower trash in the crown it sprouts tiny white mushrooms. It gets started on poorly-pollinated and aborted bunches left sitting in a damp, crowded canopy, then jumps fruit-to-fruit and bunch-to-bunch onto the healthy ones nearby.
T.K. Naliaka · CC BY-SA 4.0
Why it matters
Bunch rot attacks the one thing you grow the palm for — the fruit bunch — and rots it on the palm before you can cut it. In a wet season, in a crowded canopy with poor pollination, it can spoil up to 3 in every 10 bunches (30% of your crop), and the loss is doubly cruel: the palm still spent its potassium and its year building those bunches, but you get nothing from them. Worse, every rotting bunch you leave hanging in the crown feeds the fungus and throws its threads onto the good bunches beside it — so a few ignored bunches quietly become many.
When to act
cut out and carry away the very first bunch you find with white threads or rotting fruit — 1 rotten or aborted bunch left in the crown is enough to spread it — and clear every aborted, gappy or over-ripe bunch on sight
This guidance is general, compiled from published agronomic references including FAO and CABI. Thresholds and timing shift with your crop, your variety and the season.
In much of the region a spray is simply called mushonga — medicine. But a chemical group you cannot name is one you cannot rotate, and a product you did not write down has no pre-harvest interval you can observe. Mushonga, and other farming words →
The full oil palm bunch rot field guide
- Identify it
- Scout for it
- Control it
15 field-guide sections in the app
The full guide to oil palm bunch rot — every symptom to check, how and when to walk your field looking for it, and the controls that actually work, ranked. Built into your crop plan, so you are told to look before it costs you a harvest.
Crops it affects
Frequently asked questions
How do I identify oil palm bunch rot?
The first thing you see: a spread of white, cottony threads over the fruit bunch — like fine cobweb or a dusting of cotton — creeping down between the fruitlets and binding them together. Under and around the threads the fruit goes soft, brown and rotten, and the rot creeps outward from fruit to fruit across the bunch.
When should I take action against oil palm bunch rot?
cut out and carry away the very first bunch you find with white threads or rotting fruit — 1 rotten or aborted bunch left in the crown is enough to spread it — and clear every aborted, gappy or over-ripe bunch on sight
How do I control oil palm bunch rot?
Prevent it first — keep the pollinating weevil working (your strongest tool): a well-pollinated bunch fills up full and tight, with no gappy, seedless fruit for the rot to start on. Protect the male flowers (the weevils' breeding ground), and never blanket-spray insecticide over flowering palms — kill the weevils and you get half-empty bunches that rot. Good pollination is the cheapest bunch-rot control there is.
Which crops does oil palm bunch rot affect?
Among the crops covered here: Oil palm.
Catch it before it costs you a harvest
Divisi builds scouting into your crop plan — it tells you when to walk your field, what to look for at that stage, and what to do when you find it. Free for farmers, works offline.
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