Divisi
Rhizome rot
Pythium aphanidermatum · Fungal
Photo: Scot Nelson · CC0
Rhizome rot is a soil- and water-borne rot (caused mainly by Pythium, often joined by Fusarium) that attacks the underground rhizome and the collar — the point where the shoot meets the soil — of ginger, turmeric and banana. It thrives in warm, waterlogged, poorly drained soil and rides into a clean field on infected seed rhizomes, rotting the plant away from the base until it topples.
Scot Nelson · CC0 
Scot Nelson · CC0
Why it matters
Rhizome rot goes for the part you actually sell — the rhizome underground — so by the time the leaves tell you something is wrong, the crop below is often already spoiled. In a wet season on poorly drained land it can take up to 80% of your harvest, nearly the whole field. It is hard to beat once it starts because it lives in the soil and water and spreads plant to plant through waterlogged ground, so you cannot spray it away — the win is keeping it OUT and catching the very first sick plant before it seeds the whole field.
When to act
first yellowing shoots or soft rotting rhizomes detected in the field
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 rhizome rot field guide
- Identify it
- Scout for it
- Control it
15 field-guide sections in the app
The full guide to rhizome 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 rhizome rot?
The first thing you see (above ground): the lower, older leaves turn pale yellow, and the yellowing creeps upward up the plant. The shoot loses its stiffness and wilts even when the soil is wet — a plant that flops in damp ground is a warning sign.
When should I take action against rhizome rot?
first yellowing shoots or soft rotting rhizomes detected in the field
How do I control rhizome rot?
Prevent — start clean (most important): plant only certified disease-free seed rhizomes from a healthy crop; never replant rhizomes from a field that had rot. Handle them gently — any cut or bruise is a doorway for the rot — and let cut setts heal before planting.
Which crops does rhizome rot affect?
Among the crops covered here: Ginger, Turmeric.
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.
Check what grows on your farm