Divisi
Fusarium head blight
Fusarium graminearum · Fungal
Photo: CSIRO · CC BY 3.0
Fusarium head blight (also called head scab) is a fungal disease of the cereal head. The fungus lives on old crop trash — especially maize stalks left on the ground — and its spores blow or splash up onto the wheat, sorghum, maize or finger-millet head just as it is flowering. If the weather is warm and wet at that moment, the fungus enters the open flowers, bleaches the head, shrivels the grain, and leaves behind hidden poisons (mycotoxins) that can make the grain unsafe to eat or sell.
Scot Nelson from Honolulu, USA · CC0 
Wikimedia Commons (public domain) · Public domain
Why it matters
Head blight strikes at the worst possible time — when your crop is flowering and setting grain — and a bad attack can take up to 40% of your harvest. Worse, it does not just cut yield: it hides a poison in the grain that can make it unfit to eat, feed to animals, or sell, so you can lose the crop even after you bring it home. And there is no cure once the head is infected — the only real chance to stop it is before and during flowering, in the few days when the weather turns warm and wet. That short window is why this disease is so hard to fix.
When to act
warm, wet or humid weather forecast around flowering (heading) in a susceptible crop
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 fusarium head blight field guide
- Identify it
- Scout for it
- Control it
14 field-guide sections in the app
The full guide to fusarium head blight — 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 fusarium head blight?
The first thing you see: one or two straw-coloured, bleached spikelets on a head while the rest of that head — and the whole plant — is still green. The bleaching starts at a flower and spreads up and down the head, so you often see a head that is half-green, half-dead.
When should I take action against fusarium head blight?
warm, wet or humid weather forecast around flowering (heading) in a susceptible crop
How do I control fusarium head blight?
Prevent — clean up the trash (your strongest, cheapest tool): the fungus survives on old maize and cereal stalks on the ground. Plough in, bury, or remove maize and small-grain residue before the next crop flowers, and never plant wheat directly after maize on the same land. Rotating away from cereals to a non-cereal crop (like a legume) starves the fungus of the trash it lives on.
Which crops does fusarium head blight affect?
Among the crops covered here: Finger millet, Maize, Sorghum, Wheat.
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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