Divisi
Maize ear rot
Fusarium verticillioides · Fungal
Photo: Scot Nelson, Honolulu, USA · CC0
Maize ear rot is a group of moulds (led by Fusarium, with Aspergillus, Stenocarpella and Penicillium) that rot the cob, usually creeping in through the silks or through wounds punched by stalk borers, earworms and birds. Worse than the yield it eats, several of these moulds make mycotoxins — invisible poisons (fumonisins, aflatoxins) — that make the grain dangerous for people and livestock, so keeping it out of the field and drying fast are everything.
University of Illinois at Urbana-Champaign (UIUC) · CC BY-SA 3.0 nl 
Terry Price, Georgia Forestry Commission, Bugwood.org · CC BY 3.0 us
Why it matters
Ear rot can rot away up to 40% of your maize, but the real danger is hidden: the mould makes mycotoxins — poisons you cannot see, smell or wash off — that can sicken your family and your animals and get grain rejected at the market. Once a cob is rotting there is no spray that will cure it, and the moulds keep growing in the crib if the grain goes in even slightly damp, so a small problem at harvest can spoil a whole store. That is why this pest is won or lost before it starts — with a clean, healthy, well-dried crop.
When to act
Manage preventively; inspect cobs near maturity and harvest and dry promptly once mould appears, keeping mouldy grain out of food and feed.
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 maize ear rot field guide
- Identify it
- Scout for it
- Control it
16 field-guide sections in the app
The full guide to maize ear 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 maize ear rot?
The first sign is usually at the tip of the cob or at any spot an insect or bird has bitten: peel back the husk and you see a felt-like mould growing over the kernels and in the gaps between them, and the grain underneath is dull, shrunken and light as chaff instead of hard and full.
When should I take action against maize ear rot?
Manage preventively; inspect cobs near maturity and harvest and dry promptly once mould appears, keeping mouldy grain out of food and feed.
How do I control maize ear rot?
Prevent first — this is your strongest tool. Grow a tolerant hybrid with tight husk cover. Choose a variety known to resist ear rot whose husks wrap the cob tip snugly and stay closed, so rain and insects cannot reach the silks and kernels. Loose, open, upright cobs collect water and invite the mould.
Which crops does maize ear rot affect?
Among the crops covered here: Maize.
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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