Divisi
African armyworm
Spodoptera exempta · Insect
Photo: ChriKo · CC BY-SA 4.0
The African armyworm (Spodoptera exempta) is a migratory moth whose caterpillars erupt in sudden, dense outbreaks and march in "armies" across cereal and grass fields. Driven by rains following a dry spell, the young larvae feed together in huge numbers on the leaves of maize, sorghum, millet, wheat, rice and pasture grass, and can strip a young crop to bare ground within days before pupating in the soil and moving on.
Why it matters
African armyworm is a sudden-outbreak pest that can strip a young cereal or grass field to bare ground in just a few days — a bad attack can take your whole crop (up to 100% loss). It hits hardest at the seedling stage, arriving overnight in huge marching masses after the first rains, and the biggest caterpillars do the most damage in their final days before vanishing into the soil. Because the army marches in from surrounding fields and grassland, no one farmer can stop it alone — and by the time the damage is obvious the caterpillars are often large and hard to kill, so acting the moment they appear is everything.
When to act
Act immediately on reports of marching caterpillars or when young larvae are found feeding in numbers on seedlings and grass.
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 african armyworm field guide
- Identify it
- Scout for it
- Control it
16 field-guide sections in the app
The full guide to african armyworm — 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 african armyworm?
The damage you see first: whole patches of young cereal and grass stripped astonishingly fast — leaves eaten to ragged shreds or right down to the midrib, and bare ground where a green field stood a day or two before.
When should I take action against african armyworm?
Act immediately on reports of marching caterpillars or when young larvae are found feeding in numbers on seedlings and grass.
How do I control african armyworm?
Prevent — plant ahead of it: follow the early-warning forecasts and plant early and all at once with your neighbours, so your crop grows past the tender seedling stage before moth numbers peak. This cultural first line is cheap and it protects the whole area at once.
Which crops does african armyworm affect?
Among the crops covered here: Maize, Rice, 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.
Check what grows on your farm