Divisi
Rodents
· Rodent
Photo: Robert Taylor · CC BY 4.0
Field and house rats and mice — above all the fast-breeding multimammate rat (Mastomys natalensis), the common grain rat of African fields — that dig up newly sown seed, gnaw through young stems, and strip maturing cobs, heads and stored grain. They shelter in burrows along bunds and field margins and in untidy stores, feed mostly at night, and multiply explosively after good rains, so a whole colony can hollow out a crop in patches both in the field and after harvest.
Marius Burger · CC0 
Marius Burger · CC0
Why it matters
Rats and mice can take up to a third of your crop (30%), and they hit you twice: they dig up the seed you have just planted, then eat the grain right when it is filling on the plant and again when it is in the store, after all your work is done. Once a colony is breeding in the bunds and field margins it is very hard to stop — they multiply fast after good rains, hide underground by day, and killing a few does nothing because more simply move in from your neighbours' land. That is why the answer is to act early, rat-proof your store, and work together with your neighbours, not to wait until they are everywhere.
When to act
fresh burrows, runways or cut tillers increasing, or visible gnawing on cobs and stored grain
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 rodents field guide
- Identify it
- Scout for it
- Control it
13 field-guide sections in the app
The full guide to rodents — 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 rodents?
The first sign, at planting, is gaps in your stand — hills or rows that never come up because the seed was dug out and eaten. Look for small holes and scratch-marks where the seed sat, and patchy, uneven emergence, often in bands running in from the field edge where the rats came in.
When should I take action against rodents?
fresh burrows, runways or cut tillers increasing, or visible gnawing on cobs and stored grain
How do I control rodents?
Prevent — starve them out and shut them out, with your neighbours. Keep field margins, bunds and channels weed-free and short, and clear crop trash, rubbish piles and spilt grain that hide and feed rats. Plant and harvest in one tight window together with your neighbours so ripe grain is never left standing for long. Make your store rat-proof: raise it on smooth posts fitted with metal rat-guards (a smooth metal collar the rat cannot climb past), use metal bins or well-sealed containers, plaster the walls smooth, and keep it tidy with no spillage. One farm alone cannot win — the real payback comes when the whole community does this together.
Which crops does rodents affect?
Among the crops covered here: Groundnut, 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