Divisi
Cutworms
Agrotis ipsilon · Insect
Photo: USGS Bee Inventory and Monitoring Lab from Beltsville, Maryland, USA · Public domain
Cutworms are the fat, night-feeding caterpillars of several drab brown moths, most commonly the black cutworm (Agrotis ipsilon). They spend the day curled up in the soil and come out after dark to chew young leaves and — most damagingly — to sever seedlings clean off at ground level, felling them one by one. They attack a wide range of young crops including maize, tomato, cabbage, beans, tobacco and other vegetables, and are worst on land freshly cleared of grass or weeds, which carry their eggs and small larvae straight into the new crop.
USGS Bee Inventory and Monitoring Lab from Beltsville, Maryland, USA · Public domain 
USGS Bee Inventory and Monitoring Lab from Beltsville, Maryland, USA · Public domain
Why it matters
Cutworms are seedling killers. They come out at night and slice young plants off clean at ground level, so you wake to toppled seedlings and bare gaps in the row — and a cut seedling never grows back. A bad attack on a young field can cost you up to a third of your crop (30%) before it is even properly established. They are hard to stop once they start because the fat grey caterpillars hide in the soil by day, out of reach of any leaf spray, and each one goes on killing a fresh plant every night — so a clean, weed-free seedbed beats any cure.
When to act
Treat when 5 percent or more of seedlings are cut, or 2 to 3 larvae per square metre are found.
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 cutworms field guide
- Identify it
- Scout for it
- Control it
14 field-guide sections in the app
The full guide to cutworms — 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 cutworms?
The damage shows first. You will find young seedlings cut clean through at ground level, as if someone snipped them with scissors — the toppled plant often lies wilting right beside its own little stump, or it disappears altogether, leaving bare gaps and missing plants in patches along the row (usually several in a run, not one lonely plant here and there). Before they are big enough to fell a stem, the smaller caterpillars chew ragged notches and holes in the young leaves.
When should I take action against cutworms?
Treat when 5 percent or more of seedlings are cut, or 2 to 3 larvae per square metre are found.
How do I control cutworms?
Prevent it first — a clean, weed-free seedbed is your strongest and cheapest weapon. Cutworms ride into your field on the grass and weeds that grew before your crop. Plough your land and keep it completely weed-free for two to three weeks before you plant, so the larvae already in the soil are left with nothing to eat and starve or get picked off before your seedlings even come up. Never plant straight into freshly cleared grassland or a weedy field — that brings the worst attacks.
Which crops does cutworms affect?
Among the crops covered here: Cabbage, Maize, Tobacco, Tomato.
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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