Cutworms: how to spot and manage them

Cutworms are the fat, soft caterpillars of certain moths. They hide in the soil by day and come out at night to chew through seedling stems right at ground level — often felling a whole seedling and leaving it lying there.

How to spot them

1. Seedlings cut clean off at the base overnight.
2. Fat, greasy grey-brown caterpillars that curl into a C when you disturb them.
3. Found just under the soil surface near the fresh damage.

Plants they target

Growing any of these? See our guides to tomatoes, carrots, beetroot, potatoes and sweet corn.

Young seedlings of almost anything — tomatoes, brassicas, beans and corn.

How to manage them, safely

1. Put a collar around each seedling stem — a toilet-roll tube or a cut-down cup pushed into the soil — simple and very effective.
2. Go out at night with a torch and pick them off, or sift the top few centimetres of soil by day.
3. As cutworms are caterpillars, Bacillus thuringiensis (Bt) works too; and keep beds weed-free before planting.

For the bigger picture, see our guide to managing pests and problems safely.

Plan your patch: our free planting calendar shows what to plant now where you live. Ready to grow? Browse our raised garden beds or build your own with the garden bed builder.

Image: InsektenDoku, CC BY-SA 4.0, via Wikimedia Commons.