Ground beetle

How to recognise it

Fast-running shiny black or metallic beetles, 1-3 cm, that scuttle for cover the moment you lift a stone or a board. Long legs, powerful jaws, never fly much.

Mistaken for

Constantly mistaken for a pest because they are big, black, and found in the soil where damage happened - the classic case is finding one near a chewed plant and blaming it. They are pure predators and eat the things that did the chewing, along with slug eggs and weed seed.

What it eats

Slugs and snails, Cutworm, Cabbage root fly, Carrot fly, Vine weevil, Colorado beetle

How to attract it

Permanent undisturbed cover: a strip of rough grass, a plank or stone left in place, mulch, a beetle bank. They hunt at night and need somewhere to hide by day. Minimal digging.

Plants that help

Straw or compost mulch

Lifecycle

One generation a year, adults living two to three years. Both larvae and adults hunt in the soil surface layer.

Months: March, April, May, June, July, August, September, October

The thing people get wrong

This is the reason a beer trap set flush with the soil is a bad idea: ground beetles fall in and drown, and they are the main thing eating slug eggs underground. Leave a plank on the soil at the edge of a bed - lift it in a week and you will find your night shift.