Cabbage root fly

What you see

Nothing visible above ground until it is too late. Pull a failing plant and you find white legless maggots and a chewed, blackened root stump.

Damage

Young transplants wilt in the midday sun and recover overnight, then stop recovering. Blue-tinged, stunted leaves. The plant lifts out of the soil with almost no root.

Lifecycle on this coast

Two or three generations from April. Eggs are laid in the soil right against the stem base; the maggots eat the fine roots and then the taproot.

When to act

Zero tolerance on transplants - a plant that loses its roots does not come back. Protect at planting time.

Months: April, May, June, July, August

Plants it bothers

Cabbage, Broccoli, Cauliflower, Curly kale, Brussels sprouts, Turnip, Radish, Savoy cabbage

Natural enemies

Ground beetle, Rove beetle

Remedies

Cabbage root fly collars, Insect mesh and fleece barrier, Encourage predators

The thing people get wrong

Every year people water a wilting young cabbage harder and harder, convinced it is drought. It is almost always this. A cardboard collar at planting costs nothing and stops it outright - and a wilting brassica that perks up at night but not by day has told you exactly what is wrong.