Hardly have you planted cabbage when they appear: white butterflies dancing over the bed, and shortly after, riddled leaves. Cabbage is equally popular with two pests, and both can be kept in check without poison once you know them.
One is the cabbage white, a butterfly whose voracious caterpillars can strip whole plants bare. The other is the cabbage root fly, which works unseen below the soil and makes young plants wilt. This article shows you how to protect your cabbage from both.
Two enemies: butterfly and fly
The cabbage white lays its yellow eggs in clusters on the undersides of the leaves. From them hatch caterpillars that eat through the leaves at a furious pace. You recognise them by their yellow-black stripes and the characteristic holes.
The cabbage root fly is more insidious, because you cannot see it. It lays its eggs at the base of the stem, the maggots bore into the roots. Affected young plants wilt in the sun, stop growing and finally topple over. Against both there are simple, poison-free protective measures.
The protection tools
How to keep both pests away
- Protective net
The most effective means against both. A fine-meshed net laid closely over the bed from planting on keeps butterfly and fly out entirely. Weigh the edges down well with soil or stones.
- Collar against the root fly
A collar of felt or cardboard snugly around the stem base prevents the cabbage root fly from laying its eggs there. Simple, cheap and very effective with young plants.
- Pick off egg clusters
Without a net, check the undersides of the leaves and wipe off the yellow egg clusters of the cabbage white. Whoever finds the eggs need not hunt caterpillars later.
- Companion planting and beneficials
Fragrant neighbours like tomato, celery or herbs confuse the pests. And parasitic wasps as well as birds keep caterpillars naturally in check, see Companion planting.
How you protect your cabbage
Lay the net from the start
Right after planting, stretch a fine protective net over the bed and close the edges tightly. Laid later, the eggs are often already there.
Fit a collar at planting
Put a felt or cardboard collar around the stem of each young plant. That stops the cabbage root fly exactly where it wants to lay its eggs.
Check the leaf undersides regularly
Even under the net, check once a week. Pick off yellow egg clusters and young caterpillars before they do great damage.
Intervene biologically with heavy infestation
If hand-picking is not enough, a biological product based on Bacillus thuringiensis helps, which targets the caterpillars specifically and spares beneficials.
Net against the butterfly, collar against the fly, and a look under the leaves. Prevention beats any later fight.
The core rule for protecting cabbage
Frequently asked questions
How do I protect cabbage from the cabbage white?
Best with a fine protective net from planting on, which stops the butterflies reaching the plants at all. Without a net it helps to pick the yellow egg clusters off the leaf undersides regularly, before the caterpillars hatch.
What helps against the cabbage root fly?
A collar of felt or cardboard snugly around the stem base prevents egg-laying at ground level. A protective net protects additionally. Once the maggot is in the root, little can be done, so with this pest prevention is decisive.
Why do my young cabbage plants wilt?
If a young plant wilts in the sun although the soil is moist, the cabbage root fly is often behind it, whose maggots destroy the roots. Pull the plant gently, if it sits loose, the suspicion is confirmed. A collar at planting prevents it.
Does a net help against both pests?
Yes, a fine-meshed protective net is the most effective single measure and keeps off both the cabbage white and the cabbage root fly. It is important to lay it seamlessly from the start and weigh the edges down well, otherwise the insects slip underneath.
Do I have to spray against the caterpillars?
Usually not. Net, collar and picking off eggs are as a rule enough in the home garden. Only with heavy infestation is a biological product based on Bacillus thuringiensis worthwhile, which targets the caterpillars specifically and spares beneficials.
