Cabbage White Caterpillars
Pest · Commonly affects: Cabbage, Kale, Broccoli, Cauliflower, Brussels sprouts, Pak choi, Rocket
Cabbage white caterpillars are the larvae of large and small white butterflies, common visitors to UK vegetable plots. They feed chiefly on brassicas and can rapidly turn sound leaves into lacework. Several generations may occur through the growing season, so regular checks matter from late spring until autumn.
How to identify it
Watch for white butterflies fluttering over brassicas, then inspect leaf undersides for eggs and young caterpillars. Large white caterpillars are velvety, yellowish green with black markings and can reach about 45 mm. Small white caterpillars are usually green, velvety and up to about 30 mm. Look for ragged holes, dark droppings and caterpillars tucked along midribs or inside developing hearts. Eggs are commonly yellow and laid in groups or singly.
Damage
Caterpillars chew irregular holes in leaves and can strip outer foliage to the ribs. On cabbages, cauliflower and broccoli, droppings and hidden caterpillars may contaminate the edible heart or curd. Severe attacks weaken young plants, slow growth and make crops unattractive. Damage is often worst where plants are uncovered during warm periods of butterfly activity.
Prevention
Cover brassicas immediately after sowing or planting with fine insect mesh, securely weighted at the edges so butterflies cannot enter. Check that mesh does not rest tightly on leaves as plants grow. Rotate brassica beds where space allows, clear old crop debris and remove weed brassicas that may support caterpillars. Inspect purchased plants before planting. Grow a succession of sturdy seedlings and encourage insect-eating birds in the wider garden, while keeping netting safely tensioned.
How to manage it
Examine leaves, hearts and leaf undersides twice weekly during the season. Rub off eggs and hand-pick caterpillars into a container of water, paying particular attention to folded leaves and developing heads. Remove badly damaged outer leaves and dispose of them in household waste. Re-cover plants straight away after checking. Small outbreaks are usually manageable by persistence, and regular hand-picking prevents the next generation from becoming established.
Cabbage White Caterpillars: frequently asked questions
How do I identify cabbage white caterpillars?
Watch for white butterflies fluttering over brassicas, then inspect leaf undersides for eggs and young caterpillars.
How do I prevent cabbage white caterpillars?
Cover brassicas immediately after sowing or planting with fine insect mesh, securely weighted at the edges so butterflies cannot enter.
How do I get rid of cabbage white caterpillars?
Examine leaves, hearts and leaf undersides twice weekly during the season.
General guidance for UK home gardens and allotments, focused on prevention and non-chemical control. For a confirmed diagnosis, the RHS or a local garden centre can help. Page updated 19 Sep 2026.