Cabbage White Caterpillars is a common pest that affects kale, broccoli, cabbage in Scotland. Here is what it looks like, how to spot the damage, and which controls have been tested.

A large white butterfly caterpillar, yellow and grey-green with black speckles and fine pale hairs, on a leaf stalk.
Large white (Pieris brassicae). sannse, CC BY-SA 3.0
A small white butterfly caterpillar, plain velvety green, resting along the midrib of a leaf.
Small white (Pieris rapae). James K. Lindsey, CC BY-SA 3.0

What does it look like?

Large white caterpillars are yellow and black with obvious hairs; small white caterpillars are pale green and covered in short, velvet-like hairs.

🌱 Plants at risk

Cabbage White Caterpillars also affects these crops in our grow guide:

Symptoms

RHS: 'Holes are eaten in the outer leaves of all brassicas and damage may also be seen on the inner leaves of cabbages when the heart is cut through.'

Controls: what actually works

Every method below is graded by evidence, not by how often it gets repeated. Where a claim has been tested and failed, we say so plainly.

✓Evidence-based

Physical barrier — grow brassicas under fine netting or horticultural fleece to exclude adult butterflies

RHS: 'Growing brassicas under fine netting or horticultural fleece can exclude adult butterflies.'

Same logic as carrot fly: exclude the adult and there are no larvae. Barriers are the one control that works on both of the site's brassica insect problems.

✓Evidence-based

Tolerate populations

Tolerate them where you can: they feed parasitoid wasps, social wasps and birds. Accepting some damage lets natural predation do the population control for you.

✓Evidence-based

Inspect regularly and hand-pick eggs and caterpillars

Inspect regularly to catch infestations early, and hand-pick eggs and caterpillars.

Checking leaf undersides for egg clusters before they hatch is the high-leverage version — one wipe removes what would be dozens of caterpillars.

✓Evidence-based

Biological control — pathogenic nematodes

Pathogenic nematodes are among the recommended controls.

◦Traditional — untested

Proprietary repellent product (not named — see policy)

One proprietary repellent product is also recommended. We do not name it. The option is described here so you know it exists, without us endorsing or linking a specific brand.

Get your sowing and planting dates rightMany pests hit hardest at the seedling stage. Time your sowing to give plants the strongest start.
Planting Calendar →

Frequently asked questions

What should I do first if I find cabbage white caterpillars in my garden?

Start with physical barrier — grow brassicas under fine netting or horticultural fleece to exclude adult butterflies. After that, tolerate populations. The full list of evidenced controls is above, each graded by how much evidence supports it.

Will cabbage white caterpillars kill my plants?

They rarely kill established plants. The damage is usually cosmetic on outer leaves, and natural predators often bring numbers under control without you doing anything.

Should I just leave cabbage white caterpillars alone?

In most gardens, yes. cabbage white caterpillars are food for birds, wasps and predatory insects, and a healthy garden carries some without trouble. Tolerance is also the official position now, and the stance box above sets out that reasoning in full.

Sources

1 source, recorded with what each was used for
  • RHS1: biodiversity framing and tolerance advice, five species, large/small white caterpillar identification, damage description, netting/fleece, hand-picking, pathogenic nematodes, proprietary repellent