Are the leaves of your cabbages riddled with holes or reduced to their veins? The culprit may be the cabbage white butterfly. This pretty white butterfly is harmless, but its caterpillars can quickly devour brassicas. Netting, leaf inspection, hand-picking, and biodiversity: here’s how to protect your vegetable garden naturally.
What you should know
- The cabbage white can be present from April to October, with several generations per year.
- A properly installed insect-proof net is the most reliable preventive protection.
- Regularly inspecting the undersides of leaves helps remove eggs and young caterpillars.
- Companion planting and plant-based preparations can complement prevention, without guaranteeing total protection.
Cabbage White Butterfly: Why Should You Monitor Your Garden?
The genus Pieris includes several species of white butterflies. The adults nectar at flowers and contribute to garden life. However, it is their caterpillars that pose problems in the vegetable garden.
The most well-known is the cabbage white butterfly, Pieris rapae. Common across Europe, it is also found in parts of North Africa and Asia.
It primarily targets plants in the brassica family. Head cabbage, cauliflower, broccoli, kale, kohlrabi, turnip, and radish can serve as its pantry.
Identify the eggs and the caterpillars
The female of the cabbage white typically lays yellow eggs in clusters on the leaves. After hatching, the caterpillars stay together at first before dispersing.
They are recognizable by their green-yellow bodies speckled with black. Very voracious, they can gnaw leaves down to the large veins. Their droppings can also stain the heart of the cabbages.
Don’t confuse the Cabbage White with the Turnip White
Another common species is the Turnip White, Pieris rapae, also nicknamed “the little white of the cabbage.”
Smaller, it generally lays its eggs separately. Its green caterpillar is more discreet, but it can also cause significant damage on cabbages and other brassicas.
When does the cabbage white butterfly lay its eggs?
The cabbage white typically overwinters in the form of a chrysalis. The first adults appear in spring, and several generations may follow through to autumn.
The monitoring period generally runs from April to October, with activity often peaking in summer. Timing varies by region and weather conditions.
As of early July 2026, egg-laying and very young caterpillars were observed in several cabbage crops in Normandy. Warm, dry, sunny weather favors butterfly activity.
So it’s best to check plants at least once or twice a week. Look at both the tops and undersides of the leaves, but also the heart of young cabbages.
How to Fight the Cabbage White Butterfly Naturally?
To avoid chemical insecticides, it’s best to combine several methods. Prevention is easier than dealing with an established colony.
1. Install an insect-proof net
The insect netting is the most reliable preventive solution. Put it up at planting time, before the butterflies arrive.
Set it up on hoops so it doesn’t touch the leaves. A cabbage white could lay eggs through the mesh if the foliage stays pressed against the net.
Close the sides tightly and regularly check for holes. Before installation, inspect each plant to avoid trapping eggs or caterpillars under the protection.
A mesh of 4 to 7 mm is usually sufficient against butterflies. A finer mesh will also protect cabbages from flea beetles and other small pests.
2. Remove eggs and caterpillars by hand
In a small garden, hand-picking is simple and effective. Crush the eggs or remove the affected leaf portion. Cabbage white caterpillars are not stinging and can be picked with gloves.
Act as early as possible. A few eggs are much easier to manage than a colony of hungry caterpillars.
3. Preserve the natural enemies of the cabbage white
Insectivorous birds, certain spiders, ground beetles, and parasitoid wasps help regulate the caterpillars.
One of these tiny wasps, Cotesia glomerata, parasitizes the cabbage white caterpillars. Its cocoons look like small yellow or white clusters. If you see them near a caterpillar, leave them be: valuable allies are at work.
To attract these predators, maintain a variety of flowers, hedges, and some less-managed areas. Avoid broad-spectrum insecticides, which also kill useful species.
4. Test companion planting with realism
Garlic, onion, and other aromatic plants can disrupt host-plant finding by certain insects. You can plant them near cabbages, as well as thyme, rosemary, sage, celery, or lemon balm.
This plant diversity is beneficial for garden balance. It does not replace netting or regular leaf inspection.
5. Use nasturtium as an attractive plant
The nasturtium can also host cabbage whites, as it is among their host plants. Some gardeners use it as an attractive trap, keeping it away from the cabbages.
This technique requires careful monitoring. A nasturtium loaded with eggs could become a true caterpillar reservoir. Regularly remove eggs and heavily infested leaves.
It fits easily in a square-foot garden, where it also attracts pollinators.
6. Spray plant-based preparations as a supplement
Nettle tea, tomato-based preparations, or tansy infusion are sometimes recommended to disrupt the butterflies.
However, their effectiveness is variable and less well-established than netting. Treat them as a supplement, never as the sole protection.
Avoid spraying on flowers and do not treat when bees are present. Tansy also contains active compounds: handle with care and keep preparations out of reach of children.
7. Reserve Bacillus thuringiensis for strong outbreaks
In case of heavy infestation, some biocontrol products contain Bacillus thuringiensis, particularly subspecies kurstaki or aizawai. They mainly act on very young caterpillars.
Use only an approved product for the intended use and strictly follow its label. Spray only the affected plants, without touching surrounding vegetation.
Even though it’s organic, this treatment can affect other butterfly caterpillars. It should therefore remain a targeted solution, used after preventive measures.
Should you eliminate all cabbage whites from the garden?
No. The adult butterfly contributes to pollination and the caterpillars feed several animals. A few chewed leaves on healthy cabbages does not necessarily justify intervention.
The goal is to keep damage at an acceptable level. Prioritize protecting young plants and vegetables whose cores are just forming. Elsewhere, a little tolerance helps preserve the garden’s biodiversity.
Also read:
Seasonal Gardening: What to Do in the Garden This Month?
