The white butterflies you see fluttering around the veggie patch lay eggs that hatch into leaf-munching caterpillars. 

Stop butterflies laying eggs

To prevent damage, the key is keeping the butterflies off your crops in the first place. Use a fine mesh or netting to create a physical barrier over your plants. Make sure it allows enough light through while blocking the butterflies.

Some gardeners plant companion flowers like marigolds near their vegetables. While this won’t fully stop caterpillars on its own, it can help reduce butterfly activity around the garden and encourage beneficial insects.

Check plants regularly for caterpillars

Even with mesh in place, it’s important to check your plants often. Look for caterpillars or eggs and remove them by hand. A strong spray of water from the hose can also help dislodge them.

While numbers peak through spring and summer, caterpillars don’t completely disappear in winter. In milder regions, you can still find caterpillars feeding on winter brassicas, just at a slower pace. That’s why year-round checking is worthwhile.

Alternative Treatment

If caterpillars are widespread, there are targeted caterpillar control products available that work by being eaten by the caterpillars as they feed on the leaves. These are commonly used on edible crops and are designed to affect caterpillars without harming bees or other beneficial insects when used as directed. Your local garden centre can help you choose the right option for your garden and the time of year, and explain how and when to apply it for best results.