Cabbage white butterfly

If you’ve grown cabbages, or a host of other plants in the cabbage family (broccoli, cauliflower, pak choy, kale and more), you’ll most likely have come across cabbage white butterfly. The butterflies don’t do any damage – it’s their babies that make a mess of things. The tiny green caterpillars eat cabbage leaves and turn into big fat green caterpillars that have a voracious appetite!

The plants are susceptible to attack at any stage, even when they are seedlings. A few munches could wipe them out overnight, so you need to be onto this pest from day one.

One of the best tactics is to cover your plants with pest exclusion netting. It’s a simple set-and-forget approach because the butterflies can’t land on the leaves to lay their eggs. You can find the nets online and from garden centres in a range of sizes to suit the dimensions of your beds. They are light enough to sit on the plants without doing damage, or you can set up a simple frame to support the net – try using PVC electrical conduit or something similar.

Nets aren’t the only way to keep caterpillars at bay. Dipel (Bacillus thuringiensis) is a very effective organic control that doesn’t affect other insects or animals. Simply mix up the powder according to directions and spray all surfaces of the plants, top and bottom. Keep in mind, you will need to reapply it every 10 days or so to maintain protection.

You can also pick off the caterpillars by hand. If you see a nibbled leaf, examine both sides to find the culprit. While you’re at it, keep an eye out for tiny, pale single eggs or small clusters. Each egg removed is one less caterpillar making a meal of your cabbage. It’s laborious, but effective.

One last approach, for when it’s already too late and your brassicas are being hammered by hungry munchers, is to spray them with natural pyrethrum for an instant knockdown.

Header image by iStock