Murder Mystery in the Garden: Are your Brassicas being destroyed by a super villain?

As gardeners, we get so excited when we plant our seedlings, tucking them into their garden beds and whispering sweet promises of the growth they will see. It’s only to be expected, then, that we get downright disheartened to find holes appearing, and are forced to stand by and watch as the plants we so lovingly nurtured are assassinated before our very eyes.

The culprits for this chain of criminal destruction? Two white butterflies – one small and the other rather large, producing two different kinds of cunning caterpillars. These butterflies are vagrant wanderers, and will happily lay eggs on all brassicas. The eggs can be hard to spot, especially on the green varieties, but are easier to detect on red cabbage.

Watson! Pass me my magnifying glass!

The caterpillars from the small butterfly are the general green variety, whereas the large butterfly caterpillars are hairy, yellow and black. I wouldn’t be surprised if you notice both on your brassicas!

Like many pests, the butterfly lays its microscopic yellow or white eggs underneath the leaves. The sneaky tactic of this villain is to camouflage them by also laying along the stem, which makes them almost invisible to the eye.

Vigilance is imperative, with regular inspections on the underside of brassica leaves to identify any potential eggs before they hatch. These scoundrels work fast and will evolve into very hungry caterpillars before you can even whip out your spray gun! Run your finger along the leaves and wipe the eggs off to scupper their plans.

If you buy your seedlings, I must also remind you here that it is vital to inspect your plants before you purchase them. In my 30+ years of experience, I have found around 80% of these seedlings bring pests or disease from the garden centre to YOUR garden. Don’t unwittingly make it so easy for the baddies.

How to stop this criminal mastermind from destroying your brassicas

There are two ways to successfully grow brassicas without falling victim to caterpillar carnage.

  1. Bring in some protection:

Net your plants when they go in the ground. A micro mesh is better than bird netting, as the cunning butterflies can make themselves small enough to slip through to achieve their dastardly end goal of laying eggs. 

  1. Enlist the help of a true heroine: Mother Nature herself

The other way is to craftily balance nature out by attracting beneficial insects, most specifically the mighty parasitic wasp, who are known to penetrate the butterfly larvae and suck the goodness out.

There are many plants that attract parasitic wasps – take your pick from Yarrow, Zinnias, Fennel, Dill, Queens Anne Lace, Alyssum, Cosmos, Statice and Thyme. Now is the perfect time to plant Alyssum, Fennel, Yarrow and Thyme, and in the spring months, you are able to plant the remaining ones. 

You will discover for yourselves, as you combine your vegetables with beneficial flowers, that Mother Nature truly is the only heroine you need on your side. When nature starts to balance out in your garden, the pests begin to take care of themselves, and so you can go back to watching your favourite crime series…

Remember when the flowers go to seed, just let them do their thing and they will start to repopulate themselves.

Happy Crime Solving – I mean, Happy Gardening!

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