Battle for Brassicas

Cruciferous winter vegies are beloved by all, including unwanted pests. How do we stop them from stealing our precious bounty? Horticulturist and owner of online store Aussie Gardener, Brian Chapman shares his tips.

If you've had a go at growing anything from the brassica family like broccoli, cauliflower, cabbage and kale, you certainly know the heartache of finding your plants decimated by voracious caterpillars.

The culprits can be hard to spot, camouflaging well against the leaves, but their trail of destruction is unmissable.



Not all caterpillars are to blame. The most common pests of brassicas are the larvae of the Cabbage White Butterfly (Pieris rapae) and Cabbage Moth (Plutella xylostella).

Here are some organic ways to control this pest:

Sacrificial planting

If you like sharing, plant a sacrificial crop nearby. Indian mustard (Brassica juncea) is particularly attractive to the Cabbage White Butterfly, often preferring it over other brassicas. The somewhat romantic idea is that they will lay eggs on the mustard and the young caterpillars will feed on those plants rather than the other brassicas you want to eat.

NOTE: By doing this, you are also enabling the increase of the Cabbage White Butterfly population which your neighbouring veggie gardens may not appreciate too much.

Organic sprays

An organic spray, like Dipel (Yates) is frequently used for caterpillars. It contains an insecticide from beneficial bacteria found in the soil, on plant surfaces and also in insects. Unlike most sprays, it specifically targets caterpillars but doesn’t harm beneficial insects like bees. It is safe for birds, fish, mammals and pets. It does take a few days for them to die though so you may still see caterpillars hanging around, even after spraying.

Netting

Use a protective cover over your crop. This option involves no sprays and is a simply a case of limiting access to the plants you want to protect. Fine-mesh netting allows enough sunlight to still get through but stops insects from reaching the crop. Brassicas aren’t producing fruit so don’t need access from bee for pollination. The part we are eating is the leaves in the case of cabbage and kale, and the flowerhead for broccoli. Nets are often available in fairly large sheets to cover rows of vegetables.



Aussie Gardener Store have taken this a step further and developed a neat and effective way for covering brassicas, the Pestfree Shorty. It is a complete kit that includes heavy duty black PVC pipe, connectors, netting and matching clips, making it not only easy to set up but also looks quite stylish in the veggie patch.

For more information, visit aussiegardener.com.au/pestfree. Use the code: GARDENCLINIC to receive $10 off your purchase of a Pestfree cover.



No matter which method you choose, the key is to start early, preferably as soon as you plant your seedlings, otherwise you may find those little white butterflies doing a dance above your plants, readying their young for the growing feast.