An infamous presence on most unprotected crops.
Many thanks for your recent message regarding the problems you’ve been experiencing with caterpillars ravaging your brassica plants. The chances are your plants have been decimated by the hairy, yellow/black caterpillar larvae of the cabbage white butterfly, an infamous presence on most unprotected crops.
However, help is at hand for future crops! Heavy Duty Butterfly Netting with a 7mm mesh has been used with great effect at our own Harrod Horticultural Kitchen Garden this year, and we have no reports of any caterpillar damage to the cabbages, broccoli, Brussels sprouts and cauliflowers we’ve been growing. This netting has been used in conjunction with the Freestanding Heavy-Duty Steel Vegetable Cage and is one of this season’s success stories. We also supply an organic caterpillar control, Nemasys Caterpillar Killer . This method of biological control uses a nematode, steinernema carpocapse, which enters the caterpillar on contact and releases a bacteria which proves fatal to the caterpillar. The nematodes are applied by watering can or sprayer and must come into contact with the caterpillar to work. The nematodes are naturally occurring, will only kill the caterpillars and have no knock-on effect in the food chain.
That’s next year taken care of, but what for now? The news is not good, as there is likely to be a second wave of caterpillars present now and through September, so you could try the nematode based Caterpillar Killer now before taking steps to protect your crop next year. You might also wish to physically squash any of the yellow conical eggs which are laid on the plants leaves, and also hand-pick off any caterpillars in the meantime. Hopefully this information is of help: further reading is available in the Kitchen Garden Section of the Website