Even if you are growing your brassicas under netting, it’s worth doing a check for caterpillars as we move through summer. Be sure to look at all your brassica plants – broccoli, cabbages, cauliflowers, sprouts and kale. Interestingly, we seem to find that they are less interested in Curly Kale, but quite keen on Cavolo Nero and Red Russian Kale. Check turnips and swede too.
Look at leaves for signs of caterpillar damage – i.e holes
Where you see holes, you will probably see caterpillars, either one or two, or a cluster. Check the underside of leaves too. You can pick caterpillars off and pop them into a bucket – we normally take them down to the bottom of the garden and empty them out with lots of hole-filled leaves to nibble on until they find a new home, there are plenty of nasturtiums around for them to eat!
Check for eggs
These will usually be small dark green (slightly slimy looking) eggs laid on leaves OR hidden in the very centre of the plant (look carefully!) Or they could be tiny white/yellow clusters of eggs laid on the underside of leaves. You may also see individually laid tiny white/yellow eggs. Use dampened kitchen roll to wipe off eggs. You could also try squirting them off, using a hose, from the centre of plants where it is hard to reach. Remove as many as you can.
Cover them with insect proof mesh netting or fleece
Butterflies are still laying, and it’s better safe than sorry! It only takes a small cluster of caterpillar a few hours to destroy a single plant, and they grow up so fast and will just keep on munching until they pupate a few days later, so be aware!
If you do lose some plants to caterpillars, there is still time in June/July to re-plant many of the brassicas – kale plants, cauliflower and cabbages can all be re-planted. You also have another window of opportunity for planting extra brassicas like broccoli and turnips/swede in September and October.