Butterflywatch: Large white caterpillars thrive on perennial kale | Butterflies

I came home from a week’s vacation to find my lush patch of kale had turned into pale skeletons. Everywhere I looked, large white caterpillars were marching, looking for more leaves. They even ate my wild rocket.

This is the dreaded “cabbage white” that many gardeners detest. The caterpillars of the similar-looking small white cabbage white also feed on cabbages, but are usually solitary and seem to cause less damage. And the green-veined white cabbage white, often incorrectly called cabbage white, does not feed on cabbages at all.

I have been growing perennial kale for 10 years and large whites have often laid eggs on the plants but the caterpillars have never developed. I had assumed that these tougher perennial leaves were not tasty to hungry caterpillars.

So it is strange that in one of the worst summers ever for butterflies I have been feeding a growing large white population. But nature has a way of finding a balance and a large proportion of these caterpillars are parasitized by small wasps and will never emerge as late summer butterflies.

Like most insects, butterfly populations often decline and then recover quickly. The hope is that this year’s apparent slump – caused by persistent rains in the first half of the year, but exacerbated by the climate crisis, agrochemicals and habitat loss – will be followed by a rebound. On the crop of ’24 – including large whites – that will leave a larger generation next year.