As soon as you see those pretty white “snowflakes” dancing around above your cabbages you know the caterpillars will be only a week away.

The creamy-white eggs usually hatch within eight days, depending on the temperature, and the caterpillars that emerge are a distinctive grey-green with yellowish stripes and black dots.

These can strip the leaves from your cabbages and other brassicas such as sprouts and cauliflower frighteningly quickly.

They even eat the leaves of swedes, turnips and nasturtiums.

Meanwhile, the Small Cabbage White butterfly’s caterpillars are a plump velvety-green and eat their way through to the heart of the cabbage – making them more difficult to detect.

The best way to deal with both types of caterpillar is to check the underside of cabbage leaves regularly and if you see any eggs just wipe them off with a damp cloth.

This will give you the best results, but if you have rows and rows of brassicas you can also spray them with a pyrethrum-based insecticide.

Covering your cabbages with a fine-mesh insect-proof netting can also help, but they are not very pretty and are rarely a match for determined butterflies!