Cabbage white butterflies—Pieris rapae—are one of the most common garden visitors across southern and eastern Australia. The butterfly looks elegant in white with black dots on its wings: females have a pair of black spots and males a single spot on each forewing. But their velvety green caterpillars are ravenous beasts on brassicas—the plant family that includes common vegetable crops such as cabbages, cauliflowers, broccoli, kale and bok choy.