First recorded in Napier in 1929. Most likely, it was transported in imported coolstore vegetables at the Port of Napier. The butterfly is considered to be a pest because humans enjoy the host plant, cruciferous vegetables (Brassicaceae) in most of its forms: broccoli, Brussels sprouts, cabbage, cauliflower, kale and turnips. Cattle and sheep are also fed many species of Brassicaceae in the winter when pasture is growing slowly.
Through trade and migration humans have helped to inadvertently spread the butterfly beyond its natural range, and through the domestication and diversification of these crops humans have provided it with the food the caterpillars need to flourish.
For vegetable gardeners, some control techniques are in this leaflet put together by Rob Herd.