You can help
Find out about DOC's work and how you can help to eradicate the butterfly.
Why it's a pest
The great white butterfly (Pieris brassicae) has been declared an unwanted organism in New Zealand under the Biosecurity Act 1993. It is a significant pest of brassica crops in numerous countries across Europe and western Asia. Its caterpillars feed voraciously, reducing host plants to a skeleton.
The butterfly can fly long distances – sometimes hundreds of kilometres – so will spread further through New Zealand if not stopped.
Risk to native and cultivated brassica plants
The great white butterfly could have serious consequences for the survival of many of our native cress species. New Zealand has around 79 native cress species, 57 of which are at risk of extinction.
It is far more destructive to plants than the common small white butterfly. Great white butterfly catterpillars feed in groups, rapidly reducing plants to a skeleton.
As well as being a menace in home gardens, the great white butterfly poses a threat to commercial brassica vegetable crops - it could cost the country millions of dollars to protect these from the pest butterfly if it became widespread in New Zealand.
Brassica crops are important in New Zealand, with about 4000 hectares of vegetable brassicas grown, worth approximately $80 million per year, and a rapid expansion in production of forage brassicas. Forage brassicas are grown mainly for dairy production with around 300,000 hectares now grown annually, mostly in Canterbury.
Cultivated brassicas include cabbage, broccoli, cauliflower, rape, swedes, Brussel sprouts and turnips.