Pictured are Great White Butterfly caterpillars. Chapmen says, "These are very voracious feeders, formerly destined to progressively destroy New Zealand’s brassica crops, and capable of reducing plants to skeletons. Full marks to New Zealand’s vegetable growers, their grower organization, Vegetables NZ, the vegetables innovation board, and the Government, particularly the Department of Conservation (DOC), for launching the programme that has run for three and a half years to eradicate the Great White Butterfly.” 

He notes that DOC was particularly concerned about the Great White Butterfly, as it posed a major threat to 79 native cress species, especially the 57 at risk of extinction. “The public of Nelson also played their part, reporting butterfly finds and keeping an eye out for them in their gardens,” he adds.

Chapman says that the eradication of the Great White Butterfly is a world-first achievement.

New Zealand’s vegetable growers funded research into how to eradicate the butterfly, and DOC used innovative programmes to speed up the eradication, including offering school children $10 for each dead butterfly. Another innovation was the use of a modified garden ornament to attract butterflies, and then net them. DOC rangers carried out more than 263,000 searches of around 29,000 properties in the region for the butterfly and its eggs, caterpillars, and pupae.

An independent assessment estimated that a New Zealand-wide butterfly infestation could cost the country $43 million to $133 million a year in control costs.

“So thank you to everyone, particularly DOC and the public of Nelson, for helping eradicate the Great White Butterfly. We are most appreciative.”

Source: Horticulture New Zealand