Hawke's Bay Regional Council releases butterfly to control manuka-smothering weed

Hawke's Bay Regional Council is using nature to control pests by releasing the white admiral butterfly in the Tūtira area this month.

Using nature to control pests is known as "biocontrol", says the regional council's team leader biosecurity Pest Plants Darin Underhill.

"Biocontrol is a really good way to control well-established weeds as it's environmentally sustainable and cost-effective," Underhill said.

"However, this kind of control can take a long time to achieve results. Weeds are not usually eradicated, but their spread and negative impacts are significantly affected," says Darin.

The white admiral butterfly is being introduced to control Japanese honeysuckle, a native Japanese and Korean weed which can smother plants such as mānuka.

"The butterflies' caterpillars feed on the plant and can reduce its smothering impacts," he said.

"The white admiral butterfly was only released in New Zealand after extensive testing which found that no native plants are at risk from it."

Japanese honeysuckle was brought to New Zealand as an ornamental plant because of its appealing flowers and fragrance, and has become a real issue for native plants, he said.

It's spread by birds, wind, bees, and human activity such as dumping garden waste.

The butterfly is being released in the Tūtira area, where the regional council is working with Maungaharuru-Tangitū Trust to reduce Japanese honeysuckle's smothering effect on native plantings.