6 March 2019

Japanese honeysuckle to get butterfly attack treatment in Bothamley Park

Honshu White Admiral butterflies will be on the offensive in Bothamley Park in Porirua to help slow the spread of the destructive Japanese honeysuckle.

Porirua City Council and Greater Wellington Regional Council worked together to get 1500 White Admiral caterpillars released into the park last month, as part of a trial across the region.

Regional council biosecurity officer Megan Banks says the Japanese honeysuckle is a particularly noxious weed, as it is a climber and can smother and kill native plants when it forms into a dense mass.

“There are a number of infestations in Bothamley, which is hindering the natural regrowth of native bush,” she said.

“Some of the areas are difficult to access, which makes controlling the honeysuckle by normal methods tough.”

The butterflies are an example of a biological control insect from the home country of a plant, released to feed on it and stop the plants’ rapid growth.

Rigorous testing was carried out by the Environmental Protection Authority to ensure the butterflies will not affect any other New Zealand native plants, Ms Banks said.

“If the insect successfully establishes over time, it reduces the need and amount of herbicide required to be used to control the plants and helps to give the advantage back to the native plants.”

Porirua City Council landscape architect Andrew Gray says the butterflies are natural and sustainable.

“They keep on working year after year with no further funding required, where chemical sprays only have a short term impact,” he said.

Ms Banks said butterflies have also been released in Upper Hutt, Wellington and Otaki, beginning early in 2017.

Caption: The Honshu White Admiral butterfly has been released in Bothamley Park to combat the Japanese honeysuckle.

Facts about the Honshu white admiral:

- Endemic to the Japanese island of Honshu

- First imported into NZ by Landcare Research for testing in 2010

- Permission to release the butterfly granted in 2013

- Adult butterflies emerge in the spring.

- The white admiral is very distinctive, with white markings on top of the wings.

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