Import of Australian wasp approved to fight invasive shrub

December 1, 2022
A bud-galling wasp.

An Australian wasp will soon be found in the Manawatū-Whanganui region as authorities try to control the spread of an invasive plant.

The Environmental Protection Authority announced today it has approved the import and release of the bud-galling wasp.

It comes after the Horizons Regional Council applied in August to have the wasp imported to help control the spread of Sydney golden wattle.

The bud-galling wasp is only a few millimetres long and does not sting or bite.

"These wasps are quite docile and are only active for a few weeks a year. They prefer to remain near the host plant, further reducing any possible risk to our native plants and animals," the EPA's Chris Hill said.

Sydney Golden Wattle.

He added the arrival of the wasps will reduce the amount of pesticides needed to control Sydney golden wattle.

Hill explained the wasps lay their eggs in the wattle's flower buds, inducing abnormal growths and preventing seed production, effectively stopping its spread.

"This will in turn reduce fire hazards, increase water availability and attract native animals."

The Sydney golden wattle, which is native to Australia, was introduced to New Zealand in the 19th century and has spread throughout the North Island. It has significantly reduced the biodiversity of dunes and wetlands - some of the country's most threatened environments.

The EPA publicly consulted on the decision, with the majority of submissions in favour of the importation and release of the wasps.