Wednesday, 23 July 2025 13:55

EPA approves biological controls for noxious weed

Written by  Staff Reporters
Darwin’s barberry is a resilient noxious weed found in disturbed forests, pastures, shrubland and short tussock-land. Darwin’s barberry is a resilient noxious weed found in disturbed forests, pastures, shrubland and short tussock-land.

The Environmental Protection Authority (EPA) has approved a rust fungus and a flower weevil to control Darwin’s barberry, a spiny invasive shrub.

Environment Canterbury, on behalf of the National Biocontrol Collective, applied to use two biological control agents to combat Darwin’s Barberry in New Zealand.

Darwin’s barberry is a resilient noxious weed found in disturbed forests, pastures, shrubland and short tussock-land. It is considered a threat to indigenous ecosystems throughout the country, as well as pastures where livestock graze.

Standard control methods like herbicides or weeding can prove costly, impractical and harmful to the environment.

It is native to Chile and Argentina and was introduced into New Zealand as a garden plant in the 1940s. Fruit-eating birds deposit seeds far from the parent bush, increasing its spread.

The plant can be found throughout New Zealand – particularly in the Canterbury, Otago, and Wellington regions.

The proposed biocontrol agents could also be used to target Darwin’s barberry elsewhere in the country.

Both the flower weevil and the rust fungus proposed for introduction are native to South America.

All organisms new to New Zealand must receive approval from the EPA before being released into the New Zealand environment.

Dr Chris Hill, general manager of hazardous substances and new organisms at the EPA, says the independent decision-making committee approved the introduction of the new organisms following “rigorous, evidence-based assessment”.

“The applicant’s risk assessment showed that these agents are highly unlikely to harm native plants or animals,” Hill says.

“The weevil does not bite or sting, so there is no health risk to people, and the rust fungus is also benign,” he adds.

Hill says the decision followed public consultation, engagement with mana whenua, and consideration of international best practice.

“New Zealand has a strong track record of using biological control agents to manage invasive weeds with minimal impact on native ecosystems," he concludes.

More like this

EPA's plan 'not good enough'

The Environmental Protection Authority (EPA) is bolstering its frontline applications teams in a bid to reduce the timeframe for new product applications, but agri chemical producers say that it isn't good enough.

Featured

National

Machinery & Products

» Latest Print Issues Online

The Hound

Badge of honour!

OPINION: This old mutt thinks New Zealand should take a bow after winning the ‘Fossil of the Day’ award at COP30…

A hungry world

OPINION: The Hound reckons the argument run by the ‘agribusiness elite’ that the market will punish our exports if we don’t…

» Connect with Rural News

» eNewsletter

Subscribe to our weekly newsletter