He aha te mana koiora?

What is biocontrol?

Pest plant biocontrol is the act of introducing a natural enemy to control a pest plant. These natural enemies are either insects or pathogens. Once released in a new region, they are referred to as biocontrol agents.

How biocontrol has been used so far

Many biocontrol agents have been successful at controlling their host plants in Tāmaki Makaurau / Auckland to date. You may remember when ragwort was common around the region. Introduction of the tiny ragwort flea beetle has significantly reduced ragwort over the years.

Other notable agents include the mistflower rust fungus and the tradescantia leaf beetle, which are making their way around the region.

Biocontrol benefits

  • Long-term sustained control of the pest plant to low densities.
  • Native flora regeneration and improved biodiversity at site.
  • Cost-effectiveness.
  • Reduced reliance on herbicides.
  • Overall reduction in the dominance and impacts of widespread pest plants in the region.

Biocontrol safety

Each potential biocontrol agent is subject to years of testing to ensure it is safe to release. This includes examining whether it will feed on desirable plants or have any negative interactions with other native insects or birds.

How to introduce new biocontrol

An application to release a biocontrol agent must be approved by the Environmental Protection Authority (EPA) before we can release it in the New Zealand environment.

See the EPA website for information about the process of safely bringing a biocontrol agent into Aotearoa.

Biocontrol agents available for release in Tāmaki Makaurau / Auckland

We are currently actively releasing and monitoring:

How to suggest a site for a biocontrol release

Contact pestfree@aucklandcouncil.govt.nz if you have a good spot in mind for biocontrol agents.


  • a description of the site
  • an estimation of the size of the infestation
  • a photo.

You will need to consider that biocontrol is a long-term management tool and not a quick fix. Once an agent is established it can provide sustained control of a site for years to come.