What is kauri dieback?
Kauri dieback is a microscopic ‘fungus-like’ plant disease (pathogen) that only affects kauri and can kill them. Its botanic name is Phytophthora taxon Agathis (PTA).
Download a fact sheet about the science behind PTA (156 KB)
What symptoms do affected kauri have?
Symptoms of PTA include yellowing foliage, leaf loss, canopy thinning, dead branches and even death of the entire tree. Affected trees can also develop lesions that bleed resin, extending to the major roots and sometimes girdling the trunk as a ‘collar rot'.
Kauri tree showing thinning branches. Source: Auckland Regional Council
How is it spread?
PTA is a soil-borne species - spread by soil and water movement, plant-to-plant transmission through underground root-to-root contact, human and animal vectors.
Where did it come from?
Its closest known relative is a chestnut pathogen from Korea (Phytophthora katsurae). The assumption is that it is an exotic pathogen, possibly tropical in origin. However, nothing is known about this particular species overseas.
Which kauri does it affect?
So far there appears to be no resistance to the disease and it can affect and/or kill kauri of all ages and sizes - from saplings to long-lived trees.
Where is it?
The disease has been isolated from soil in Northland and the Department of Conservation is currently carrying out more soil testing to confirm where the disease may have spread to.
The disease has also been found recently in the Rodney District and North Shore City and has also been identified in the Waitakere Ranges and Great Barrier Island
How can I stop PTA spreading?
- Make sure your shoes and equipment are clean of dirt before visiting kauri forest.
- Clean your shoes and any other equipment that comes into contact with soil after every visit, especially if you intend to visit other bush areas.
- Keep to tracks at all times. Any movement of soil around the roots of a tree has the potential to spread the disease.
- Keep your dog on a leash at all times. Dogs can inadvertently spread the disease if they disturb the soil around the trees.
More research into PTA control methods is being conducted by Landcare Research with funding support from the Auckland Regional Council.
What should I do if I have kauri on my land?
- Minimise movement around kauri roots.
- Keep dogs and animals away from kauri as much as possible.
- If you think kauri on your land have symptoms of PTA disease, contact the contact the Kauri Dieback Response Team on 0800 NZ KAURI (69 52874).
- Erect a warning sign to alert your visitors to the dangers of spreading the disease. This can be laminated to make it more durable.
Download 'protect our kauri' A4 sign (141 KB)
If you need a more durable sign, please contact the Kauri Dieback Response Team on 0800 NZ KAURI (69 52874).
Will parks or reserves be closed?
At this stage there are no plans to close parks or reserves, but it is something we may have to consider in the future.
What is being done?
The Kauri Dieback Response Team is currently:
- Assessing the risk posed by the organism to individual trees and their ecosystem.
- Determining methods and their feasibility to limit the spread of the pathogen through the application of appropriate measures.
- Collecting further information to inform a response decision (how widespread and what we can do about it).
- Ensuring a coordinated inter-agency approach to Phytophthora taxon Agathis including the appropriate management of communications and information.
In October 2009 the Minister of Conservation, Hon Tim Groser announced that the Government is to inject $4.7 million into a programme to help save kauri trees threatened by a disease known as kauri dieback (Phytophthora taxon Agathis).
The five-year programme will cover research into the detection and spread of kauri dieback and methods to control it. A public awareness campaign to arrest its spread will also be developed.
Read the full press release
For further information about Kauri dieback:
A joint agency response with:
MAF Biosecurity New Zealand, Auckland Regional Council, Department of Conservation, Environment Bay of Plenty, Waikato Regional Council and Northland Regional Council