Kauri dieback: how you can help

What is PTA?

Phytophthora taxon Agathis is a microscopic "fungus-like" plant pathogen. PTA only affects kauri.

What does it do to kauri trees?

Symptoms include yellowing of foliage, loss of leaves, canopy thinning, dead branches and tree death. Affected trees can also develop lesions that bleed resin, extending to the major roots and sometimes girdling the trunk as a ‘collar rot'.

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How is it spread?

PTA is a soil borne species - spread by soil and soil 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.

Does it kill all trees?

Yes. So far there is no resistance to the disease and it kills trees of all ages and sizes, from saplings to long lived trees.

Where is it?

So far in the Waitakere Ranges it has been identified along the Maungaroa Ridge at Piha, at Huia and the Cascades - Kauri.

The disease has also been identified as present on Great Barrier Island, and has also been isolated from soil in Northland. Recently it has also been found in Rodney District and North Shore City.

How can we stop it spreading?

Make sure your shoes and equipment are clean of dirt before visiting kauri forest.

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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 control methods is being conducted by Landcare Research with funding support from the ARC.

Standard Operating Procedures are in place for all ARC staff, contractors and volunteers. These will be on the website soon.

What should I do if I have kauri on my land?

If you think trees on your land have symptoms of kauri dieback contact the ARC Biosecurity team on 09 366 2000 or 0800 80 60 40 or biosecurity@arc.govt.nz
Minimise movement around kauri tree roots
Keep dogs and animals away from kauri trees as much as possible
Download a warning sign and put it up to alert visitors to the dangers of spreading the disease

Protect our kauri A3 sign (91.3 KB PDF)

Protect our kauri A4 sign (82.3 KB PDF)

If you need a more durable sign please contact the ARC Biosecurity team on 09 366 2000 or 0800 80 60 40 or biosecurity@arc.govt.nz