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  Services » Regional Services » Plant and animal pests » Pest plants » Kauri dieback

Kauri dieback

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Our magnificant taonga, Kauri, are being attacked by a disease for which there is no cure.

Being an ancient species of tree, kauri unfortunately do not have the ability to ward off  the nasty new invader that causes kauri dieback (Phytophthora agathidicida). Sadly, once infected, the tree will die. 

It is up to all of  us to help prevent the spread of  this deadly  incurable disease. 

Kauri dieback can be found on Great Barrier Island, in Northland and Auckland and, in 2014, it was confirmed to be on the Coromandel. Fortunately, other than the Coromandel sites (Whangapoua & Hukarahi) no other sites have been identified in the Waikato region.

On this page 

What causes kauri dieback?

Kauri dieback is caused by a tiny microscopic organism which lives in the soil, known as Phytophthora agathadicida. The disease is specific to kauri trees and kills them by destroying their feeding roots, which in turn starves the tree to death.

What are the symptoms?

The main symptoms you might see is a thinning canopy, or bleeding around the base of the tree.

Canopy Gum bleeding
A thinning canopy with only outer leaves remaining Gum bleeds at the base of the tree's trunk
Yellow and/or browning leaves Typically the bleeds will be an upside down U from the ground
Retained dead branches  

Kauri can exhibit these symptoms for other reasons as well.  The best way to find out for sure if a tree has kauri dieback is to have regional council staff take soil samples and have them analysed.  To do this phone 0800 NZ KAURI (0800 695874).

How is the disease spread?

The disease is spread through soil - even a pin prick of soil can shift the disease. The main movers of the disease are thought to be people, pigs, and cattle, but really anything that can move soil can also move the disease.

How can we stop the spread of the disease

The best way to stop the spread is to prevent any soil movement. This means:

  • stay on marked tracks.
  • avoid going near kauri; if you are near kauri, stay at a distance of at least three times the size of the tree canopy - this is where the kauri roots are.
  • always clean you and your equipment / machinery of soil (click here for machinery hygiene quidelines).
  • fence of your bush, this will have a bunch of other biodiversity benefits as well as protecting your kauri (contact one of our catchment management team if you'd like to fence off bush on your farm, there may be funding opportunities - call 0800 800 401).
  • if you're taking your dog into the bush, either keep it on it's lead or wash it before leaving the bush.

Advice for rural landowners:

  • fence stock from bushed areas
  • keep existing fences well maintained
  • consider convenanting area with kauri
  • keep stock away from areas with kauri, especially when muddy
  • avoid using machinery when conditions are muddy, and ensure machinery coming on to your property is clean
  • know where stock you are buying is from, don't purchase stock from kauri areas
  • ask hunters to clean all gear thoroughly
  • ensure any visitors clean shoes thoroughly.

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About the disease - Phytophthora agathadicida

The organism which causes kauri dieback is a new-to-science organism called Phytophthora agathadicida

This soil-borne organism specifically affects kauri trees and kills them by destroying their feeding roots, effectively starving the tree to death. Although the disease is new -to-science (formally  identified in 2009), the disease is known to have been infecting kauri since the 1950's.

These organisms are tiny: 3 microns or three ten thousandths of a millimetre.

Click here for more on ‘the science behind kauri dieback.(external link)

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