Our magnificent, ancient taonga kauri are under threat from kauri dieback.
Stop the spread – stop soil movement.
Kauri dieback has been found in Northland, Auckland and on Great Barrier Island but is not widespread in the Waikato region, with only a few sites on the eastern Coromandel (Whangapoua, Hukarahi and Tairua).
Kauri dieback is caused by the microscopic soil-borne organism Phytophthora agathidicida (PA). It affects kauri of any age by infecting and damaging its feeder roots, which cuts nutrients to the tree. Nearly all trees infected with it will die, making protecting trees from this organism extremely important.
How is it spread?
A pin-head of soil is all that’s needed to spread the disease. The organism causing kauri dieback produces spores, which are only spread via soil. It can move between trees via root contact and over tiny distances in wet soil. Oospores, its long-lived survival structures, can survive away from kauri roots for at least three years in infected soils. Spread of the organism is naturally slow. Its long distance spread is mainly via human activity and animals.
Because kauri dieback is not widespread in the Waikato region, it is a high priority to reduce further spread of the disease by stopping the movement of any contaminated soil.
Recognising the symptoms
Kauri infected with kauri dieback may have yellowing leaves, a loss of leaves and thinning canopy, dead branches, or lesions and gum bleeding around the base of its trunk. However, kauri can exhibit symptoms like these for other reasons too. The only way to confirm whether a tree has kauri dieback is through sampling and analysis of the soil around them. To report kauri that have these symptoms either REPORT THIS PEST or freephone 0800 NZ KAURI (0800 695874).
This autumn contractors BioSense are injecting phosphite into more than 2500 infected kauri near Whangapoua. While not a cure for the disease, research has shown that phosphite will boost a kauri's immune system and help them to fight back against the disease.