During the vaccination, a solution containing a verticillium fungus is injected into the active sapwood of the tree at 10cm intervals around the circumference of the trunk. The injection initiates a defence response from the tree that allows it to fight off infection caused by the disease and reduces the chances of it dying if afflicted.
However, Waipā District Council community services manager Brad Ward said the vaccination came “too late” for the vulnerable tree.
“The tree had been in decline for a couple of years and the canopy had been pruned in an effort to improve its health.”
Dutch elm disease has claimed the life of a 100-year-old tree in Cambridge. Photo / Google Street View
In mid-December, symptoms began to show, and the council swiftly removed the tree on Cambridge’s Victoria Square as a precaution against further transmission.
“Monitoring of [the] council’s elm trees showed the tree had sudden browning of leaves and die-back of branches,” Ward said.
“We decided to remove the tree before the test results came back due to the timing of the discovery and contractor availability over the holiday period.”
He said the other elm trees in Victoria Square and around the town hall had been inspected and were currently in good health.
The council said with the confirmation of infection in the centre of Cambridge, it was possible there are other affected trees on private land.
The council said they were continuing to closely monitor the other elm trees in the district to watch for any further transmission of the disease.
All council-owned trees in the Waipā district have been vaccinated against Dutch elm disease. Photo / Waipā District Council
Dutch elm disease is spread by elm bark beetles, which carry the fungus from an infected tree and bore into new trees nearby.
However, it can also be spread via the trees’ connected root systems, by movement of firewood, or by contaminated pruning tools.
“The public should be vigilant and seek professional advice from an arborist if they are worried about their elm trees,” Ward said.
If residents suspect the disease is present on an elm tree, please report it to the Ministry for Primary Industries’ Exotic Pest and Disease Hotline on 0800 80 99 66.
