New Zealand’s largest pohutukawa has been infected with myrtle rust – leaving local iwi fearing they could be among the last of some 24 generations to live with the famous tree.
Myrtle rust is a fungus that attacks and can seriously affect myrtle species plants, including some significant natives such as pohutukawa, manuka, kanuka and rata.
First found in a Kerikeri nursery in 2017, it’s since spread across the North Island and to the top of the South Island.
Now, it’s been reported the fungus has infected what’s held to be our greatest pohutukawa: Te Waha Rerekohu, or the mouth of Rerekohu.
Found at Te Araroa on the North Island’s East Coast, and under the guardianship of hapu Te Whānau a Hinerupe, the sprawling tree spans nearly 40m wide, stands almost 20m high, and is thought to be hundreds of years old.
Its plight was described in a social media post by Graeme Atkins, a Tikapa resident who served as a Department of Conservation ranger on the East Coast, and who’s since been seconded to a local myrtle rust-focused project under the Jobs for Nature programme.
“World famous as one of the largest and finest specimens of his kind, our pohutukawa has seen twenty four generations of locals born live and die around him,” Atkins said.
“To think that we could be the last generations to have the presence of our rakau rangatira amongst us is pretty sobering.”
Atkins said he first found myrtle rust three months ago, on some leaves on a small branch lower down the tree.
“Since then, myrtle rust has been found on several parts of the rakau with recent drone footage confirming rust on the upper parts of the rakau.”
A recent bout of humid weather had “wreaked havoc” with pohutukawa in the wider East Cape and Cape Runaway area, he said, with many seedlings and saplings struggling with the constant reinfections.
“This same area has already lost three native myrtle species since the arrival of myrtle rust five years ago.”
They included ramarama, Lophomyrtus bullata, Rohutu, Lophomyrtus obcordata and Akakura, Metrosideros colensoi.
“This last species was a personal favourite of mine with its spectacular weeping foliage.”
He said the only “shining light” in the saga was the myrtle rust project, named Te Whakapae Ururoa, and employing seven people over three years.
The project involved establishing long-term monitoring lines, or transects, that had many native myrtles along them.
“Infected myrtles are scored for percentage of coverage of the rust on them and overall health. These lines are revisited monthly,” he said.
“Tracking these lines through time and space will provide good data on the impact that myrtle rust is having on our native myrtles and our Taiao in general.”
The Herald has contacted Atkins for further comment.
When myrtle rust was first found in New Zealand, authorities launched a full-scale biosecurity response to try to prevent its spread.
Within months, however, it became apparent that the disease was widely dispersed, with winds carrying its spores over large distances.
In May 2018, the Government closed its response and moved its focus to finding ways to manage the disease in the longer term.
This month, Scion scientists revealed they’d found a new way to quickly detect myrtle rust days before plants show signs of infection, providing hope that nurseries in the future can start control treatment much sooner and stop disease outbreaks in their tracks.