Auckland could be facing the loss of some of its pōhutakawa trees to myrtle rust if infection levels seen this summer continue, researchers say. Photo / George Novak
Auckland could be facing the loss of some of its pōhutakawa trees to myrtle rust if infection levels seen this summer continue, researchers say. Photo / George Novak
Auckland could be facing the loss of some of its pōhutakawa trees to myrtle rust if infection levels seen this summer continue, researchers say.
Myrtle rust, a windborne fungal disease, kills trees in the myrtle family; pōhutakawa, mānuka, kānuka, swamp maire, ramarama and rōhutu.
And the number of pōhutakawa treesinfected in Auckland this summer was “unprecedented”, Landcare Research said.
The first case of the disease on Rangitoto Island was also discovered, a particular concern because the island had the world’s largest pōhutakawa forest.
Myrtle rust is “a slow-acting” disease and the full extent of infections may not be understood for several years.
“If the uptick in infection severity ... is anything to go by, this is only the beginning,” Landcare Research said.
The evidence came from a citizen science platform called iNaturalist, where members of the public had reported cases of myrtle rust.
A recent University of Auckland survey also revealed some trees were experiencing a “particularly high level of infection”.
“If this level of infection keeps happening every myrtle rust season, then we could potentially lose some of these trees,” Beyond Myrtle Rust research programme leader Dr Mahajabeen Padamsee said.
“My daughter has learned songs about the pōhutukawa tree at school [and] I want her to be able to see these trees when she grows up,” Padamsee said.
“The real worry is that the infection might interfere with seed production.
“We’ve seen from ramarama and rōhutu that once the bud and seedpods are infected, they don’t go through their reproductive cycle.”
Summertime conditions were ideal for myrtle rust to thrive - and every year since the disease first arrived here from Australia in 2017, the number of serious infections had spread to different tree species.
Summertime conditions were ideal for myrtle rust to thrive - and every year since the disease first arrived here from Australia in 2017, the number of serious infections had spread to different tree species.
Padamsee said swamp maire was badly impacted last season and anecdotal evidence showed pōhutakawa were hard hit this summer.
Myrtle rust is “a slow-acting” disease and the full extent of infections may not be understood for several years, Padamsee said.
Endemic myrtle trees [only found in] Australia have already been going extinct because of the disease, Padamsee said.
