NZ ‘may have lost myrtle rust battle’
Scientist fears action on fungus has come too late to save some species
New Zealand may have “lost the battle” in beating myrtle rust, a top scientist fears, and the official leading the response against the serious plant disease says we could be facing the loss of some vulnerable species.
But there’s now some hope that manuka, the lifeblood of our $300 million manuka honey industry, could fare better than first thought against the wind-blown scourge.
The fungus attacks and can seriously affect myrtle species plants, including some significant natives such as pohutukawa, manuka, feijoa, bottlebrush, kanuka and rata.
First found in a Kerikeri nursery in May, it has now been confirmed at more than 100 sites across Taranaki, Te Puke, Waikato, Northland, Auckland and Wellington.
Authorities have met the threat with a large biosecurity response involving 100 people on the ground and millions of dollars in new research.
The coming warmer summer months, offering ideal conditions for spread, will prove crucial for the fight.
Landcare Research scientist Dr Andrea Byrom fears efforts may be doomed.
“It doesn’t mean we shouldn’t be having as good a crack at it as we can . . . [but] given where in the country it’s been found so far, we may have lost that battle.”
Ministry for Primary Industries (MPI) incident controller Catherine Duthie said the incursion had been unfolding at a rate that was expected.
It wasn’t yet clear how bad the situation could get.
One assessment produced by the Government in 2011 warned large areas of the country could be affected and, at one extreme, some species could die on a “landscape scale”, as had happened in other countries.
In Australia, the fungus has had different levels of impact on myrtle species and has caused the extinction of several plant species of significance to Aboriginal Australians.
“The worst-case scenario is we may lose some particularly vulnerable species like Bartlett’s rata, particularly as they exist in the wild and because
The worst-case scenario is we may lose some particularly vulnerable species. Dr Andrea Byrom Landcare Research
there’s only a few individuals left,” Duthie said.
“What we are thinking is there’s likely to be genetic diversity within populations where some species will be resistant — and of course, there will be less impacts in the cooler regions of the country.
“But it’s absolutely too early to tell at this point . . . the Australians have been dealing with it for almost a decade and they are still learning.”
An incursion the like of myrtle rust had never been seen before in New Zealand.
“This is unusual for rust, in that it impacts multiple species — rusts are usually very specific — so it’s unprecedented.”
Its eventual detection triggered an eleventh-hour seed-banking effort around the country, with the Department of Conservation directing hundreds of officials to collect seeds of more than 30 native plant species.
There are some positive signs for manuka. Officials have searched more than 8500 manuka plants and only turned up one infected plant.
Byrom directs the col- laborative Biological Heritage National Science Challenge, which, shortly before myrtle rust hit, had funded a multidisciplinary research project aimed at boosting the preparedness of New Zealand’s biosecurity system for an incursion of the pathogen.
While the MPI has said it had long had a “wellstructured and rehearsed” sys- tem for biosecurity incursions like myrtle rust, the Herald is aware of frustration among scientists, with some questioning why a specific strategy wasn’t put in place when the disease was first found in Australia in 2010.
“We should be planning ahead — and we should have planned further ahead,” said Byrom.
Anyone believing they have seen myrtle rust on plants in NZ are asked to call MPI on 0800 80 99 66.
It is important for people not to touch the plants or try to collect samples as this would spread the disease.
People can also check for and report myrtle rust using the new bilingual Myrtle Rust Reporter smartphone app.