Myrtle rust appears as yellow spores. Photo / Supplied
Myrtle rust appears as yellow spores. Photo / Supplied
While some growers feel like they have dodged a myrtle rust bullet, others have concerns that the plant disease will kill off native flora.
Myrtle rust was found for the first time in New Zealand five years ago, posing a threat to native species.
The Bay of Plenty was oneof the first regions impacted, and it soon became obvious that the disease could not be contained. It became widely dispersed throughout the North Island.
The disease has been reported throughout the region, including Tauranga and Rotorua, and threatens native myrtle species such as pōhutukawa, mānuka and rātā.
But NZ Feijoa Growers Association manager Ian Turk said the industry had since been struck off the list of at risk.
"We've dodged a bullet there. We're just keeping an eye on it."
Comvita head of industry affairs Tony Wright said while it monitored for the disease across the whole of its mānuka operations there had been no issues.
The response had shifted from containment to research in 2018, and late last year the Government announced a Jobs for Nature-funded collaboration.
Conservation Minister Kiri Allan said the disease posed a threat to some of the most abundant native myrtle species, as well as a threat to the mānuka and kānuka honey industry.
There were two projects, including one in the Bay of Plenty, to focus on monitoring myrtle rust infestation, mapping its spread and ramping up the propagation of plants showing the most resistance to the disease.
She said the effects of the disease were becoming increasingly apparent.
"Overseas experience indicates localised extinctions are something we need to be prepared for."
It led to a loss of biodiversity, which in turn impacted the wider ecosystem and cultural identity, she said.
The project, based in Rotorua, would identify where the most vulnerable myrtle species are in native forests in the Bay of Plenty region, determine the extent of each population and record the incidence and severity of myrtle rust within them.
Cuttings will be taken and seed collections started with the intention of establishing a resistance-breeding programme.
Scion was leading the recently launched project and Kāuru co-leader Mariana Te Rangi said many of the things New Zealanders enjoy could disappear if the disease spread out of control.
Death of mature ramarama trees had been recently observed in the East Cape and the disease was escalating in the Bay of Plenty.
Scion scientist Heidi Dungey said while the work would not prevent infections, it would help with understanding when and where the most susceptible myrtle species were within the region and provide ways to support them.
Biosecurity New Zealand's Pest Management Group manager John Sanson said not all native myrtle species were equally susceptible to myrtle rust.
"While plants like mānuka, kānuka and rawiri mānuka, show some level of resistance, other native species like pōhutukawa, rātā and swamp maire (waiwaka) are more susceptible to the disease."
If people suspect they have found myrtle rust they should photograph it and send the photo to the iNaturalist website, where experts can check and confirm whether the observations are correct, he said.
What is myrtle rust?
Myrtle rust is a serious fungal disease that affects plants in the myrtle family.
Plants in the myrtle family include New Zealand's native pōhutukawa, mānuka, rātā, and some common ornamental garden plants like bottlebrush and lilly pilly.
Myrtle rust spores are microscopic and travel large distances by wind, or by insects, birds, people, or machinery.
It is believed that wind carried spores here from Australia, where myrtle rust was first found in 2010.
The fungus has spread rapidly since the first case in New Zealand was identified in 2017.
It was first found in the Bay of Plenty in June 2017
