An anniversary, but not a celebration
Five years this month myrtle rust, an invasive and potentially destructive fungal disease affecting plants of the myrtle family, including iconic New Zealand trees pōhutukawa and mānuka, was first found in NZ. Jenny Leonard looks at what has happened since, and what needs to happen.
Bio-protection advocates, the nursery trade, mana whenua, plant pathologists, and conservation groups are doing their best to combat myrtle rust with the funding, public interest and management structures available. But the patchy nature of resources is undermining their efforts to protect our taonga from disease.
When I first spotted myrtle rust on a hedge in Tā maki Makaurau/Auckland, it was like a celebrity sighting. I had been writing about it for the research programme Beyond Myrtle Rust. I knew the disease was caused by the fungus Austropuccinia psidii, and I knew it had arrived on the wind from Australia. I knew it was first detected on mainland New Zealand in May 2017.
I knew a lot, but I had never seen it with my own eyes. And here it was. Fungal spores had burst through the leaf’s surface in intense yellow clusters, contorting the still-living leaf.
Myrtle rust is dangerous. Originally from South America, the pandemic strain of Austropuccinia psidii has brought carnage wherever it has turned up. Since arriving in Australia in 2010, the disease has been detected on 358 native Australian species – 16 of them are now predicted to be extinct in the wild within a generation. New Zealand has 27 species of Myrtaceae, including pō hutukawa, mā nuka, and maire tawake/swamp maire. So far, 17 of our native Myrtaceae are known to be susceptible.
To me, myrtle rust is intensely interesting, so I’m perplexed by posts on social media to the effect of ‘‘So whatever happened to myrtle rust? Is that still a thing?’’ It makes me wonder why, five years on, myrtle rust seems to have been forgotten when other diseases, like kauri dieback, are still front and centre in many people’s minds.
Myrtle rust should be getting at least as much attention (and funding!) as kauri dieback. But it doesn’t. Why? I asked some of the passionate few about why attention to myrtle rust has been so variable, and an interesting story emerged.
When myrtle rust arrived in mainland New Zealand, there was an immediate response from MPI, DOC, nurseries generally and New Zealand Plant Producers Incorporated (NZPPI) specifically, iwi and researchers. Research activities were launched, and MPI initially tried to eradicate the disease.
‘‘Nurseries were shut down and millions of dollars of plants were destroyed,’’ says Matt Dolan, chief executive of NZPPI, the industry body for plant nurseries and related businesses. ‘‘It was a very stressful time for everybody.’’
When it became clear eradication wouldn’t work, the crown investment went to research. In mid-2018, $13 million launched a five-year collaborative research programme, Beyond Myrtle Rust. Later, an additional $13.75m was awarded to Ngā Rā kau Taketake (Saving Our Iconic Trees – a programme within the BioHeritage National Science Challenge) for research into both kauri dieback and myrtle rust.
The shift from visible eradication action to the slower pace of research made it feel like myrtle rust had just gone away.
‘‘It’s a phenomenon I like to call myrtle rust amnesia,’’ says Cheri van Schravendijk-Goodman (Te Ā tihaunui a Pā pā rangi, Ngā ti Apa, Ngā ti Rangi), a communitybased researcher. ‘‘It became really hard to convince our people that it was still a problem.’’
The research being done out of sight was out of the minds of the public.
‘‘Perception is everything,’’ says Graeme Atkins (Ngā ti Porou, Rongomaiwahine), a Department of Conservation ranger and tangata whenua of the East Cape. ‘‘[This disease] is serious, but when you don’t see anything happening on the ground, it doesn’t look like the powers that be see it that way.’’
Myrtle rust suddenly became visible again when whole-tree death was reported in the East Cape. Atkins first spotted myrtle rust on ramarama (Lophomyrtus bullata) in April 2018. Over two years, he had to watch helplessly as the trees died.
‘‘Ramarama has pretty much become functionally extinct in our region,’’ says Atkins.
This has effects on forest health.
‘‘The understorey is gone,’’ says Katrin Webb, principal adviser of science investment within the Threats portfolio at DOC. ‘‘That has effects on insects that may feed or breed on those [plant] species. It changes how much light comes through.’’
Losing ramarama also changes how efficiently forests store carbon. Recent research from Beyond Myrtle Rust has highlighted how important Myrtaceae are to our forests – several tree species from this family are tall, dense, and longlived, making them ideal for locking away carbon.
‘‘Planting trees is a strategic priority in terms of climate change,’’ says Joris de Bres, chairperson for Project Crimson. Through its programme Trees That Count, Project Crimson has helped plant millions of native trees. ‘‘You plant a tree because of the carbon it will absorb over the next 100 years, not over the next
The understorey is gone. That has effects on insects that may feed or breed on those [plant] species. It changes how much light comes through.’’
- Katrin Webb, DOC.
two years. You don’t want to be planting things that are going to die before their time.’’
There are also specific cultural impacts that the disease could have, particularly in the East Cape, home to Te Waha o Rerekohu, one of the oldest (at about 600 years) and largest pō hutukawa trees in Aotearoa.
‘‘Generations of locals have lived and died around that tree,’’ says Atkins. ‘‘It’s part of the community.’’
It took the deaths of a valleyfull of mature trees and the eloquent, respected Atkins as a spokesperson to win back attention for myrtle rust in late 2020. The media coverage that followed significantly raised its profile.
‘‘I think prior to [this media coverage] most people thought that myrtle rust had gone away,’’ says Atkins. ‘‘Now we’ve got a whole lot of media focus on it and people are realising.’’
Unfortunately, the concern generated has not translated into the cold hard cash needed to continue fighting this disease. Besides two Jobs for Nature projects for myrtle rust announced in 2021, there’s been almost no new funding. The Government allocated no funding for myrtle rust initiatives in Budget 2021 (kauri dieback got $28m), even though the Myrtle Rust Strategic Science
Advisory Group organised by MPI suggested in 2019 that an additional $39.25m is required to augment the myrtle rust research that’s currently under way.
Minimal funding has meant that things like monitoring have fallen by the wayside.
‘‘One has the idea that maybe this should be done at a national level by government,’’ says de Bres. ‘‘And if not by government, then by someone who is enabled to do it by government.’’
Coordinated, nationwide monitoring can’t happen without dedicated funds.
‘‘At the moment, no agency holds resources for nationwide monitoring of myrtle rust,’’ says Clare Stringer, who was a senior advisor for conservation at Biosecurity New Zealand (MPI) when I spoke to her for this article.
This poses a problem for land managers, researchers and communities.
‘‘You don’t know how bad it is if you don’t look,’’ says Webb. ‘‘If [we] don’t know where it is, we can’t make informed management decisions on where to put investments.’’
Besides a handful of locationspecific monitoring efforts, agencies have been relying on iNaturalist NZ – Mā taki Taiao to track the spread of myrtle rust. In fact, the official advice from MPI is to report myrtle rust on iNaturalist.
That day of my first myrtle rust sighting, I downloaded the app to make the report. My identification was confirmed by generous researchers and nature enthusiasts who check the app in their spare time. To date, I’ve made 19 observations around Tā maki Makaurau – about half of these are myrtle rust (either on exotic lilly pilly hedges or pō hutukawa), but I’ve also submitted photos of mushrooms, beetles and moths I was curious about.
The app is great – it’s a fun way to get involved in the natural world, and it’s neat to contribute to the national understanding of a native or exotic organism. And it has also proven to be a good, centralised space for multiple agencies (and the public) to store records of myrtle rust sightings.
But it is no substitute for the nationwide monitoring of a disease that threatens the biosecurity of Aotearoa. Crowdsourced monitoring is biased – there are more reports in highly populated urban areas on plants that are easy to identify, like pō hutukawa. These reports are important, but they represent an incomplete picture of the spread and severity of the disease at a national level.
When I get frustrated by all of this, I have to remind myself that Aotearoa is a small country with a small tax base, and there are many causes that are also deserving of the limited capital the Government can gather.
Still, I do have hope that more funding will be freed up for myrtle rust. A lot of faith is being placed in our ability to sequester carbon in our ngahere (forests), and we’ll need to know everything we can about the diseases that threaten our trees to ensure they can do their job.
Until more resources are available, a lot can be done on an individual level.
When you’re out in your garden or tramping, keep your gear clean.
For your garden, choose plants that are not susceptible to myrtle rust, prune your existing Myrtaceae in winter when the disease is less active, and water at night at the base of the plant.
If you see myrtle rust, report it on iNaturalist. It’s not an ideal tool, but it’s what we have, so we might as well use it.
Follow along with Beyond Myrtle Rust and Ngā Rā kau Taketake research on their websites, newsletter and social media platforms.
Covid has taught us that our personal choices and actions make a difference in slowing the spread of disease. So clean your gear, choose your plants wisely, track the spread, and stay informed. By doing so, you are joining a community of people dedicated to protecting our iconic trees. Be kaitiaki (guardians) for our taonga species.