21-05-2025
Invasive plant pathogen myrtle rust detected at National Museum of Australia, sparking concerns for eucalypts
The invasive plant pathogen myrtle rust has been detected near the National Museum of Australia in Canberra, concerning experts.
Myrtle rust is a bright yellow-looking fungus that infects plants, like other fungal infections, by penetrating into a plant's living tissue.
Originally from South America, the single strain that's made it to Australia can be found on a plant's young leaves, flower buds and young fruits and will in severe cases appear as a yellow sticky powder.
It targets the eucalypt family — which includes not just eucalypts but tea trees, lilly pillies and other plants — with sometimes devastating effect.
Founder of the Invasive Species Council Tim Low said 16 species of rainforest tree were likely to go extinct without emergency intervention.
The pathogen was first reported in the gardens of the National Museum of Australia by a citizen scientist in February.
The citizen scientist put the location of the infected plants in the National Museum gardens, off Lawson Crescent and the Tim and Gina Fairfax Discovery Centre.
The report was later confirmed by the ACT government's biosecurity and invasive plants team and the NSW Department of Primary Industries, which found two Geraldton wax flower plants were infected. They were removed in April.
Mr Low told the ABC the Canberra plant most susceptible to myrtle rust was the prickly tea tree, but called the Geraldton wax flower "highly vulnerable" and noted the pathogen might cause greater damage to garden plants than natives if it were to spread across the ACT.
The ACT Environment, Planning and Sustainable Development Directorate (EPSDD) said follow-up surveillance on the infection would be conducted again in spring.
This infection does not mark the first myrtle rust detection in Canberra.
EPSDD says myrtle rust was detected in 2022 at a plant nursery, but the plants were removed and the nursery has remained free of the pathogen since.
And according to to the National Myrtle Rust Working Group, the invasive plant pathogen has been detected multiple times at the Australian National Botanic Gardens.
But this infection at the National Museum has sparked more concern, with the Department of Climate Change, Energy, the Environment and Water updating its webpage on myrtle rust to include the ACT in response.
"The Australian National Botanical Garden had several detections of myrtle rust before, but none of them has established," Dr Benjamin Schwessinger, a researcher at the Australian National University studying myrtle rust and other fungi which infect plants in Australia, told the ABC.
When asked about the significance of the National Museum myrtle rust detection, Dr Schwessinger said it indicated a possible wider spread.
"The National Museum is a well-frequented place … So if it's probably detected there, it's probably not the first real incursion on the only affected tree in the ACT," he said.
"It's an airborne pathogen. So, yeah, it gets blown around quite a bit. It can probably travel thousands of kilometres in the air."
He said myrtle rust became concerning when it was "established" – meaning the infection was seen year on year in the same area.
However, that the National Museum infection was detected out of season is also a concern.
"We would normally not expect it. It's more [likely] in springtime," Dr Schwessinger said.
Mr Low also noted the risk of myrtle rust spread but added Canberra's weather might help fight back against the pathogen.
"It's really good at spreading. It's spreading on the wind, it's spread by honeybees," he said.
He said the pathogen could be treated with fungicides but this was often not feasible in a national park or wild area, and advocated for the government to instate tighter biosecurity measures against myrtle rust.
"We ... are not confident they are doing everything they can to keep out myrtle rust strains," he said.
