While most Australians have never heard of the plant disease known as myrtle rust (Austropuccinia psidii), the scientific community monitoring its spread and impact are very concerned.
The fungal disease arrived here only eight years ago but has already been compared to feral cats for its potential to wipe out native species.
Myrtle rust affects many species in the family Myrtaceae (Eucalypt family) including several rainforest species in the Australian and New Zealand flora. It has already been shown to have severely decreased the natural occurrence of once widespread rainforest trees like the scrub stringybark (Rhodamnia rubescens) and the native guava (Rhodomyrtus psidioides) in NSW and Queensland.
In April last year, myrtle rust was confirmed on the Kermadec Islands, approximately 1,000 km north east of Aotearoa New Zealand. By May it had been detected on the North Island. Within three months there were 101 confirmed myrtle rust sites, affecting four native NZ genera of Myrtaceae and threatening species of immense cultural, economic and ecological significance.
The first response of the New Zealand government, the Māori Biosecurity Network Te Tira Whakamātaki and the Millennium Seed Bank Partnership (MSBP, managed by the Royal Botanic Garden Kew) was to urgently start a seed collection and storage program.
Specialist training in wild plant seed conservation techniques, supported by MSB and the NZ government, was delivered during two five-day courses were held in Wellington and Auckland in December for practitioners from all around New Zealand. The courses covered the theory and practice of wild species seed conservation as well as Myrtaceae identification.
Graeme Errington (pictured below) from the Australian PlantBank (Australian Botanic Garden Mount Annan) was invited to deliver part of the training, chosen for his expertise in seed collection and storage.
It is hoped that New Zealand and Australia can work together and share knowledge to face the challenges presented by myrtle rust and secure a future for their respective native Myrtaceae species.
The Royal Botanic Garden Sydney and Australian Botanic Garden Mount Annan are part of a network botanic gardens raising awareness, providing expertise and establishing conservation programs in response to the threat of myrtle rust. The science team at our Gardens are working in the following areas:
Taxonomy: Identifying affected plants to ensure that a database of susceptible and vulnerable species is available and accurate
Education: In collaboration with several partners, Garden staff have run workshops in Australia, New Zealand, PNG and Indonesia to empower practitioners to prepare and respond to myrtle rust.
Collaboration: Dr Brett Summerell is a member of the Myrtle Rust Environmental Impact Working Group and is currently part of the national Environmental Impacts of Myrtle Rust forum in Canberra.