Myrtle rust

Scientific name: Austropuccinia psidii

Description

Myrtle rust, a plant disease caused by the introduced fungal pathogen Austropuccinia psidii, poses a serious and urgent threat to Australia’s native biodiversity. Myrtle rust affects plant species in the family Myrtaceae (paperbarks, tea-trees, eucalypts, and lillipillies), which are key and often dominant species in many Australian ecosystems.

The pathogen attacks new growth on species in the plant family Myrtaceae and many other groups. Seedlings are particularly vulnerable, and repeated infection of adult plants of highly susceptible species can lead to defoliation, loss of reproductive capacity and death. It favours moist habitats and under current climate conditions is unlikely to be a threat in drier areas.

It is now fully naturalised along most of the east coast and in parts of the Northern Territory and marginally established in Victoria and Tasmania. The most serious species declines are in New South Wales and South East Queensland. Declines are suspected, but not well documented, in the Wet Tropics and adjacent areas of North Queensland.

It has proven capable of infecting 382 native species and this number is likely to grow. Serious declines towards extinction are underway in some species, and broader ecological consequences are expected.

Myrtle rust is likely to have a significant impact on listed threatened species and ecological communities, wetlands of international importance, world heritage properties and national heritage places. Loss of Myrtaceae species habitat may affect some animal species, human economic, social and cultural values and amenity, as well as ecosystem integrity.

The spread of Myrtle rust will result in an economic impact for the tourism, recreation, and nursery and garden industries, including rural and regional and Indigenous enterprises. Primary industry and biosecurity agencies provided valuable leadership when the pathogen arrived in Australia in 2010, and have supported some important research since.

The Myrtle rust pathogen is included in the Key Threatening Process ‘Novel biota and their impact on biodiversity’ listed in 2013 under the Australian Government’s Environment Protection and Biodiversity Conservation Act 1999. This Key Threatening Process applies to introduced and invasive species that have a significant detrimental impact on the environment.

Managing Myrtle rust

There is a National Action Plan for Myrtle rust in Australia and the Department of Environment and Science has adopted this to guide actions in Queensland. A collaborative partnership to deliver on-ground recovery actions across the state is being established.

Related information

• Makinson RO, Pegg GS, Carnegie AJ, (2020) Myrtle rust in Australia – a National Action Plan, Australian Plant Biosecurity Science Foundation, Canberra, Australia.
• Australian Network for Plant Conservation Myrtle rust webpage
• Silcock, J., Collingwood, T., Llorens, T., Fensham R. 2021. Action Plan for Australia's Imperilled Plants. NESP Threatened Species Recovery Hub, Brisbane.