Myrtle rust yellow spores on Geraldton wax flowers. Photo by Geoff Pegg
Myrtle rust yellow spores on Geraldton wax flowers. Photo by Geoff Pegg

What is Myrtle rust?

Myrtle rust is a serious plant disease from South America caused by a rust fungus called Austropuccinia psidii, which spreads via wind-borne spores. Myrtle rust affects plant species in the Myrtaceae family. 

The bright yellow (rarely yellow-orange) masses of spores are a distinguishing feature of myrtle rust. Myrtle rust attacks actively growing shoots, stems and other soft young tissues such as fruits, flowers and emerging seedlings.  

This fungal pathogen of the Myrtaceae family (which includes iconic native plants such as Geraldton wax, bottlebrush and eucalyptus) originated in South America and was first detected on the east coast of Australia in 2010. It has since spread to all States and Territories except South Australia and Western Australia. The department is working with DPIRD to keep Myrtle rust out of Western Australia.  

Is Myrtle rust in Western Australia?

No! To date, Myrtle rust has not been detected in Western Australia or South Australia and we want to keep it out. Myrtle rust was first detected in Australia (in NSW) in 2010 and by 2015 it had spread to Queensland, Victoria, Tasmania and the Northern Territory. Myrtle rust is having severe impacts in native plant communities of NSW and Queensland where it has driven some species to the brink of extinction.  

Map of Western Australia showing Myrtle rust distribution along the east coast
Map of Australia showing the current distribution of Myrtle rust (red). Image - DBCA (adapted from Government of Queensland occurrence map).

Why keep Myrtle rust out of WA?

Myrtle rust attacks plants from the Myrtaceae family and WA is home to over 1,800 native myrtaceous taxa. We know that at least some of our native myrtaceous plant species are extremely susceptible to myrtle rust from glasshouse trials in the eastern states and observations of the impact of the pathogen on WA species that are grown as ornamentals in the eastern states. The Myrtaceae family contains many iconic and ecologically important species including:

  • eucalypts and paperbarks; 
  • bottlebrushes;
  • Geraldton wax; and
  • WA peppermint trees, to name just a few.

Myrtle rust can also affect industries including nursery, forestry, cut flower and apiary.  Attempts to eradicate Myrtle rust in the eastern states were unsuccessful. 

How to protect WA from Myrtle rust

Quarantine  - don’t bring Myrtaceae plants into WA.

Hygiene  - ensure all equipment, clothing and personal items are clean before re-entering WA from the eastern states or overseas.

Surveillance – learn how to recognise Myrtle rust, keep an eye out for it and report it immediately if you think you see it. 

How to recognise Myrtle rust

Early signs - look for raised spots which are brown-grey with red-purple haloes. In the next two weeks, yellow spores will begin to appear. Look for infection on the softer underside of leaves, as well as shoot tips, fruits, flowers and new growth.

Four photos showing the early or infectious stages of Myrtle rust on leaves, fruits and flowers
Myrtle rust symptoms expressing on soft leaves, the underside of leaves, on berries and flowers. Early symptoms (top-left) are brown-grey raised spots with red-purple haloes. The wind-borne yellow spores (top-right, bottom-left, bottom-right) develop later. Photos - Geoff Pegg/ Department of Agriculture and Fisheries Queensland

What to do if you spot Myrtle rust in WA

If you think you have spotted Myrtle rust:

  1. Do not take a sample or touch it because spores can be easily spread.
  2. Do immediately report your sighting using the MyPestGuideTM app or website (mypestguide.agric.wa.gov.au) or contact the DPIRD Pest and Disease Information Service on 9368 3080 or padis@dpird.wa.gov.au.
  3. Do take photos of the symptoms and the plant, and precise details about the location to provide with your report.

Early detection and reporting may prevent or reduce the long-term impact of a Myrtle rust incursion into WA!
Photos and location information can additionally be submitted via the DPIRD MyPestGuide Reporter app.

Contact details for reporting plant disease observations

Further resources

Department of Primary Industries and Regional Development (WA) - Myrtle rust threat

Department of Agriculture, Water and the Environment (Fed) - Myrtle rust (Austropuccinia psidii)

Invasive Species Council - Myrtle rust

Myrtle rust National Action Plan 

Myrtle rust article - Bushland News Summer 2020-2021
 

Page reviewed 10 Aug 2021