Myrtle rust: Biosecurity alert

Page last updated: Wednesday, 7 September 2022 - 9:35am

Please note: This content may be out of date and is currently under review.

Myrtle rust is a serious disease that infects and kills many plants belonging to the Myrtaceae family including eucalypts, bottlebrushes, paperbarks and peppermint trees.

This fungus was found in Australia for the first time in 2010 and was detected in the northern part of Western Australia in June 2022.

Bushwalkers and travellers are urged to look out for and report plants with signs of myrtle rust and take precautions when travelling in and out of affected areas to reduce the spread.

About myrtle rust

Myrtle rust, caused by the fungus Austropuccinia psidii, was first discovered in Australia in April 2010 in a New South Wales nursery. It has now been detected in Queensland, Victoria, Tasmania, Northern Territory and most recently on an isolated property in the northern part of Western Australia (WA).

Laboratory trials have shown that a large number of plant species will be affected by this disease, although it is not yet known how climate differences might influence its spread in WA compared to its spread on the eastern seaboard. 

Many of WA’s tree species can be infected by myrtle rust, including peppermint trees, turpentine, bottlebrush, paperbark, tea tree and lilly pilly.

Myrtle rust could also damage eucalyptus or oil mallee plantations, apiculture, the cut native flower trade and the garden industry, and its spread could affect tourism if natural landscapes were badly damaged.

Myrtle rust can be controlled by chemicals such as copper oxychloride, triforine, mancozeb, tebuconazole and trifloxystrobin in the home garden, but chemical control is not a viable option for large-scale landscapes, native forests and other natural ecosystems.

Stop the spread of myrtle rust in WA

WA bush walkers and travellers to northern WA are encouraged to look and report signs of myrtle rust.

Leaves with yellow powdery rust spores.
Myrtle rust could devastate many important and unique plant species. It is readily identified by its unique bright yellow or orange spores or pustules on leaves.

Myrtle rust is readily identified by its unique bright yellow or orange spores or pustules on leaves.

Wind naturally disperses myrtle rust spores to new areas, but the tiny spores are highly transportable and can stick to clothing, hats, footwear, vehicles and equipment.  Anyone who visits areas known to be affected by myrtle rust should take the following precautions:

  • If travelling by road, shake out floor mats, wash down tyres and check that the vehicle, caravan, trailer and any gardening equipment contain no plant material. Do this before leaving an infected area and do it again before entering areas that could be affected by myrtle rust.
  • If possible, change into fresh clothing and footwear and pack away anything that was worn in myrtle rust infected areas. Once home, wash everything that was used on the trip.
  • Travellers are reminded that any plant material or items contaminated by soil are prohibited entry into WA.

Recognising myrtle rust

Myrtle rust attacks young, soft, actively growing leaves, shoot tips and stems. It also attacks fruit and flowers of susceptible plants.

The first signs of rust infection are tiny, raised spots or pustules. After a few days, the pustules may turn a distinctive egg-yolk yellow colour.

Twisted leaves with brown myrtle rust spores.
Myrtle rust.

If you see signs of myrtle rust

1. Avoid contamination of yourself and any equipment with the spores.

2. Take a photograph (do not collect samples or handle the plant).

3. Record the location of the infected plant(s) - GPS is ideal, but a detailed description of the location is important.

4. Record what you see (what the infection looks like, the extent of the infection, how many plants are infected etc.). If you know the species of plant infected, record that as well.

5. As soon as you can, report your observations to the department using the MyPestGuide Reporter app or by calling the Pest and Disease information Service.

Contact information

Mypestguide Mypestguide
Pest and Disease Information Service (PaDIS)
+61 (0)8 9368 3080