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Home > CHABG > Myrtle Rust > Fact Sheet

photo: Myrtle Rust on Melaleuca nodosa, by Peter Entwistle

Myrtle rust

A new disease in Australia with potential impact on botanic gardens

Botanic gardens are special places for people to relax, learn and enjoy plants. They also play an important role in plant conservation, research and to raise public awareness about the importance of biodiversity. The living collections held by Australian botanic gardens are an immense biological resource of information on both individual plants and plant biodiversity.

An emerging threat to plants in the Myrtaceae family, both within botanic gardens and the Australian landscape, is a recently introduced fungal disease Myrtle rust.

What is myrtle rust?

Myrtle rust is a fungal disease affecting plants in the Myrtaceae family, including Australian natives like bottle brushes, tea trees and eucalypts.

Rust diseases are very specific to plant species and Myrtle rust is unlikely to affect plants other than those in the Myrtaceae family. Myrtle rust on affected plants is typified by a large number of yellow spores that can be easily spread by wind, humans and animals.

The spores prefer high humidity, low light, temperatures over 15 °C and moisture on leaves and stems to germinate.

Where has Myrtle rust been found in Australia?

Myrtle rust belongs to a group of fungi known as the ‘guava rust complex’. This complex of diseases is native to South America and also present in Hawaii, Florida and Mexico. It is not known how the disease entered Australia.

Myrtle rust first emerged on the central coast of New South Wales in April 2010. It has since been detected along the NSW south and north coast and into South East Queensland and as far north as Cairns.

Due to the increasing number of locations that Myrtle rust has been detected and expanding host range, further spread of the disease is anticipated.

What does Myrtle rust look like?

The first signs of rust infection are tiny raised spots on young, actively growing leaves, shoot tips, young stems, fruits and flower parts. The spots develop into powdery bright yellow or orange-yellow pustules after a few days. The pustules turn pale yellow then grey with age.

If untreated, the disease can cause deformed leaves, heavy defoliation of branches, die-back and stunted growth.

How to monitor your plants for Myrtle rust

Many popular Myrtaceae garden plants are affected by Myrtle rust and gardeners should be vigilant in monitoring their home gardens for Myrtle rust.

Further Information

Australian Network for Plant Conservation:

Australian Quarantine and Inspection Service:

NSW Department of Industry and Investment:

Queensland Primary Industries and Fisheries:

Department of Primary Industries, Victoria:

Department of Primary Industries, Parks, Water and Environment, Tasmania:

Biosecurity South Australia:

Department of Agriculture and Food, Western Australia:

Department of Resources, Northern Territory:,%20Pests%20and%20diseases&newscat2=Plant,%20Pests%20and%20diseases&header=Exotic%20outbreaks%20and%20diseases


Updated 21 September, 2017, webmaster, ANBG (