Guava rust (eucalyptus/myrtle) rust
Guava (eucalyptus) rust
Exotic to Australia
Life form: Fungus
Distribution: Central America and Caribbean, United States (Florida,
Hawaii), South America, Asia, South Africa, Oceania (New Caledonia)
Features: Yellowish pustules on young leaves, shoots, stems
Pathways: Plant propagative material, contaminant on clothing
and machinery; wind-blown, human-assisted movement
At risk: More than 100 plant species, mainly Myrtaceae family
Guava rust (also known as eucalyptus rust) is part of the Puccinia psidii species complex, and is considered to be one of the most serious threats to Australia’s eucalypt plantations, commercial native forests and natural ecosystems. It is a disease caused by the fungus Puccinia psidii sensu lato which infects plants belonging to the plant family of the Myrtaceae. The Myrtaceae are a large plant family which includes eucalypts, paper barks (melaleucas), bottle brushes (callistemons), lilly pillies (syzygiums) and a wide range of other important Australian genera.
Guava rust is closely related to myrtle rust, with both belonging to the Puccinia psidii species complex. Myrtle rust has been introduced to Australia, and has spread across the eastern states, Tasmania and the Tiwi Islands in Northern Territory.
How to identify Guava rust (Puccinia psidii sensu lato)
Everyone needs to keep an eye out for guava rust. Key symptoms are lesions forming on leaves and containing yellow spores.
Guava rust can spread easily over long distances through the movement of:
- infected plant material (cut flowers, nursery stock and seeds)
- spores being carried on clothing, shoes, other personal effects and equipment
- wood packaging
- wind-borne spores.
Guava rust attacks young, soft, actively-growing leaves, shoot tips and young stems. Fruit and flower parts are also susceptible. The first signs of infection are tiny pustules usually on young leaves. After a few days, the pustules erupt with the production of distinctive, yellow spores. The infected area spreads and multiple pustules eventually merge. Left untreated, the disease can cause deformed leaves, heavy defoliation of branches, dieback, stunted growth and even plant death.
If guava rust became established in Australia, it could have a significant impact on eucalypt plantations, native forests and urban flora with indirect impacts on native fauna and human lifestyles.
Illegal importation of infected plant material poses the greatest risk for the disease to enter Australia. If you work around imported plant material, including cut flowers and nursery stock you need to look for disease symptoms.
Foresters and home gardeners
Early detection of guava rust is the best way to reduce the spread, if it were to establish in Australia.
Be vigilant and look for any signs or symptoms in:
- bottle brushes (callistemons)
- lilly pillies (syzygiums)
- paper barks (melaleucas)
- and other Australian myrtaceous plants.
Keep Guava rust (Puccinia psidii sensu lato) out of Australia
All Australians and international tourists have a role to keep out exotic pests and diseases.
Australia remains free of this exotic disease. We need your help to keep it this way.
Check what you can and cannot bring into Australia, whether you are a:
I love my home among the gum trees
Guava rust and myrtle rust combined would have serious combined impact on our eucalyptus trees if Guava rust were to enter Australia. We do not want to further endanger our iconic eucalyptus species through introduction of this pathogen.
Import restrictions and biosecurity measures
Some items, by law, are subject to certain import conditions to be allowed into Australia. Please check the Biosecurity Import Condition System (BICON).
Be aware of any guava rust biosecurity measures that may be in place for incoming goods and conveyances. Industry advice notices are reviewed regularly and could change.
Secure any suspect specimens
Containment is critical.
In as little of 10 days the fungus can produce thousands of spores. Spores can spread very easily through the movement of infected plant material, clothing, equipment and wind.
It is important to not move samples to reduce the risk of spread. Take a photo, record the location and get it checked by an expert.
Report detections of exotic pests
Any detections of guava rust must be reported to the authorities.
If you receive or work around goods imported from overseas, including mail, you need to be vigilant to guava rust and other exotic pests.
If you see an unusual pest, secure the goods to limit the movement of the pest and immediately report it to the Department of Agriculture's SEE. SECURE. REPORT. Hotline 1800 798 636 or by using the online form.
Growers and home gardeners
If you seeguava rust or anything unusual, report it to the Exotic Plant Pest Hotline 1800 084 881. This will put you in touch with the Department of Primary Industries or agriculture in your state or territory.
When reporting your concern, you will be given advice on handling the specimen and what to do next until an officer can investigate.