• Worldwide distribution. In Australia, New Caledonia, New Zealand.
• Serious fungal disease of Myrtaceae causing spots, distortions, defoliation, dieback and death depending on species. Major threat to native environments.
• Pustules (uredinia) on foliage and flowers, sometime purplish borders, producing masses of vivid yellow spores (urediniospores); occasionally, another thick-walled survival spore (teliospores) forms in the pustules on underside of leaves.
• Spread: spores on the wind; rain splash; on clothing, vehicles, animals, and the trade in wood and live plants.
• Biosecurity: difficult because wind dispersed, but regulation of movement of plant hosts important.
• Cultural control: regulate plant nurseries; avoid replanting susceptible species; hygiene measure (clothing, tools, vehicles) avoiding transfer of spores to healthy areas.
• Chemical control: strobilurin and sterol biosynthesis inhibitor (SBI) fungicides registered in Australia. Copper and mancozeb fungicides also likely effective.

Myrtle rust. It has other names based on the hosts infected, e.g., guava rust, eucalyptus rust, ohi'a rust.

Austropuccinia psidii; previous names are Puccina psidii, and Uredo rangelii. There are several strains or races that show different reactions on a  range of host plants.