- Distribution: Widespread throughout the Hawaiian Islands (except Niihau)
- Hosts: Wide range of hosts on various members of the Family Myrtaceae including ohia, Eucalyptus, paperbark, guava, rose apple, allspice, species of Eugenia, myrtle, and others.
- Other common names: eucalyptus rust, guava rust
- Symptoms: Starts as tiny bright yellow powdery eruptions in a circular pattern. These expand causing necrosis of infected leaves, stems, or shoots. Most often seen on tender, young growing points.
- Treatment: No approved fungicide as yet. Good sanitation practices recommended to bag or destroy infected leaves or other plant parts. Keep foliage dry when irrigating. Do not move infected plants between islands. Under Plant Quarantine Interim Rule 07-2, importation of plants in the family Myrtaceae are prohibited from areas known to be infested with ohia rust (California, Florida, South America) to prevent the introduction of possibly more virulent strains of the virus.
Source: State of Hawaii Department of Agriculture New Pest Advisory No. 05-04 Updated December 2007.
Ohia rust – photo courtesy Dr. Scot Nelson, UH CTAHR
