Puccinia psidii
Puccinia psidii, also known as guava rust or ʻōhiʻa rust, is a rust native to Brazil with a very broad host range in the myrtle family. Puccinia psidii can have very serious consequences to various species of plants in the Myrtaceae. This family includes guava, eucalyptus, melaleuca, and a number of species native to Hawaii, including some endemic species and at least one important native forest tree. There are numerous strains of the Puccinia psidii rust—some known to be established in Florida, and at least one reported from California and there is concern that strains may exist or develop that could be devastating to ʻōhiʻa, one of Hawaii's dominant native trees, a foundation species for many remaining Hawaiian native ecosystems. However currently, the major threat of Puccinia in Hawaii is the massive damage it is doing to Eugenia koolauensis, a federally listed endangered species.
