Myrtle rust, also called guava rust or ʻōhiʻa rust in Hawaiʻi, is a plant pathogen that has spread from its origin in Latin America to Hawaiʻi, the Pacific, Australia, and New Zealand in the past few years. The fungus has a broad host range, attacking most trees in the myrtle family (Myrtaceae), including guava, Eucalyptus, Eugenia, Melaleuca (paperbark), and Metrosideros (ʻōhiʻa and pohutukawa), and Syzygium (mountain apple and rose apple in Hawaiʻi).
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