Rust (Puccinia psidii) recorded in Indonesia poses a threat to forests and forestry in South-East Asia

Over the past decade, Puccinia psidii, which causes rust on species of Myrtaceae, has spread rapidly to new areas and is now widespread. Quarantine has done little to prevent its movement through the Americas, the Pacific, Africa, and in this report, South-East Asia. Puccinia psidii is reported for the first time from Indonesia on two genera of Myrtaceae, namely Eucalyptus and Melaleuca. Its identity was confirmed using morphology, a molecular barcode comparison to an epitype specimen, and with a molecular phylogenetic approach. Comparison of seven microsatellite markers indicates that the rust genotype in Indonesia and Australia is identical. The potential impacts of P. psidii in South-East Asia to the natural environment and plantation forestry are discussed in light of this first report from the region