Australasian Plant Pathology

, Volume 41, Issue 1, pp 13–29

Rapidly expanding host range for Puccinia psidii sensu lato in Australia



A rust affecting Myrtaceae was recently detected in New South Wales, Australia. Based on urediniospore morphology and host range, it was identified as Uredo rangelii, a taxon regarded as a member of the eucalyptus/guava rust (Puccinia psidii sensu lato) complex, although confusion currently surrounds its taxonomy. The exotic rust was given the common name of myrtle rust to distinguish it from eucalyptus/guava rust. The more recent discovery of teliospores in NSW that match those of P. psidii sensu stricto indicates the rust in Australia is a strain (with tonsured urediniospores) of P. psidii s.l. Outside Australia, P. psidii has a wide host range within Myrtaceae, being reported from 129 species in 33 genera, and is very damaging in South and Central America–including in eucalypt plantations in Brazil–the Caribbean and in Florida and Hawaii. To ascertain the potential threat to forestry in Australia posed by the introduced rust, we tested key forestry species, as well as key known hosts of eucalyptus/guava rust, in artificial inoculation experiments. We showed that several species of Eucalyptus are susceptible (viz. E. pilularis, E. cloeziana, E. agglomerata and E. grandis), as is Melaleuca quinquenervia. Observations during testing revealed a lengthened latent period (from inoculation until pustule formation and eruption) of four to five weeks during winter. Here we also report on observations on new hosts from surveys in NSW under the emergency response that followed the detection of the exotic rust, and surveys in NSW and Queensland following the cessation of the emergency response. In Australia, P. psidii s.l. has currently been found on 107 host species in 30 genera during surveys, including species in Angophora, Asteromyrtus, Austromyrtus, Backhousia, Callistemon, Chamelaucium, Choricarpia, Decaspermum, Eucalyptus, Eugenia, Gossia, Lenwebbia, Leptospermum, Lophomyrtus, Melaleuca, Metrosideros, Myrtus, Pilidiostigma, Rhodamnia, Rhodomyrtus, Ristantia, Stockwellia, Syncarpia, Syzygium, Tristania, Tristaniopsis, Ugni, Uromyrtus and Xanthostemon. Species under cultivation (in nurseries and gardens) that are severely affected include Gossiainophloia, Agonis flexuosa, Syzygium jambos and S. anisatum while species that are severely damaged in native bushland include Rhodamnia rubescens, Rhodomyrtus psidioides, Choricarpia leptopetala and Melaleuca quinquenervia.


Biosecurity Host testing Surveillance Exotic rust 

Copyright information

© Australasian Plant Pathology Society Inc. 2011

Authors and Affiliations

  1. 1.Forest Biosecurity & Productivity Assessment, NSW Department of Primary IndustriesForest Science CentreBeecroftAustralia
  2. 2.Forest and Rangelands Ecosystems, NSW Department of Primary IndustriesForest Science CentreBeecroftAustralia

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