Impact of Austropuccinia psidii (myrtle rust) on Myrtaceae-rich wet sclerophyll forests in south east Queensland.

Geoff Pegg,Peter Entwistle,Gordon Guymer,Fiona Giblin,Tamara Taylor,Angus Carnegie,Sabrina Sarrocco

doi:10.1371/journal.pone.0188058

Abstract

In April 2010, Austropuccinia psidii (formerly Puccinia psidii) was detected for the first time in Australia on the central coast of New South Wales. The fungus spread rapidly along the east coast and can now be found infecting vegetation in a range of native forest ecosystems with disease impacts ranging from minor leaf spots to severe shoot and stem blight and tree dieback. Localised extinction of some plant species has been recorded. In 2014, the impact of A. psidii was observed for the first time in a wet sclerophyll site with a rainforest understory, dominated by species of Myrtaceae, in Tallebudgera Valley, south east Queensland, Australia. This study aimed to determine the impact of A. psidii on individual species and species composition. Here we provide quantitative and qualitative evidence on the significant impact A. psidii has in native ecosystems, on a broader range of species than previously reported. Archirhodomyrtus beckleri, Decaspermum humile, Gossia hillii and Rhodamnia maideniana are in serious decline, with significant increases in tree mortality over the period of our study. This research further highlights the potential of this invasive pathogen to negatively impact native ecosystems and biodiversity.

Highlights

Austropuccinia psidii [1] is a serious pathogen whose rapid global spread impacts commercially and ecologically important species of Myrtaceae [2]
Austropuccinia psidii was detected in Australia in April 2010 on the central coast of New South Wales (NSW) [7]
Archirhodomyrtus beckleri, Decaspermum humile, Gossia hillii and Rhodamnia maideniana were the most common mid- and under-story species of Myrtaceae. All these taxa were significantly impacted upon by A. psidii with branch death and dieback recorded on all trees, with significant increases in mortality for A. beckleri, D. humile and G. hillii

Summary

Introduction

Austropuccinia psidii (formerly Puccinia psidii) [1] (myrtle rust) is a serious pathogen whose rapid global spread impacts commercially and ecologically important species of Myrtaceae [2] It was first reported from Brazil in 1884 infecting Psidium guajava [3] and occurs in numerous South and Central American countries [2], as well as USA (Hawaii, Florida, California) [4,5,6], Australia [7], New Caledonia [8,9], South Africa [10], Indonesia [11] Singapore [12] and most recently New Zealand (www.mpi.govt.nz: Accessed 5 September 2017). A range of vertebrates and invertebrates take nectar and pollen from inflorescences and fruits, and fleshyfruited species provide a food source for a range of birds and mammals [13]

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