Environmental issues

Pests and weeds

Management Plan for Myrtle Rust on the National Parks Estate

Myrtle rust is a plant disease caused by the exotic fungus Uredo rangelii. It was first detected in Australia on 23 April 2010 on the NSW Central Coast. It has established in coastal NSW from the Clyde River north into Queensland (see map below). Myrtle rust is likely to spread rapidly to the extent of its biological range as the spores are dispersed readily by wind. Eradication is unfeasible.

 

Map of NSW showing myrtle rust distribution - on the eastern seaboard from the Queensland border to south of Nowra

Approximate distribution of myrtle rust Uredo rangelii as of 24/01/2011.

Uredo rangelii belongs to a group of closely-related fungi known as the guava or eucalyptus rust complex. The complex includes the fungus Puccinia psidii which has had severe impacts on eucalypt plantations in Brazil and has been found in other parts of the Americas, Hawaii and Japan. P. psidii was considered as a potential biocontrol agent in the Florida everglades for the invasive plant Melaleuca quinquenervia, but it has since been found to attack some native American species, including a threatened species.

Myrtle rust affects plants in the family Myrtaceae, including the genera Eucalyptus, Angophora, Callistemon, and Melaleuca. Infection occurs on young growing shoots, leaves, flower buds and fruits. It produces masses of powdery bright yellow or orange-yellow spores on the infected areas. Leaves may become buckled and twisted and die as a result of infection. Images of myrtle rust on a range on Myrtaceae can be found at http://www.dpi.nsw.gov.au/biosecurity/plant/myrtle-rust/image-gallery

The likely impacts of myrtle rust on biodiversity in Australia are unknown. Like P. psidii, infection with myrtle rust may cause significant mortality among younger plants and hence reduce recruitment into adult populations. This may contribute to the decline and extinction of species, which is of immediate concern for those species already at high risk, i.e. threatened species. Reduced recruitment may also have severe impacts on the structure and function of the many natural ecosystems that depend on Myrtaceae. As at 28 March 2011, myrtle rust had been detected in 68 species of Myrtaceae, spanning 27 genera. Severe infection had been observed in relatively few species (most notably scrub turpentine Rhodamnia rubescens and native guava Rhodomyrtus psidoides) but the number of species so affected may increase as new strains of rust evolve. All five threatened species of Myrtaceae exposed to myrtle rust under laboratory test conditions became infected.

This plan outlines how myrtle rust will be managed on the national park estate in NSW, including the potential impacts of myrtle rust on threatened species. The plan also provides guidance to managers of other bushland and threatened species sites. More information on myrtle rust and guidance for managing myrtle rust in other environments can be found on the NSW Department of Primary Industries website at www.dpi.nsw.gov.au/biosecurity/plant/myrtle-rust

The format and structure of this publication may have been adapted for web delivery.

Page last updated: 13 January 2015