Review of intensified management response to Myrtle rust

DAFF

3 September 2010

Review of intensifed management response to Myrtle rust

The Myrtle rust National Management Group (NMG) met on 2 September 2010 to consider the outcomes of intensified surveillance and containment actions for Myrtle rust (Uredo rangelii).

Myrtle rust was first detected in Australia in April 2010 at a cut flower growing facility in the central coast of New South Wales. Recent indications suggest that the rust may have been in Australia for more than a year.
 
To date, there has been no detection of the disease on Eucalyptus and other species of Myrtaceae in surrounding native forests.

Myrtle rust has now been confirmed on fourteen sites in New South Wales extending from inland of Gosford to just north of Wollongong. With one exception, of a single tree in a backyard, the infected sites are retail garden centres, wholesale nurseries and cut flower facilities.  The sites have been detected through tracing the movement of plants to and from infected properties and surveillance. A quarantine area has been established by NSW Government Authorities. Infected plants have been destroyed and all plants on the infected properties have been sprayed with fungicide to reduce the risk of further spread.  Quarantine controls have been placed on these properties to prevent further movements of infected plants.

An interim response plan was implemented by the Myrtle rust NMG on 2 July 2010, to suppress Myrtle rust with a long-term view to  possibly eradicate this disease and collate data for the management should it become necessary.  Actions in the interim response plan included:

• host testing under controlled circumstances
• DNA analysis
• surveillance of known infected properties and the natural environment
• destruction of host material
• ongoing suppression activities, including the application of fungicides, at known infected properties.

New measures to intensify the management response were agreed by the Myrtle rust NMG on 17 August 2010 to continue to suppress the disease and assist in its delimitation.

The new measures included:

• the destruction and disposal of all commercial Myrtaceae plants on the two properties most severely infected
• increased fungicide application on all known infected properties including spraying a buffer zone around each property
• the application of fungicide to a 30 m wide strip of bushland where it adjoins known infected properties
• surveillance in a buffer area around each of the known infected properties with a particular focus on susceptible hosts
• increased surveillance of all commercial nurseries with Myrtaceae within the quarantine area established by NSW authorities
• inspection of Myrtaceae on approximately 310 domestic premises in the quarantine area
• targeted communication activities in NSW including the distribution of educational materials to commercial nurseries, information to local residents, meetings with stakeholders and road signage in the quarantine area. 

All commercial Myrtaceae plants on the two most infected properties have now been destroyed. Myrtaceae on a third property have also been destroyed in line with the plan.  The remaining activities will continue with the new infected properties.

Surveillance work has so far found evidence of eight species of plants in the plant family Myrtaceae currently affected by Myrtle rust in the infected properties:

• willow myrtle (Agonis flexuosa)
• turpentine (Syncarpia glomulifera)
• bottlebrush (Callistemon viminalis)
• round-leaved tea tree (Leptospermum rotundifolium)
• water gum (Tristania neriifolia)
• tahiti (Metrosideros collina “dwarf”)
• thready-barked myrtle, aurora and blushing beauty (Austromyrtus inophloia – renamed Gossia inophloia)
• a cultivated hybrid of lilly pilly (Syzygium leumannii x Syzygium wilsonii).

Testing completed to date has shown a wider range of Myrtaceae species may be susceptible to the disease. However, this testing has been under controlled laboratory conditions rather than field trials. This work is continuing.

While every effort is being made to suppress the disease, the NMG recognises that eradication may not be possible based on the increasing number of infected sites and technical information that is being collected and analysed.  Analysis of infected material that has been found in the last week suggests that the disease may have been here longer than initially thought, and possibly for longer than 12 months. The NMG notes that Myrtle rust infections have not been found in any native forest or bushland. 

Rust spores are highly transportable and can be spread via contaminated clothing, insect movement and wind dispersal. Warmer spring weather conditions and actively growing host plants will be key factors in determining whether the fungus is suppressed and if it can be effectively contained and eradicated.

Activities to manage Myrtle rust are being implemented under the Emergency Plant Pest Response Deed (EPPRD) - a legally binding agreement between the Australian Government, all state and territory governments, national plant industry body signatories and Plant Health Australia.

The Myrtle rust NMG is comprised of the chief executive officers of the national and state/territory departments of agriculture and primary industries across Australia, representatives of peak industry bodies and Plant Health Australia. The group is chaired by the Secretary of the Australian Government Department of Agriculture, Fisheries and Forestry, Dr Conall O’Connell. 

Further advice on Myrtle rust and actions to suppress it can be found in these questions and answers and on the website of the NSW Department of Industry and Investment.