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Myrtle rust

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Myrtle rust detected on the Tiwi Islands

[ 06/07/2015 ]


Myrtle rust was detected on Melville Island on 15 May, 2015.
The initial identification was made by the Northern Australia Quarantine Strategy (NAQS) team as part of their annual plant survey on the Tiwi Islands.
Myrtle rust has been in Australia since it was first detected in New South Wales in 2010 and subsequently in Queensland, Victoria and Tasmania. It is not known how myrtle rust entered Australia.
Myrtle rust is a fungal disease that attacks trees and shrubs in the Myrtaceae family of plants which includes Australian natives such as bottle brush, tea tree and eucalypts.
It’s distinctive in that it produces masses of powdery bright yellow or orange-yellow spores on infected plant parts. Left untreated it can cause deformed leaves, defoliation of branches, and plant death.
In December 2010, the heads of Australian Government and state agencies responsible for biosecurity took the decision, based on expert technical advice, that it was not technically feasible to eradicate myrtle rust from Australia.
Myrtle rust is extremely difficult to eradicate because its spores can be easily dispersed by the wind, water, people, vehicles, equipment and animals.
How was myrtle rust detected in the Northern Territory?
The team took samples on two ornamental plants in a college, then along kilometres of roadside in the natural environment and in an area around a waterfall that is frequently used as a swimming place.
Samples were provided to the Department of Primary Industry’s Plant Pathology Laboratory for diagnostics which returned a positive result for myrtle rust. The necessary confirmation was provided by Queensland Department of Agriculture & Fisheries.
Further DNA diagnostic work will be done to verify that this instance of myrtle rust is the same as the rest of Australia and not a new incursion of a different strain.
What does it look like?
This photo gallery can help you identify myrtle rust.
Myrtle rust in the Top End of the Northern Territory, photos courtesy of Northern Australia Quarantine Strategy (NAQS):
Myrtle rust photos courtesy of the Queensland Government Department of Agriculture and Fisheries
How did the Northern Territory get myrtle rust?
Investigations to date have not provided any significant leads as to how or when  myrtle rust entered the Northern Territory.
Who will be affected?
Myrtle rust is a threat to the nursery and garden industry, forestry, tea tree oil production and natural ecosystems.
The Tiwi Islands forestry plantation is based on Acacia mangium, which is known not to be a host for myrtle rust.
Because myrtle rust is relatively new to Australia, the full host range of plants is as yet unknown. The Melville Island detection has added one new host species for Australia and globally to the list of over 336 known myrtle rust hosts in Australia.
What is being done about Myrtle rust?
The Northern Territory Government takes biosecurity very seriously.
The Department of Primary Industry and Fisheries is investigating the extent of the myrtle rust infection area and working to identify the source of the infection.
Further DNA diagnostic work will be done to verify that this instance of Myrtle Rust is the same as the rest of Australia and not a new incursion of a different strain.
The Department has been working with the Tiwi Island Land Council in these investigations to date including their assistance in the delimiting surveillance and provision of information and advice on the ongoing management of myrtle rust on Melville Island.
Information has been provided to Tiwi Plantations Corporation for their consideration on future plantings on the island post the current harvest of Acacia for wood chips.
Can it be eradicated?
Myrtle rust cannot be eradicated, nor effectively contained or controlled in the natural environment. It will continue to spread because of the volume of spores it produces and their intense dispersal rate.
Although we can't eradicate the disease, we can attempt to reduce the rate at which it spreads in backyards and in native vegetation be it in park or in bushland.
We ask the community to do all it can to avoid spreading myrtle rust by being myrtle rust aware in their own backyard, in local parks and reserves and in the bush.
The Department of Primary Industry and Fisheries will be working with the nursery and garden industry to assist them in the ongoing management of myrtle rust in nurseries.
How can myrtle rust be managed?
In commercial nurseries, only use clean plant material, continuously monitor all known and potential host plants for symptoms, manage the plantings within the nursery to limit spread, implement a fungicide spray program for myrtaceous plants as this can effectively reduce the levels of myrtle rust infection in retail, wholesale and production nurseries and destroy any infected plants.
In backyards, do not move any infected host plants – destroy them, keep checking any known (check online lists) or potential hosts that you may have growing, only buy clean plants and clean any equipment or tools that you use and wash your clothes.
The full extent of myrtle rust in the Territory is not yet known. So any bushland that you are visiting could be infected with myrtle rust without you knowing it. Limit its potential spread by knowing what myrtle rust looks like on plants and avoid any areas of infection you come across, stay on tracks, clean all of your clothing, equipment and boots before moving to another bush location, make sure your vehicle is clean and report any suspect sighting.
Biosecurity is everyone’s responsibility, we all share the risk and we all share the responsibility to do everything we can to protect our natural resources.
How do I report suspected cases of myrtle rust?
Northern Territory residents and commercial nursery growers are asked to report any suspicious plant symptoms by contacting the Exotic Plant Pest Hotline on 1800 084 881.
We have learned from previous exotic plant disease detections that early detection and identification is vital to monitoring the spread and impact of a biosecurity incursion.