Myrtle rust spreading on the wind
A spate of recent detections on the NSW North Coast and in Queensland indicates that Myrtle rust is spreading readily, the NSW Chief Plant Protection Officer, Dr Satendra Kumar said.
"It has always been known that Myrtle rust – like other rust diseases – is highly transportable, making it extremely difficult to contain and eradicate," Dr Kumar said.
"We know it is widely distributed on the central coast from Sydney up to Newcastle in people's backyards and in bushland.
"With these latest detections on the North Coast, and detections in south east Queensland, it appears that Myrtle rust is spreading quickly and eradication is clearly not feasible.
"This is often the case with some plant pests as by the time they are reported to authorities they have already become established and spread in production and natural vegetation."
Dr Kumar said it is now believed that Myrtle rust was present in Australia many months prior to detection in April 2010, and that it took some time for the rust to build up to detectable levels.
"Once detected, extensive surveillance was conducted and an eradication attempt was initiated, even though the chances of containment and eradication were low," he said.
"Air currents, coupled with high summer temperatures and humidity are ideal conditions for Myrtle rust spores to travel on warm air currents and settle on susceptible host plants.
"It can also be easily spread by humans on clothing, equipment, vehicles and the movement of infected plants.
"Unfortunately Myrtle rust is now considered established in parts of NSW and will invade other parts of the state where environmental conditions are right.
"Our job is now to work with industries in assisting them to improve their biosecurity measures and get them working with scientists and research and development organisations to develop integrated disease management for this serious pest."
Management zones have been established in NSW to assist ongoing management of Myrtle rust.
"The red zone, stretching along the eastern seaboard from Shoalhaven local government area to the Queensland border is where Myrtle rust is considered established and the remainder of the State is a green zone," Dr Kumar said.
"Our aim is to minimise human spread of the rust from the red zone to the green zone.
"A large part of this will rely on Government, industries and community groups doing all they can to reduce the risk of spreading this disease through their day to day activities."
Myrtle rust is a pathogen of Eucalypts and other plants in the family Myrtaceae that are important to forestry, nursery, tea tree oil and bush food production, as well as being important assets to Australia's floral biodiversity.