Jennifer Marohasy

a forum for the discussion of issues concerning the natural environment

Exotic Disease Threatens Australian Eucalyptus

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Exotic diseases represent a significant threat to Australia’s unique fauna and flora.

Dramatic declines in frog numbers in the 1970s were initially blamed on habitat destruction associated with logging.  It was not until twenty years later that the disease Chytridiomycosis caused by the fungal pathogen Batrachochytrium dendrobatidis was positively identified and is now officially recognized as the cause of four species extinctions.  The disease is thought to have spread from Africa.

The Myrtle rust is an exotic disease from South America with the potential to infest many Australian native plants including Eucalyptus.  The disease was first detected in Australia on the Central Coast of New South Wales in April 2010.   Recently it was found in southeastern Queensland.   In an attempt to stop the spread of the disease it is rumoured some National Parks could be closed to visitors.

According to advice from the Commonwealth:

“The fungus that causes Myrtle rust has not been found before in Australia. It belongs to a group of fungi known as the ‘guava rust complex’. This complex of diseases is native to South America and is also present in the United States of America (Florida and Hawaii) and Mexico. It is not known how Myrtle rust entered Australia. Rust fungi produce microscopic spores which are carried by wind, people’s clothing, plants or goods that are shipped around the world.

“Based on advice from the Consultative Committee on Emergency Plant Pests and following the completion of actions undertaken under an interim response plan, the Myrtle rust NMG has agreed that it is not technically feasible to eradicate the rust.

“The decision of the NMG reflects the impossibility of eradicating and slowing the spread of this disease. This is based on understanding the behavior of the disease, its increasing host range and its spread beyond the New South Wales Central Coast to a large number of domestic, commercial, public and recreational sites.

“However, recognising the importance of ongoing chemical control, the Myrtle rust NMG has agreed that securing product registration for chemical use for all jurisdictions beyond the emergency response is an immediate priority…

http://www.daff.gov.au/aqis/quarantine/pests-diseases/myrtle-rust/update_on_response_to_myrtle_rust

And also:

Bell Miner Associated Dieback (BMAD) currently occurs through sclerophyll forests on public and private lands in New South Wales, Victoria and Queensland. These forests are regionally important for plant and animal conservation, water catchment management, tourism and the production of honey and timber. This form of dieback is of national significance as it is spreading through forest ecosystems in eastern Australia…

http://www.bmad.com.au/about.html

Reader Interactions

Comments

  1. Ian Mott says

    Given the Qld governments callous and indifferent treatment of farmers under the vegetation legislation over the past decade, it is quite likely that a black market could develop for infected material to aid in the removal of vegetation this community no longer deserves. If communities get the government they deserve then communities also get the environment their government deserves.

    I actually raised this prospect of South American pathogens in eucalypt plantations making their way here at a meeting of the Regrowth Foresters almost a decade ago. One member, only half jokingly, volunteered to go there and bring some back, but only if we paid his airfare. We had some lengthy discussion as to how the impacts could be minimised in our own forests and how they would be exacerbated in national parks. But no notes were taken and the general mood of the meeting was basically one of “f@$& you, Aila, you’ve had it coming”.

  2. Jennifer Marohasy says

    from Bill Burrows
    ********************

    G’day

    This organism attacks species in the Myrtaceae family which not only includes the eucalypts
    but also the beach cherry (Eugenia reinwardtiana) which I am growing for its very tasty cherry like fruit. If it took hold here it would certainly lower the capacity of our eucs to act as a CO2 sink (which if counted in Qld alone would reduce Australia’s stated net emissions by c.25%). So at least from the atmospheric concentration point of view the arrival of this disease could have a significant impact – although whether good or bad in this case depends on your global warming beliefs.

    But I for one would hate to see the eucs infested as they get a good enough doing over by native insects already (spray the foliage of an accessible tree regularly with Rogor or visit California to see what a euc with intact foliage really looks like!). And even in my most enthusiastic woodland management moments I have always argued for at least 20% retention in intact blocks or strips. However It is unlikely that if the organism naturalises here it will be kind enough to leave even my ‘retained’ trees in good shape.

    Of course there are a few factors also in our favour in limiting potential spread – the dry climate & regular burning (as in pre-european) should act as a good brake. But neither would help the avid urban greenie with his native garden. Then again if you recall over the years there have been a multitude of introduced organisms going to wipe out this or that but our native systems have generally adapted over time to leave the organism as a chronic pest, rather than a portent of Armageddon.

    Cheers
    bill b

  3. Larry Fields says

    I’ve read about a similar problem with root-rot in Jarrahs in the SW part of WA, and about the vehicle-access-limitation measures being taken to limit the spread. If I ever visit your charming little continent, hiking in a Jarrah forest, and experiencing these magnificent trees will be high on my list of priorities.