Australia: Deadly New rust spore disease savages east coast trees
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-Pastor-Dale-Morgan-
Mar 12, 2012, 3:56:37 AM3/12/12
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Plagues,
Pestilences and Diseases
Australia: Deadly New rust spore disease savages east coast trees
The World Today
By Timothy McDonald
Posted March 12, 2012 15:47:06
Photo: Myrtle rust attacks trees' leaves. (ABC News: Timothy McDonald)
A newly arrived tree disease is spreading rapidly along Australia's east coast, and advocacy groups say it should serve as a wake-up call for the Government to overhaul its procedures for halting invasive species.
Myrtle rust originated in South America, where it probably evolved as part of a wider ecosystem and therefore did not pose much of a threat to local species.
But it has been on the radar as a potential problem for Australia for some time because it did have a significant impact on eucalyptus plantations there.
Spores of the strain in Australia most likely came in from Hawaii, maybe on the bottom of a pallet or possibly on someone's hiking boot. Nobody really knows.
But the impact could be huge because hundreds of Australian native species are susceptible to the rust, which infects and often kills off new leaves.
It was first discovered in Australia on the central coast of New South Wales.
Dr Angus Carnegie, a senior research scientist with the NSW Department of Primary Industries, is monitoring a patch of turpentine trees in the Olney State Forest, north of Sydney, where current conditions are ideal for the rust.
"It needs this sort of nice, moist weather - leaf wetness and good temperature are really good conditions for the rust," he said.
"But to help it spread it actually needs dry conditions... so if you have nice weather like we've had in the last couple of days in Sydney and then you get a string of really nice, hot days, then you can get the rust developing and producing a lot of spores, a lot of pustules."
Here to stay
Dr Carnegie says myrtle rust is here to stay, and the best the authorities can hope for now is to try and manage the problem.
"These old leaves that have been sitting on here for 12 or more months, they'll eventually drop off and all these new leaves are getting severely diseased and they die as well," he said.
"What we're trying to do here is compare the impact of the disease on a tree that has the disease and one that doesn't have the disease. And one of the things we're trying to look at here also is these trees that are severely diseased, do they flower, and therefore fruit, and then provide for the next generation of seedlings?"
But he says at this stage there is no indication one way or the other.
"We know that the fruit and flower are infected and Geoff Pegg, a colleague in Queensland, has been monitoring fruit infection of Rhodamnia up there, and what happens is the fruit gets infected and it's prematurely dropped," he said.
"So one of the things that we're hoping to look at is seeing how widespread that it, is there any viable seed within those fruit capsules and things like that."
Flow-on effect
Dr Carnegie says it may also have a flow-on effect to animals.
"Just looking around us here within a sort of 10-metre radius, there's several hundred of these plants here. So it's quite a dense understorey here," he said.
"If this all dies out, what replaces it? Is it a weed like lantana? Is it another native rainforest species? And what are the flow-on effects for the fauna - vertebrates and mammals, birds - that use the fruit and the flowers?"
Photo: Dr Angus Carnegie, a senior research scientist with the New South Wales Department of Primary Industries, examines a leaf with myrtle rust. (ABC News: Timothy McDonald)
Dr Matthew Crowther, a lecturer in wildlife management at Sydney University, says the fact the rust attacks freshly sprouted leaves suggests it could be a very serious problem for koalas.
"Attacking young leaves and basically getting rid of them is of particular concern - not just to the short term of the koalas eating those leaves but in the long term for the viability of that plant to support koalas," he said.
Anthony Kachenko, the environmental and technical policy manager for Nursery Garden Industry Australia, says there is potential for economic impact as well.
"We don't have data to actually pinpoint how much it has in fact cost the industry as a whole," he said.
"However, there are cases where individual growers, for example, have invested up to $50,000 in new spray rigs."
'Nuclear bomb'
One advocacy group says the authorities knew of its effect on South American plantations for years before its arrival in Australia, so they should have seen myrtle rust coming.
Invasive Species Council chief executive John Dejose says it is the equivalent of a nuclear bomb for Australian ecosystems.
"We just cannot understand the decision after only one week to declare the myrtle rust ineradicable," he said.
"In the event this was a decision that was reversed, and then reversed again, we can't get any straight answers out of the Department of Agriculture, Fisheries and Forestries about the myrtle rust incursion response.
"They don't seem to want to talk about it. We think that there is a review needed."
The World Today approached the Department of Agriculture, Fisheries and Forestry for a response. The Department did not provide comment.
Topics: environment, pests, natives, rain-forests-and-forest, nsw, australia
Australia: Deadly New rust spore disease savages east coast trees
The World Today
By Timothy McDonald
Posted March 12, 2012 15:47:06
Photo: Myrtle rust attacks trees' leaves. (ABC News: Timothy McDonald)
A newly arrived tree disease is spreading rapidly along Australia's east coast, and advocacy groups say it should serve as a wake-up call for the Government to overhaul its procedures for halting invasive species.
Myrtle rust originated in South America, where it probably evolved as part of a wider ecosystem and therefore did not pose much of a threat to local species.
But it has been on the radar as a potential problem for Australia for some time because it did have a significant impact on eucalyptus plantations there.
Spores of the strain in Australia most likely came in from Hawaii, maybe on the bottom of a pallet or possibly on someone's hiking boot. Nobody really knows.
But the impact could be huge because hundreds of Australian native species are susceptible to the rust, which infects and often kills off new leaves.
It was first discovered in Australia on the central coast of New South Wales.
Dr Angus Carnegie, a senior research scientist with the NSW Department of Primary Industries, is monitoring a patch of turpentine trees in the Olney State Forest, north of Sydney, where current conditions are ideal for the rust.
"It needs this sort of nice, moist weather - leaf wetness and good temperature are really good conditions for the rust," he said.
"But to help it spread it actually needs dry conditions... so if you have nice weather like we've had in the last couple of days in Sydney and then you get a string of really nice, hot days, then you can get the rust developing and producing a lot of spores, a lot of pustules."
Here to stay
Dr Carnegie says myrtle rust is here to stay, and the best the authorities can hope for now is to try and manage the problem.
"These old leaves that have been sitting on here for 12 or more months, they'll eventually drop off and all these new leaves are getting severely diseased and they die as well," he said.
"What we're trying to do here is compare the impact of the disease on a tree that has the disease and one that doesn't have the disease. And one of the things we're trying to look at here also is these trees that are severely diseased, do they flower, and therefore fruit, and then provide for the next generation of seedlings?"
But he says at this stage there is no indication one way or the other.
"We know that the fruit and flower are infected and Geoff Pegg, a colleague in Queensland, has been monitoring fruit infection of Rhodamnia up there, and what happens is the fruit gets infected and it's prematurely dropped," he said.
"So one of the things that we're hoping to look at is seeing how widespread that it, is there any viable seed within those fruit capsules and things like that."
Flow-on effect
Dr Carnegie says it may also have a flow-on effect to animals.
"Just looking around us here within a sort of 10-metre radius, there's several hundred of these plants here. So it's quite a dense understorey here," he said.
"If this all dies out, what replaces it? Is it a weed like lantana? Is it another native rainforest species? And what are the flow-on effects for the fauna - vertebrates and mammals, birds - that use the fruit and the flowers?"
Photo: Dr Angus Carnegie, a senior research scientist with the New South Wales Department of Primary Industries, examines a leaf with myrtle rust. (ABC News: Timothy McDonald)
Dr Matthew Crowther, a lecturer in wildlife management at Sydney University, says the fact the rust attacks freshly sprouted leaves suggests it could be a very serious problem for koalas.
"Attacking young leaves and basically getting rid of them is of particular concern - not just to the short term of the koalas eating those leaves but in the long term for the viability of that plant to support koalas," he said.
Anthony Kachenko, the environmental and technical policy manager for Nursery Garden Industry Australia, says there is potential for economic impact as well.
"We don't have data to actually pinpoint how much it has in fact cost the industry as a whole," he said.
"However, there are cases where individual growers, for example, have invested up to $50,000 in new spray rigs."
'Nuclear bomb'
One advocacy group says the authorities knew of its effect on South American plantations for years before its arrival in Australia, so they should have seen myrtle rust coming.
Invasive Species Council chief executive John Dejose says it is the equivalent of a nuclear bomb for Australian ecosystems.
"We just cannot understand the decision after only one week to declare the myrtle rust ineradicable," he said.
"In the event this was a decision that was reversed, and then reversed again, we can't get any straight answers out of the Department of Agriculture, Fisheries and Forestries about the myrtle rust incursion response.
"They don't seem to want to talk about it. We think that there is a review needed."
The World Today approached the Department of Agriculture, Fisheries and Forestry for a response. The Department did not provide comment.
Topics: environment, pests, natives, rain-forests-and-forest, nsw, australia
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