Sweetwater Fishing Forums
General Category => News Views & Press Releases => Topic started by: Qld Fisheries, Editor on March 11, 2011, 04:00:43 PM
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Closing in on aquatic weed control
Biosecurity Queensland has three of the world's worst aquatic weeds in its sights with the completion of a crucial study into their control.
Water lettuce, water hyacinth and salvinia are considered to be some of the most invasive and difficult to control floating aquatic plants.
Biosecurity Queensland weed scientist Dr Tobias Bickel said these weeds quickly spread within waterways, smothering natural ecosystems and interfering with both agricultural and recreational use.
"They are notorious for not only outcompeting native vegetation, but for actually damaging the environment," Dr Bickel said.
"They significantly affect water quality by reducing oxygen levels, which can be deadly for many native aquatic animals.
"Add this to the fact that water hyacinth makes the water more acidic and increases loss of precious freshwater resources through transpiration.
"Aquatic animals are not the only ones that suffer, with these weeds providing the perfect breeding grounds for mosquitoes, which can be a threat to human health."
The study not only compared the weeds to determine which was the worst ecologically, but also looked at the success of various herbicides used to control them.
"We tested a range of herbicides to see how effective they were in controlling these weeds throughout different seasons," Dr Bickel said.
"While water lettuce was readily controlled and water hyacinth responded well to one of the herbicides, salvinia was harder to deal with.
"We found that the herbicide most successful on salvinia is currently not registered for its control, although we understand that this will change in the not too distant future."
Dr Bickel said timing also played a large part in the efficient control of these weeds as they reacted at different rates according to season.
"Herbicidal control works better in warmer conditions when the weeds are actively growing," he said.
"Ironically, killing aquatic weeds too fast can cause problems as well.
"The dead and dying weeds create a mat on the water and start to decay. This adds even more nutrients to the water and reduces oxygen levels.
"The study will certainly assist in developing effective aquatic weed management strategies and is an important step in the fight against these weeds."
For more information on aquatic weeds contact Biosecurity Queensland on 13 25 23 or visit www.biosecurity.qld.gov.au
Follow us on twitter @BiosecurityQld and on Facebook: Biosecurity Queensland.
http://www.dpi.qld.gov.au/30_20172.htm
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One of the most effective strategies for dealing with aquatic weeds particularly floating ones, is to jump on the gains provided by large flood spates like we've just experienced throughout Qld - mopping up small residual infestation in weed refugia uses less chemical than tackling entrenched infestations head on and prevents the accumulation of biomass/ and organic matter that underpins nutrient levels supporting infestations and which crashes dissolved oxygen levels when spayed and left to sink/decay !
I hope NRM organisations and biosecurity agencies throughout the State are currently out there doing just that...? :)
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From the top flexibility in funding, from ground level the foresight to see the opportunities and from the regionals pulling it together. A bit of work there.
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A fanstastic opportunity to erradicate many weeds is here. In my local area, the Brisbane River runs right in front of here. It was totally blocked not so long back in rafts over a kilometer long. I'd hate to see it get back to that state..... :walkplank
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I thought they had a bug to chew up the salvinia?
I've not seen any salvinia at all in North Pine since the big floods, be good to be rid of it for a while. Hope they are out there spraying the residual!
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http://www.dpi.qld.gov.au/documents/Biosecurity_EnvironmentalPests/IPA-Salvinia-PP12.pdf
Salvinia weevil, not as effective in some places as it is in others. The double edged sword with flood events is that they can spread weeds into uninfested areas as well as reduce their presence