A NEW aquatic herbicide is being used locally to control one of Australia’s worst aquatic weeds before it can spread.
Cabomba, a weed of national significance, was once a popular aquarium plant that has since become a serious weed in many waterways.
The frontline weapon is the recently released shark herbicide, which was approved for registration by the Australian Pesticides and Veterinary Medicines Authority in 2011 for use against cabomba after research by the Department of Primary Industries (DPI).
Great Lakes Council and the Mid-North Coast Weeds Committee have joined forces to tackle the weed which forms dense underwater thickets that can displace native plants and significantly reduce fish stocks.
Great Lakes Council’s noxious weeds inspector Terry Inkson says cabomba poses a significant risk to waterways in the Great Lakes Council area.
“Nine cabomba infestations in the local government area are contained in pond waterways such as farm dams,” Mr Inkson said “but each could spread if they go unmanaged.
“It could threaten the significant biodiversity values of the Ramsar wetlands of Myall Lakes National Park, should it get there,” he said.
According to Andrew Petroeschevsky from the Department of Primary Industries, severe infestations can also pose a safety risk to swimmers as the plants can be hard to see and it’s possible for swimmers to get entangled in the thickets.
In 2011 the Mid-North Coast Weeds Committee received a Caring for our Country grant to destroy cabomba infestations.
According to Mr Inkson the shark herbicide provides the only feasible solution.
Being a submerged plant cabomba is very difficult to control. There are no biological controls available and other options such as mechanical removal or temporarily draining dams do not provide a long term solution - the weed just comes back after a few months.
“We are pioneering the use of this product so we will be working closely with DPI and the herbicide manufacturer to gauge its performance.”
Recent wet weather caused a delay but with resumption, the goal is now to destroy infestations by June 2013.
Mr Inkson said results of the first herbicide applications were promising.