Multi-pronged attack needed in fight against fleabane weed
Grain growers are being advised to adopt a multi-pronged attack in their efforts to combat the weed flaxleaf fleabane, which in recent years has become a major issue in southern cropping regions.
Weed management authorities, with support from the Grains Research and Development Authority (GRDC), say the best form of defence against fleabane is an integrated approach combining the use of competitive crops and pastures, grazing, herbicides, cultivation and targeting weeds at the vulnerable stages of their lifecycle.
Consultant Chris Minehan, of Rural Management Strategies at Wagga Wagga (NSW), says early detection of fleabane is important and therefore growers should now be controlling autumn germinations.
“Fleabane can produce in excess of 100,000 seeds per plant, allowing it to rapidly colonise bare ground.
“While most problematic in summer, fleabane can germinate at any time of the year given moisture and appropriate temperature,” said Mr Minehan, who has been speaking about the problem at GRDC grains research Updates.
“Fleabane seedlings germinate from the soil surface and even young seedlings are relatively tolerant to glyphosate herbicides.
“The evolution of cropping systems from broad scale cultivation towards chemical weed control based largely on glyphosate has provided fleabane and other surface germinating weeds with a competitive advantage.”
Mr Minehan said it was therefore necessary to enlist additional forms of control, and regardless of the measures used, targeting weeds when young and actively growing was the factor most critical to effective management.
A ‘double knock’ approach with a range of primary herbicides, followed by paraquat, is one recommended component of an integrated control management program.
Because fleabane seeds require sunlight to germinate and weeds are relatively uncompetitive as seedlings, growing competitive crops and pastures is another strategy, while grazing also offers benefits.
“Sheep and cattle will both graze fleabane, particularly when little other food is available,” Mr Minehan said.
“Grazing can be particularly useful in stubble situations where fleabane populations are low. Other weeds can be controlled cheaply and easily, leaving only the fleabane alive for stock to graze.”
Landholders are advised to also target fencelines and roadsides, as well as crops, pastures and fallow paddocks, in their bid to manage the weed.
The GRDC is currently funding research into the biology and management of fleabane.
Caption: Landholders are advised to also target fencelines and roadsides, as well as crops, pastures and fallow paddocks, in their bid to manage fleabane.
GRDC Project Code: ORM00001, UA000113
Media releases and other media products can be found at www.grdc.com.au/media
For further information: Chris Minehan
Rural Management Strategies
Contact: Sharon Watt
GRDC Project Code