Target fleabane in early spring
GroundCover™ Issue: 106 | Author: Deanna Lush
Moving the main battle against fleabane to earlier in the season when plants are seedlings, rather than late spring and summer, is the key to improving control.
New South Wales Department of Primary Industries senior weeds research scientist Dr Hanwen Wu says there are seven species of fleabane, but the three most common in southern Australia are flaxleaf, tall and Canadian fleabane.
“Of these three common species, flaxleaf fleabane is the most predominant in cropping regions,” he says. “But it is easy to confuse the different fleabane species, particularly when plants are in early growth stages.”
The tools to control fleabane include herbicide, strategic cultivation, crop and pasture competition, mowing and grazing.
Dr Wu says in-crop management to tackle plants while they are small should be the first and most effective strategy. Currently, Amicide® Advance 700 is the only registered in-crop option for control of fleabane up to the six-leaf stage in cereals. FallowBoss® TORDON is a new in-crop option that will be available from October 2013.
The most consistent and widely adopted double-knock for fleabane control in fallow is a mix of glyphosate and 2,4-D as the first application, followed several days later by a paraquat or paraquat and diquat-based product as the second knock.
The double-knock is more reliable than single-knock treatments across seasons, especially on older fleabane.
If populations are dense and herbicide is ineffective, strategic cultivation to pull out plants and bury seeds can be used where there is an appropriate opportunity within a farm system.
Fleabane is a poor competitor, so improved crop or pasture competition can be an effective non-chemical option for reducing fleabane.
IMAG Consulting agronomist Cameron Corke, from Forbes, NSW, says early control, when the weed is young and small, is easier than when plants are larger. But if control is attempted on bigger plants, a double-knock is still an effective option in summer fallow.
He says drier conditions have seen the decline of fleabane in the past year, to the point where some growers believe they have the weed under control. But he says a wet summer will test the extent to which weed control has improved.
More information:Dr Hanwen Wu,
02 6938 1602,
GRDC Project Code CSU00006
Region South, North