Driving down the seedbanks of difficult-to-control weeds such as flaxleaf fleabane requires diligent monitoring and control of herbicide survivors.
That’s the message from Dr Steve Walker, The University of Queensland (UQ), Queensland Alliance for Agriculture and Food Innovation (QAAFI) associate professor, Toowoomba who says seedbank management is a vital practice for all landholders.
“This approach will drive the seed bank down to very low numbers within several years, with few problems in following years,” Dr Walker said.
“Added to this, for best results, growers need to employ a combination of chemical and non-chemical tactics in the cropping and fallow phases.”
A new QAAFI fact sheet delivers the latest research recommendations for managing fleabane, including results of trials funded by the Grains Research and Development Corporation (GRDC).
Dr Walker says fleabane is very susceptible to several residual herbicides that can be used in fallows and a range of crops.
Other tactics include:
- a strategic soil disturbance that can create a soil environment unfavourable for germination;
- targeting small, actively growing weeds as age and, to a lesser extent, moisture stress, have a substantial adverse impact on efficacy of knockdown and selective herbicides;
- using the mix of glyphosate and 2,4-D (Amicide Advance 700®) or picloram + 2,4-D (Tordon 75-D®) to effectively control low-density infestations of young flaxleaf fleabane in fallows;
- employing the double-knock tactic to control dense infestations, especially if the weeds are more than one month old in fallows;
- choosing selective Group I herbicides to provide good control of young flaxleaf fleabane in wheat;
- considering crop competition to suppress fleabane growth and seed production; and
- maintaining good on-farm hygiene, with emphasis on controlling fleabane in areas surrounding paddocks to prevent new incursions.
To download the QAAFI fact sheet, visit www.qaafi.uq.edu.au/content/Documents/weeds/IWM-Fleabane-guide.pdf.
For more information on GRDC-funded weed research, visit www.grdc.com.au/weedlinks.
Dr Steve Walker
Associate Professor, The University of Queensland
Queensland Alliance for Agriculture and Food Innovation, Toowoomba
07 4639 8838 / 0419 463988
Rachel Bowman, Senior Consultant, Cox Inall Communications
07 3846 4380 / 0412 290 673