About 300 growers and advisers from across Australia’s grain-growing regions journeyed to Port Lincoln on South Australia’s Eyre Peninsula last month to share their stories, ideas and concerns at WeedSmart Week 2024.
WeedSmart’s project manager, Karen Smith, said the record crowd at the annual flagship WeedSmart event demonstrated how much growers value this practical and grower-centric gathering of minds.
“I’m incredibly proud of the program the WeedSmart team brought together again this year, led by Jana Freebairn and Chris Davey, our independent WeedSmart agronomists in South Australia, and several experienced Eyre Peninsula agronomists,” she said.
“The presentations were thought-provoking and highly relevant to farmers wanting to gain an upper hand on their weed challenges. The discussions amongst growers, advisors, and weed researchers brought to light many strategies that have been thoroughly tested in the field and research trial work.”
The broad cross-section of growers responded to the opportunity to engage with WeedSmart’s industry sponsors, who showcased their weed management products at the forum and the machinery expo.
WeedSmart is an independent stewardship project supported by the Grains Research and Development Corporation (GRDC), major agricultural companies, and university and government research partners, all of whom have a stake in sustainable farming systems.
Plant Science Consulting Dr Peter Boutsalis provided a resistance status update for the Eyre Peninsula, outlining the findings from recent herbicide resistance surveys and the implications for growers in the region.
The key weeds with herbicide resistance on the Eyre Peninsula are annual ryegrass, sowthistle and Indian hedge mustard.
Dr Boutsalis highlighted the importance of targeting weeds while they are small to maximise the efficacy of herbicides. The next national herbicide resistance survey is being conducted this season, and he is also investigating the control options for summer-germinating annual ryegrass on the Eyre Peninsula.
“Ryegrass on the Eyre Peninsula is accumulating resistance mechanisms, including an increase in resistance to the dim mode of action,” Dr Boutsalis says.
“Glyphosate resistance is allowing ryegrass to germinate and grow during the summer. Stopping weed seed set is crucial to slowing the progression of herbicide resistance,” he said.
Double-break cropping is a strategy that Nutrien Cleve Ag Services agronomist Giles Kearsley is implementing with some of his clients on the Eyre Peninsula to improve weed control, store sub-soil moisture, gain better nitrogen efficiency and grow more competitive crops.
To achieve long-term weed control, Mr Kearsley advocates identifying problem weeds on-farm and developing a three to five-year control plan that uses crop diversity to build soil fertility and utilise multiple herbicide modes of action. The plan is adjusted based on ongoing evaluation of any weeds that escape the control efforts in each crop phase.
David Giddings from Beaumont Farms summarised his approach to weed seed bank discipline and the value of soil amelioration and liming on the family’s 2100 ha cropping program at Wanilla and Wangary.
He aims to maintain low weed numbers by preventing weed seed set throughout the year, following a double-break rotation of lupins, canola, wheat, and barley, using the best available herbicide technologies and running an impact mill to collect and destroy weed seed present at harvest.
He finds long-term economic benefits flow from having a consistent rotation and being able to plan weed control strategies well into the future.
In an overview of summer weed control strategies for problem weeds, Josh Hollitt from Hollitt Consulting, Port Lincoln noted the importance of spraying small, actively growing weeds under the right conditions, using the best herbicides for the job, including well-planned residuals, and having a plan for particularly hard-to-kill weeds.
Vicky French farms with her husband Stewart at Derrinallum, in the high rainfall zone of southwest Victoria, where they are winning despite glyphosate resistance.
She believes acknowledging the existence and extent of herbicide resistance on-farm is a critical first step in addressing the problem and making the necessary changes to manage the weed seed bank.
The couple use all the WeedSmart Big 6 tactics to minimise the annual ryegrass and wild radish on their 800 ha mixed farming enterprise.
Ben and Belinda Wundersitz and the Anna Binna team have a 7000ha aggregation of farms on the central Yorke Peninsula, many of which were purchased with known weed and agronomic challenges. Lentils have been a key to their success in controlling weeds in the high, medium and lower rainfall zones.
The Anna Binna team has set about overcoming soil constraints such as rockiness, low nutrition and salinity to bring lentils into the rotation in areas where the crop was previously thought unsuitable. After rejuvenating the soils, Mr Wundersitz uses an effective herbicide package at seeding and utilises on-row seeding to maximise crop competition and achieve a 25 per cent yield improvement.
During the season, their agronomist visits the farms every ten days to respond to any emerging weed issues. They have also embraced new spray and harvest weed seed control technologies while keeping older techniques, like wick-wiping, in the toolkit. Their impact mill is proving very effective, particularly in lentils and windrowed barley.
On the second day Michael and James Minhard of Wilderness Trading welcomed the convoy of buses and utes to sites on their farms at Cummins.
The Minhard’s use tile drainage to improve spray timeliness for better weed management on poorly drained areas and a Reefinator to increase topsoil depth on rocky paddocks previously used for grazing sheep.
The final stop was a visit to Wilksch Agriculture farms in the Yeelanna and Cockaleechie districts on the Lower Eyre Peninsula. Jordan Wilksch outlined how they adapt their management on different soil types to implement the WeedSmart Big 6 strategies to keep weed numbers low.
No effort was spared to prepare for the machinery expo to showcase the herbicide application, weed detection, climate sensors, and harvest weed seed control technologies that WeedSmart partner companies offer.
Plans are in place for WeedSmart Week 2025 in Geraldton, to bring regionally-specific information on science-backed weed control solutions to growers and agronomists in Western Australia’s Wheatbelt region in August 2025.
For more information about integrated weed management, please visit the website: www.weedsmart.org.au
