They’re a constant headache for Aussie growers, but you don’t have to tackle the weed battle alone. WeedSmart brings the industry together with practical, science-backed tactics that keep herbicides effective and crops thriving. It’s now the go-to hub nationwide for strategies that fight weeds and safeguard your farm’s future.
Program manager Karen Smith says it’s all about giving farmers confidence and control. “When growers implement WeedSmart’s Big 6 management practices, the resulting low weed environment allows them to make business decisions that are no longer dictated by weed pressure,” she says. “WeedSmart’s mission is to engage growers and advisors to adopt effective and practical weed management practices that result in ‘more crop and fewer weeds’.”
Australian grain producers have been contending with herbicide resistance in weeds since 1982. Since its launch in2013, WeedSmart has been helping growers and agronomists tackle herbicide resistance with practical, science-backed advice. The WeedSmart’s Big6 gives farmers an easy-to-follow roadmap for sustainable herbicide use, integrated weed management, and smarter, long-term cropping decisions.
For over a decade, WeedSmart has built a dynamic, national team of extension agronomists and communication specialist with financial backing from growers through GRDC investment and broad industry support from commercial machinery and agri-chemical partners. With a strong farming systems approach to integrated weed management, WeedSmart brings growers, agronomists and researchers together to formulate and share innovative and practical solutions to persistent and emerging weed challenges.
Why it matters
Weeds are a costly enemy. A recent report estimates that the average annual spend on weed control is $176/ha on grain farms — a huge outlay, but one that pays off by keeping residual weed densities low and yields intact. The challenge? Herbicide resistance is spreading, and without diverse tactics, costs will only climb.
That’s why WeedSmart’s Big 6 integrated weed management program is such a game-changer. It gives farmers a clear, practical framework for reducing weed populations and extending the life of herbicides.
WeedSmart’s Big 6 in action
Herbicide resistance can be tricky to manage, but with good advice and WeedSmart’s Big 6 checklist, you can quickly get an integrated plan in place to keep weed numbers down.
Chris Davey, WeedSmart’s southern extension agronomist based at Wallaroo, SA, says crop competition is a bit of a quiet achiever in weed control— and it works even better when combined with other tactics.
Chris says that if you do nothing else different except increase crop competitiveness, there will be fewer weeds in the crop and fewer weed seeds added to the seed bank. Increasing cropcompetition often reduces weedseed production by around 50%.
“When there is a competitive crop growing, the herbicides work better and harvest weed seed control works better,” Chris says. “By suppressing weed numbers, growers can avoid the difficulties that come with herbicide resistance and weeds have less control over crop choices.
“Everyone has seen weeds flourish in a bare patch in-crop,” he says. “The quicker the crop can cover the inter-row space, the better. This is where pre-emergent herbicides and varieties with rapid early growth work well together. More competitive crops also assist with holding weed seed heads in the canopy ready for destruction with harvest weed seed control tactics.”
WeedSmart’s Big 6 starts with boosting crop competition to keep weed seed production in check. From there, you layer on the other strategies — rotating crops, mixing herbicide modes of action, stopping weed seed set, and using harvest weed seed control — to tackle herbicide resistance and protect your business.
Let’s break it down….
Strategy 1: Increase crop competition
A competitive crop suffers less yield loss from weeds and helps reduce weed seed set. Choose crops and varieties that naturally suppress weed growth through shading and resource competition, focusing on early vigour and good canopy closure. There are six ways to boost crop competition: increase seedin grate, use narrower row spacing, plant east–west, address soil constraints, select vigorous or competitive varieties, and sow at the right time.
Strategy 2: Rotate crops and pastures
Short rotations can speed up herbicide resistance because weeds quickly adapt to predictable management. Mix up your cropping and pastures, using different planting and harvest times to disrupt weed life cycles. Double-breaks are an effective tool to drive down the seed bank of aggressive weeds like annual ryegrass.
Strategy 3: Mix and rotate herbicides
Relying too heavily on one or two herbicide modes of action is a recipe for resistance. Rotate modes of action to keep herbicides effective longer and use compatible mixes to protect each mode of action. Test weeds for resistance and susceptibility, and always apply herbicides at the full label rate.
Strategy 4: Optimise spray efficacy
Even the best herbicide won’t work if it doesn’t hit its target properly. Use the right application techniques and equipment, including nozzle type, spray pressure, and volume for the specific weeds you’re targeting. Make sure every dose counts.
Strategy 5: Stop weed seed set
Don’t let weeds top up the seedbank. Catch them early andprevent escapes by targetingweed patches effectively.Swathing, crop-topping, brownmanuring and cutting for hay areall very effective ways to nip aweed problem in the bud.
Strategy 6: Use harvest weed seed control
Capture and destroy weed seeds during harvest to stop them coming back next season. Timing and header height matter — aim to get as many weed seeds as possible into the header. There are six highly effective harvest weed seed control tools, including chaff carts, chaff lining, and impact mills. Pick the one that suits your operation best. You can also run management scenarios using AHRI’s Weed Integrated Management (WIM)software for annual ryegrass, brome grass, barley grass, wildoats, and barnyard grass. Weeds are persistent, so keeping them under control takes determination — and a solid plan. By implementing the Big6 strategies, you can cut weed numbers to reduce their impact on your crops and keep your weed control options wide open.
Big thanks to Chris Davey and Cindy Benjamin from WeedSmart for their valuable insight. Want more tips? You’ll find plenty of practical, cost-saving advice at their website : weedsmart.org.au