A new report reveals Australian grain and cotton growers are achieving productivity gains by investing in smarter, long-term weed management strategies, proving weeds can be beaten.
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A decade from the last national estimate, new CSIRO research has found weeds cost the grain and cotton industries an estimated $4.43 billion per year.
Considering inflation and adjusted values, this is a 7 per cent increase in costs for grain growers, however despite this increase in costs, growers are reaping the rewards of their investment.
Through proactive management and innovation, the impact of weeds on crop yield has fallen, from 2.8 million tonnes in 2016 to 1.2 million tonnes in 2025 translating into higher production and income.
“Weed control remains one of the biggest annual costs for growers, but the investment is paying off,” says Rick Llewellyn, the CSIRO research scientist who co-authored the report led by Jackie Ouzman.
“By staying ahead of the weed seed bank, resistance and adopting smarter, more targeted practices, growers are protecting long-term profitability and enabling flexibility in their system,” he says.
Australian growers lead the way with integrated weed management, combining pre-emergent herbicides, harvest weed seed control, crop rotation and new precision technologies such as camera-guided spraying.
One of the biggest gains comes from improved summer fallow weed control, which helps conserve valuable soil moisture and supports better crop establishment in drier seasons, an essential part of farming in a changing climate.
“Effective weed control is a critical part of climate adaptation,” Dr Llewellyn says.
“With increasingly variable rainfall and larger cropping programs, growers need to sow crops when conditions are right without delays for weed control,” he says.
The 2025 study also includes cotton production for the first time, offering a fuller picture of weed impacts across Australia’s two largest cropping sectors.
Weeds cost producers on average ($203 per ha) in grain crops and ($445 per hectare) in cotton crops – with cotton growers shown to invest heavily in keeping weed densities exceptionally low.
“Australian growers are showing global leadership in weed management, but the cost increases are real,” Dr Llewellyn says.
“We need to keep supporting research and find ways to stay ahead of evolving weed challenges while also reducing these costs,” said Dr Llewellyn.
The study reaffirms continued investment in weed management research, not just for reducing losses, but for unlocking gains in productivity, climate resilience and sustainable land use.
Ryegrass in wheat is an annual headache
According to Rick Llewellyn from CSIRO, weed control remains one of the biggest annual costs for growers.
“The only reason we’re not seeing widespread yield losses from weeds today is because of years of sustained research and grower innovation,” Dr Llewellyn said.
“This is a quiet success story, but it’s a battle where you can’t pause - the weed challenge keeps evolving and demanding new solutions.”
New weed threats continue to emerge at a local level but nationally the costliest weeds remain familiar: ryegrass, brome grass, sow thistle, wild radish and wild oats, while the costliest fallow weeds in grain production at a national level are melons, heliotrope and fleabane.
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