Farmers get on front foot in evolving war against weeds

Australia's science agency has studied how farmers stay one step ahead in the war against weeds. (Lukas Coch/AAP PHOTOS)

Australian grain and cotton growers are proving weeds can be beaten, investing significantly in strategies to help improve their control.

Managing weeds costs the grain and cotton industries an estimated $4.4 billion per year, a report from Australia's national science agency CSIRO has found.

Despite the large expenditure, growers are reaping the rewards. The impact of crop yield has fallen from 2.8 million tonnes in 2016 to 1.2 million tonnes in 2025, which translates into higher production and income.

Weed control is among the biggest costs for farmers but success can greatly increase yields. (HANDOUT/CSIRO)

"Weed control remains one of the biggest annual costs for growers, but the investment is paying off," CSIRO research scientist Rick Llewellyn said.

"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."

Weed management demands being on the front foot and strategic planning, central west NSW fifth-generation farmer Richie Quigley said.

"We spend a huge amount of time and money combating weeds and there is a lot of strategy behind it to make sure we are using all the tools in the toolbox," he told AAP.

"They are becoming much harder to kill and control and we have to be at the top of our game to be able to manage them."

Cotton growers and others are deploying strategy and technology as weeds become harder to manage. (Dave Hunt/AAP PHOTOS)

Growers are combining pre-emergent herbicides, harvest weed seed control, crop rotation and new precision spraying technologies in their management strategy.

Effective weed control was critical in adapting to climate change, CSIRO technical officer Jackie Ouzman said.

"Climate variability does pose significant challenges to growers but they are responding really positively to these challenges," she said.

"Growers are well positioned to cope with more variable climate, with the practises they're currently doing."

Ryegrass is among the most costly for Australian farmers in the evolving battle against weeds. (HANDOUT/CSIRO)

The most costly weeds to manage are 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.

The CSIRO study shows the need for continued investment in weed management research to unlock productivity, climate resilience and sustainable land use.

"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."