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Farmers agree they should do more herbicide resistance testing

Updated: Dec 16, 2021

Testing weeds for herbicide resistance is an important tool in weed management, yet it is underutilised by many grain farmers. The Grains Research & Development Corporation (GRDC) has recently invested with the Australian Herbicide Resistance Initiative (AHRI) team targeting the sampling of problem weed populations on farms to be tested against both single and combinations of herbicides.

This investment also partnered with UWA and CSIRO researchers to design and conduct a survey to identify farmers’ and agronomists’ perception of each sample herbicide resistance status. Each herbicide resistance test result was compared to each farmers perception of the resistance status. Agronomists were asked about their perception of each farm’s resistance status.

The results clearly showed that:

  • most farmers relied on visual survival of weeds to inform their perception of herbicide resistance status;

  • farmers often overestimated their resistance status of some herbicides, and this potentially limited their use of certain effective herbicides;

  • farmers were more likely to underestimate the resistance status of wild radish to important broadleaf herbicides;

  • often the value of having accurate information on weed resistance status is being able to use cheaper chemicals for longer by knowing susceptibility status;

  • barriers to adopting more resistance testing and ideas for making testing easier for farmers were brainstormed.

After the survey and analysis of the results, the researchers conducted a series of workshops with farmers and agronomists to present the findings on the resistance test results, and the comparison between actual test result and farmers perception. The workshops were a good way to build understanding on the issue of herbicide behaviour and testing with the farmers.

We probably overestimate our amount of herbicide resistance. Testing is the key to knowing.” [Farmer]
"(A benefit of the workshop is that) the information is coming straight from the research team… I think it sinks in better.” [Farmer]

Through these workshop discussions it became evident that most farmers agreed more resistance testing was needed in future.

I think this project could not have had a greater impact. Credit to GRDC to have identified the need for behavioural economists together with the herbicide resistance research component” [Dr Roberto Busi, Australian Herbicide Resistance Initiative]

GRDC Project Code: UWA2006-006SAX

For more information, contact UWA researcher, Fiona Dempster at:


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