The need to learn to love the herbicides we have

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Herbicide-resistant weeds represent the single largest threat to Australian and global food security – and cost Australian growers more than $200 million every year.

However, along with having the second largest herbicide resistance problem in the world (we were recently knocked out of first place by the US), Australia is also a world-leader in managing herbicide-resistant weeds. Necessity and targeted research, development and extension investment have bred impressive and world-renowned success in developing integrated approaches to weed management.

Innovations such as the GRDC-funded Harrington Seed Destructor (HSD), which can remove up to 95 per cent of weed seed in the harvested chaff fraction, are set to have a significant impact on reducing the effect of weeds and herbicide resistance in our cropping systems. Developed initially by Western Australian inventor and grower Ray Harrington, with GRDC funding the HSD has recently been fully integrated into a class 9 header and will become widely used within the next few years.

The GRDC’s investment in herbicide resistance RD&E is channelled through the Australian Herbicide Resistance Initiative (AHRI), which is based in Perth and directed by a world leader in herbicide resistance research, Professor Stephen Powles. Through AHRI, integrated management systems for each of Australia’s growing regions have been developed and tested and the genetic mechanisms through which weeds outsmart herbicides are continuing to be unravelled.

With six weed species now confirmed to have glyphosate-resistant populations across Australian cropping systems, the work of the GRDC-supported Australian Glyphosate Sustainability Working Group is more important than ever. The group’s national training work in integrated weed management is helping to prolong the life of our most valuable knockdown herbicide, better understand how weeds become resistant to its chemistry, and monitor and better manage the risk of glyphosate resistance spreading further.

Australian cropping systems rely on herbicides with only six modes of action and the likelihood of herbicides with different chemistries becoming available in the near future is very low. Professor Powles says: “We need to learn to love the herbicides we’ve got”. This means implementing chemical and non-chemical practices that curb herbicide resistance developing in weed populations.

The GRDC, with government, university and commercial partners, has launched a website ( – a first-point-of-call website where growers and advisers can access the latest information on sustainable herbicide use in Australian agriculture.

This Ground Cover supplement outlines ways to make our limited herbicides last as long as possible so that our cropping systems continue to be productive and viable.

More information:

Dr Ken Young, GRDC,
02 6166 4500,

Next: Glyphosate lost to the US