Look west for directions in combating herbicide resistance

Author: Sharon Watt | Date: 09 May 2013

wheat

Herbicide-resistant weeds – the single largest threat to Australian and global food security – are spreading throughout the southern cropping region of southern New South Wales, Victoria, South Australia and Tasmania.

As the shift to more intensive cropping systems gains momentum and herbicide use increases, authorities say it could only be a matter of time before resistance levels in southern cropping states reach those of Western Australia where growers have been battling the nation’s highest incidence of herbicide resistance.

However, experts say the adoption of certain weed-seed control techniques that are now proving successful in WA could slow the spread of herbicide resistance in the southern region.

The Grains Research and Development Corporation (GRDC) and its research partners are advising southern grain growers to look to their counterparts in the West and learn from their experiences.

GRDC Plant Health Technologies Program Manager, Dr Ken Young, says along with having the second largest herbicide resistance problem in the world (behind the USA), Australia is also a world-leader in managing herbicide resistant weeds, which cost the nation’s growers more than $200 million every year.

“Necessity and targeted research, development and extension (RD&E) investment have bred impressive and world-renowned success in developing integrated approaches to weed management, and much of those advances have occurred in WA,” Dr Young said.

Dr Young said successful outcomes in the fight against herbicide resistance have been detailed in a new GRDC publication which outlines ways to extend the longevity of available herbicides so that cropping systems can continue to be productive and viable.

“The Making Herbicides Last supplement in Ground Cover magazine provides a comprehensive snapshot of the extent of herbicide resistance in Australia and around the globe, and offers useful information on the measures that can be taken to thwart the spread of resistance.” The supplement has been mailed to growers with the latest edition of Ground Cover magazine and is also available for viewing and downloading via www.grdc.com.au/GCS104.

The publication includes information of 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 – which are set to have a significant impact on reducing the effect of weeds and herbicide resistance in Australian cropping systems.

“The GRDC together with the University of South Australia have invested in the development of the next generation of HSD technology (the brainchild of WA inventor and grower Ray Harrington), with a longer term aim of integrating an ‘HSD-like’ process into the harvester itself. The plan is to produce a fully functional prototype, capable of being retrofitted to a class 9 harvester.

“This technology will be in addition to the commercial trail-behind HSD units that are already in production and available through DeBruin Engineering of Mount Gambier in SA,” Dr Young said.

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,” Dr Young said.

“And 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.”

As herbicide resistance in ryegrass and wild radish continues to increase in the southern cropping region, Dr Young said implementation of chemical and non-chemical practices that curb herbicide resistance developing in weed populations was essential.

To further assist the grains industry in combating herbicide resistance, the GRDC has teamed with government, university and commercial partners to launch the website www.weedsmart.org.au – a first-point-of-call resource hub where growers and advisers can access the latest information on sustainable herbicide use in Australian agriculture.

Caption: A new GRDC publication outlines ways to extend the longevity of available herbicides so that cropping systems can continue to be productive and viable.

For Interviews

Dr Ken Young, GRDC
02 6166 4500

Sharon Watt, Porter Novelli
0409 675100

GRDC Project Code UWA00146, UWA00124, DAW00196, UQ00067

Region South, North