Western Australia
May 4, 2011

With the recent discovery of WA’s first glyphosate-resistant awnless barnyard grass from the Ord River region growers are being urged to consider using a range of weed control options.

Agronomist Andrew Cripps from the Ord River District Co-operative Ltd (ORDCO) identified suspect populations and contacted the Australian Herbicide Resistance Initiative (AHRI) for assistance in confirming resistance.

Research associate Dr Todd Gaines from AHRI based at The University of Western Australia (UWA) visited Kununurra and has now shown that several populations of awnless barnyard grass (Echinochloa colona) are glyphosate-resistant.

Glyphosate-resistant awnless barnyard grass in a paddock near Kununurra, WA. (Source: Todd Gaines AHRI)

“We confirmed populations from two paddocks that are 8-fold more resistant than susceptible populations collected in the region. The good news is that these populations are controlled by Group A and B herbicides, as well as paraquat and glufosinate.” Dr Gaines said.

Agronomist Andrew Cripps who has been working in the Ord River region for several years explains “The Ord River region is home to diverse cropping systems in a tropical environment, with horticulture, tree and grain crops being the major crops grown. Glyphosate is relied upon heavily for weed control in this area and growers need to start implementing a range of weed control tactics in order to sustain the life of glyphosate in the Ord.”

A paddock near Kununurra, WA, infested with glyphosate-resistant awnless barnyard grass. (Source: Todd Gaines AHRI)

AHRI Director Professor Stephen Powles stated “Future AHRI research will involve investigating the resistance mechanism in these populations, as well as providing recommendations to Ord River region farmers about how to manage and minimize the evolution of glyphosate resistance in barnyard grass.”

Professor Powles stated “There are several glyphosate-resistant barnyard grass populations in Queensland and New South Wales. It’s important for all industries who use glyphosate for weed control to understand and recognise that glyphosate resistance can and will evolve. To combat resistance, diversity in weed control tactics is essential to help minimize resistance evolution.”

Contact: Dr Todd Gaines, 08 6488 7872 todd.gaines@uwa.edu.au , Professor Stephen Powles; Director, AHRI on 08 6488 7833 or 0418 927 181 or Neree Martinez 08 6488 1512.

For more information on glyphosate resistance please see the following websites.
- AHRI www.ahri.uwa.edu.au  
- Australian Glyphosate Sustainability Working Group www.glyphosateresistance.org.au  

Website: http://www.ahri.uwa.edu.au/

Published: May 4, 2011