by Emma Leonard
There are now 40 confirmed annual ryegrass populations in Australia with resistance to glyphosate. Intensive glyphosate use and lack of tillage have been found to be two of the key predisposing factors for glyphosate resistance in broadacre cropping.
The National Glyphosate Sustainability Working Group has established an online register of glyphosate-resistant populations in Australia, as well as guides to growers and advisers on how to keep glyphosate resistance to a minimum.
Supported by AVCARE and the CRC for Australian Weed Management (Weed CRC), the group brings together glyphosate experience from Monsanto, Syngenta, Nufarm, WA Herbicide Resistance Initiative (University of WA), University of Adelaide, Charles Sturt University, Queensland Department of Primary Industries and Fisheries, Department of Agriculture WA, NSW Department of Primary Industries and the GRDC. The group is chaired by the Weed CRC"s Dr Rick Llewellyn (UWA).
"The Australian Glyphosate Resistance Register has been produced to promote awareness and accurate reporting of the number and background of glyphosate resistant weed populations in Australia," says Dr Llewellyn. "It is managed by Weed CRC herbicide resistance expert Dr Chris Preston, and is now accessible on our website."
Another key output from the group is the "Keep Glyphosate Resistance Rare" guide. Launched at this year"s Adviser Updates across the three GRDC regions, this information details practices that increase or decrease your risk of developing glyphosate-resistant annual ryegrass.
"Practices such as effective in-crop weed control, non-herbicide practices for weed seed-kill and use of the "double knock" technique, that is full cut cultivation or the full label rate of a paraquat-based product following the use of glyphosate as a knockdown application, can all help growers to use glyphosate while minimising the risk of resistance," Dr Llewellyn says.
For more information: www.weeds.crc.org.au/glyphosate