The weed has been a priority for the Dubbo-based GOA in its three years of operation, funded by the Grains Research and Development Corporation (GRDC) to fast-track extension of research to growers in the NSW central west.

Chief Executive of GOA Maurie Street says this season GOA will focus on herbicide systems, which are a necessary short-term solution to the problem.

"We're thinking outside the square, so it's not just different application rates and timing of the usual herbicides; trials will look at different herbicide groupings, where residuals might fit, and knock-down alternatives," Mr Street said.

"There are already many growers implementing systems that have been developed to date, which are vital in trying to stop the spread of windmill grass and to overcome potential yield losses.

Mr Street recommends growers use the double-knock technique to control the weed. The only registered herbicide for the weed in summer fallow is Touchdown Hi Tech® (500gm/L glyphosate), and products registered for selective control include butroxydim and chlorthal-dimethyl.

"We need to continually improve management options, because at the moment we're holding back the weed but not beating it.

"Windmill grass is continuing to spread, and we now have the added difficulty of populations proving to be glyphosate resistant.

"The long-term solutions are most likely to be in the weed's ecology and other control options - and the GRDC is proactively supporting many projects looking into those solutions" Mr Street said.

The other key priority for GOA's summer trials is fleabane, which is a growing threat across the state.

Details of how to manage windmill grass, fleabane and a range of other major weeds, can be found on the GRDC website at www.grdc.com.au/weedlinks