Source: The Grains Research & Development Corporation Grain zone

Research summary

• As weed resistance continues to develop to herbicide groups, growers are becoming increasingly reliant on fewer herbicides to control resistant populations of annual ryegrass and wild radish in WA.
   
• Farming systems have become more reliant on soil-incorporated herbicides to control annual ryegrass in most crops due to the diminishing number of post emergent herbicide options. Little research is being undertaken by the herbicide manufacturing industry to develop a new and unique generation of herbicides for growers in the near future.
   
• As herbicides are adopted into the farming system, growers need to be aware of the range of non-herbicide Integrated Weed Management (IWM) strategies that can be adopted to ensure the prolonged longevity of new herbicides. Without a holistic approach, herbicides will become ineffective faster than they can be evaluated, registered and adopted.
   
• Some of the products evaluated in the field during this project need to be registered to ensure growers have access to herbicides with unique chemical properties. These include Cinmethylin (Argold®), (which was shown to have similar potency to trifluralin for controlling annual ryegrass) and products that have not been widely used in broadacre agriculture such as Kerb®. The herbicide, AGT01, also consistently provided over 90% control of resistant ryegrass populations and gave some suppression of wild radish.
   
• Conversely, some evaluated products (e.g. IPU and 22DPA) failed to provide the required level of crop safety or herbicide efficacy on target weeds, and as a result, are not suitable for WA farming systems.
   
• Detailed assessments of the herbicides tested are provided below.

Report: http://www.grdc.com.au/growers/res_summ/AGT13.htm