With increasing annual ryegrass pressure in Western Australia’s cropping areas, many growers will be assessing their options for crop-topping to prevent the weed setting seed.
Other reasons for late season herbicide use include management of other late season weeds just prior to harvest, and pre-harvest crop desiccation to accelerate or even-up crop ripening.
Information about stewardship for late season application of herbicides in winter crops is available in the new Grains Research and Development Corporation (GRDC) Late Season Herbicide Use Fact Sheet.
GRDC plant health senior manager Rohan Rainbow said herbicide application late in the season must be carried out cautiously and in line with herbicide label recommendations.
“It is essential to check if these practices are acceptable to buyers, as in some situations markets have extremely low or even zero tolerance to some pesticide and herbicide residues,” Dr Rainbow said.
The fact sheet, which includes registered product options for late season weed control and desiccation in a variety of crops, was included in the September-October edition of the GRDC magazine Ground Cover and is available at www.grdc.com.au/GRDC-FS-LateHerbicideUse
PHOTO CAPTION: Diquat is the only herbicide registered for use in pre-harvest weed control in barley. Photo by Emma Leonard.
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