Western Australia
April 20, 2015
DAFWA technical officer Paul Bartlett (left), principal research officer Dr Abul Hashem and research officer Dr Mohammad Amjad inspect the efficacy of various herbicides on button grass population on Critch family’s property, Mullewa.
Many broadacre growers across the wheatbelt are in the unusual predicament of having to battle both summer and winter weeds, as a result of extensive summer rainfall and warm temperatures.
Department of Agriculture and Food principal research officer Abul Hashem urged growers to take action to control both summer and winter weeds in one hit.
“Summer weeds, such as afghan melon, button grass, caltrop, couch, fleabane, roly-poly and tar vine can remove soil moisture and make soil nutrients unavailable to winter crops during the early stage of growth,” Dr Hashem said.
“Winter weeds, such as annual ryegrass, marshmallow, wild oats, wild radish and wire weeds are now also emerging in paddocks.
“Growers preparing their sowing program, especially those planting crops like canola, would be advised to control both summer and winter weeds that are already present in paddocks.”
The department has trialled a variety of treatments to test the efficacy of a range of herbicides on summer weeds, which Dr Hashem said would also be effective on winter weeds.
“Many of the treatments were double knockdowns, which will also effectively control most winter weeds,” he said.
The field trials were undertaken with the support of the Grains Research and Development Corporation and cooperation from growers at Grass Valley, Jennacubbine, Mullewa and Geraldton over the 2014-15 summer.
The trials applied several herbicides alone, as a tank mix or in sequence on a wide range of summer weeds.
“While some herbicides were effective as a single application in some situations, applications of a mixture of glyphosate and 2,4-D, as a tank mix, followed by a mixture of paraquat and diquat were highly effective on most weeds across all locations,” Dr Hashem said.
“A mixture of glyphosate and 2, 4-D, as a tank mix, followed by the application of a mixture of amitrole and paraquat was also highly effective at all sites. However, rate and proportion of herbicides in the mixture as well as the application time are highly important to control weeds.
“These treatments will control most summer weeds and new winter weed seedlings at the same time.”
Research results in the eastern states have also shown that the use of herbicides, such as 2, 4-D, at the early or late bud formation stage can also reduce seed set of some weeds, such as fleabane.
The department will continue to monitor the trial sites to examine the impact of summer weeds on this season’s winter crops.