Australian researchers find cause of brome grass resistance to glyphosate

Researchers at Australia’s University of Adelaide reported Tuesday that they have identified the mechanism behind the resistance of the cereal weed brome grass to the widely used herbicide glyphosate.

Their report, which was published online ahead of its appearance in the journal Pest Management Science, said cereal weed brome grass is the first weed species that has shown this mechanism of resistance.

Jenna Malone, researcher from the School of Agriculture, Food and Wine at the university’s Waite campus, said great brome is a significant weed of both crops and pastures across the southern and western Australian cereal belts, causing contamination, yield reductions and damage to meat and livestock.

“Glyphosate is the most widely used and versatile herbicide in the world and one of the most important herbicides for weed management in Australian agriculture,” Malone said. “Loss of glyphosate for brome grass control would cause serious issues for farmers.”

Research group leader Christopher Preston said their finding underlines the importance of using diverse practices for management of brome grass to reduce the risk of resistance developing.

“The bad news for farmers is that brome grass is another weed that will become increasingly harder to control,” Preston said. “This finding reinforces the need to not overuse glyphosate; and to employ good practice of diverse weed management, including crop rotations, fallow periods, interspersing with grazing cycles and other control mechanisms.”