Fight weeds with time

Cheat and cheatgrass ring true to their names – they sneak into wheatfields, grow alongside the grain and then rob farmers of winter wheat yields. To help farmers fight the troublesome grassy weeds, researchers recently published a study examining the best planting date, herbicide choice, and winter wheat variety selection for controlling cheat and cheatgrass -- also known as downy brome.

Their research found that delaying wheat planting dates and applying ALS-inhibiting herbicides greatly reduced cheat and downy brome, but winter wheat yields suffered as planting dates got later, according to University of Georgia graduate student Hannah Lindell and her then-Oklahoma State advisor, weed scientist Misha Manuchehri. Winter wheat variety showed no effect on weed management, potentially due to sporadic weed pressure or the use of limited varieties.

Cheat and downy brome are particularly difficult to combat because they emerge with winter wheat, which explains why delaying planting can help farmers fight the pesky grasses.

“Our worst weeds are those that mimic the crop cycle; it can be a challenge to successfully kill a weed that’s similar to the crop,” Manuchehri said.

Pushing back winter wheat’s planting date two to six weeks after the optimal planting window in the fall gives farmers more options to combat those weed species, Lindell and Manuchehri explain.

Lindell said, “If you are a producer who has a really high infestation of these grasses, you might want to think about delaying that planting date. That way you can spray a burndown herbicide or work ground a couple of times and get the first emergence of true cheat and downy brome grass.”

Farmers risk injuring their winter wheat or stunting its growth by broadcasting ALS-inhibiting herbicides after planting.