Utah State University Extension specialists are asking Utah farmers and ranchers to be on the lookout for a threatening rangeland weed that has this year infested the state for the first time.

Medusahead rye is an extremely hardy weed that crowds out even other weeds, said Steve Dewey, USU Extension specialist. And because it is inedible by livestock, grazing capacity on infested rangeland can be reduced by more than 75 percent.In addition, the weed's seeds are barbed and snag the eyes, nose and ears of animals, causing debilitating infections.

"Losses in range productivity in Idaho now exceed $3.5 million annually," Dewey said.

The weed, which is spread throughout Idaho and the Pacific Northwest, was found in Box Elder County last summer, in Utah's first documented siting.

"Early detection and eradication of any new outbreaks in Utah are essential if we are to keep medusahead from establishing itself on, and taking over, our rangelands," Dewey warned.

"Most of our semi-arid rangelands offer ideal habitat for medusahead rye and are considered highly vulnerable to invasion."

The weed is a winter annual grass that grows to a height of 10 to 20 inches, and looks similar to downy brome in its early stages. In later stages, it can be easily confused with species of foxtails or wild barley, Dewey said.

The weed's distinguishing characteristics are a large seed head with two or three spikelets per node, and a seed head skeleton that remains intact and attached to the stem after the seeds fall off.

The seed itself is also unusual. It is about 1/4-inch long and tipped with a long, flat, wavy awn, he said.