By Tony White, Ph.D.
Jointed goatgrass is typically recognized as a threat in only winter wheat fields. Winter wheat and jointed goatgrass have very similar life cycles, germinating in the fall, overwintering, and setting seed in late spring for an early summer harvest. However, jointed goatgrass is known to germinate in the early spring and possess the ability to produce seed.
Ranchers and farmers in Utah are now battling jointed goatgrass outside of their winter wheat fields. The problem now lies in pasture areas. Jointed goatgrass was likely introduced in these areas with hay to feed livestock, but the exact source of the infestation remains a mystery. Although the invasiveness of jointed goatgrass is unclear, the weed can quickly take over an overgrazed or otherwise mismanaged pasture. Currently, scientists are trying to determine if the jointed goatgrass infestation in pastures is increasing or becoming smaller due to competition with native grass species.
Dr. Ralph Whitesides, Extension Weed Scientist at Utah State University, has started research looking at the possibility of using Plateau® herbicide to eliminate emerged jointed goatgrass while keeping the native grass species. Overseeding desired pasture species can then be done in early fall to fill in where jointed goatgrass once thrived. Preliminary results show this practice to be promising, but additional research is necessary to determine the long term effects of the herbicide treatment and the effects of subsequent jointed goatgrass germination events.
Preventing an initial jointed goatgrass infestation in a pasture is the best control method. The weed is difficult to control in pasture once it becomes established. Preventative measures include scouting pastures to identify potential problems as early as possible, inspecting hay for jointed goatgrass seed prior to feeding in a pasture, and spot spraying small areas with glyphosate or similar products. Producers should limit grazing to maximize ground cover and prevent jointed goatgrass from becoming established.
If timed properly, mowing can be effective to manage small infested areas. Mowing too early may allow enough time for jointed goatgrass to regrow and produce seed. Mowing after heading may be too late and allow viable seed to be scattered over a larger area. Mowing around boot stage of jointed goatgrass appears to be most effective, but the area may need to be mowed several times to prevent seed production.
Plateau® herbicide is a registered trademark of BASF Corporation, 26 Davis Drive, Research Triangle Park, NC 27709. Follow label directions on all pesticides.