Annual ryegrass (Lolium multiflorum) is the most damaging weed in soft red winter wheat in Northeast Texas. It was originally introduced to this region as a forage plant for grazing, but has spread to crop fields and become a noxious weed. Annual losses from this pest in this region run in the millions of dollars.

When the sulfonylurea (SU) herbicides (Amber, Glean) were developed in the mid 1980s, they provided excellent control of this weed.  However, over time, efficacy of the SUs has decreased, causing the weed to reemerge as a difficult problem for area wheat producers.

Hoelon, an ACCase mode of action herbicide, replaced Amber and Glean in the late 1980s, but its effectiveness has been declining over the past few years. Axial XL, another ACCase herbicide, was introduced in 2008 and has been the most effective herbicide for the control of annual ryegrass in recent years. Although Axial XL is still providing good ryegrass control in some regional wheat fields, we are beginning to see reduced control with this product in many fields across the region.

Wheat can be successfully grown in fields that are infested with herbicide resistant annual ryegrass. Each of the following suggestions will improve the chances of success in infested fields. When all of these tactics are employed together in an IPM approach, the odds of producing a profitable wheat crop are greatly enhanced.  

Annual ryegrass populations (both resistant and susceptible) in cropland can be greatly reduced by using cultural and mechanical means in combination with chemical control techniques.