Growers have asked how to control forage species in field headlands when these areas are returned to corn production. Typically, Roundup or tillage are thought to be the only options.
High rates of Roundup are required to control bromegrass and orchardgrass in ther spring. Fall application of Roundup usually controls these species more consistently and at lower rates than does spring application.
Better yet, grow soybeans and use the appropriate registered postemergence herbicide to control the grass forage species. If alfalfa also occurs in the field, consider a preplant application of 2,4-D and delay planting the appropriate amount of time.
Tillage is not the best option due to concerns about erosion and probable regrowth of the forage species.
Iowa State University has evaluated control of alfalfa, orchardgrass, and bromegrass at one location. Split applications of Extrazine II (early preplant or preemergence) followed by Accent (postemergence) and split applications of Accent (early preplant and postemergence) demonstrated acceptable, although not complete, control of the forages. Bullet plus Roundup also demonstrated acceptable control at this location.
This experiment did not consider economics, and treatments were not necessarily within the recommendations on the label. Only consider these treatments as recommendations for this specific use.
These data were listed in the 1992 Weed Science Research Results. Complete results are available from the authors upon request.