Hairy buttercup and cutleaf evening primrose are winter annual weeds that have become more problematic for winter wheat growers in the southern Great Plains and the midsouthern United States in recent years. Little research exists on which to base recommendations for controlling hairy buttercup in wheat, and little research has been published on cutleaf evening primrose control in recent years. With growing concerns of increased herbicide resistance among winter annual weeds, incorporating new herbicide sites of action has become necessary. The objective of this study was to assess halauxifen-methyl as a novel herbicide to control these two problematic winter annual broadleaf weeds in winter wheat in Mississippi and Oklahoma. Studies were conducted across four site-years in Mississippi and one site-year in Oklahoma comparing 15 herbicide programs with and without halauxifen-methyl. Hairy buttercup and cutleaf evening-primrose control was the greatest when a synthetic auxin was combined with an acetolactate synthase–inhibiting herbicide. Treatments including halauxifen-methyl resulted in the greatest control of hairy buttercup, whereas a synthetic auxin herbicide plus chlorsulfuron and metsulfuron resulted in the greatest control of cutleaf evening primrose. Halauxifen-methyl is an effective addition for control of winter annual broadleaf weeds like hairy buttercup and cutleaf evening primrose in winter wheat.

Nomenclature: Chlorsulfuron; metsulfuron; cutleaf evening primrose, Oenothera laciniata Hill; hairy buttercup, Ranunculus sardous Crantz; wheat, Triticum aestivum L.