Herbicide-resistant Palmer amaranth is the number one threat to row crop production throughout Arkansas. At present, all row crop production counties in the state have Palmer amaranth populations with resistance to glyphosate and the ALS-inhibiting herbicides, and these multiple-resistant biotypes are common along roadsides based on recent surveys. Additionally, barnyardgrass, the number one weed of rice continues to evolve resistance to a wide array of herbicides, including propanil, quinclorac, clomazone, and several ALS inhibitors. Based on recent surveys approximately 50% of rice fields in Arkansas have barnyardgrass populations having resistance to propanil, and quinclorac resistance exists in about 25% of all fields. Most often, barnyardgrass populations having resistance to quinclorac likewise exhibit multiple resistance to propanil (about 20% samples tested).