Glyphosate-resistant (GR) johnsongrass was confirmed in Louisiana in 2010. It is essential to develop a management plan for GR johnsongrass that includes crop and herbicide rotation. In corn, plant a hybrid that is Roundup Ready and Liberty Link, don’t apply an organophosphate insecticide in-furrow at planting, and utilize ALS-inhibiting herbicides such as Accent Q, Capreno, Corvus, and Steadfast Q. For GR johnsongrass management in cotton and soybean, utilization of varieties that are resistant to Liberty (Liberty Link) and applications of graminicides are crucial. If Roundup Ready cotton or soybean is planted, graminicides are the only herbicide choice if an area is infested with GR johnsongrass. However, reliance upon a single herbicide or herbicidal mode of action may lead to resistance; therefore, overuse of graminicides could cause resistance. Crop and herbicide rotations have the potential to effectively mitigate and/or manage GR johnsongrass.
