The Intacta 2 Xtend system was developed to allow selective dicamba use in dicamba‐resistant soybean (DRS), aiding in the management of tolerant and resistant broadleaf weeds. This study evaluated the control of broadleaf weeds following single or sequential postemergence applications of dicamba (alone or tank‐mixed with glyphosate) in DRS. Experiments were arranged in a randomized block design with four replications. Treatments included single and sequential applications of dicamba (360 and 720 g a.e. ha −1 ) and its tank mixture with glyphosate (1,080 g a.e. ha −1 ), alongside weedy and weed‐free checks. Weed control was assessed for Conyza spp., Amaranthus viridis , Amaranthus hybridus , Euphorbia heterophylla , Ipomoea spp., and Raphanus raphanistrum , along with soybean yield. Single dicamba applications at 360 g a.e. ha −1 were insufficient to control A. viridis . Effective control of A. hybridus , E. heterophylla , and Ipomoea spp. required sequential dicamba at 720 g a.e. ha −1 or dicamba (360 or 720 g a.e. ha −1 ) tank‐mixed with glyphosate. For R. raphanistrum , only sequential dicamba + glyphosate treatments were effective, whereas Conyza spp. was controlled only by sequential applications of dicamba (720 g a.e. ha −1 ) + glyphosate. Overall, sequential dicamba + glyphosate applications provided superior weed control, without negatively impacting DRS yield.
Camintia et al. (Sun,) studied this question.