Effects of a Simulated Dicamba Misapplication on Non-tolerant Soybeans (Glycine max)

Abstract

Approval is pending for the registration of dicamba tolerant (DT) soybeans [Glycine max (L.) Merr.]. The use of dicamba on DT soybeans and other DT crops will increase. Risks associated with dicamba applications include off-target movement to sensitive crops. The objective of this study was to evaluate misapplication of dicamba on non-DT soybeans. Greenhouse and field studies examined a rate titration (0.004 to 0.5 lb ai a-1) of dicamba on non-DT soybeans (V3 stage - three trifoliates). Field studies also examined dicamba application to various growth stages (PRE- preemergence to R5- early pod fill) of non-DT soybeans. Results from the greenhouse and field studies showed that as the rate of dicamba increased, the level of injury to vegetative and yield components also increased. Soybean growth stage at time of application influenced the amount of injury. Less injury was observed when dicamba was applied at the PRE growth stage.