Phytotoxicity in soybean crop caused by simulated dicamba drift

Abstract: The objective of this work was to evaluate injury symptoms on soybean not tolerant dicamba (3,6-dichloro-2-methoxybenzoic acid), as well crop yield, after the application sub-rates herbicide simulate physical drift in tropical conditions. Dicamba rates 0, 5.8, 14.4, 28.8, 57.6, and 576 g acid equivalent per hectare were applied at vegetative (V3) reproductive (R1) stages soybean, using a backpack sprayer pressurized with CO2, equipped air-induction flat fan spray nozzles; pressure rate 250 kPa 200 L ha-1, respectively. Visible injury, soil-plant analysis development (SPAD) index (leaf chlorophyll content) 14 days application, yield evaluated. These variables influenced by stage which applied. Rates below 28.8 ha-1 caused less when R1 stage; however, there no differences between stages. A 1% conditions reduces 12%.