Simulated 2,4-D Drift On Glyphosate Resistant Soybean.

New trait technologies incorporating 2,4-D tolerance in soybean will increase the use of 2,4-D causing a greater potential for drift or tank contamination onto sensitive crops. Drift of pesticide application can be caused by many factors including wind speed, nozzle type and spacing, carrier volume and pressure, boom height, travel speed, distance of particle travel to reach the target, formulation, and additives; whereas, tank contamination can occur when not properly flushed, leaving residues in the tank. Our objective was to quantify (a) plant injury, (b) changes in yield components and (c) yield loss from simulated 2,4-D drift on glyphosate-tolerant soybean. Ten rates (0, 0.112, 1.12, 11.2, 35, 70, 140, 280, 560 and 2240 g ae ha^-1) were applied at three timings (V2, V5 and R2) on Becks brand 342NRR soybean planted at Lafayette and Fowler, IN and Urbana, IL. Crop injury started to occur at 11.2 g ae ha^-1 at all timings. 2,4-D at rates greater than 140 g ae ha^-1 caused reduction in pod number and correspondingly a loss in yield. Yield loss was highly correlated with injury at 21 days after treatment for the V2 and V5 applications.