2019 West Texas Auxin Herbicide Drift Evaluation Trial and Demonstration

Two locations were utilized for this trial designed to capture and demonstrate West Texas’ potential for volatility and physical drift issues from labeled use in cotton from both types of auxin herbicides. One location was at the Halfway Experiment Station in Hale County, the other was near San Angelo in Tom Green County, Texas.  At each location two block planted areas of cotton, one of Enlist Cotton and one of XtendFlex Cotton, were planted.  Two small plot areas (13.3’X40’) were selected with in each large plot area for applying the opposing or wrong auxin treatments.  Prior to applications, small portions of all small plot areas and on adjacent rows, 13’, 30’, and 60’ downwind were fully protected with chemical proof coverings.  These coverings were removed within 30 minutes of herbicide applications in an effort to measure any volatility.  A few additional plants within the small plot areas and on adjacent downwind rows at Halfway were sheltered via common milk jugs with cutaway bottoms that exposed only the area just above the soil surface to herbicide treatments.  These were used to capture any odd physical drift and were removed at the same time as the full shielding covers to capture any additional volatility.

No volatility was measured for any Enlist treatment at either location by the fully protected plants and only slight, non-economic volatility was measured from the Enginia treatment. No physical drift for either treatment was measured past 5.2 feet downwind for either treatment.  Oddly, physical drift that did cause some economic damage did occur at Halfway under the milk jug sheltered plants for both treatments but was more severe and longer lasting (at least 50 DAT) for the Enlist treated area.