Use of Dicamba on Dicamba-resistant Soybean

By Bob Hartzler

Most people are aware that EPA approved new labels for the dicamba products used on dicamba-resistant crops.  The following describes major changes in the labels and important restictions.  The labels only describe use on the dicamba-resistant crops, therefore eliminating some of the confusion on earlier labels.

Major changes to dicamba use on DR soybean

• Must use volatility-reduction agent;
• Apply before June 30 or up to R1 stage, whichever comes first. The Engenia label doesn't have the R1 cutoff, just the June 30 restriction, so in some situations Engenia could be applied later in the season than Xtendimax.
• Always maintain a 240-ft buffer between last treated row and downwind field edge (roads, mowed grass, tolerant crops can be included in the buffer). The previous Xtendimax label required a 110 ft buffer at 22 oz and a 220 ft buffer at 44 oz.  The 44 oz rate has been eliminated from the label.

General restrictions

• Apply only one hour after sunrise through two hours before sunset;
• Apply when wind speed at boom height is between 3 and 10 MPH;
• Do not apply during temperature inversions;
• Do not apply product if sensitive crops or certain plants are in an adjacent downwind field;
• Do not apply if rain is expected in next 48 hours that may result in runoff;
• Maximum boom height of 24”, maximum ground speed of 15 MPH;
• Dicamba specific training still required;
• 57 ft omni-directional buffer required in counties with endangered species (In Iowa, Hardin County and several counties in NE IA are affected by this).

This list isn't comprehensive, just a quick summary of the label. I assume other products will have similar restrictions.