Most producers have probably already heard that EPA, and the companies selling dicamba products registered for use on Xtend soybeans and cotton, have reached an agreement on label modifications and application requirements to try and further minimize the potential for off-target damage to susceptible crops. Below is a brief summary of the key changes to the Xtendimax, Fexapan, and Engenia product labels.
In addition, remember that AMS is not allowed with any of these products because it greatly increases the volatility of dicamba. Approved tank-mixes, adjuvants, spray tips, and maximum pressures are still presented at the corresponding websites for each respective product as listed below:
There is still a great deal of debate in the scientific community about the degree of vapor drift that might be occurring from dicamba applications. Most of the new application guidelines are directed more towards minimizing physical spray drift vs vapor drift. The time-of-day restrictions are intended to help reduce applications during temperature inversions (see eUpdate Issue 657 for more information on temperature inversions), which could result in greater off-target movement from both fine droplets and vapor. Be aware that the majority of problems seemed to occur from postemergence applications made after soybeans were emerged and during warmer conditions. Applications earlier in the season may help minimize off-target issues.
Keep in mind that additional restrictions may be implemented by state regulatory agencies.
Dallas Peterson, Extension Weed Management
Curtis Thompson, Weed Management Specialist and Extension Agronomy State Leader
Doug Shoup, Southeast Area Crops and Soils Specialist