By Dallas Peterson, Curtis Thompson and Doug Shoup
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.
- All products will be classified as “restricted use”, permitting only certified applicators to purchase and apply or supervise the application of the products.
- Supplemental labeling will be incorporated into the regular labels, and application guidelines will be the same for all uses, including dicamba and non-dicamba tolerant crops.
- Applicators must complete dicamba or auxin-specific training prior to application.
- Requires more specific record keeping of applications, including checking for the presence of sensitive crops in the area.
- Do not spray when wind is blowing in the direction of neighboring sensitive crops, including non-Xtend crops. More clearly states that this restriction includes non-Xtend soybeans and cotton.
- Restricts applications to wind speeds between 3 and 10 mph. Reduced maximum wind speed from 15 mph in 2017 and prohibits all applications at less than 3 mph when temperature inversions are more likely to occur.
- Prohibits applications between sundown and sunrise. All applications prohibited during temperature inversions regardless of time of day.
- Restricts the maximum application ground speed to less than 15 mph, with 5 mph recommended on field edges.
- Thoroughly clean spray equipment before and after application. Must be documented.
- Use an approved buffering agent if the water source or tank mix components result in an acidic spray solution less than pH 5.
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.