Get Ready to Use Dicamba in 2019 


Integrated weed management programs have used dicamba for many years. This auxin-class herbicide is highly effective at burndown of many of the most troublesome broadleaf weeds and has effectively been used for post-emergence weed control in grassy crops. The more recent release of dicamba tolerant soybeans and cotton has opened up dicamba use and significantly increased its utilization in the major corn and soybean production regions. 
 
Successful management of the dicamba tolerant soybean system requires a complete, full-season pest management program. The program should include effective burndown, using multiple sites of action and layered residual herbicides, in addition to applying post-emergence herbicides.
 
Preparing to Grow Dicamba-Tolerant Crops
Dicamba-tolerant cropping systems are unique in that application techniques and equipment should be reviewed and updated to meet current label requirements and use only approved tank mixes (following the approved listings provided by the herbicide manufacturers). Pay close attention to labeling language and restrictions; learn how to measure, monitor and document environmental conditions in fields and complete all required training and recordkeeping requirements.
 
Farmers must also remember that the best use of dicamba is in an integrated system with proper selection and application of effective soil-residual herbicides along with timely post-emergence dicamba applications to small weeds. This type of program is made more effective when the herbicide mode of action is rotated between seasons.
 
The Label Is the Law! 
Dicamba labels have become increasingly complex. It is the applicator’s responsibility to fully read and understand all application requirements listed on the dicamba product labels, including dicamba products for use in dicamba-tolerant cropping systems. Every herbicide label is considered legal and enforceable documentation of the use pattern and recordkeeping requirements that must be followed for that herbicide. Dicamba labels are no exception. Growers must follow the application requirements and label restrictions for the product applied to the specific field. There are no universal labels!
 
Dicamba Label Changes for 2019
The only three approved dicamba products received new registration and federal labels late in 2018. This re-registration was mandated in the initial approval for the cropping system. Several significant changes were made to the product labels as part of re-registration, the most significant of which are: 

  • Application Date and Growth Stage Restrictions. Dicamba applications can only be made pre-plant or up to 45 days after planting dicamba tolerant soybeans or PRIOR to R1 growth stage (first flower), whichever comes first. Later dicamba applications were highly correlated with increased potential of off-target herbicide movement. South and North Dakota have further restricted application dates by mandating a June 30 cutoff date in addition to the other restrictions, whichever of the restrictions comes first
  • Daily Hours of Application Restrictions. Applications will only be allowed from one hour after sunrise to two hours before sunset. This is more restrictive than previous seasons. The reason for this change is the high incidence of temperature inversions occurring during evening, overnight and early morning hours.
  • Changes in Downwind Buffer Requirements, Sensitive Areas and Documentation. There are changes in requirements for identifying sensitive areas downwind and required buffer zone documentation. Maintained (mowed) roadway right-of-way may be used as part of buffer zone calculations.
  • Changes in Sprayer Cleanout and Awareness of Spray Solution pH. There are now additional requirements associated with tank cleanout before and after dicamba application.  There is also a notation and caution on the effect of lower spray solution pH and the increased volatilization risk.
Complete details will be presented at mandated annual dicamba certification training.
 
Mandated Applicator Training
All applicators who plan to apply any approved dicamba products MUST receive 2019 dicamba certification. This yearly training is now mandated. Applicators must attend one in-person training event or may obtain certification through online training modules (once they are complete and receive regulatory approval).
 
To register for a dicamba applicator training event:
  1. Contact any local Agtegra Agronomist
  2. Browse the links below to find a training event near you: