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Agronomic Crops > Crops Blog > Posts > Dicamba Tolerant Crops: Let’s Continue to Stay On-Target

If you have been reading farm magazines, webblogs, or even the newspaper, chances are that  you have heard about dicamba (Engenia, Xtendimax or Fexapan) drift or some type of off-target movement from applications to Xtend soybean or Xtend cotton to sensitive crops like non-dicamba tolerant soybeans in several states across the south (particularly the mid-south). Alabama has no such reported incidences to the Alabama Department of Agriculture at the time of this publication. Arkansas, Missouri, Mississippi, and Tennessee have reported complaints to their Departments of Agriculture of over 500, 130, 62 and 70, respectively through the end of 1st week of July. Arkansas issued a 120 day ban or stop sale and use for any dicamba containing products. Not only the new formulations, but also the older formulations like Banvel and Clarity type products (including generics) due to suspected off-label use like last year. Missouri issued what has become a seven-day temporary ban until a section 24C label could be written and approved, whereas Tennessee similarly put restrictions on Engenia, Xtendimax and Fexapan applications going forward that provides that only certified pesticide applicators can treat fields, applications can only be applied during the day, all other dicamba formulations cannot be used on any crops through Oct 1, 2017 and cotton can only be sprayed up to 1st bloom.

At this point I would like to say thank you! I know all of you went through extensive and sometimes inconvenient education and training in the winter and early spring to be able to apply these new herbicides. It was obviously very important since application requirements were so restrictive and  tank-mix partner websites were ever-changing. These were things we've never seen before in the industry on pesticide labels. You all have taken this seriously and have implemented this technology very well. After all, first and foremost, these dicamba tolerant weed control systems have been developed to give us another tool in the tool box to stem the expanding weed resistance problems that continue to grow and develop 

Now is the time to "Stay the Course" and continue to mind our application P's and Q's as we come to the end of another herbicide spraying season. There are still double crop Xtend soybeans that need to be sprayed and maybe an Xtend cotton layby application on some fields. So, lets finish strong. Again, thank you for your efforts. As a reminder please see Best Management Practices below that reinforce the label requirements that were discussed in depth at the state certification meetings.      

Best Management Practices.

  • Communicate with neighbors.
  • Only use Engenia, Xtendimax or Fexapan. These low-volatile formulations are the only approved products for postemergence applications. Older, generic formulations of dicamba are highly volatile and very likely to move off-target.
  • Only tankmix with labeled products. Tankmixes can affect the size of the droplets that leave the spray tip as well as degree of volatility. Go to websites: and
  • Only use labeled nozzles. Do not use flat fan or other nozzles that produce very small droplets, which take longer to reach their target. (see tankmix websites)
  • Keep the spray boom low (no higher than 24" off the target). The higher the boom, the more time the spray droplet is in the air where it can be moved by winds.
  • Avoid spraying in a temperature inversion (see below).  This is environment and weather dependent and one we don't have much experience. This may be the biggest concern in the mid-south this year.

Spotting an Inversion

A temperature inversion occurs when air temperature rises with altitude. In other words, cooler air is closer to the ground. Signs of an inversion include no wind, fog, heavy dew on leaves, or dust hanging in the air. In an inversion, tiny spray droplets will hang in the cooler air, often for hours. When the inversion lifts, the droplets could move anywhere. Night time spraying probably provides the greatest concern. Any herbicide can drift during a temperature inversion. 

For details, download this publication: Timely Information Engenia number 12 updated.pdf

Joyce Tredaway, 

Extension Weed Scientist


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