Dicamba in 2018: What’s at Stake?

Manufacturers have weighed in. Farmers and retailers have stated their cases and shared their experiences. Labels have been tweaked. University extension specialists and county educators have taught until there is no more to teach. State agriculture officials and pesticide regulators have inspected, pored over data, and made decisions about the regulations and restrictions to impose for this season. Now, as is so often the case, it’s incumbent on the agricultural retailers to execute the application, and advise farmers on how to properly follow all the requirements for implementing a dicamba-tolerant cropping system.


This won’t be easy. Some of the challenges will remain, like ensuring comprehensive sprayer cleanout, properly matching tank mix partners, and finding out if non-dicamba beans have been planted. Some will intensify – 2018 label requirements will likely reduce the number of available application hours per day by a significant measure for the first postemergent applications as winds gain velocity, winds blow out of different directions, and temperatures rise. And some states have gone above the label and further restricted application during the hottest months of the season.

Another big challenge is the state of the row crop economy, and the temptation some growers who do their own application work will apply even when weather conditions or surrounding crops are not label compliant.

But at the end of the day, this is at the heart of what being a professional retailer is all about – and beyond the legal requirements for managing dicamba, from a business and customer service standpoint it’s a battle worth fighting. Bill Johnson, Professor of Weed Science at Purdue University, is quick to rattle off some of the most important reasons for keying in on dicamba management:

  1. Exponential Weed Resistance. “Weed control expenses have more than quadrupled in the last seven or eight years,” says Johnson, but poor management of herbicide systems could make things much more expensive. Resistance of multiple weeds to multiple herbicides is a game-changer, and the threat is real. By themselves, weeds resistant to glyphosate such as marestail ($20/a), giant ragweed ($30/a), and waterhemp and Palmer amaranth ($50/a) are a weed program budget buster. But when any of these weeds turn a corner and emerge with multiple resistance, the cost to control will continue to escalate.
  2. Limited Options in the Near Term. When Enlist and its 2,4-D technology gains approval in China, there will be another weed system option to add to the rotation. And in time, crops will carry multiple resistance traits to provide more flexibility, including glyphosate and glufosinate. But since the options are not yet available, resistance that’s created in the next couple of seasons could cripple these trait technologies before they even get commercially launched. “One of the biggest fears we have in the weed science community is with low commodity prices,” says Johnson. “Are financially stressed growers going to apply a single mode of action and increase the selection pressure we’re already experiencing?”
  3. No New Modes on the Horizon. There are simply no products coming on line in the future for weed management, so protecting what weapons we have in our arsenals is critical.
  4. Regulatory Threat. Finally, if we fail to manage applications properly and product drift damage persists, the dicamba label could be lost altogether nationally, or further restricted on a state-by-state basis.

The dicamba-tolerant cropping system is an important tool for weed management now and in the future, and its preservation will depend on the detailed, professional work of the ag retailer both in their own applications and the advice they provide to their customers.

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Avatar for Jean Payne Jean Payne says:

Paul and team, excellent start to this series, thank you!