Caution Lights Ahead For Dicamba Use

Dennis Riley, left, and Mark Wilson of Hutson Inc., worked together to install a new direct-injection sprayer systems for Security Seed. Photo by Brad Rankin

It’s early March, and Security Seed and Chemical applicators are busy prepping equipment for the upcoming spray season. In a few days, they’ll make burndown treatments in sun-warmed Tennessee river-bottom fields, where green weeds are just starting to poke through the ground.

The company annually custom sprays about 1 million acres of corn, soybean and wheat ground across parts of Illinois, Indiana, Kentucky and its home state of Tennessee. This year, many of those acres will be treated with one of the new dicamba formulations that the Environmental Protection Agency (EPA) has approved for use in dicamba-tolerant soybeans and cotton–BASF Engenia, Monsanto XtendiMax with VaporGrip Technology or FeXapan with VaporGrip, which Monsanto has licensed to DuPont.

Security Seed and Chemical’s 35-member custom-application team has invested countless man hours in reviewing the new technology and learning how to best use it.

“We’ve had two rounds of classroom instruction and two rounds of in-field training,” says Dennis Riley, sales manager for the Clarksville-based company.

Riley says farmers are battling 10 different species of glyphosate-resistant weeds in Tennessee. Growers there regularly encounter PPO-resistant pigweed as well. In some areas, that weed alone has reduced soybean yields by up to 50%.

“We have customers who’ve had to just go in and disk up fields because they couldn’t control the pigweed,” he says. “We’ve burned through two chemistries now. We can’t afford to burn through a third.”

Responsible Stewardship. Hands-on training, a strict label and a good dose of caution have convinced Security Seed and Chemical to use the new dicamba products only in a comprehensive weed-management program. That means residuals will have been used first. The company has informed farmers that it won’t apply the new formulations in a rescue treatment.

“There’s no room to live in the gray with these dicamba products,” Riley says. “The label’s the law, and we’re following it to a tee.”

Following the label is a seemingly simple but not-so-easy task, notes Jean Payne, president of the Illinois Fertilizer and Chemical Association. “You have to be reading these labels now and understanding what they really require because there’s never been a pesticide label as detailed as this one,” she says.

Indeed, the six-plus pages of supplemental product labels that EPA approved for Engenia and XtendiMax, respectively, require serious study. Both labels specify nozzle use; how high above the crop canopy you can spray (no more than 24”); the size of buffer needed between you and dicamba-sensitive crops (at least 110’, and that’s debatable); and wind speed (up to 15 mph; 10 mph in some scenarios). Plus, you must spray when weeds are small (no taller than 4”).

EPA is giving the agricultural community only two seasons to use the new dicamba formulations correctly. At the end of 2018, the EPA will either let the supplemental product labels expire or extend the registrations for three more years.

“If we’re not successful with our management, we’ll lose these tools and potentially others in the product chain in the future,” Payne cautions.

Ron Moore, an Illinois farmer and president of the American Soybean Association, says BASF, Monsanto and retailers can encourage good stewardship by competitively pricing the new products and applications. “That would help us minimize off-label use of older formulations this season,” he says. Moore is splitting his 900 acres of soybeans between Engenia and XtendiMax.

BMPs Are Important. Concerns about dicamba misuse are justified, based on problems that occurred last year in the mid-South.

Various formulations of dicamba were applied off-label in 2016 on Roundup Ready 2 Xtend (RR2X) soybeans, which are dicamba-tolerant. It was a situation University of Arkansas weed scientist Bob Scott describes as “products that were legal to buy but illegal to spray that way.”

The resulting damage in farmers’ soybean fields ranged in severity from not much to extreme. The most tragic dispute involving dicamba drift resulted in the death of a northeast Arkansas farmer.

By last August, in Missouri, 117 confirmed cases of dicamba damage
on 42,000 crop acres were reported to
the state plant board and shared with
the EPA. That was the tip of the iceberg. The agency wrote in its compliance advisory that “similar complaints alleging misuse of dicamba products [were] received by Alabama, Arkansas, Illinois, Kentucky, Minnesota, Mississippi, North Carolina, Tennessee and Texas.”

Moore believes off-label dicamba use last season could have been minimized if EPA had approved the new dicamba formulations when the agency approved the dicamba trait. “EPA didn’t do their job as timely as they should have,” he says. “We think the EPA and their regulatory approval process (are) based on political positions instead of sound science for when they approve these new products.”

As a result of the off-label use, some of the states–40 had approved one or both of the new dicamba formulations at press time–are tightening their grip on the products to safeguard the chemistry, crops and people. Although the new formulations have a federal label, each state can specify how, when or whether they can be used.

“We want people to know what they’re getting into with these products,” Scott says. “Don’t get caught up in the hype. There are benefits and drawbacks.”

The applicator of the technology is ultimately responsible and liable for how the products are used. If a retailer suspects a customer is buying any dicamba for off-label use in-season, then Scott encourages, “Don’t turn a blind eye.”

Assumptions Cause Mistakes. Payne says retailers have a good grasp of the technology but is concerned stewardship messages are falling on some deaf ears at the grower level. She says anyone who assumes they know how to use the new formulations based on their previous experience with older dicamba products could be ill-prepared to apply the new ones responsibly. Those are the cases she worries will create hard feelings between neighbors and even lawsuits.

“I’ve heard too many people comment, ‘This is just like the introduction of Roundup Ready soybeans in 1996. It’s not that big of a deal. We’ll be fine,’” she says. “But it is different. In 1996, we didn’t have Snapchat, Facebook, Twitter, Instagram or YouTube, and we didn’t have the non-GMO movement with consumers. We have all of that now. How many pictures of damaged gardens and trees have to be on the Internet before people call up their legislators to take action?”

Retailers and farmers also need to be aware that the various dicamba chemistries in the marketplace aren’t necessarily interchangeable. A survey last summer of 636 Missouri pesticide applicators by Kevin Bradley, University of Missouri Extension weed scientist, found that 74% of the respondents were aware of that fact, but 26% thought otherwise.

The two new dicamba formulations aren’t the same.

Engenia contains a BAMPA (N,N-Bis-(3-aminopropyl)methylamine) salt of dicamba with 5 lb. acid equivalent of dicamba per gallon. XtendiMax contains a DGA (diglycolamine) salt of dicamba plus the additive VaporGrip, which is designed to reduce volatility. The dicamba acid concentration equals 2.9 lb. acid equivalent per gallon for this formulation.


Extra Precautions Can Help. Security Seed and Chemical’s Riley is doing everything he can to make using the new dicamba formulations a positive experience for his company and customers this season. To support that effort, the retailer has installed new direct-injection systems on sprayers used with dicamba, so it never goes into the tank.

“We don’t want potential contamination in our tanks; this will limit any liability when it comes to spraying other crops,” Riley notes. “The injection system is an investment we’re having to make to do all we can to prevent issues. We don’t want to deal with any issues.”

Also, the company is giving its applicators on the front line more decision-making authority this year.

“If our applicators get into a field and it’s windy, they have permission to tell the farmer and our sales agronomists, ‘No, they’re not going to spray,’” Riley says. “We’re going to steward this technology as best we can because we hope to use it for a long time.”

By Rhonda Brooks March 06, 2017 | 5:25 am EST