Dicamba-injury complaints are down nationwide compared to last year, statistics show.

But is it enough to convince the U.S. Environmental Protection Agency (EPA) to allow the weed killer to be sprayed over-the-top of soybeans in 2019 and beyond? The agency’s acting administrator said a decision will be made soon.

“The EPA is still collecting data on dicamba and we’re having frequent discussions about it,” Andrew Wheeler said during a recent roundtable discussion with Iowa farmers and industry officials.

Conditional two-year EPA registrations for new low-volatile formulations of dicamba — Bayer’s XtendiMax™ with VaporGrip Technology, BASF’s Engenia and Corteva Agriscience’s FeXapan plus VaporGrip — are set to expire Nov. 9. Damage to nontolerant soybeans and other sensitive plants, along with calls to ban in-season use from America’s two biggest independent seed companies, threaten the future of the herbicides.

Ryan Rubischko, Bayer’s dicamba portfolio lead, is confident the EPA will re-authorize in-season use of dicamba. Label changes, extensive education efforts by manufacturers and required applicator training greatly improved on-target application this year, he said.

“This is the common phrase I’m hearing from farmers and applicators: ‘As long as I follow labels and appropriate do’s and don’ts, I’ve been successful,’” Rubischko said. “We’ve seen significantly less inquires of concerns with symptomology.”

The number of calls to Bayer’s toll-free dicamba hotline have dropped significantly. People call for label and application advice. They can also report suspected dicamba injury concerns, which initiates an investigation by the company.

There’s been about 13 inquires per 1 million acres of Roundup Ready 2 Xtend soybeans and Xtend cotton, genetically engineered to tolerate glyphosate and dicamba, Rubischko said. That’s compared to about 99 inquires per 1 million acres last year.

More than 40 million acres of Xtend soybeans were planted nationwide — roughly half of the nation’s crop — about twice as much as last year.

“We continue to see farmers adopt the technology at a significant pace,” Rubischko said.

Downward Trend

Some people choose to notify university weed scientists and state agriculture departments about suspected dicamba damage instead of manufacturers, Rubischko said.

University weed scientists nationwide estimated 1.1 million acres of non-tolerant soybeans have sustained dicamba injury as of July 15 compared to 2.5 million acres on July 25, 2017. Total reported acres last year were 3.6 million.

Drift — either wind or volatility (herbicide turns to gas after application), tank contamination and not following label instructions are often the main culprits, according to industry officials.

There were 605 dicamba-related injury investigations nationwide as of July 15, as reported by state departments of agriculture. There were 1,411 investigations July 25, 2017, and more than 2,700 for the year.

Kevin Bradley, University of Missouri weed specialist, compiles dicamba-injury statistics for the EPA. But data stopped coming in after mid-July, he said.

Bradley and Bob Hartzler, Iowa State University weed scientist, were unavailable for comment.

There have been 138 plant growth regulator complaints in Iowa reported as of Sept. 4, according to the Iowa Department of Agriculture and Land Stewardship (IDALS). Fifty-six are confirmed to be dicamba-related injury. Last year, there were 110 dicamba-injury investigations in Iowa.

In mid-June, Bradley’s data showed an estimated 1,200 acres of dicamba-injured soybeans in Iowa. An update wasn’t submitted in July.

Iowa Deputy Secretary of Agriculture Julie Kenney said IDALS shares dicamba data with the EPA. She stressed to Wheeler that a dicamba decision needs to be made before farmers buy seed and inputs for next year and effective weed-control tools are a must.

“Farmers need certainty to make plans for 2019 and beyond. They (EPA) understand the urgency,” Kenney said.

Even though investigations are ongoing, she said it appears on-target applications of dicamba improved.

“I do think the expanded training was helpful,” Kenney added.

IDALS issued a Special Local Need registration for dicamba chemistries applied in-season. As a restricted use herbicide, the label requires auxin-specific training for farmers and certified applicators to use the products.

Classroom and online training were required to cover the following topics:

  • New use pattern for dicamba-tolerant soybeans
  • Application requirements to include wind speed and direction and use of a buffer
  • Temperature inversions
  • Changes in record-keeping requirement
  • Sprayer tank clean-out
  • Off-target movement

Bayer trained 96,000 applicators. The company recently acquired Monsanto, which developed XtendiMax with VaporGrip Technology and Roundup Ready 2 Xtend soybeans.

“Farmers and applicators tell us the training and education brought a level of awareness to successfully apply XtendiMax this season,” Rubischko said.

Officials with Beck’s Hybrids and Stine Seed told Reuters they are pushing government regulators to bar dicamba spraying during the growing season.

“Anybody that sprays it, you have issue with the volatilization,” Beck’s CEO Sonny Beck told the news service.

Field Observations

Jeff Jorgenson, an Iowa Soybean Association director from Sidney, planted Roundup Ready 2 Xtend soybeans and sprayed dicamba over 80 percent of the acres. Problems with herbicide-resistant waterhemp dictated the move, he said.

The results were outstanding, according to Jorgenson.

“Everything went perfectly. They are the cleanest fields I have — no weed escapes,” he said. “I followed the label and didn’t have any off-target issues that I know of. It just flat out worked.”

Jorgenson said it was difficult to get all his spraying done given wind and rain label restrictions. The spraying window was basically limited to 10 a.m. to 1 p.m. on most days, he said. Adhering to buffer requirements are very important, he added.

Many Bayer investigations found dicamba injury was caused by applicators not following wind speed and direction (wind blowing toward nontolerant soybeans) requirements, Rubischko said. Dicamba can only be sprayed when the wind is 3 to 10 mph and rain isn’t forecasted in a 24-hour period.

Drift due to temperature inversion is still a problem to tackle, Rubischko said. It’s a weather phenomenon in which the air at the earth’s surface is cooler than the air above. Inversion increases the risk that dicamba can drift onto nearby fields because tiny herbicide droplets remain suspended in the air.

Bayer’s Xtend Spray App can help farmers make decisions when to spray to mitigate inversion drift. It was downloaded 20,000 times, officials said.

North Central Cooperative, based in Clarion, sprayed about 1,800 acres of Dicamba for customers this year. Agronomy Department Manager John Rohrer reported no off-target issues.

“The performance was great,” he said. “It went really well.”