Reports of dicamba damage to crops are back again

Bryce Gray St. Louis Post-Dispatch
Farm Forum

For some farmers and weed scientists, puckered leaves on certain crops and other plants have become a familiar summertime sight — one that can suggest vapor from the weedkiller dicamba has moved through the air.

What many now refer to as “the D-word” is once again a topic of conversation — and controversy — as a third-straight summer of widely reported crop damage could be starting to unfold across the Mid-South and in other states in the heartland.

The University of Missouri Division of Plant Sciences, which last year emerged as a national leader in tracking alleged dicamba issues, says that as of mid-June, estimated damage affects more than 383,000 acres of soybeans across at least 10 states, including Missouri and Illinois. Trees, vegetables and specialty crops are also showing signs of injury this year.

The years-long saga has wrought deep divisions in the agriculture community, pitting farmers against farmers and sparking tension between university weed scientists and industry leaders selling the technology, such as the Creve Coeur-based agribusiness giant, Monsanto.

A question at the heart of the debate is whether dicamba — a decades-old chemical that has a tendency to evaporate, or volatize, and move off-target — can coexist on a broad scale with plants that are not genetically modified to tolerate it, without inflicting harm.

The debate has grown steadily since 2015, when a new variety of cotton kicked off Monsanto’s rollout of its “Xtend” seeds engineered to withstand dicamba — a herbicide lauded by the company and many farmers as a much-needed tool in the fight against Roundup-resistant “superweeds.” But new, less-volatile forms of dicamba spray had not yet been approved for use with the Xtend crops, creating a situation where some farmers are accused of illegally using older varieties of the chemical — a choice that would not harm Xtend plantings, but left surrounding farmers vulnerable to crop damage if volatization or physical drift occurred.

By the end of 2015 growing season, some farmers say they were already seeing symptoms that resembled possible dicamba damage. Those reports have gotten worse ever since.

Cases of suspected dicamba injury snowballed in 2016, when Monsanto added Xtend soybean seeds to the market. But an approved, lower-volatility form of the herbicide itself was still not available — an absence that many farmers and lawsuit plaintiffs say led predictably to more applications of illegal substitutes.

Some thought things may be better in 2017, after proper, lower-volatility forms of the spray finally gained regulatory approval. But as the national acreage of Xtend plantings rose, reports of dicamba damage swelled to more than 3 million acres for soybeans alone.

But this year’s initial tally from the University of Missouri shows that similar damage reports persist, despite extensive education campaigns and classes about application techniques that aim to minimize — or, ideally, negate — the threat of off-target movement.

Estimated damage is the worst, this year, in Illinois, after being most heavily concentrated in places like Arkansas and southeast Missouri’s Bootheel region in previous years.

“In (southeast Missouri), I’m convinced that the adoption of the Xtend trait in cotton and soybean is as high as anywhere in the country,” wrote Kevin Bradley, a University of Missouri plant sciences professor and the author of the report of damage estimates. “Many growers in this area have adopted the Xtend trait so they don’t experience dicamba injury on their soybean crop for a third season in a row. Since the adoption of the Xtend trait is so high in this area, relatively speaking there seem to be fewer soybean fields with injury this year compared to last.

“However, just as in the past two seasons, there are still fields of non-Xtend soybean in this area showing injury from one end to the other,” Bradley’s report continued. “More surprising to me than that has been the extent of the trees that are showing symptoms of growth regulator herbicide injury in that part of the state where the adoption of this trait is so high.”

Monsanto officials insist that incidents of suspected damage have been relatively low in 2018, and that any problems stem from user error as opposed to volatility or any defects of the dicamba weed control system.

“Overall, we see the 2018 season off to a really great start,” said Ryan Rubischko, the North America dicamba portfolio lead for Monsanto. “When you follow the label, you can do this successfully.”

He said that sales of Xtend seeds doubled from 25 million acres last year to more than 50 million acres in 2018, including 50 percent of all U.S. soybeans. He added that 94,000 applicators received classroom training over the winter and that the company continues aggressive efforts to “review and evaluate what is leading to this off-target movement.”

Though many farmers have embraced dicamba in the fight against weeds, others say the system is inherently flawed and that problems will remain as long as it’s on the market.

Tom Burnham, a farmer in extreme southeast Missouri and northeast Arkansas who estimates he suffered $60,000 to $100,000 in dicamba-related yield losses last year, told the Post-Dispatch in mid-June that he began to see alleged dicamba damage resurface on his soybeans.

“They’ve got a terrible product problem. I don’t see any way that this can work,” said Burnham, who has been a vocal critic of dicamba. “The window (to spray) is so narrow that you can’t do it right.”