In a normal year, Kevin Bradley, a professor of weed science at the University of Missouri, would have spent his summer testing new ways to control a troublesome little plant called water hemp.
This has not been a normal year.
“I don’t even talk about weed management anymore,” Bradley tells me, and he sounds disgusted. “Nobody calls me and ask me those questions. I barely have time to even work with my graduate students. Everything is about dicamba. Every single day.”
Dicamba, an old weedkiller that is being used in new ways, has thrust Bradley and a half-dozen other university weed scientists into the unfamiliar role of whistleblower, confronting what they believe are misleading and scientifically unfounded claims by one of the country’s biggest seed and pesticide companies: Monsanto.
“It’s not comfortable. I’m like anybody else, I don’t like [it when] people are unhappy with me,” says Mike Owen, a weed specialist at Iowa State University. Then he chuckles. “But sometimes, like John Wayne said, a man’s got to do what a man’s got to do!”
“Certainly, there’s not a weed scientist in any of these states who would back down, who would change their story,” says Aaron Hager, at the University of Illinois.
The tensions between Monsanto and the nation’s weed scientists actually began several years ago, when Monsanto first moved to make dicamba the centerpiece of a new weedkilling strategy. The company tweaked the genes in soybeans and cotton and created genetically modified varieties of those crops that can tolerate doses of dicamba. (Normally, dicamba kills those crops.) This allowed farmers to spray the weedkiller directly on their soybean or cotton plants, killing the weeds while their crops survived.
It’s an approach that Monsanto pioneered with crops that were genetically modified to tolerate glyphosate, or Roundup. After two decades of heavy exposure to glyphosate, however, devastating weeds like Palmer amaranth, or pigweed, developed resistance to it. So farmers are looking for new weedkilling tools.
Dicamba, however, has a well-known defect. It’s volatile; it tends to evaporate from the soil or vegetation where it has been sprayed, creating a cloud of plant-killing vapor that can spread in unpredictable directions. It happens more in hot weather, and Monsanto’s new strategy inevitably would mean spraying dicamba in the heat of summer.
Monsanto and two other chemical companies, BASF and DuPont, announced that they had solved this problem with new “low-volatility” formulations of dicamba that don’t evaporate as easily. Yet the companies — especially Monsanto — made it difficult for university scientists to verify those claims with independent tests before the products were released commercially.
“I wish we could have done more testing. We’ve been asking to do more testing for several years, but the product was not made available to us,” says Bob Scott, a weed scientist at the University of Arkansas. “These are proprietary products. Until they release those formulations for testing, we’re not allowed to [test them].”
To make matters worse, Monsanto started selling its new dicamba-tolerant soybeans in 2016, before the new low-volatility formulations of dicamba were even approved for sale. It tempted farmers to use older versions of dicamba on these crops, illegally, and some farmers couldn’t resist that temptation. In Arkansas, there were widespread reports that dicamba was damaging neighboring fields that didn’t have the benefit of Monsanto’s new genes. In one case, a dispute between farmers led to a fatal shooting.
That fall, at a meeting of weed scientists, Hager confronted Monsanto’s representatives. According to Hager, he told the company that “you knowingly released these varieties in an area of the U.S. where you knew that glyphosate resistance [in weeds] was rampant. When you did that … you knew what was going to happen.”
“I got a blank stare,” Hager recalls.
This past summer, the floodgates on dicamba use opened. The new formulations of dicamba were approved for use (although Arkansas only allowed farmers to use BASF’s product, not Monsanto’s) and farmers rushed to adopt the new technology. They planted dicamba-tolerant crops on 26 million acres.
“The demand for it is overwhelming. The need to control these difficult-to-manage weeds is huge,” says Scott Partridge, Monsanto’s vice president of global strategy.
When spraying started, complaints rolled in. The new “low volatility” versions of dicamba didn’t stay where they belonged. They drifted into nearby fields, damaging crops there — mostly soybeans, but also vegetables and orchards. There were reports of damage from Mississippi to Minnesota, but the problem was worst in Arkansas, Missouri and Tennessee.
“By the end of May, first of June, it became impossible; the calls were coming in, three or four a day. Sometimes eight or 12 a day,” says the University of Arkansas’ Scott. “There is no precedent for what we’ve seen this year.”
At first, the companies selling these herbicides — both Monsanto and BASF — seemed unconcerned.
“All I got was denial that there was a problem,” Bradley says. “What I kept hearing was: It’s not a big problem nationwide; we always have these kinds of mistakes or accidents with the introduction of any new technology.”
So Bradley, a past president of the Weed Science Society of America, started collecting data on crop damage from across the country, mapping the epidemic. By the end of the summer, Bradley estimated that at least 3.1 million acres of crops had shown some injury from drifting dicamba.
With the scale of dicamba damage increasingly clear, a fierce debate erupted over its cause.
Monsanto’s executives insist that the people who sprayed dicamba were just learning how to do it properly and didn’t follow directions. Partridge says his company checked out more than a thousand cases of dicamba damage, “and in 88 percent of those instances, the label was not followed.” Farmers or pesticide applicators sprayed dicamba too close to neighboring fields, didn’t clean out their equipment properly or used the wrong nozzles.
“Every one of those [mistakes] is fixable by education,” Partridge says.
University weed scientists say that that is only part of the explanation and that the problem can’t be fixed so easily.
Bradley, Scott and their colleagues in other states say that much of the damage they saw this year didn’t appear to come from “physical drift” of windblown droplets of dicamba, coming directly from a sprayer. Physical drift, they say, typically produces a plume of damage that diminishes with distance from the source of the spray. Instead, they saw entire hundred-acre fields of soybeans with cupped leaves, and the damage was uniform from one end to the other. They also saw damage in orchards and fields that were far removed from any fields sprayed with dicamba.
This pattern, they say, looks more like what they had feared all along: volatilization.
The Washington Post/Getty Images
ClarificationOct. 26, 2017
A headline on a previous version of this story incorrectly suggested dicamba is a new weedkiller. It is actually an old product being used in a new strategy.