For two decades, Nick Pehle’s grapes, pressed and distilled, have filled glasses at wineries across Missouri. Most seasons, the vines on his 20-acre farm in Etlah are clustered with different cultivars — vignoles, aromellas, chambourcins.
Last year was different.
In May, before the vines could bloom, their leaves started curling into the shape of small bowls. When the fruit did grow, much of it stayed green, never ripening to full maturity.
Pehle’s harvest was lighter than past seasons — by about 40 tons. Compared to previous years, his crop was reduced by almost half and his profit by around $50,000.
“There’s some dead plants out there,” Pehle said, “and there’s getting to be more every year.”
Pehle doesn’t know exactly what caused his fruit to die. But the symptoms point to pesticide drift.
Crops genetically bred to withstand heavy doses of herbicides are everywhere. According to the United States Geological Survey, an estimated 28 million pounds of pesticides were sprayed over Missouri’s cash crops in 2019. And that doesn’t include those that saturate suburban lawns, golf courses and roadsides.
Pesticides, which include fungicides, insecticides and herbicides, have been around for decades. But 21st-century upgrades to chemicals like 2,4-D and dicamba have led to an acceleration of negative effects.
Once used on individual weeds, herbicides are now sprayed over the top of entire fields. If handled incorrectly, they can drift, finding their way into places they shouldn’t be and hurting sensitive crops.
For many farmers, drift is a top concern. That’s according to a report by the University of Missouri that interviewed 50 fruit and vegetable farmers from across the state.
In 2024, a federal court tossed out the Environmental Protection Agency’s authorization of one of the most notorious drifters, dicamba. But President Trump’s administration is taking a different approach. In February, the EPA reapproved the use of dicamba for the 2026 growing season. This new approval includes new temperature limits, halving the amount farmers can apply annually and conservation measures meant to prevent spread.
Vineyards are especially sensitive to pesticides. Application to row crops is often measured by pounds per acre, but grapes can show injury from less than an ounce.
Dean Volenberg, viticulture program leader at the University of Missouri-Columbia, knew when he received a call from Nick Pehle detailing the damage in his vineyard, it wouldn’t be the last call for the season. For Volenberg, grapes are “canaries in the coal mine” for larger drift problems.
“We see some damage every year,” Volenberg said in an interview last fall. “In 2025, it’s everywhere.”
Now every year, clouds of chemical drift sweep over farmlands and touch large-scale wineries, small-town vineyards and organic farms alike.
Squeezing profits along with grapes.
Shifting winds
Outsiders might be unaware of Missouri’s storied and still-developing winemaking history. A million gallons of wine flow each year from 1,700 acres of vineyards perched upon the Show Me State’s rocky bluffs. Taking into account tourism, taxes and wages, the industry fuels nearly $5.5 billion in economic activity, a trade group says.
Those wine-making traditions run deep along the state’s midsection, following the flow of the Missouri River in from the west and out through the east. Credit largely goes to German immigrants who brought their viticultural traditions with them, settling a region that has since been nicknamed Missouri’s Rhineland.
By 1835, almost 60 wineries had taken root around Hermann and Augusta, making Missouri one of the largest wine producers in the country before Prohibition.
Nowhere is that tradition more apparent than the oldest winery in the state, Stone Hill.
Almost 200 acres of Stone Hill’s vineyards dot Hermann’s bluffs. For thousands of years, the winds swirling above the river have lifted rich soil from the Missouri River’s banks onto the surrounding bluffs, creating fertile hilltops perfect for growing grapes.
Now these enriching winds carry destruction. Nathan Held is vice president of sales and marketing at Stone Hill Winery and a third-generation winegrower.
“On the north side, it’s almost all row crops,” Held said, indicating the fields across the river. “Nowadays, it’s causing some of that drift. And it seems like farmers are now using more volatile chemicals.”
Stone Hill Winery’s vineyards are spread throughout Hermann, so one major drift won’t cripple an entire harvest. But signs of pesticide drift have become common.
“In recent history, we see it every year,” Held said. “Not on every vineyard site, but we’ll see a little bit, at least, on most of the sites.”
One way the state tracks the frequency of pesticide drift is through voluntary reports from farmers.
According to the Missouri Department of Agriculture, 133 pesticide drift complaints were filed in 2025, including 10 from grape growers. That’s compared to seven out of 89 in 2024.
Volenberg advises every person he talks to to tell state regulators if they’ve been drifted and submit a complaint. But vineyards may be holding back.
“Some people almost have got — and I don’t even know the correct term — used to it,” Volenberg said.
Some call it ‘over-the-top’
The 1996 release of Roundup Ready seeds was a turning point in agriculture. Hidden within each of these seeds is a genetic code that makes the plant resistant to glyphosate, the active ingredient in Roundup weedkiller.
Instead of spraying individual weeds, farmers could spray herbicide over their entire field. This led to the term ‘over-the-top’ pesticides. By 2004, 85% of all soybeans grown in the United States were designed with herbicide resistance.
But this breakthrough in resistance had unforeseen consequences. Herbicide-resistant weeds started to outcompete and breed with once easily killable plants, and species like waterhemp, ragweed and amaranth developed tolerances for glyphosate. Two decades after Roundup Ready hit the market, eight glyphosate-resistant weeds would be identified in Missouri.
In 2016, the agricultural-chemical company Monsanto released another genetically modified weapon in the war on weeds. These seeds were resistant to dicamba, a synthetic auxin discovered in the ’50s.
Auxins are to plants as growth hormones are to humans. They regulate virtually every aspect of development. As chemical messengers, they are both integral to a plant’s growth and easy to mimic.
Synthetic auxins do just that. Sprayed onto a broadleaf plant, like dandelion or bull thistle, the chemical mimics auxin, binding to its hormone receptors and overstimulating it. One dose and that plant grows to death.
Farmers could now target their glyphosate-resistant weeds with dicamba at their disposal. But dicamba was prone to drift.
Drift primarily happens two ways. One is when droplets of pesticides applied when winds are strong or blowing towards sensitive crops veer off course.
The second way is as a vapor. If already applied chemicals are rehydrated, they could evaporate and settle onto plants miles from their intended target. Through volatilization, even pesticides initially applied in perfect conditions can still risk drifting.
In 2017, as chemical clouds settled across America’s Corn Belt, farmers saw their crops withering in the field. An estimated 3.1 million acres of farmland west of the Rockies were injured by dicamba drift during the growing season, according to the University of Missouri-Columbia.
“Is there really any way to have an organic production system in Missouri with all of this material going in and about all the time in Missouri?” Volenberg said. “It really makes you wonder. It makes me wonder at least.”
For Aaron Hager, professor at the University of Illinois, dicamba’s habit of drifting wasn’t a surprise. Since its release in the 1960s, dicamba has had a reputation as a volatile herbicide.
“I’ve been here for going on 33 years,” Hager said, “and I’ve seen evidence of off-target dicamba movement every year.”
According to Hager, what made the 2017 drift event different from dicamba’s prior 50 years of use was the extent, quantity and time of year it was being sprayed.
By 2018, Monsanto’s dicamba-resistant seeds were sprouting in almost one-third of Missouri’s soybean fields. Dicamba had previously been used on crops that are planted much earlier in the season, like corn. Later application times meant hotter temperatures and an increased chance of wandering.
Since dicamba’s record-breaking years, new pesticide-resistant crops have entered the market.
Use of 2,4-D, an ingredient in the U.S.’s infamous Agent Orange campaign during the Vietnam War, has skyrocketed. Illinois counties have recorded a median increase of 341% since 2017. Though 2,4-D is less likely to volatilize, it is far more potent to grapevines than dicamba.
Viticulturists such as Nick Pehle see this problem getting worse before it gets better. Alongside his own vineyard, Pehle runs a consulting business where he installs vines and advises other grape growers. Of the almost 40 growers he works with, he said almost every vineyard shows symptoms of drift.
It’s not a matter of if they get drifted, but how bad of a year it will be.
“I call it chemical trespass now, instead of pesticide drift,” Pehle said. “If you can’t keep what you’re doing on your side of your property, you shouldn’t be doing it, is the bottom line.”
Pehle still considers himself lucky. He received partial compensation after a drift incident in 2022 when a neighbor unknowingly sprayed an herbicide containing 2,4-D on his row crops.
But having already uprooted two vineyards that experienced consecutive years of drift, he worries about the vigor of his vines.
“I’m still on the watch, waiting and hoping for the best,” Pehle said. “We have a lot of optimism to be a farmer, especially a specialty crop farmer in Missouri.”
This story is a product of the Mississippi River Basin Ag & Water Desk, an independent reporting network based at the University of Missouri in partnership with Report for America, with major funding from the Walton Family Foundation.
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