Week 2: Mind the Vines—Preventing
By Natalie van Hoose
The sight of whitened, curled leaves on his grapevines no longer surprises Dave Simmons, co-owner of Simmons Winery in Columbus, Ind.
Simmons' vineyards are hit nearly every year by drift, the aerial migration of herbicides from row-crop fields to non-targeted areas, such as vineyards. The impact of drift on the highly sensitive grapevines is easy to identify: stunted vines, distorted leaves and shrunken canopies.
"This year is probably worse in overall damage," Simmons says. "A lot of the vines are weak, unhealthy. Some of them, like Marechal Foch, just look awful."
Drift poses a significant threat to grape growers, particularly in the Midwest where vineyards are often surrounded by corn and soybean fields that are sprayed with plant growth regulators such as dicamba and 2,4-D. The herbicides are designed to squelch weeds, but they can spread to other areas in droplet form or by volatizing into the air as a gas.
Purdue viticulture specialist Bruce Bordelon discusses drift, the aerial migration of herbicides from crop fields to highly sensitive vineyards.
Some grapevines affected by drift grow out of the damage while others are permanently stunted. If a vineyard is struck by drift before the grapes have set, fruit development and yields may suffer. In severe cases, vines can wither and die.
Larry Pampel, co-owner of Whyte Horse Winery in Monticello, Ind., says the loss of a vine is especially painful because of the time it takes to rear a fruit-bearing grapevine.
"It's not like a row crop that you can replant and harvest the next year," he says. "If you lose a vine, you're looking at three to four years to recovery."
Growers can report drift incidents to the Office of Indiana State Chemist, which regulates the use of pesticides. The OISC, based at Purdue University, will try to pinpoint the source of the drift to verify that label laws have been followed properly. Sprayers who violate label laws face penalties and reparation costs.
Drift damage is the top pesticide complaint fielded by the OISC, which investigates about 50 cases of drift a year. But Dave Scott, manager of the OISC Pesticide Program Administration, says identifying the source can be difficult.
"Grapes are extremely sensitive to any growth regulator herbicide," says Scott. "Even in low amounts, herbicides will have some impact."
Simmons has twice filed complaints with the OISC. In one case, the OISC determined that a neighbor had sprayed on a windy day, and Simmons was compensated; no direct cause could be found for the second incident, and Simmons says he no longer reports drift.
"It's usually impossible to find out who caused it," he says. "It's just out there in the air. Someone could spray two miles down the road, and it can volatize and move down here."
To help minimize the potential for drift, growers of specialty crops can publicize their location on the online registry DriftWatch, created by Purdue. Pesticide applicators can use the maps on DriftWatch to note sensitive areas nearby before spraying. Leighanne Hahn, the website's director of operations, says the agricultural community has accepted DriftWatch tools readily.
Indiana has about 600 acres of grapes, compared with about 11.3 million acres of corn and soybeans.
Since January of 2012, the number of pesticide applicators who have registered with DriftWatch has risen from 175 to 458. Registered growers of specialty crops increased from 500 to 2017, and the number of registered pesticide-sensitive fields jumped from 727 to 2866.
Sources: U.S. Department of Agriculture, DriftWatch
"Our users tell us that it works," she says. "As the interaction between row- crop farmers and growers of specialty crops increases, mutual respect is going to continue to develop. Everybody's going to find ways to work together."
Kim DeWees, president of Vision Ag Inc., a company hired by row-crop farmers to spray their fields, says her employees use DriftWatch maps to look for sensitive areas before spraying. Applicators also are trained to use proper nozzles, check wind speed and follow label instructions to prevent drift, and a drift guard agent is added to sprayer tanks if needed.
"We try hard," says DeWees. "No one wants drift to happen."
Grape growers Simmons and Pampel, who is also president of the Indiana Winery and Vineyard Association, try to protect their vineyards in the most direct way possible—establishing good relations with local row-crop farmers.
"All of my neighbors are aware that I grow grapes, and they don't spray 2,4-D out of respect for that," says Simmons. "You can also go to the local agribusinesses responsible for spraying and let them know. They'll work with you."
Scott says that while there is always potential for tension among growers, he has seen a change in attitude over the last 30 years.
"There's been an increase in awareness among row-crop farmers," he says. "They understand that corn and soybeans are not the only crops in the state—some producers grow specialty crops as well. They recognize the benefit of diversity in agriculture and the need to coexist."
Credits: Photos by Tom Campbell & Natalie van Hoose. Video by Kelsey Getzin. Web version by Andrew Banta. Through the Grapevine graphic by Russ Merzdorf.