University of Arkansas weed scientist Jason Norsworthy described the weedkiller dicamba as “a product that is broken,” and told a state task force that he could not recommend its use in the state in 2018, said the Arkansas Democrat newspaper. Arkansas leads the nation in reports of damage to crops when dicamba is sprayed on nearby fields.
Some 3.1 million acres of soybeans are reported to be damaged by dicamba nationwide, including 900,000 acres in Arkansas, according to a University of Missouri weed specialist. The reports cover 3.5 percent of U.S. soybean plantings and 27 percent of Arkansas soybean land. Other crops, such as peanuts, fruits and vegetables, are vulnerable to dicamba.
Arkansas convened its dicamba task force with the goal of producing long-term recommendations for the chemical. Cotton and soybean growers have embraced new GMO crop varieties that tolerate dicamba as a way to combat invasive weeds, such as Palmer amaranth, that are resistant to other herbicides. Farmer David Wildy, who says he could sustain a $1 million loss on cotton and soybeans due to dicamba damage, told the task force that dicamba can be a useful tool. “But if I can’t keep it on target, it’s not one that I can use.”
Norsworthy said tests in at least four states show the weedkiller can “volatilize” into a vapor and travel into other fields under certain conditions. The Arkansas Democrat quoted him as saying, “I can fix drift. I can’t do anything about volatility.” Norsworthy said volatility was the biggest problem with the weedkiller this year. Chemical companies have suggested improper application was to blame or that other diseases or chemicals cause the same symptoms as dicamba damage. A BASF official told the task force that he doesn’t believe volatility was the major factor in the reported damage.