After shutting down row-crop use of dicamba for the rest of this growing season, the U.S. Arkansas state has appointed a 21-member task force to look for a long-term solution to the nearly 900 complaints about the herbicide this year. “The task force will attempt to reach consensus on a set of recommendations for the use of dicamba products in Arkansas as quickly as possible in order to provide certainty for the 2018 growing season,” said the state Agriculture Department.
Task force members will hold their first meeting August 17 and will confront an explosion of complaints despite EPA approval of drift-resistant formulations of the weedkiller. Last year, problems were blamed on illegal spraying of cotton and soybean crops with older, unapproved dicamba formulations as a way to combat invasive weeds resistant to other weed killers. Seed companies are selling cotton and soybean strains genetically engineered to tolerate dicamba.
University of Missouri weed specialist Kevin Bradley said dicamba damage was alleged on 2.5 million acres of soybeans in 17 states as of late July. Missouri agriculture officials tightened their rules on when the weed killer could be used and limited use to three drift-resistant products, one each from Monsanto, BASF, and DuPont.
On Monday, Agriculture Secretary Sonny Perdue told reporters that he would prefer “a bottom-up” resolution of dicamba problems by growers and chemical companies rather a “top-down (set) of rules and regulations.”
Bradley and two other researchers, from Arkansas and Illinois, told Reuters that Monsanto provided samples of its drift-resistant dicamba prior to EPA approval but barred them from testing its volatility. Monsanto said such tests were unnecessary because it had already proven the new formulations were far less likely to drift onto neighboring fields.
There are stringent rules on application of dicamba — only on relatively calm days, using special nozzles and keeping sprayer booms close to the ground while leaving a buffer between treated fields and sensitive crops. Some of the dicamba complaints have been blamed on improper application of the herbicide, but some weed experts, such as Ford Baldwin, says the drift-resistant formulations “are less volatile but not nonvolatile.”