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Arkansas and Missouri ban dicamba herbicide

Complaints about damaged soybeans from spray drift prompt states to act

by Britt E. Erickson
July 13, 2017 | A version of this story appeared in Volume 95, Issue 29

Credit: University of Arkansas Cooperative Extension Service
Dicamba causes leaves of soybeans not genetically modified to withstand the herbicide to curl into cuplike shapes.
Soybean leaves forming cuplike shapes.
Credit: University of Arkansas Cooperative Extension Service
Dicamba causes leaves of soybeans not genetically modified to withstand the herbicide to curl into cuplike shapes.

In response to escalating concerns about alleged misuse of the herbicide dicamba, Arkansas and Missouri have halted the sale and use of the chemical. The states received hundreds of complaints this year from farmers who say dicamba spray drifted onto their property from neighboring fields and damaged their soybeans that have not been genetically engineered to tolerate the herbicide.

On July 7, the Missouri Department of Agriculture banned the sale and use of all dicamba products labeled for agricultural use in the state, effective immediately. Also on July 7, the Arkansas Agriculture Department halted the sale of dicamba for agricultural use in that state for 120 days, effective on July 11.

Chris Chinn, director of the Missouri Department of Agriculture, says Missouri’s ban will be lifted once companies, the state, and the U.S. Environmental Protection Agency agree to new restrictions to be printed on dicamba product labels.

Dicamba (3,6-dichloro-2-methoxybenzoic acid) is found in herbicides produced by Monsanto, BASF, and DuPont for use on soybeans and cotton that are genetically modified to tolerate the chemical. EPA cleared the way for these uses in 2016 to combat broadleaf weeds that have developed resistance to glyphosate and other herbicides.

Complaints about spray drift and soybean damage from illegal use of dicamba in 2015 and 2016 led companies to develop formulations that are less volatile.

BASF developed Engenia, an N,N-bis-(3-aminopropyl)methylamine salt of dicamba designed to reduce drift. Monsanto created its XtendiMax with VaporGrip technology “to minimize the potential for off-site movement.”

The companies are worried about the timing of the state bans. “We are concerned this abrupt decision in the middle of a growing season will negatively impact many farmers in Arkansas,” Monsanto says in a statement. Monsanto calls the Arkansas ban “premature since the causes of any crop injury have not been fully investigated.”

In response to Missouri’s action, Monsanto encouraged growers, retailers, and distributors to comply with the ban. “We want to stress how important it is that growers and applicators who use our product follow the label requirements and any local requirements,” Monsanto says.

The Missouri Soybean Association claims that more than 200,000 acres of soybeans in Missouri have been damaged by dicamba this year. “It’s clear that action is needed,” says farmer Matt McCrate, president of the growers’ group.



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