Complaints over dicamba chemical continue in Missouri

COLUMBIA, Mo. -- The Missouri Department of Agriculture is continuing to receive complaints from farmers about the chemical dicamba drifting onto their fields and damaging their crops, especially soybeans.

More than 310 complaints have come into the agency so far this year, the highest number in years, with most of the complaints coming from Southeast Missouri, The Columbia Missourian reported. An estimated 325,000 acres of farmland in Missouri were damaged this summer.

Kevin Bradley, a plant-science professor at the University of Missouri, said he never has seen dicamba damage on this scale before. It's estimated 3.1 million acres of farmland in the U.S. have been harmed this summer, and more than 2,000 complaints have filed nationwide so far this season.

Missouri placed a temporary ban on dicamba in July but lifted it within a week with restrictions on its use, including spraying during certain times of day and under a specific wind speed. Complaints resumed after the ban was lifted and some farmers have sued dicamba producers. Several states and the Environmental Protection Agency are considering new rules for its use.

Scott Partridge, a representative of Monsanto, which produces the dicamba product Xtendimax, said farmers have been using the chemical for 50 years. About a decade ago, Monsanto adjusted the formula for dicamba to give farmers "multiple modes of action" against weeds, Partridge said. At the same time, Monsanto and others developed dicamba-resistant crops, including soybeans and cotton.

Although it frequently has been used by farmers on dicamba-resistant corn, this summer was the first season farmers used it on soybeans. Because it has a tendency to vaporize, dicamba moves through the air and drifts onto other fields. While its volatility can't be eliminated completely, Xtendimax reduced it up to 90 percent, according to Partridge.

The agriculture department said farmers are required to spray dicamba in accordance with certain restrictions, such as at 10 mph and between the hours of 9 a.m. and 3 p.m. Operators must also be certified and keep detailed records of their use of the chemical.

Researchers are trying to determine how environmental factors such as air and soil temperature affect dicamba. Bradley recommended farmers who want to plant resistant soybeans next year should spray dicamba on weeds earlier in the season and avoid using it on weeds that sprout later in the season.

Partridge said giving farmers proper education could help prevent dicamba drift. He said that in Georgia, where training for applying dicamba is mandatory, the state hasn't received a single report of dicamba drift damaging crops.

Information from: Columbia Missourian, http://www.columbiamissourian.com