Dealing with dicamba drift

Abstract

In many midwestern soybean fields, a plant called Palmer amaranth is enemy number one. This B horror movie of a weed can grow more than 15 cm in a week. It steals sunlight, water, and nutrients from slower-growing soybeans. An individual plant can produce 100,000 seeds and grow thick enough to bust a tractor. So it was more than inconvenient when the best solution for controlling Palmer amaranth turned out to be enemy number two. New formulations of dicamba herbicide introduced last year by Monsanto, BASF, and DuPont were excellent at controlling amaranth in fields of soybeans engineered by Monsanto to be tolerant to the herbicide. But farmers filed thousands of reports alleging the herbicide drifted off target, damaging nontolerant soybeans as well as trees, tomatoes, and other plants. The reports of damaged crops prompted the U.S. Environmental Protection Agency to change the label instructions on the chemical, such as