U.S. farmers confused by Monsanto weed killer's complex instructions

By Tom Polansek and Karl Plume CHICAGO (Reuters) - With Monsanto Co's latest flagship weed killer, dicamba, banned in Arkansas and under review by U.S. regulators over concerns it can drift in the wind, farmers and weed scientists are also complaining that confusing directions on the label make the product hard to use safely. Dicamba, sold under different brand names by BASF and DuPont , can vaporize under certain conditions and the wind can blow it into nearby crops and other plants. To prevent that from happening, Monsanto created a 4,550-word label with detailed instructions.