"Miracle" Weed Killer Dicamba was Supposed to Save Farms - Instead it’s Devastating ThemThe damage here in northeast Arkansas and across the Midwest - sickly soybeans, trees and other crops - has become emblematic of a deepening crisis in American agriculture. Farmers are locked in an arms race between ever-stronger weeds and ever-stronger weed killers. The dicamba system, approved for use for the first time this spring, was supposed to break the cycle and guarantee weed control in soybeans and cotton. The herbicide - used in combination with a genetically modified dicamba-resistant soybean - promises better control of unwanted plants such as pigweed, which has become resistant to common weed killers. The problem, farmers and weed scientists say, is that dicamba has drifted from the fields where it was sprayed, damaging millions of acres of unprotected soybeans and other crops in what some are calling a man-made disaster. Critics contend that the herbicide was approved by federal officials without enough data, particularly on the critical question of whether it could drift off target.