An advanced weed-killing chemical, dicamba, which had long been used in the United States to kill weeds before fields were planted, has twice come back to haunt Missouri and Arkansas farmers.
Its use spiked last year after regulators approved a new formulation that allowed farmers to apply it to growing plants.
That should have been good news for hundreds of farmers, who used it to control hard-to-kill weeds in fields planted with crops bioengineered to survive the chemical.
Instead, farmers reported the agricultural chemical was drifting into neighboring fields and damaging crops unable to resist it. Last month, in response to the reports, Missouri and Arkansas temporarily banned its use.
The fallout from dicamba has hit farmers on two fronts. First, the drifting chemicals stunted unprotected soybean crops and marked the plants with damaged, withered leaves. Next, a ban of the herbicide meant they could no longer use it on the dicamba-resistant soybeans and cotton it was meant to protect.
Crops have suffered damage across much of the farm belt. Governments in 17 states are investigating more than 1,400 complaints of dicamba problems covering 2.5 million acres, Kevin Bradley, a University of Missouri associate professor in the plant sciences division, wrote last week.
The three companies that sell the chemical in the United States for use on growing crops of soybeans and cotton, Monsanto Co., BASF and DuPont, say their products have not always been used according to label instructions.
Read more: St. Louis Post-Dispatch