The EPA last week tweaked requirements for applying dicamba over-the-top in soybeans and cotton, but the changes are unlikely to solve many of the challenges with off-target movement that have occurred during the past two growing seasons, weed scientists said last week.

“The EPA is in a very difficult position in regulating this technology. Whatever they do is going to be criticized by some people,” said Iowa State University Extension weed scientist Bob Hartzler. “Unfortunately, I don’t think these new restrictions will...