Dicamba injury is extensive this summer, according to a long time Iowa State University weed scientist.
ISU Extension’s Bob Hartzler says that reports from agronomist across Iowa indicate nearly all non-dicamba-tolerant soybeans are showing symptoms characteristic of dicamba. “It’s from fence row to fence row in those fields. You can’t see where the source came from...that’s a type of injury we’ve never seen before,” Hartzler notes.
Hartzler thinks several factors contributed to the increase in dicamba damage, including confusion over the Ninth Circuit court’s decision, this summer’s environmental conditions, and an increased use of dicamba on corn. He says that it is hard to predict what the EPA will do with re-registration of those dicamba herbicides for 2021, but new formulations of dicamba with lower volatility than current products are currently being evaluated.
Significant reduction in volatility and better drift management practices could greatly reduce risks associated with dicamba and the new formulations should also be mandated for use on corn, that is according to Hartzler.
Other ag departments are also logging dicamba drift complaints. Minnesota reports more than 70 cases, while Michigan reports a limited amount. Experts remind growers to follow label instructions because certain wind and temperature conditions can create drift.