Complaints of crop damage from the powerful and volatile weedkiller dicamba have increased rapidly around the country.

According to weed scientist and University of Missouri associate professor Kevin Bradley, 17 state governments are investigating more than 1,400 official complaints of dicamba-related injuries this year covering 2.5 million acres.

“This is a substantial problem that needs to be addressed,” Bradley wrote.

Reports suggest that farmers applied the herbicide to Monsanto Co.’s new dicamba-tolerant soybean and cotton crops to beat back ever-resistant weeds, but the drift-prone chemical can be picked up by the wind and land on neighboring non-target fields, crops and native plants. Fruits and vegetables, as well as other crops that are not genetically engineered to withstand dicamba, are often left cupped and distorted when exposed to the chemical.

The current rash of complaints echoes the similar devastation last summer, when 10 states reported hundreds of thousands of crop acres adversely impacted by the apparent misuse of the herbicide. 

Although dicamba has been around for decades, Monsanto, DuPont Co. and BASF SE sells new formulations of the herbicide that’s said to be less drift-prone and volatile than older versions when used correctly.

Monsanto execs defended its product, blaming growers for using older versions of dicamba or not following directions on the new product label. As reported by Bloomberg: 

The company attributes the drifting problem to farmers using illegal, off-label products that are more volatile—and thus more prone to drift—than the latest versions of dicamba. They may also be cleaning or using their spraying equipment incorrectly, or applying dicamba when it’s windy, said Robb Fraley, executive vice president and chief technology officer.