By Tom Polansek
CHICAGO (Reuters) - Monsanto Co sued Arkansas agricultural officials on Friday to stop a proposed summer ban on a weed killer linked to widespread crop damage beyond the major farm state's borders.
The lawsuit seeks to block the Arkansas State Plant Board from prohibiting the use of dicamba herbicides, manufactured by Monsanto and BASF SE, during summer when the products are meant to be sprayed on soybeans and cotton engineered by Monsanto to resist the chemical.
Growers across the farm belt said this summer that dicamba hit areas other than where it was sprayed, damaging millions of acres of crops that could not tolerate the herbicides. Experts say dicamba is more likely to vaporize in high temperatures in a process known as volatility.
Chemical companies, though, have blamed the damage on farmers misusing dicamba.
To prevent damage, the Arkansas plant board advanced a proposal at a September meeting that put the state just one step away from banning dicamba sprayings after April 15, 2018.
However, the board did not review 14 studies on volatility Monsanto submitted at the meeting, according to the lawsuit.
The board's action hurt Monsanto and its dicamba herbicide brand through the loss of direct sales and indirect business through distribution and licensing agreements, the complaint said.
"The plant board's action disadvantages Arkansas farmers," Scott Partridge, vice president of global strategy for Monsanto, said on Friday.
Terry Walker, director of the plant board, said on Friday he had not seen Monsanto's lawsuit and declined to comment. Board spokeswoman Adriane Barnes also had no immediate comment on the complaint.
Arkansas previously prevented farmers from using Monsanto's dicamba herbicide, called XtendiMax with VaporGrip, in 2017. The state allowed sales of a version made by rival BASF SE.
The U.S. Environmental Protection Agency (EPA) approved use of the herbicides on crops that had emerged from the ground only through next year and could stop sprayings beyond 2018 if farmers suffer another year of damage.
The case is Monsanto Co v Arkansas State Plant Board et al, Circuit Court of Pulaski County, Arkansas, No. CV-17-5964.
(Reporting by Tom Polansek; Editing by Matthew Lewis and Richard Chang)