Monsanto develops product to deactivate controversial farm chemical

By Tom Polansek

CHICAGO (Reuters) - Monsanto Co (MON.N) is launching the first product that deactivates a controversial weed killer inside spraying equipment after it is used, the company said on Tuesday, its latest attempt to prevent unintended crop damage associated with the herbicide.

The product aims to stop farmers from accidentally applying traces of the herbicide, known as dicamba, on crops that can not tolerate it when the chemical's residue remains in spraying equipment.

Growers across the U.S. farm belt said last summer that dicamba herbicides, which are also sold by BASF SE (BASFn.DE) and DowDuPont Inc (DWDP.N), vaporized and drifted away from where they were sprayed on soybeans and cotton that Monsanto engineered to resist the chemical. This damaged millions of acres of other crops, triggering lawsuits against the manufacturers.

Monsanto has blamed much of last year's field damage on improper applications, including by farmers who did not adequately clean spraying equipment. The company has said its dicamba-based herbicide is safe when used properly.

The product that deactivates dicamba will be launched in the coming weeks, as U.S. farmers advance crop plantings, said Ryan Rubischko, Monsanto's dicamba portfolio lead.

"Having technologies like this, it helps farmers be able to really just focus in further on ensuring their sprayer systems are clean and preventing this from happening," he said about equipment contamination.

Monsanto and a company called Adjuvants Unlimited tested the product, which does not have a name yet, over the past few years, according to a statement.

Weed experts doubted it would do much on its own to prevent the type of crop damage associated with dicamba in 2017.

"That's not going to solve the problem," said Bob Hartzler, an agronomy professor at Iowa State University.

Last year's problems were more commonly associated with dicamba evaporating in a process known as volatilization and drifting, experts said.

In Indiana, contaminated spraying tanks were linked to 3 percent of complaints about crop damage associated with dicamba, according to a Purdue University presentation.

"That did not make but just a small fraction of the claims," said Fred Whitford, director of Purdue's pesticides programme.

Monsanto, which is being acquired by Bayer AG (BAYGn.DE), is banking on its dicamba-based herbicide and soybean seeds engineered to resist it to dominate soybean production in the United States, the world’s second-largest exporter.

Facing complaints last year, the company proposed changes to the herbicide's label instructions that the U.S. Environmental Protection Agency approved for 2018.

(Reporting by Tom Polansek; Editing by Tom Brown)