CHICAGO (Reuters) - With Monsanto Co's (MON.N) latest flagship weed killer, dicamba, banned in Arkansas and under review by U.S. regulators over concerns it can drift in the wind, farmers and weed scientists are also complaining that confusing directions on the label make the product hard to use safely.
Dicamba, sold under different brand names by BASF (BASFn.DE) and DuPont (DD.N), can vaporize under certain conditions and the wind can blow it into nearby crops and other plants. The herbicide can damage or even kill crops that have not been genetically engineered to resist it.
To prevent that from happening, Monsanto created a 4,550-word label with detailed instructions. Its complexity is now being cited by farmers and critics of the product. It was even singled out in a lawsuit as evidence that Monsanto's product may be virtually impossible to use properly.
At stake for Monsanto is the fate of Xtend soybeans, it largest ever biotech seed launch.
Monsanto's label, which the U.S. Environmental Protection Agency (EPA) reviewed and approved, instructs farmers to apply the company's XtendiMax with VaporGrip on its latest genetically engineered soybeans only when winds are blowing at least 3 miles per hour, but not more than 15 mph.
Growers must also spray it from no higher than 24 inches above the crops. They must adjust spraying equipment to produce larger droplets of the herbicide when temperatures creep above 91 degrees Fahrenheit. After using the product, they must rinse out spraying equipment. Three times.
"The restriction on these labels is unlike anything that's ever been seen before," said Bob Hartzler, an agronomy professor and weed specialist at Iowa State University.
The label instructions are also of interest to lawyers for farmers suing Monsanto, BASF and DuPont over damage they attribute to the potent weed killer moving off-target to nearby plants.
The companies failed "to inform the EPA that their label instructions were unrealistic," the lawsuit said.