An Arkansas judge has allowed six farmers to spray Monsanto’s controversial dicamba-based herbicide on their crops after a 15 April cut-off date despite concerns over its potential to cause damage to surrounding crops not engineered to tolerate it.

Arkansas banned the spraying of dicamba between 16 April and 31 October after it caused crop damage by evaporating from soyabean fields and drifting over to areas where crops were not engineered to resist the weed killer.

Arkansas Pulaski County Circuit Judge Tim Fox gave six farmers permission to spray the chemical even though he earlier dismissed a case where growers tried to sue the Arkansas State Plant Board to remove the cut-off date, said Farm Ireland on 3 April.

Fox’s dismissal was based on an Arkansas Supreme Court decision stating that the state could not be a defendant in court, but he said the farmers were exempt from the spraying deadline in any case as their inability to sue violated their due process rights.

Grant Ballard, an attorney at law firm Ark Ag Law who represented the six farmers, said he considered Fox’s decision a win.

“We hoped every Arkansas farmer that used the technology responsibly would have the option [to spray it after the cutoff date],” said Ballard.

But Terry Fuller, a member of Arkansas State Plant Board, was concerned that allowing even six growers to spray dicamba during the growing season could risk crop damage.

Thousands of US farmers filed complaints or sued Monsanto last year for crop damage linked to its use last summer. Other states have also limited its use.

Monsanto, which is currently awaiting regulatory approval for its merger with German chemical firm Bayer, maintains that dicamba is safe to use throughout the growing seasons if farmers follow its extensive usage instructions.