American agrichemicals giant Monsanto has lost its bid to prevent the US state of Arkansas from prohibiting the use of its controversial dicamba herbicide during the 2018 season.

Circuit Court Judge Chris Piazza ruled that due to a recent Arkansas Supreme Court decision, the state could not be made the defendant for the lawsuit which Monsanto filed last year, Reuters reported on 16 February.

Arkansas banned the spraying of dicamba between 16 April and 31 October after it caused crop damage around the USA last year by evaporating from the soyabean fields and drifting over to areas with crop that had not been engineered to resist the toxin.

Monsanto, which is being acquired by Bayer in a US$66bn deal, has repeatedly claimed that dicamba was safe if used according to the extensive label instructions, and said that it would consider further legal action in the case.

The company was looking to use dicamba – which is also produced by BASF and DowDuPont – to replace the use of glyphosate on US soya farms, which would give its soyabeans engineered to resist the chemical a significant slice of the market.

Monsanto claimed that the Arkansas ban hurt its ability to sell the dicamba resistant seeds and had caused “irreparable harm” to the company, particularly as the state had also limited the herbicide’s use in 2017 but allowed other companies to continue sales.