A US appeals court has ruled that seed and crop protection company Corteva can continue to sell an agricultural weedkiller that environmentalists said was harmful to plants and wildlife, Reuters reported on 22 July.

The decision to allow sales of Corteva’s Enlist Duo followed a decision by the same court to block a rival herbicide sold by German chemical firm Bayer.

Enlist Duo, a blend of the chemicals 2,4-D choline and glyphosate, is sprayed on soyabeans, corn and cotton that are designed to resist it.

The 9th US Circuit Court of Appeals rejected a claim from environmental groups that the US Environmental Protection Agency (EPA) had failed to properly consider the product’s volatility, or tendency to evaporate into a gas and drift away. They said the agency had correctly relied on studies to conclude that the volatility of 2,4.D choline salt would not cause unreasonable harm to the environment.

“Corteva is confident in the sustainability and effectiveness of Enlist Duo,” the company said in a statement.

The court’s decision was criticised by environmental groups.

“The research the EPA cites does not even qualify as scientific data,” said Stephanie Parent, a Center for Biological Diversity attorney involved in the case.

In its earlier decision, on 3 June, the court ruled that the EPA had substantially understated the risks related to the use of dicamba, a chemical found in herbicides sold by Bayer and rivals that are sprayed on genetically engineered soyabeans and cotton.

The ruling had also blocked sales of dicamba-based herbicides like BASF’s Engenia and Corteva AgriSciences’ FeXapan, Reuters reported on 4 June.

BASF and Bayer had said they disagreed with the court’s judgement, while Corteva had stated it was reviewing the decision and believed dicamba was safe to use.

Bayer is also facing a legal battle over allegations that its glyphosate-based weedkiller Roundup causes cancer. The company had reached verbal agreements to resolve up to 85,000 of the 125,000 Roundup lawsuits it faced in the USA, the Independent reported on 26 May. The verbal agreements were part of a US$10bn plan to end the legal battle.

The company had inherited the lawsuits when it bought US agrochemicals company Monsanto in 2018.

Bayer has consistently claimed that Roundup can be used safely and that glyphosate, the most commonly used herbicide among farmers, is not carcinogenic.