The chemical giant Corteva will stop producing Enlist Duo, a herbicide considered to be among the most dangerous still used in the US by environmentalists because it contains a mix of Agent Orange and glyphosate, which have both been linked to cancer and widespread ecological damage.

The US military deployed Agent Orange, a chemical weapon, to destroy vegetation during the Vietnam war, causing serious health problems among soldiers and Vietnamese residents.

Glyphosate, meanwhile, is a highly controversial and toxic herbicide ingredient that has prompted similar litigation. Both are banned or severely restricted in many industrialized countries.

Despite the risks of combining the substances, the US Environmental Protection Agency has twice approved it for use on food crops. The compound is annually spread on around 4.5m acres of fields in which corn, soybeans and genetically engineered cotton are grown.