Metalaxyl-M is the ISO common name[4] and Ridomil Gold is the trade name for the optically pure (-) / D / R active stereoisomer, which is also known as mefenoxam.

However, in the summer of 1980, in the Republic of Ireland, the crop was devastated by a potato blight epidemic after a resistant race of the oomycete appeared.

[citation needed] Maximum pesticide residue limits for the EU/UK are set at 0.5 mg/kg for oranges and 1.0 mg/kg for apples.

[citation needed] As early as 1998 Pythium was known to be widely developing resistance to metalaxyl[8] which was the most effective control at the time.

[11][12] The homochiral, single-isomer version of the chemical, which retains all its fungicidal activity, has been manufactured.