Brussels has launched an in-depth probe into German chemical giant Bayer’s $66bn purchase of Monsanto, the latest in a trio of megamergers reshaping the global agri-business industry and one that would create the world’s largest supplier of seeds and crop chemicals.

European antitrust authorities worry the deal would “reduce competition in a number of different markets resulting in higher prices, lower quality, less choice and less innovation”. The view echoes concerns raised by some farmers, regulators and politicians over a combination one environmental campaigner has dubbed a “marriage made in hell”.

Margrethe Vestager, European competition commissioner, is concerned the deal could reduce competition and research and development in pesticides, seeds and so-called traits, which are the patented characteristics of genetically modified seeds.