German crop chemical group Bayer has made an offer of $62bn (£43bn) for seed company Monsanto in a deal that would create the world's biggest agricultural supplier.
The unsolicited proposal, which includes debt, would be the largest foreign takeover by a German company if accepted.
Monsanto is primarily known for genetically modified crops, often leading to vocal activist criticism.
Bayer said it was offering to buy Monsanto for $122 per share, a 37 per cent premium to its undisturbed share price of $89.03 on May 9.
"Monsanto is a perfect match to our agricultural business," Bayer CEO Werner Baumann said in a video message posted on his company's website.
"We would combine complementary skills with minimal geographic overlap."
"The acquisition of Monsanto checks all the boxes in terms of strategic fit and value creation potential," he added.
"At the same time, ongoing consolidation activities in the industry make this combination by far the most attractive one."
Bayer said it planned to finance the deal with a combination of debt and equity, primarily via a rights offering. Equity would account for about a quarter of the deal value.
Low commodity prices—which have caused farmers to cut orders for supplies—have piled the pressure on agricultural suppliers like Monsanto, which is based in Saint Louis, Missouri.
The industry has seen two big merger deals recently, which are still undergoing regulatory reviews in the United States.
The approach comes as the agriculture sector faces heavy pressure after three years of falling crop prices, which is slashing US farmers' income.
Monsanto in May cut its profit forecast for the year and said it is eliminating about 16% of its employees.