Bayer of Germany has made a takeover bid for Monsanto, potentially signaling another huge merger in the business of crop seeds and pesticides.

While the companies did not disclose details of the offer, a tie-up of the two companies would yield a giant whose products encompass antibiotics, genetically modified crop seeds and pesticides. It would have a combined annual revenue of more than $67 billion.

In a short statement late Wednesday, Monsanto said its board was reviewing the proposal. Bayer said early Thursday that it had recently met with Monsanto executives to discuss a potential deal, saying it “would create a leading integrated agriculture business.”

News of Bayer’s interest in Monsanto has percolated over the last several weeks, stirring speculation that the agricultural sector could see another big deal after Dow Chemical and DuPont agreed last year to merge.