Bayer

Monsanto, a company based in St. Louis for more than 100 years, is now part of Bayer.

The roughly $63-billion acquisition closed Thursday, nearly two years after the companies first announced the deal. Regulators in Canada and Mexico were among the last international watchdogs to approve the combination.

The U.S. Department of Justice signed off on it late last month after Bayer committed to shedding about $9 billion in several areas to chemical giant BASF.

That includes Bayer's Liberty-brand herbicides, which compete with Monsanto's Roundup.

Originally, it was just a name — Olga Monsanto's name, to be precise.

Around the turn of the 20th century, she married a man named John Francis Queeny. He named his artificial sweetener company after her. And over decades, that company expanded from the sweetness business into agri-chemicals, where it began to dominate the industry.

In the global debate over neonicotinoid pesticides, the company that makes most of them has relied on one primary argument to defend its product: The evidence that these chemicals, commonly called "neonics," are harmful to bees has been gathered in artificial conditions, force-feeding bees in the laboratory, rather than in the real world of farm fields.