Bayer Vows Stronger Roundup Defense as It Absorbs Monsanto

Bayer AG vowed to step up its defense against a wave of U.S. lawsuits over the herbicide Roundup as it began the formal integration of Monsanto Co., acquired for $66 billion in June.

The German drug and chemical giant said it will formally absorb the U.S. company after selling some crop-science businesses to competitor BASF SE to resolve regulatory concerns. Because U.S. authorities insisted that the businesses operate separately until that sale was complete, Bayer said it previously had been barred from steering Monsanto’s legal strategy.

That will now change as the stakes mount in the U.S. battle ...