The second phase of the case, which begins Wednesday, will focus on whether Monsanto, which was acquired by Bayer AG last year, should be held liable for partly causing Mr. Hardeman’s cancer, said his lawyer, Jennifer Moore. Ms. Moore said lawyers would seek to prove that Monsanto manipulated public opinion and science to play down Roundup’s health risks.

Lawyers will argue that Monsanto knew or should have known that Roundup causes cancer, Ms. Moore said in an interview Tuesday. Mr. Hardeman’s team will ask that the jury have the company pay his medical bills and an undetermined amount of damages, she added.

“We feel confident based on the evidence that a jury, when presented with all of the evidence, will see that Monsanto has committed 40 years of corporate malfeasance,” Ms. Moore said.

Bayer said in a statement Tuesday that it was disappointed in the jury’s verdict and that “the evidence in phase two will show that Monsanto’s conduct has been appropriate and the company should not be liable for Mr. Hardeman’s cancer.”

“We have great sympathy for Mr. Hardeman and his family, but an extensive body of science supports the conclusion that Roundup was not the cause of his cancer,” Bayer said in the statement. “Bayer stands behind these products and will vigorously defend them.”