BERLIN—Shares in Bayer AG rose 2.5 percent in pre-market trade on Wednesday after the German agricultural and pharmaceuticals firm won its first trial over claims its Roundup weedkiller causes cancer. A California jury found that the herbicide was not a substantial cause of a child’s rare form of non-Hodgkin’s lymphoma, the company said on Tuesday. The verdict is the fourth involving Roundup and the first in the company’s favor. Roundup-related lawsuits have dogged Bayer since it acquired the brand as part of its $63 billion purchase of agricultural seeds and pesticides maker Monsanto in 2018. By Emma Thomasson