(Adds Bayer declining to comment, detail on board statement)
BERLIN, May 1 (Reuters) - The supervisory board of Bayer is planning an extraordinary meeting to discuss a crisis of confidence in its leadership after an investor rebuke at the German drugmaker's annual meeting, a magazine reported on Wednesday.
Citing an unnamed board member, Wirtschaftswoche magazine said the meeting would take place in the next two or three weeks: "We can't just carry on like this," the person said.
A Bayer spokesman declined to comment.
At Bayer's annual shareholder meeting on Friday a majority of investors cast a vote of disapproval of top management's actions.
On Saturday, the supervisory board said in a statement that it unanimously stands behind the company's management, adding that it would continue to examine the results of the AGM in the weeks ahead.
On Monday, three of Bayer's largest German investors said the drugmaker's management needed to stay at the helm to avoid further upheaval, despite their unease over a share price slump in the wake of the company's $63 billion takeover of Monsanto.
About 30 billion euros ($34 billion) have been wiped off Bayer's market value since August, when a U.S. jury found it liable because Monsanto had not warned of alleged cancer risks linked to its weedkiller Roundup. More than 13,000 plaintiffs are claiming damages.
Bayer is appealing or plans to appeal the Roundup verdicts and has pointed to global regulators' findings that the use of glyphosate, the active ingredient in the herbicide, is safe.
On Tuesday, the U.S. Environmental Protection Agency (EPA) said that glyphosate is not a carcinogen, contradicting decisions by U.S. juries that found it caused cancer in people.
$1 = 0.8904 euros Reporting by Emma Thomasson; editing by Jason Neely and Susan Fenton