Werner Baumann, CEO of Bayer AG speaks during the annual results news conference of the German drugmaker in Leverkusen, Germany February 27, 2019. REUTERS/Wolfgang Rattay

COLOGNE, Germany (Reuters) - Bayer’s chief executive on Thursday acknowledged the German maker of pharmaceuticals and crop chemicals was facing massive challenges from a wave of lawsuits over an alleged carcinogenic effect of its Roundup weedkiller.

“We have lost two cases in lower courts. That is why the company is massively affected. You see it in our share price,” CEO Werner Baumann said in a panel discussion at an academic business event in Cologne.

“You see it selectively, mainly here in Germany and in France - less so in the USA - in our reputational scores,” he added.

Bayer has seen about 30 billion euros ($34 billion) wiped off its market value since August, when a U.S. jury found Bayer liable because Monsanto, acquired by Bayer for $63 billion last year, had not warned of weedkiller Roundup’s alleged cancer risks.

It suffered a similar courtroom defeat last month and more than 10,000 cases are pending.

“There’s lots of politicking, campaigning and propaganda that goes entirely against the current regulatory status of our products. That has prompted U.S. lawyers to sue for damages - a big industry in the USA - following an outlier assessment of the potential risk by a subordinate organization,” Baumann added.

The U.S. Environmental Protection Agency, the European Chemicals Agency and other regulators across the globe have found that glyphosate, the active ingredient in Roundup, is not likely carcinogenic to humans.

However, the World Health Organization’s cancer arm in 2015 reached a different conclusion, classifying glyphosate as “probably carcinogenic to humans”.

Bayer is legally challenging the verdicts and has stressed that regulators across the globe have found the product to be safe.