ZURICH (Reuters) - Germany's Bayer has advised wine grape growers not to use its Moon Privilege fungicide until its CropScience arm has investigated whether there is a connection between the product's use and reported crop damage.
Growers have reported deformed leaves and lower yields from their crops this year.
Referring to "atypical symptoms" in vines where Moon Privilege -- known as Luna Privilege in some markets -- had been deployed in 2014, a statement on the company's website said: "As long as the cause of this change in the grape vines remains unexplained, we recommend for precautionary reasons not to use Luna Privilege for wine growing.
The statement also said that Bayer regrets the situation and is doing everything necessary to discover the cause.
Some Swiss wine grape growers claim that the fungicide is responsible for the damage and are demanding compensation, Schweiz am Sonntag newspaper reported on Sunday.
Growers have estimated a potential loss of up to 10 percent of the Swiss wine grape harvest, the paper said.
"The damage will, in any event, be in the three-digit millions (of Swiss francs)," Andreas Meier, a grower in the northern Swiss canton of Aargau, was quoted as saying.
The paper also said that Bayer has acknowledged in a letter to growers a "high probability" of a connection between the fungicide and damage to the 2015 harvest.
Bayer CropScience did not respond immediately to Reuters' telephone and emailed requests for comment on Sunday.
Last year Bayer said it expected more than 250 million euros ($279 million) in annual peak sales from its Luna group of products, which were launched in 2012 and are used for fruit and vegetable crops.
(Reporting by John Miller; Editing by David Goodman)