US processors reject Bayer fungicide

J.R. Simplot Co. and Lamb Weston have informed potato growers in Idaho that they will not be accepting produce that has been treated with Bayer CropScience's Luna Tranquility (active ingredients: fluopyram + pyrimethanil).

A spokesman for Simplot explained that the decision was based on the fact that Japan, which buys Simplot products, had not yet accepted a maximum residue limit for the newly released treatment.

Lamb Weston also released a statement that said it was conducting its own trials with Luna Tranquillity and would be seeking to establish residue limits with Pacific Rim trading partners.

For the same reason the two companies are also rejecting potatoes treated with Vertisan (active ingredient: penthiopyrad) from DuPont. DuPont have suggested that this is not really an issue as they are yet to commercially release the product.

Luna Tranquillity is an alternative to Endura from BASF, which had began to lose effectiveness against earl blight.

"It would have been a change-up, which is always good for us to change from a chemistry to another chemistry so we don’t get resistance," said Klaren Koompin, an American Falls grower, describing the loss of Luna as inconvenient but not devastating. "The studies look extremely good."

Herb Young, fungicide product manager with Bayer, explained the EPA set the Luna maximum residue limit for the U.S. at 0.02 parts per million. In tests involving five Luna applications, the highest residue concentration on spuds was 0.016 parts per million.

Young said it takes about a year after approval of a U.S. label to get a maximum residue limit in Japan, which would be April of 2013 for Luna. Prior to setting a limit, Japan temporarily utilizes a standard level for all products of 0.01 parts per million, well below the Luna test results.

Young said Bayer has delayed release of Luna Sensation, used for cherries, anticipating challenges with Japan’s limit, but he never anticipated there would be an issue with spuds.

He said Luna Tranquility would typically be applied no more than twice in actual production. Furthermore, Japan, which buys 1.6 percent of the U.S. potato crop on average, accepts only processed U.S. spuds. The combination of washing and peeling a potato reduces residue by 85 percent, Young said.

McCain have not yet reached a decision on whether they will be accepting potatoes treated with Luna.