By JOHN O'CONNELL
Japan and Korea have set maximum residue limits for Bayer's Luna-Tranquility fungicide, prompting spud growers to quickly buy up available inventories.
Though Luna received registration from the U.S. Environmental Protection Agency in 2012, the major processors instructed growers against using it, until recently, because a maximum residue limit hadn't been set in Japan.
The processors indicated they had no way of segregating products containing potatoes grown with Luna to keep them out of the country. Fresh growers also avoided Luna because their culled spuds are sometimes diverted to processing.
On July 2 the Japanese Ministry of Health, Labor and Welfare approved a 0.02 parts per million maximum residue limit for Luna that took immediate effect. South Korea also recently set an MRL for Luna, 0.5 parts per million.
Growers depleted inventories of the fungicide in the Pasco, Wash., and Twin Falls, Idaho, warehouses within a few days of the product becoming available in the Pacific Northwest, according to an Idaho Bayer sales representative.
More product should be in stock at both warehouse locations by July 12, said Phil Sarasqueta, based in Twin Falls.
McCain Foods approved Luna use for its growers on July 3, with approval following a couple of days later from J.R. Simplot and Lamb Weston. Heinz approved Luna for its growers on July 9, Sarasqueta said.
Bayer boasts that Luna introduces a new chemistry to growers facing disease resistance issues with other products and is effective against early blight, powdery mildew, botrytis, white mold and black dot.
Though the announcement has come in mid-season, Sarasqueta said he's been inundated with calls and surprised by the sales.
"It will be in the thousands of gallons. The rate is 11 ounces per acre, per application," Sarasqueta said of this season's Pacific Northwest sales.
Jeff Miller, a scientist with Miller Research in Rupert, Idaho, who has conducted Luna trials fro the past four years, said the product has consistently provided the best control of any fungicide for both white mold and early blight, which are the two most common diseases growers face in Idaho.
"A lot of our growers use (the BASF fungicide) Endura to manage early blight and white mold. We're seeing resistance to that fungicide in the early blight population," Miller said. "The early blight pathogen is still controlled by Luna-Tranquility."
Miller explained Luna-Traquility is a combination of two active ingredients -- a new chemistry called fluopyram, which penetrates the mitochondria of fungal cells and shuts down the pathogens, and pyrimethanil, a chemical Bayer has marketed as a stand-alone product called Scala.
Miller believes the presence of both chemicals will prolong resistance from developing in Luna.