February 2014
Learning Curve By Bill Schaefer

Globalization has been the catchphrase for U.S. agriculture for a while now. As multinational corporations (MNCs) continue to develop and introduce new fungicides into the marketplace, we are witnessing world markets that transcend national borders.

While world markets continue to grow there remain national barriers that growers and MNCs must contend with as they introduce new fungicides into foreign markets.

It’s become a fact of doing business that when a company registers a new product in the U.S. it still has to contend with Maximum Residue Limits (MRLs) regulations in foreign markets before the product will gain widespread use by growers.

These days the big news isn’t when a fungicide is approved by the EPA for the U.S. market. It is when a fungicide meets established default Maximum Residue Limits (MRLs) for major export markets that companies begin to enjoy widespread use domestically.

Such has been the case in recent years with Bayer CropScience’s (BCS) Luna Tranquility, Syngenta’s Stadium, DuPont’s Vertisan, and two fungicides from BASF –Priaxor and Zampro.

All three fungicides have been registered in the U.S. but many growers have been reluctant to use the fungicides until they’ve received default MRLs in countries along the Pacific Rim and southern Asia.

Luna Tranquility was introduced in 2012 to the U.S. market but was met with some industry resistance until Japan’s Ministry of Health, Labor and Welfare established an MRL of 0.2 parts per million in July 2013, the same MRL established in the U.S.

Kelly Luff, senior scientist for Bayer CropScience, said that Luna Tranquility now has been cleared by all processors for use.

Luna is a foliar fungicide with a dual mode of action. It has proven efficacy against early blight, white mold and brown spot. Luna is listed in Fungicide Resistance Action Committee (FRAC) group 7 for fluopyram and group 9 for pyrimethanil.

Last year BCS introduced Emesto Silver, a liquid seed treatment with a dual mode of action, penflufen and prothioconazol. It is listed in FRAC group 7 and FRAC group 3.

Emesto Silver protects against black scurf, silver scurf and stem and stolon canker caused by fusarium dry rot and rhizoctonia. Emesto is only good for use against seedborne disease but not soilborne fusarium dry rot and rhizoctonia.

DuPont’s Vertisan fungicide received registration for potato use in 2012. It is listed in FRAC group 7 for penthiopyrad. It has broad spectrum disease control for rhizoctonia, black dot, early blight, powdery mildew, brown spot and botrytis.

Redge Bodily, DuPont’s sales manager for the Pacific Northwest, said that Japanese MRLs are expected to be in place the first quarter of 2014 for Vertisan. Bodily said that once that hurdle is crossed, MRLs will be established for all major countries.

However, until the MRLs are established, always consult with your potato buyer or processor prior to using Vertisan,” Bodily said.

Syngenta’s Stadium is a post-harvest fungicide used to prevent silver scurf and fusarium dry rot. Stadium is composed of a three-way mixture containing difenoconazole, azoxystrobin and fludioxonil. With the three modes of action it is listed in FRAC groups 3, 11 and 12.

MRLs in export countries outside North America are lower than U.S. levels. Syngenta is working to harmonize the MRLs but does not anticipate the levels in export countries to change in 2014.

Syngenta advises growers to check with their potato buyers prior to using Stadium.

BASF’s Priaxor has two modes of action and is used to prevent early blight and white mold. It contains F500, the same ingredient in Headline fungicide, as well as Xemium, an ingredient in the carboxamide family. Priaxor is listed in FRAC groups 7 and 11. BASF recommends no more than two consecutive treatments with Priaxor before alternating to a different mode of action.

Priaxor also can used as an in-furrow treatment to control rhizoctonia.

BASF’s Zampro is designed to manage late blight. It has a dual mode of action with ametocatradin and dimethmorph. With these two modes of action, Zampro is listed in FRAC groups 40 and 45. BASF recommends that it be applied a maximum of three times per season and with no more than two consecutive applications.

Currently Zampro is registered in every state except New York and California.

The MRL status with export markets and state registration of all these fungicides could change at any time in 2014. A universal thread of advice for all growers is, if in doubt, check with your buyers prior to application of any fungicide.

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