US soybean growers now will be able to use up to three applications of approved Section 18 fungicides for soybean rust in a season, an increase from the prior maximum of two such treatments. The change by the EPA gives growers more flexibility, although they still must limit application of any one of the active ingredients in the emergency exemption products to no more than two.

The March 28, 2005, amendment letter from the EPA to the Minnesota Department of Agriculture was signed by Dan Rosenblatt, chief of the EPA's Minor Use, Inerts and Emergency Response Branch (MUIERB). The letter was obtained this weekend by StopSoybeanRust.com.

The letter signaled approval of several amendments to the Sec. 18 exemptions for propiconazole, tebuconazole, trifloxystrobin, myclobutanil and tetraconazole on soybeans to control soybean rust in Minnesota. If the process flows as it did for the original Sec. 18 approvals, this will be the template for the other 28 or so states that were allowed to join those requests by referencing the full emergency exemption applications of Minnesota and South Dakota.

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The amendment allowing a maximum of three total applications of approved Sec. 18 products "includes all products that have been approved or may be approved for use at a later date." The new ruling did say that use of the three applications in Minnesota was "at the discretion of the Minnesota Department of Agriculture."

The letter went on to specify label statements that must be added to all the previously approved Sec. 18 products, in most cases to alert growers and applicators not to make more than two applications of the particular active ingredient and limiting the total amount (in pounds or ounces) of active ingredient that can be applied per acre per year.

Other amendments approved, and in some cases mandated, were:

• The new expiration date for all the issued soybean/soybean rust exemptions was made standard across all states and products: November 10, 2007.

• For the newly registered combination product Quilt from Syngenta, use directions should "specify the soybean growth stage - R6 - up to which propiconazole may be applied" in addition to the two-application limit, total of 40 ounces of Quilt limit and specific amounts of the two active ingredients. The letter said that based on available residue data, the R6 growth-stage cut-off was approved in place of a pre-harvest interval (PHI) proposed by the registrant.

• For Headline SBR, the use directions "must be amended by changing the pre-harvest interval from 21 days to 30 days to correspond with the available field trial data on soybeans."

• EPA acknowledged that Bayer CropScience had changed the use directions for Folicur to change the spray interval to 10 to 21 days (appears this way on Sec. 18 labels now). The previous interval was 10 to 14 days.

• The agency ruled that Folicur use directions must be amended to lengthen the pre-harvest interval from 21 days to 30 days, based on available field trial data on soybeans. This change does not yet appear on the product label.

• The letter acknowledged that use directions for Stratego already have been changed by the manufacturer to revise the spray interval to 10 to 21 days (from 10 to 14); to allow the use of spray adjuvants; and removing the statement requiring alternating chemistries.

"All other conditions and restrictions in the original soybean rust authorizations still apply," the letter concluded.

StopSoybeanRust.com is a Web site with news, information and resources about Asian soybean rust, created by the Greenbook, Dealer & Applicator magazine and Successful Farming magazine. It is sponsored by Bayer CropScience US. Cooperating partners include the United Soybean Board and the Crop Advisor Institute.