Asian soybean rust has been found in leaf samples taken from a county in Mississippi and a research station in Florida, USDA's Animal Plant Health Inspection Service (APHIS) confirmed today.

USDA's soybean rust detection assessment team was dispatched last week after two leaf samples from a research farm at Louisiana State University were confirmed to have the yield-robbing fungal disease. APHIS and Agricultural Research Service scientists believe the introduction of the fungus in the continental U.S. was caused by a windblown event related to this year's unusual hurricane season.

Rust control options. Since there is no way to prevent rust, farmers’ options are currently limited to scouting and timely treatment with fungicides during next year's growing season. Two fungicides, chlorothalonil and azoxystrobin, already have full registration for soybean rust control, according to the EPA.

Chlorothalonil is the active ingredient found, for example, in Syngenta's Bravo and Sipcam Agro's Echo 720. Azoxystrobin is the active ingredient found in Syngenta's Quadris SC.

More fungicides. At least five additional fungicides have received Federal Insecticide and Rodenticide Act (FIFRA) Section 18 Emergency Exemptions in soybean-producing states. The list includes but is not necessarily limited to: myclobutanil — in Dow AgroSciences' Laredo EC and Laredo EW; propiconazole — in Syngenta's Tilt EC, Dow AgroSciences' PropiMax EC, and Makhteshim-Agan's Bumper EC; boscalid — in BASF's Pristine; pyraclostrobin — in BASF's Headline EC; and tebuconazole — found in Bayer CropScience's Folicur F.

Two additional fungicides, trifloxystrobin and tetraconazole, may also get FIFRA Section 18 approvals in some states. Examples of products that contain trifloxystrobin are Bayer Corporation's Stratego, Flint and Compass. Tetraconazole is found in Sipcam Agro's Domark SL. For a table of application rates for the various fungicides, visit http://planthealth.info/rust/rust.htm.