Since June 15th, 2005, there have been 39 new counties reported with rust. That is an average of a new county report every 1.8 days with 29 new county reports in August alone, according to the USDA's Public Soybean Rust Web site.
And with the high winds of Katrina the number of counties with soybean rust may quickly increase. Last year's hurricane season led to the initial introduction of soybean rust to the continental United States.
USDA's soybean rust model predicts two separate pathways for spore transport and depositions. A cold front moving eastward is dissipating over central New York and the Mid-Atlantic states as a second cold front is passing through the central Great Lakes region. The first pathway, associated with that dissipating cold front, has spores spreading into eastern Texas, northern Louisiana, Arkansas, and western Tennessee.
The second pathway, associated with Hurricane Katrina, has spores spreading into southeastern U.S. including Florida, coastal Louisiana, Mississippi, and Alabama, and southern Georgia. The second pathway becomes the dominant transport route as spores are predicted to spread further north on Monday (today) into eastern Texas, all of Arkansas, Louisiana, Mississippi, Alabama, Florida, Georgia, and South Carolina, Tennessee, southern Kentucky, and western North Carolina.
New spore transport and depositions are forecast to continue spreading northward into the Ohio River Valley on Tuesday as Katrina moves further inland.
Favorable disease weather will be limited to the eastern Mid-Atlantic states and New England and along the Gulf Coast. It will spread northward from the Gulf Coast into most of the southeastern U.S. on Monday and into the Ohio River Valley on Tuesday.
Oconee County in Georgia is the furthest northern location in 2005 where soybean rust has been found. Hampton County in SC is the furthest east that soybean while Pearl River County in Mississippi is the furthest west that rust has been found in 2005.
Alabama now has 12 counties reported positive with rust; Florida has 19; Georgia has 12; Mississippi has two; and South Carolina has one. New reports for soybean rust are expected to continue within states already reporting rust and potential adjacent states to the north.