Soybean Rust Update August 23, 2017
from Jim Dunphy, Extension Soybean Crop Scientist,
and Lindsey Thiessen, Extension Soybean Plant Pathologist
NC State University
South Carolina announced its first find of Asiatic Soybean Rust this year, in Hampton County. The soybeans were at stage R3 (early pod development), and only one of 50 leaves showed any detectable pustules. This is a little closer to many of our NC soybeans than any of the previous confirmed finds, at 380 miles from Elizabeth City, 265 miles from Raleigh, 310 miles from Washington, and 215 miles from Wilmington. Burke County, GA is still the closest find to Charlotte (165 miles), Fayetteville (225 miles), and Winston-Salem (235 miles). The closest find to Murphy is still Morgan County, AL.
Including detections of ASR on kudzu, the disease has been confirmed to date in 31 counties in Alabama, 4 counties in Florida, 9 counties in Georgia, 9 parishes in Louisiana, 20 counties in Mississippi, and 1 county in South Carolina.
We recommend spraying a fungicide to prevent infection of ASR on soybeans if ASR is confirmed on soybeans within 100 miles of your field, and the soybeans are between first bloom and stage R5 (early seed development).
The current status of rust in the continental US can be found anytime at http://sbr.ipmpipe.org.