Soybean Rust Update October 5, 2017
from Jim Dunphy, Extension Soybean Crop Scientist,
and Lindsey Thiessen, Extension Soybean Plant Pathologist
NC State University
Asiatic Soybean Rust (ASR) has been confirmed closer to most of our NC soybeans this week, with detections in Jasper and Dillon counties, SC. Dillon County is just across the state line from Lumberton and Laurenburg, NC. Rust was detected on 2 out of 100 leaves, with one small cluster of pustules on each of the two leaves.
The closest rust on soybeans to Charlotte is now 100 miles, to Elizabeth City is 220 miles, to Fayetteville is 55 miles, to Murphy is 20 miles, to Raleigh is 100 miles, to Washington is 165 miles, to Wilmington is 80 miles, and to Winston-Salem is 130 miles.
ASR has now been confirmed on soybeans in 12 counties in AL, 7 counties in AR, 3 counties in FL, 7 counties in GA, 56 counties in MS, 7 counties in SC, and 7 counties in TN.
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). By the time soybeans reach stage R6 (full sized beans in a pod on one of the top four nodes), they will typically lose all their leaves normally before rust detected now has time to defoliate them earlier, so rust no longer has the potential to cause economic damage.
The current status of rust in the continental US can be found anytime at http://sbr.ipmpipe.org.