Soybean rust (SBR) has not been confirmed in Tennessee. Samples collected from soybean sentinel plots this past week across the southern border of middle and western Tennessee have all been negative for soybean rust. Although SBR has not been found, there is a high probability that it has entered Tennessee at a low level due the increase in SBR in northeastern Alabama.

SBR was detected at high levels in a soybean research trial at the Sand Mountain Research Station in Crossville, AL in DeKalb County located in the northeastern section of the state. This field should be at R6 growth stage but pods are still trying to fill, and leaves have been defoliated due to SBR. Opposed to Alabama’s SBR presence, Mississippi is not finding high levels of SBR most likely due to dry weather.

Soybean fields at most risk of SBR in Tennessee include those along the southern border in middle Tennessee that have not reached R5 growth stage (beginning seed).  In the higher risk areas the decision to apply a fungicide should be based upon the yield potential of the crop and the risk of frost damage before harvest. If a field in the higher risk area has not reached R5, but will most likely be harvested before a frost and has good yield potential it will most likely benefit from a fungicide application to protect from SBR. More information on soybean diseases and fungicides can be found at UTcrops.com/soybean/diseases.