SOUTH CAROLINA SOYBEAN RUST NEWS NOTE
30 July 2021
FROM: Jonathan Croft, Clemson Extension Agronomic Agent, Joe Varn, Clemson Extension
Agronomic Agent, and Dr. John Mueller, Extension Soybean Pathologist, Edisto Research
and Education Center.
SOYBEAN RUST HAS NOT BEEN DETECTED IN SOUTH CAROLINA AS OF 30 JULY 2021.
During the week of July 26th – July 30th samples were examined from Bamberg,
Barnwell, Clarendon, Dorchester, Hampton, and Orangeburg Counties. Growth
stages of the soybeans sampled ranged from R1 to R3.
On July 28th, Asian Soybean Rust (ASR) was identified on soybean in Burke County, Ga. ASR was
identified in soybean sentinel plots in Midville, Ga. The soybeans in this sentinel plot are in
the R6 growth stage. This is the closest find of ASR on soybean to SC currently. Midville, Ga is
approximately 40 miles from the South Carolina border. The referenced location of ASR can be
found on the reporting map at https://www.eddmaps.org/distribution/uscounty.cfm?sub=9298.
Note the advanced growth stage, R6, in the field reporting rust in Georgia. Most of the
soybeans in South Carolina are still in much earlier growth stages. We rarely see rust
before R3 in an individual field.
Again, at this time ASR as not been identified in SC. Growers in counties that border the
Savannah River, in southwestern SC, should consider a fungicide application to protect
their soybeans that have a high yield potential and that have reached at least the R3 growth
Growers in the rest of SC should be planning to make a fungicide application to high yield
potential soybeans if we find ASR in SC and conditions favor development of rust. Timing
of this fungicide should be delayed until at least R3-R4 growth stage.
For specific fungicide recommendations please consult the Clemson Pest Management
seasecontrol.pdf or call your local Clemson Extension Agent.
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