Clemson scientists monitoring South Carolina for soybean rust

Published: July 20, 2010

Clemson University Public Service and Agriculture image by: Clemson University

BLACKVILLE — It’s soybean rust season, and Clemson University scientists will again release regular reports throughout the summer from rust monitoring plots around the state.

The spread of rust seems to be slightly slower this year compared to previous years, said John Mueller, Clemson University Extension soybean pathologist at the Edisto Research and Education Center.

The nearest rust to South Carolina is along the Florida Panhandle. Rust also has been found in southern Alabama and southern Texas and in several areas of Mexico.

In South Carolina, monitoring plots are up and running in the following counties: Aiken, Anderson, Bamberg, Barnwell, Berkeley, Calhoun, Darlington, Dorchester, Hampton, Horry, Kershaw, Marion, Lee, Newberry, Orangeburg and Sumter.

“We certainly need to thank all the county agents who are helping this year,” Mueller said. “We could not do this project without them.” 

Typically, rust is not observed in South Carolina until at least the middle of August, Mueller said.

The dates for first rust observation in South Carolina in the last five years were:

• 2005: Aug. 31
• 2006: Aug. 17
• 2007: Sept. 17
• 2008: Sept. 15
• 2009: Sept. 1

Monitoring systems and reduced sprays save South Carolina growers more than $25 million a year, with about $10 million in reduced crop losses and about $15 million in reduced spraying costs.

In 2009, South Carolina growers produced more than 14 million bushes on 590,000 acres with a gross value of nearly $140 million. Thanks, in part, to Clemson’s monitoring program, less than 1 percent of the state’s soybean crop is lost to rust.

To reduce the threat of rust affecting crops, Mueller recommends that growers plant earlier — April instead of June — so most soybeans will be harvested before rust arrives. He also suggests spraying only in areas where rust is found by monitoring.

Clemson’s monitoring project has been funded by the U.S Department of Agriculture, United Soybean Board, S.C. Soybean Board and the North Central Soybean Research Council.

Soybean rust — yellowish in appearance on plant leaves — is a disease that causes early maturation and severe loss of yield through premature foliation and decreased seed weight. 

“With every day that goes by ‘rust-free,’ the odds of rust damage to our early planted soybeans becomes less and less,” Mueller said.

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