BLACKVILLE – Soybean rust was found Sept. 28 in samples collected from soybeans in a field at the Clemson University Edisto Research and Education Center in Barnwell County.


Rust was present on three of 100 leaves. One leaf had 15 to 20 pustules in a cluster with all pustules producing spores. The second leaf had 20 to 30 pustules. Most looked very young and just starting to produce spores. The third leaf had 10 to 15 pustules with about half of the pustules not yet producing spores.


These leaves had been allowed to incubate for seven days, which may account for all of the young pustules, said John Mueller, Clemson University extension soybean pathologist at the Edisto research center.


So far this year, rust has been found in Barnwell, Berkeley and Dorchester counties. However, cooler weather is likely to hamper spread of the disease, Mueller said.


“Our crop is moving rapidly toward harvest,” Mueller said. “You would need to have some very late-planted, late-maturing soybeans to be worried about spraying a fungicide now.”  


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