South Carolina joins Louisiana as the state with the most counties positive for soybean rust, 14 now that the disease was discovered in commercial fields in Allendale County, S.C.

According to this afternoon's South Carolina state commentary on

"Today rust was found at relatively high levels in two commercial soybean fields in Allendale County. The two fields are located approximately 2 miles east of the town of Allendale. In the first field, which was growth stage R-6, nine out of 50 leaves had 5 to 10 pustules per leaf. In the second field, which was growth stage R-5.2, 10 out of 25 leaves had 5 to 75 pustules per leaf.

"The 14 counties in South Carolina with rust are: Allendale, Anderson, Barnwell, Calhoun, Colleton, Darlington, Dorchester, Edgefield, Florence, Hampton, Horry, Lee, Orangeburg and Sumter. In addition to the original finds, there have been commercial fields turned in from Orangeburg and Dorchester counties.

"Counties sampled last week in which we could not find rust included: Allendale (now with rust), Bamberg, Greenville, Lexington, Newberry, and Williamsburg. We will continue to monitor these counties for rust.

"Rust is widespread enough in the state that anyone with soybeans in the R4 to early R5 stage should consider spraying with a fungicide. Since rust seems to be established in a wide area, the use of a triazole to help eradicate the rust that is already present is warranted. If controlling foliar and pod & stem diseases is also an objective the triazole needs to be combined with a strobilurin."

The commentary said most of the Maturity Group 4 soybeans in South Carolina are being harvested. Most Maturity Group 5 and 6 fields are defoliating. Most of the May-planted Group 7 and 8 soybeans are past R6. All fields, including double-cropped fields, are at least at R4.

To date, 46 counties in the U.S. have had soybean rust confirmed on soybeans in eight states. In the same eight states, there are 66 counties and parishes with positive rust findings on kudzu and/or soybeans. They are, in descending order of rust occurrences: 14 in Louisiana, 14 in South Carolina, 13 in Florida, 11 in Georgia, five in Alabama, four in North Carolina, three in Texas, two in Mississippi.

On this date last year, there were only 61 positive counties in five states: Florida (22); Georgia (19); Alabama (15); South Carolina (3); Mississippi (2).

SOURCE: South Carolina state commentary on and archives.