The system of statewide sentinel plots in South Carolina is working as designed, giving growers ample time to treat for soybean rust.

As of Sept. 11, 10 counties, with multiple levels of infection have been reported.

Except for one find, all of the infections were found in Maturity Group V Sentinel Plots.(Orangeburg was Group IV & V Sentinel Plots). Clemson University Plant Pathologist John Mueller says, “I would characterize all of the finds as relatively light in severity except Horry, Orangeburg, and Sumter counties which had slightly higher levels of rust.

Rust is widespread enough in South Carolina that anyone with soybeans in the R4 to early R5 stage should consider spraying with a fungicide, according to Mueller. Since rust seems to be established in a wide area, a triazole to help eradicate the rust is warranted. If controlling foliar and pod and stem diseases is also an objective, the triazole needs to be combined with a strobilurin, Mueller says.

Stink bugs have been a major problem in cotton in South Carolina this year and appear to be spreading into soybeans. Many growers are combining their fungicide sprays with an insecticide for these pests. Pyrethroids remain the most economical and efficacious materials for control of stink bugs, and these insecticides tank-mix well with most fungicides.

Mueller adds that growers should be particularly careful when selecting a pyrethroid insecticide because many of the generic pyrethroids labeled for use in cotton are not labeled for use in soybean.