South Carolina Soybean Rust Update – 7/28

July 28, 2023


28 July 2023

FROM:  Jonathan Croft, Clemson Extension Agronomic Agent, Joe Varn, Clemson Extension Agronomic Agent, Rogan Gibson, Clemson Extension Agronomic Agent, and Dr. John Mueller, Extension Soybean Pathologist, Edisto Research and Education Center.

At this time, Asian Soybean Rust has NOT been identified in South Carolina.

Samples were collected and examined from Allendale, Bamberg, Dorchester and Orangeburg Counties. Soybean growth stages ranged from early bloom to R5.2.

While sampling this week, frogeye leaf spot was observed in an irrigated group 6 soybean in Orangeburg County. In South Carolina, frogeye leaf spot is normally controlled with plant resistance. We recommend that growers review the disease ratings of the soybeans planted on their farms and extra scouting should be done on varieties considered susceptible or moderately susceptible to frogeye leaf spot.

If you think you have rust or other foliar diseases in a field collect 25 to 50 of the leaves you are “suspicious” of.  Place them in a “ziplock” type bag.  Keep bag out of direct sunlight and in a cool place if possible.  Do not allow it to freeze or get close to freezing.  Contact your local county agronomic agent for evaluation.