Asian Soybean Rust (ASR)

October 10, 2022

Jonathan K. Croft and Joe Varn, Agriculture Extension Agents

Asian soybean rust (ASR) is a disease that affects soybeans and can significantly reduce soybean yields if left untreated. ASR first entered the United States in 2004 and has migrated out of overwintering sites to infect soybeans in South Carolina each year since it first arrived in the United States, except in the 2011 crop season. The best management option for soybean rust is proper monitoring and correctly timed fungicide applications.

During the 2022 growing season, Clemson Extension Agent Jonathan Croft of Orangeburg County, Clemson Extension Agent Joe Varn of Bamberg County, and Dr. John Mueller, Clemson Extension State Soybean Plant Pathologist, monitored for the incidence of Asian Soybean Rust in SC.  The monitoring program was funded through a grant from the SC Soybean Board.

In 2022, the first ASR incidence found in South Carolina was in Lee County. This find was made on September 16, 2022. At that time, recommendations were given to soybean producers to apply foliar fungicides to protect the yield potential of late-planted soybeans. Early planted soybeans at that time were not at much risk of yield loss due to their advanced growth stage.

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