Submitted to: Plant Health Progress
Publication Type: Peer reviewed journal
Publication Acceptance Date: 4/24/2007
Publication Date: 9/17/2007
Citation: Li, S., Moore, W.F., Spinks, B.L., Wells, B.C., Sciumbato, G.L., Robinson, S.J., Libous Bailey, L.M. 2007. Occurrence of Asian Soybean Rust Caused by Phakopsora pachyrhizi in Mississippi. Plant Health Progress. doi:10.1094/PHP-2007-0917-02-BR Interpretive Summary: Asian soybean rust (ASR) caused by a fungus (mold) is a new soybean disease in the continental United States. The first detection of ASR in Mississippi on soybean was in Adams County on November 16, 2004, and later that month, ASR was found in four other Mississippi counties. In July 2005, ASR was found in Pearl River and George counties, and in 2006 ASR was first observed on August 1. As of November 2006, ASR was found in nine counties in 20 locations. Information obtained in the discovery of ASR in Mississippi will help to develop disease control strategies for this emerging disease.
Technical Abstract: Asian soybean rust (ASR) caused by Phakopsora pachyrhizi is one of the most destructive diseases of soybean. The first detection of ASR in Mississippi on soybean was in Adams County on November 16, 2004. Later that month, ASR also was found in Holmes, Jefferson, Warren, and Washington counties. In July 2005, ASR was found in Pearl River and George counties through monitoring of sentinel plots. In 2006, ASR in Mississippi was first observed in one soybean field and one kudzu site in Jefferson County on August 1. At that time, soybeans in southwestern Mississippi were mostly in reproductive growth stage R5. Fungicide application was recommended. However, in the major soybean growing areas in northeastern Mississippi and the Delta, the extremely hot and dry conditions were unfavorable for rust development. As of November 2006, ASR was found in Claiborne, George, Issaquena, Jackson, Jefferson, Lee, Warren, Washington, and Yazoo counties in 20 locations. ASR was identified by light and electron microscopic observations, enzyme-linked immunosorbent assay, and polymerase chain reactions using specific primer set for P. pachyrhizi and was also checked with the primers for P. meibomiae. ASR specimens have been placed in USDA–APHIS PPQ approved Stoneville Research Quarantine Facility. Purification of ASR isolates using soybean seedlings and detached leaves are underway for characterization of isolates, and for preparing inocula for evaluation of soybean resistance. Information obtained in the discovery of ASR in Mississippi will help to develop effective disease control strategies for this emerging disease.