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USDA Public Soybean Rust Web Site 2008 Confirmed ASR Finds - compiled by P&PDL Purdue University Soybean Rust Hotline - 866-458-RUST (7878) 2007 National Soybean Rust Symposium Proceedings Preparing for Soybean Rust (pdf file) - Purdue publication, order hard copies here On October 17, 2007 soybean rust was found for the first time this year in Indiana on soybeans in Owen County. This is the first instance of soybean rust in Indiana for 2007. For more information, please see Dr. Greg Shaner's commentary. In 2007 Asian soybean rust was found in 336 counties in 19 states in the continental U.S. as well as Hawaii, Canada and Mexico. This is the most widespread and numerous distribution of this disease since it was first discovered in the U.S. in 2004. Soybean rust pushed farther north and west than in previous seasons, however most areas in the Midwest and plains regions discovered rust late enough in the season that it did not affect production. First time findings were reported in Iowa, Kansas, Nebraska, and Oklahoma. SBR has not yet been found in Ohio. Scouting for soybean rust on kudzu will continue through the winter. Asian soybean rust (ASR) is a serious disease caused by the fungus Phakopsora pachyrhizi. Soybean rust is spread by windblown spores and has caused significant crop losses in many soybean-growing regions of the world (pdf file). On November 10, 2004 USDA's Animal and Plant Health Inspection Service (APHIS) announced the first confirmation of Asian soybean rust in the continental United States (Louisiana), followed by finds in 8 additional southern states. In 2005, soybean rust was confirmed on soybeans in 29 counties in Georgia, 23 counties in South Carolina, 21 counties in Alabama, 18 counties in North Carolina,12 counties in Florida, 2 counties in Mississippi, and one county in Louisiana. Fourteen Alabama counties have confirmed soybean rust on kudzu, along with 13 counties in Florida, 7 counties in Georgia, and one county each in South Carolina, Kentucky, Louisiana, and Texas. Phakopsora pachyrhizi is an obligate parasite, meaning that it must have live, green tissue to survive. The host range of the soybean rust fungus is quite broad. In addition to soybeans, the ASR fungus is able to infect over 30 legumes including edible bean crops and kudzu. In November 2005, P. pachyrhizi was confirmed on Florida Beggarweed (Desmodium tortuosum) in Georgia. These additional hosts can serve as overwintering reservoirs for the pathogen and allow for build-up of inoculum, in those environs free from freezing temperatures. The pathogen is well adapted for long-distance dispersal, because spores can be readily carried long distances by the wind to new, rust-free regions. Early symptoms appear as chlorosis and brown flecking on the lower leaves in the canopy. Developing lesions can be confused with symptoms caused by other foliar diseases, such as bacterial pustule, bacterial blight, downy mildew and Septoria brown spot. The key diagnostic features of soybean rust are the cone-shaped pustules that form mostly on the undersides of the leaves and the dusty, light-tannish colored spores that erupt from the pustules. When untreated, soybean rust, causes yield losses due to premature defoliation, fewer seeds per pod and decreased number of filled pods per plant. For state-specific information on diagnosing the presence of soybean rust contact your state's land-grant university diagnostic clinic (pdf file).
Rust ID/Sample Submission
Soybean Rust - PowerPoint Presentations
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Site last updated:
8 May, 2008