Asian Soybean Rust
Public Soybean Rust Web Site
Purdue University Soybean Rust Hotline - 866-458-RUST (7878)
for Soybean Rust (pdf file) - Purdue publication,
order hard copies here
Soybean rust was confirmed June 10, in the US for the first time this season on soybean in Hidalgo county, Texas. Rust has also been confirmed on soybean in the neighboring Mexican state of Tamaulipas. Soybean rust has also been confirmed this month (June) on kudzu in Mobile, Alabama, and Jefferson, Florida.
In 2009, soybean rust was found in 16 states and
over 576 counties in the United States, and in three states and
nine municipalities in Mexico.
Soybean rust was found in 392 counties in the United
States in 2008. This is the highest number of counties reporting
the disease since it was first discovered in the continental
U.S. in 2004.
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.
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).
- Government Links
- University Links
- Industry Links
- Other Links
- News Links
Rust ID/Sample Submission
Soybean Rust - PowerPoint Presentations
and Identifying Soybean Rust" -- a PowerPoint
presentation from the Great Plains Diagnostic Network.
Good images and tips on identifying Asian soybean rust
in the field.
- Soybean Rust: What Happened in 2005? What’s
Ahead? - Greg Shaner, Purdue University
- Revised January 2006
- The Economic Drama of Soybean Rust in 2005
- Corinne Alexander, Chris Hurt, Craig Dobbins, George
Patrick, Purdue University
- January 2005
- Agronomic Implications of Soybean Rust -
Dr. Shawn Conley and Dr. Ellsworth Christmas, Purdue University
- January 2005
- Soybean - Biology and Diagnostics - Dr.
Greg Shaner and Gail Ruhl, Purdue University
- Revised January 2006
- Dr. Kiersten Wise (
), Extension Plant Pathologist
and Soybean Rust Specialist, Department of Botany & Plant
Pathology, Purdue University
- Dr. Greg Shaner (
), Retired Extension Plant Pathologist and Soybean
Rust Specialist, Department of Botany & Plant Pathology,
- Dr. Corinne Alexander (
Assistant professor, Department of Agriculture Economics,
Ray D. Martyn (
Professor of plant pathology, Botany & Plant Pathology,
and Director of the Center for Crop Biosecurity, Purdue
- Plant and Pest Diagnostic
- Gary W.
), Indiana State Plant Health Director
- Dr. Phil Marshall (
), Indiana State Plant Regulatory Officer, IN
Department of Natural Resources - Director of the Division
of Entomology & Plant Pathology
Forecasting & Tracking
Public Soybean Rust Web Site -
Track the movement of ASR in the U.S. -
(Mac users need to use Mozilla, Firefox or Safari
- 2007 Information
- 2008 Information