On October 7th soybean rust (SBR) was reported in Massac, Pope, Pulaski
and Union counties in Illinois. Illinois is the 12th state to report
the disease in 2013.
Information on Soybean Rust can been found on the USDA Soybean Rust website:
http://sbr.ipmpipe.org
From the Bulletin:
Every year since 2006, soybean rust has made its way into Illinois late in the growing season. Soybean rust was confirmed late last week in Illinois. The first two confirmations came from samples collected from soybean fields in Johnson and Massac counties; Alexander, Gallatin, Hardin, Jackson, McDonough, Pope, Pulaski, Saline, Union, White, and Williamson counties soon followed. For the most up-to-date distribution of soybean rust in Illinois and North America, go to the IPM PIPE Soybean Rust website (www.sbrusa.net).
Soybean rust found this late in the season should have no impact on soybean yields in Illinois this year; however, we were only a few weeks from having potential problems in a few late-planted double-crop fields in the very southern portion of the state. More than a few double-crop soybean fields in southern Illinois are still very green, but they are at or past the R5 (beginning seed) developmental stage. Most of the research on soybean rust in the U.S. and South America has shown that plants are most susceptible to rust and yield loss between the R1 (beginning flower) and R5 stages of development; fields in Illinois thus should be in the clear now.
Finding soybean rust in Illinois this year will have no impact on the risk for next year, although it does show that the pathogen is very capable of making it this far north. Will this pattern of late-season soybean rust always hold true for Illinois? Unfortunately, it may not. Soybean rust is still in its infancy in the U.S.--we are still experiencing it only a few years after its first introduction into North America. The pathogen is very capable of adapting, and it is likely that every year it will adapt better to surviving on the kudzu biotypes in the southern U.S. If this happens, the potential for rust's appearing earlier in the southern states will be present, which would mean a larger build-up of rust spores earlier in the season. A scenario like this would certainly put the Midwest at greater risk, depending on the presence of storm systems to push the spores northward and on local weather conditions.
Soybean rust pustules on the underside of a soybean leaflet (magnified).
Close-up of soybean rust pustules with spores exuding from the pustule (magnified).
It is likely that soybean rust is currently present in more than 13 counties in Illinois and that additional counties will be confirmed before the season is over. To be alerted when Illinois counties become positive, you can sign up for e-mail alerts at the IPM PIPE website.--Carl A. Bradley
From the USDA IPMpipe website:
United States Soybean Rust Commentary (updated: 10/24/08)
On October 24th, soybean rust was reported in Jefferson and Mitchell counties in Georgia.
On October 23nd, soybean rust was reported for the first time in Illinois, Missouri and Oklahoma in 2008. The disease was detected on soybeans in McLean County in central Illinois, in Scott County in eastern Missouri, and in Bryan County in southern Oklahoma. Soybean rust was also reported in McLean county in Kentucky.
Since January of 2008, soybean rust has been reported in 15 states. This includes 52 counties in Alabama, 32 counties in Arkansas, 31 counties in Georgia, 24 counties in Florida, one county in Illinois, 27 parishes in Louisiana, two counties in Kentucky, 78 counties in Mississippi, one county in Missouri; five counties in North Carolina, one county in Oklahoma, 16 counties in South Carolina, two counties in Tennessee, five counties in Texas, and four counties in Virginia. Rust was also reported in 10 municipalities (counties) in Mexico. Soybean rust is expected to spread northward until frost.
from Integrated Crop Management newsletter
Daren Mueller, Iowa State University, Department of Plant Pathology
Despite soybean rust infecting fields in Iowa last fall, the pathogen needs to retrace its steps to get back to Iowa in 2008. The first critical step is for the pathogen to survive somewhere over the winter in places like Florida, Texas or Mexico.
An extensive study on the survival of soybean rust was completed in Florida by W. Jurick, J. Marios, D. Wright and P. Harmon. Their data was presented at the National Soybean Rust Symposium. Some of the main conclusions were:
1. Pathogen populations in a kudzu patch are reduced each year and build from low levels of initial inoculum
2. Local survival of the pathogen is dependent on temperature and moisture conditions (they had some kudzu patches die from drought)
3. Protected live vines or dried leaf litter in niche microenvironments may harbor pathogen until favorable conditions for disease occur
4. Pathogen may survive further north than was previously predicted
As spring nears (at least in the South), there have been a couple of noteworthy developments. First, soybean rust continues to survive in kudzu patches in Louisiana and Texas, which are further west than survival in previous years. Second, the ipmPIPE web site has made their service available for Mexican plant pathologists to track soybean rust in Mexico. This winter they reported soybean rust on jicama (yam bean) and soybean in a couple of different locations.
Temperatures in the south are beginning to warm, but there is still a chance for more killing frosts. Researchers in the southern states will continue to track the survival of soybean rust on kudzu in the U.S. and jicama and soybean in Mexico. For now, the soybean rust pathogen has survived in expected places (Mexico, Florida, southern Georgia and Alabama) and some unexpected places (central Texas and Louisiana).
Having this information is critical for the accuracy of the predictive models for the movement of soybean rust during the season. For growers, if soybean rust continues to survive in Mexico, Texas and Louisiana, this means the pathogen has passed the first critical step in getting back to Iowa. The next step will be to build up the inoculum this spring when the soybean plants and kudzu vines begin to grow in the southern states.
The complete article, with maps can be found at Integrated Crop Management. While this article refers to Iowa soybean production, many of the principles Daren discusses remain important to soybean growers in Illinois as well.
Observation and Outlook: Sentinel plots
On the national scene for 2008 (obtained from the ipmPIPE website):
On January 21st, rust was reported in Hidalgo county, Texas. On January 14th, soybean rust was reported in Jefferson and Leon counties in Florida and in Altamira municipality in the state of Tamaulipas, Mexico. On January 11th, soybean rust was reported in Mobile County in Alabama. On January 7th, soybean rust was reported in Bolivar County in Mississippi. On January 5th, soybean rust was reported in Liberty and Polk Counties in Texas.
In 2007, soybean rust was reported in 19 States and 336 counties in the continental U.S. Soybean rust also was detected in Hawaii, in one Province in Canada, and in two states in Mexico.
Soybean rust monitoring will continue on kudzu throughout the winter months in the southern states.
For the Illinois scene in 2007 (provided by Carl Bradley, Illinois Extension Plant Pathologist, obtained from the ipmPIPE website):
For the 2007 growing season, soybean rust was confirmed in Champaign and Bureau Counties on October 30; confirmed in Massac and McDonough Counties on October 23rd.
Observation and Outlook: Experimental spore traps
For the 2007 growing season, spores resembling soybean rust were captured in experimental spore traps in Will and Adams Counties. Experimental spore trapping systems will be continued in the 2008 growing season.
