Asian soybean rust was detected on soybean for the first time ever in Kentucky on Friday, Oct. 6. Between then and today (10/11), it was found on soybeans in seven counties in the western part of the state.

The infected counties are Caldwell, Christian, Hopkins, Lyon, Marshall, Todd, and Union. Last year, only Caldwell County had any rust, and that was on kudzu, discovered Nov. 11, 2005.

These finds take the U.S. count to 110 infected counties in nine states. These new counties are much farther north than any other U.S. rust locations in 2006.

Don Hershman, plant pathologist with the University of Kentucky, posted this in today's state commentary on

"Soybean rust was detected on soybean for the first time ever in Kentucky on Friday, Oct. 6, 2006. The find was in the corner of an otherwise mature sentinel plot located at the UK Research and Education Center in Princeton. Incidence was about 40 percent to 50 percent, and severity around 10 percent.

"Then, between Sunday Oct. 8 and Tuesday Oct. 10, soybean rust was detected at various levels in six additional counties -- Christian, Hopkins, Lyon, Marshall, Todd, and Union Counties. All of the finds, thus far, are in the lakes region of west Kentucky. Finds were in "mobile plots," except for the Caldwell and Union County finds, which were in sentinel plots," he said.

"Incidence in additional counties was generally low (0.1 percent to 10 percent.) With the exception of the Hopkins County find, which had extremely low severity (

Hershman believes spores blew in two weeks ago

"For all finds, the stage of pustules was mostly uniform," Hershman said. "This suggests to me that a large number of spores blew in sometime over the past two weeks and cut a pretty large swath in west Kentucky. We are in the process of looking to the west and east to see if an even larger area of spore deposition and infection may have occurred.

"This find will have absolutely NO impact on the 2006 soybean crop in Kentucky or anywhere else for that matter," Hershman said. "In fact, soybean rust will 'go away' from Kentucky as soon as there is hard frost. It simply cannot survive this far north.

"However, these finds are of great importance to the soybean rust predictive models. Thus, we are making great effort to know the extent of infection before the frost hits (maybe tonight) or until there are no soybean leaves in which the rust can survive (the disease has NOT been seen in kudzu here). I am hoping to find a location that has decent infection that would provide for an educational opportunity or two.

"The bottom line is this: The soybean rust finds will not impact soybean in Kentucky or the U.S. this year. But, they will help us to refine soybean rust predictive models, which will help greatly with SBR management in future crops," Hershman said.

SOURCE: Article from based on information from