For the first time ever, Asian soybean rust has been confirmed in a Kansas soybean field.
Kansas State University researchers and the Kansas Department of Agriculture have confirmed that a leaf sample from a soybean plant collected from a sentinel plot in Montgomery County has the disease.
"Asian soybean rust's arrival in Kansas was expected," says Kansas Secretary of Agriculture Adrian Polansky. "and we must continue to be vigilant scouting for this disease in the coming years to ensure we detect it early enough for growers to take action to protect their crops."
The site where the positive sample was found is one of 20 that the U.S. Department of Agriculture, working with KDA and K-State, planted around the state to monitor for the disease.
"For this year, this will only be a problem in late-planted soybeans," says Kansas State University plant pathologist Doug Jardine. "There are 300,000 to 400,000 acres of late-planted soybeans this year that are potentially in danger. This represents about 10-15% of the state's crop."
In university research trials during the 2005 and 2006 growing seasons, measured yield losses to soybean rust ranged from 6% to 32%, Jardine says. He anticipates that any potential yield loss in Kansas this year in the late-planted bean crop would likely be at the lower end of this range.
Soybean rust was first found in the United States Nov. 6, 2004 in Louisiana. Since then, it has spread to several states.
The disease is caused by either of two fungal species – Phakopsora pachyrhizi, also know as the Asian species, and Phakopsora meibomiae, the New World species. The Asian species is the more aggressive of the two, and causes more damage to soybean plants, says Jardine, who is the plant pathology state leader for K-State Research and Extension.
The disease is spread by wind-borne spores capable of being transported over long distances.