Asian soybean rust has never been identified in an Iowa field since the disease was reported in the continental U.S. in November 2004. However, the disease now has been conclusively identified on soybean plant tissue, which was submitted to the Iowa Soybean Rust Team last week. This soybean residue is reported to have been recovered from a bin of soybeans produced in Iowa in 2006. Efforts are underway to identify other remnant plant residue that may show symptoms and signs of the disease in order to discern details of this event.
The fungus and the spores that cause the disease cannot survive without green leaf tissue and will die during Iowa winters. The recently discovered rust fungus does not pose a risk of infection for the 2007 growing season in Iowa.
"The fast, conclusive identification of soybean rust in this one particular plant residue sample illustrates the rapid diagnostic capabilities available at Iowa State University to protect the state's soybean crop from the threat of this disease," says Iowa State University College of Agriculture Dean Wendy Wintersteen.
"This discovery reminds us that it is possible for Iowa fields to become infected with this disease," says David Wright, director of contract research at the Iowa Soybean Association. "Nonetheless, growers should not overreact to this development. Instead, growers must be ready to act appropriately and economically in 2007 should this disease again show up in Iowa and be a threat to soybean yields."
Bill Northey, Secretary of Agriculture with the Iowa Department of Agriculture and Land Stewardship, says the finding does not necessarily increase the risk for next year's crop.
"The confirmation of this disease in the 2006 crop does not guarantee that we will have Asian soybean rust in the 2007 Iowa soybean crop. As in previous years, producers should monitor conditions that favor rust and consult with extension specialists on identification and management plans. However, it is imperative for producers to avoid the inclination to panic and take drastic, costly and unnecessary action before positively identifying soybean rust in their fields," Northey says.
The Iowa Soybean Rust Team comprises personnel from Iowa State University College of Agriculture and ISU Extension, the Iowa Soybean Association, the Iowa Department of Agriculture and Land Stewardship and the USDA Animal and Plant Health Inspection Service. The Iowa Rust Team recruited and trained more than 600 agribusiness professionals from 2004 to 2006 to serve as "First Detectors" who can examine leaf samples and decide whether the samples warrant further investigation for possible infection with soybean rust by ISU Extension personnel in the state or by campus-based ISU scientists.
Growers are encouraged to consult with Iowa Soybean Rust Team First Detectors in the 2007 growing season if they observe plants that they suspect might have soybean rust. There is no charge to consult with these First Detectors concerning possible soybean rust infections. The names and contact information for First Detectors is available on the Internet at www.soybeanrust.info and at county extension offices.