In recent years, the aggressive form of the disease has moved from Asia to Africa and into parts of South America. It first showed up in Paraguay in 2001 and now is a problem for many of the major soybean-growing areas in Brazil and Argentina. While not yet found in the United States, the recent introduction of the disease into South America raises the danger that it eventually could spread to the United States.

The latest computer models from the Illinois study indicate that the disease has most likely already spread to soybean-growing areas in Brazil and Venezuela located north of the equator, making it inevitable that rust will reach the United States in a relatively short time.

"Our work shows that the U.S. is at high risk once the pathogen that causes the disease expands its range into the northern part of South America," said aerobiologist Scott Isard of the geography department at Illinois. "We have received credible reports that this has already happened, although the Brazilian government has not confirmed it so far. If it's already established there, we could even see rust in the U.S. as soon as the current growing season and certainly no later than a year or two down the road."

With an additional grant from the USDA's National Research Initiative, Isard is working with USDA plant pathologists Glen Hartman and Montes Miles, both based on the Illinois campus, and agricultural meteorologist Joseph Russo of ZedX Inc. in Bellefonte, Pa., to further enhance the predictive capabilities of the models.

Isard notes that the model already has been used to track the past movement of rust from Asia into Africa in 1996 and the subsequent spread i
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Contact: Rob Wynstra, Agricultural Communications Specialist
wynstra@uiuc.edu
217-333-9446
University of Illinois at Urbana-Champaign
25-May-2004