Experts are advising producers not to confuse Asian soybean rust with common wet-weather soybean diseases. Soybean rust is not expected in the United States this year and has not been found north of the equator in South America.

Earlier this month the Iowa Soybean Rust Team invited crop professionals to a workshop to learn about soybean rust.

"It is important to emphasize that Asian soybean rust has not been found in the United States," said Alison Robertson, Iowa State University assistant professor of plant pathology.

Robertson was one of several presenters at five training sessions held throughout Iowa earlier this month. About 400 certified crop consultants, certified professional agronomists and independent crop consultants attended the sessions to learn how to identify soybean rust and the procedure for submitting samples to the "fast track" soybean rust identification program.

"We are seeking your assistance in helping Iowa growers be on the look out for Asian soybean rust," said Greg Tylka, Iowa State plant pathology professor.

Two diseases often confused with soybean rust are brown spot and bacterial blight. The early stages of these diseases produce symptoms similar to soybean rust. Brown spot, which is a fungus, is spread from the soil to soybean plants by splashing rain and causes dark brown spots on both upper and lower leaf surfaces.

Bacterial blight causes small, angular, water-soaked, yellow-to-brown spots on leaves. The lesions enlarge in rainy weather and merge to produce large dead areas. The diseases don't cause significant yield losses in Iowa and are more frequent in areas that have had heavy rainfall.

"If brown spot is found, it is likely that bacterial blight also will be found because both are common in cool, rainy seasons," said X.B. Yang, Iowa State professor of plant pathology. "Diseases such as brown spot and bacterial blight can be mistaken for soybean rust."

Tylka said it's important to provide up-to-date information about soybean rust, which is the goal of the Iowa Soybean Rust Team formed last fall. The team includes representatives from Iowa State University, ISU Extension, Iowa Department of Agriculture and Land Stewardship, the Iowa Soybean Promotion Board/Iowa Soybean Association and the U.S. Department of Agriculture Animal and Plant Health Inspection Service.

Iowa is the largest producing soybean state in the nation with 10.4 million acres in production this year. Palle Pedersen, Iowa State assistant professor of agronomy, said he is finding some brown spot and bacterial blight but overall the soybean crop is in excellent condition.

"We have nice canopy closures in many fields so it's looking good and there are very few disease and pest problems," Pedersen said. "It's been a little cool so we are below average in growing degree units, but it is warmer than it's been in the last three years."