Best Head Start Yet For Soybean Rust

As U.S. growers begin planting soybeans, the potential for a Asian soybean rust is in the back of many Midwestern minds. For Southern growers, the threat is much more tangible, especially in light of current rust conditions. Could this be the year that soybean rust breaks out?

No one knows. The past winter has resulted in some new milestones for rust, which may or may not be a sign of things to come during the 2009 growing season. While current indicators are favorable for some level of soybean rust infestation, Extension experts caution that it’s way too early to predict its severity or even which areas will be affected at this time.

Still, the implications of the conditions coming out of the winter season will be interesting for Extension plant pathologists to monitor and learn from as the season progresses.

“This is the first year that soybean rust has successfully overwintered in Alabama, Georgia, and Louisiana without a break in detection,” explains Don Hershman, University of Kentucky Extension plant pathologist.

“Weather conditions have been favorable to highly favorable for soybean rust development in those states – plus Arkansas, Florida, and Mississippi – for much of this spring,” he says. “There has been some new soybean rust activity in Florida and disease incidence is increasing on kudzu in positive sites in Louisiana, but there has been no spread to new kudzu patches or to soybean to date.

“Specialists in many Southern states are expecting soybean rust to begin spreading into new areas soon, provided conditions remain favorble for disease development,” Hershman adds.

“Delayed planting of soybean in many states, due to wet conditions, may push crop maturity back a few weeks,” Hershman says. “This — plus the potential for earlier disease development due to successful overwintering in the mid-Gulf region – could increase the potential for soybean rust to cause more crop damage than we have seen to date."

It’s not time to push any panic buttons, Hershman says. “Of course, if conditions turn drier, this increased disease potential may translate into nothing,” he notes. “We all hope this is the case.”

Hershman advises retailers and their grower-customers that “it would be prudent to keep tabs on this developing situation.” Visit http://sbr.ipmpipe.org/cgi-bin/sbr/public.cgi to track soybean rust and soybean aphids this season.

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