July 13, 2005

US hurricane remnants may spread soybean rust
 

Remnants of Hurricane Dennis could bring more than rainfall to the Midwest's parched fields: The storm clouds could also carry spores of a potentially devastating soybean fungus.

When Dennis made landfall along the Gulf Coast Sunday, its winds swept an area of southwestern Alabama State, where fields were infected with soybean rust, said Purdue University's plant pathologist, Greg Shaner. The storm then moved inland toward the Tennessee and Ohio river valleys.

Shaner said farmers and agricultural scientists nationwide would be looking for any signs over the next few weeks that the fungus has spread. The rust appeared as pustules on the leaves of soybean plants. Heat and high humidity could fuel its development.

Fungicides could control soybean rust, but only if they were applied immediately after it has been detected.

"The message we are trying to get out is that farmers should be out scouting their fields for this fungus. The more people we have out looking, the better," Shaner said.

Soybean rust has not caused any significant damage in the United States since it arrived in 2004 from South America, likely on the winds of Hurricane Ivan. The fungus was confirmed in eight states last year, but so far this year, active infections have been confirmed only in Alabama, Florida and Georgia.

Last year, the fungus cost farmers in Brazil about US$1 billion in crop losses and fungicide treatments. Yield losses have ranged from 10-80 percent in infected soybean fields in the country.

Coanne O' Hern, a soybean rust detection coordinator with the USDA, said because the fungus was a relatively new arrival in North America, plant pathologists were uncertain how it would impact the nation's soybean crops.

"We just don't know what soybean rust might do in the United States. This is really the first full growing season with this fungus," she said.