October 16, 2006

Asian soybean rust discovered in US state Illinois

Asian soybean rust has been reported in Illinois--the leading US soybean-producing state--for the first time ever. The outbreak was reported early Friday (Oct 13), via the US Department of Agriculture's public rust website.

"Soybean rust was detected for the first time in Illinois, on a sample taken October 11," stated University of Illinois Extension Plant Pathologist Suzanne Bissonnette. "The find was in the extreme southern Illinois, in Pope County, on late group-5 soybeans. Adjacent counties are being sampled to determine the spread of the outbreak."

USDA currently expects Illinois to serve as the nation's leading soybean-producing state, forecasting total production of 512.55 million bushels from more than 10 million acres.

"The finding of soybean rust in southern Illinois was not unexpected," said Bissonnette, noting that Kentucky discovered soybean rust in eight counties adjacent to southern Illinois earlier this week.

"The finding of soybean rust in Illinois at this time will have no impact on the 2006 soybean crop," Bissonnette said. "Soybean harvest is well under way across the state (47 percent complete as of Tuesday). Soybeans are reaching full maturity across the state (with 96 percent dropping leaves entering the week)."

As such, the pathologist said there is no need for growers or commercial applicators to begin spraying to protect the Illinois crop from the airborne fungus, which has now been found in more than 120 counties across 10 states--Alabama, Florida, South Carolina, Louisiana, Georgia, Texas, Mississippi, North Carolina, Kentucky and Illinois--this season.

The plant pathogen flourishes in warm, damp, overcast weather, causing premature defoliation of immature soybeans and sometimes major yield losses, unless immediately countered with chemical fungicide.

An infection forecast from USDA said a sharp cold front that was producing rain across the Gulf Coast early Friday will also generate an increased risk of fresh rust outbreaks for eastern Texas, Louisiana and southern Mississippi through Friday, "due to heavier periods of rainfall, onshore (air) flow and limited sunshine," according to the USDA website.