Compaction, earlier planting, susceptible varieties, a major biological reaction and excessive rain have all played a role in creating huge problems with Sudden Death Syndrome (SDS) in soybeans this year, says Bob Streit, a crop consultant and owner of Central Iowa Agronomics in Boone, Iowa.

“In southeast and east central Iowa, it’s going to have a major impact in 80% to 95% of the soybean fields,” Streit says. “Reductions in yields from 10 to 30 bushels per acre have been seen in past years and are possible this year.”

100% Infected Fields.

In north central Iowa, around the cities of Fort Dodge, Humboldt and Clarion, the problem is severe, he says.

“In one 6-mile stretch south of Fort Dodge, you have fields where Sudden Death Syndrome is covering 100% of the acres in many fields,” Streit says.

Wet fields during the 2008 and 2009 harvest and last spring led to compaction on headlands, end rows and heavily trafficked places. This includes areas where loaded grain carts, semi-trucks and combines traveled. These were the areas where SDS typically showed up, Streit says.

“This year, Sudden Death Syndrome is in whole fields,” he says. “Typically, SDS loves heavy, compacted, saturated soil.”

The combination of severe compaction and ponding from torrential rains has made SDS worse this year than in the recent past, Streit says. The problem may be from the weight to the water on the soil or because the water kills beneficial soil organisms.

“In some places, there were 40 to…