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Posted 25 July 2011. PMN Crop News.

Soybeans Affected by Damping Off Disease This Year

Source: Kansas State University Press Release.

Manhattan, Kansas (July 1, 2011)--Pythium damping off disease has been rampant on soybeans this spring throughout eastern and central Kansas, said Doug Jardine, K-State Research and Extension plant pathologist.


Pythium is most active on soybeans that emerge into cool, wet soils, Jardine said. Producers in eastern and central Kansas who planted their soybeans in mid-May ran into this problem in many cases this year, said Stu Duncan, K-State Research and Extension crops and soils specialist.

“A lot of soybeans were planted about May 15-20 in northeast Kansas. Then there was some rain and the soil cooled down, which created ideal conditions for Pythium,” Duncan said.

Certain fungicide seed treatments will help protect against Pythium for about 10-14 days, Jardine said.

“But this may not work in all cases, especially if the lowest labeled rates of the product are used. Even with higher product use rates, if the disease pressure is high enough, Pythium can overwhelm the seed treatment. Evidently there are several cases this year where this has happened,” he explained.

If affected fields are replanted now, seed treatments would not be as necessary as they are for earlier planting dates, Jardine added.

Where soybeans have been infected with Pythium this year, the lesson to learn is that soybeans planted no-till before June 1 in Kansas should be treated with a fungicide seed treatment, just to be safe -- and the higher the rate of product used, the better, Jardine said. The seed treatment should contain mefenoxam or metalaxyl, he said.

Doug Jardine