If you think seedling blight has struck your field, dig up a few plants. In corn, look for rotted seeds, a brown mesocotyl and mushy, underdeveloped roots.
Prepare now to prevent seedling disease in your fields
When temperatures warmed up and fields looked ready for planting early this spring, it seemed too good to be true. Unfortunately for some farmers, it was.
After several weeks of ideal planting weather, the temperatures cooled and the rain started. With the cooler, wet weather came another problem: seedling blight.
"We had corn and soybean fields that needed to be replanted due to poor emergence," says Carl Bradley, plant pathologist at the University of Illinois. "It’s kind of hard to believe it now, with the hot, dry weather we’ve been having."
Reports of seedling blight sprung up throughout the Corn Belt, from Ohio to Minnesota to Nebraska. Blight can affect both corn and soybean fields, as well as some other crops such as rice and canola.
Bradley says those farmers who planted early in his state were the ones hit with blight the hardest. He says seedling blight generally occurs during cool, wet weather, so fields that are planted early are usually the ones at greatest risk.
However, Anne Dorrance, plant pathologist at The Ohio State University, cautions that soil temperature shouldn’t be given too much consideration, as different plant pathogens prefer different temperatures.
"Really, it just needs to be wet," she says.
In some fields hit with blight, the plants never really recover, and they might be less resilient to future damage from weather or pests.
"The weather that follows planting drives everything else," Bradley says. "Some plants may grow out of it, but in many plants the roots have been injured. Those that don’t have good root development suffer the most."
Kiersten Wise, plant pathologist at Purdue University, says fields in southern Indiana also experienced emergence problems, and some of those plants have been struggling since.
"We had lots of corn that went in early when we had those perfect conditions," she says. Then the rain struck and so did blight.
"We’ve been very dry since, so those plants that might not have had good root development to begin with have not been able to recover," she says.
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Farm Journal - Seed Guide 2012
