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Fungus seen in eight Indiana counties threatens soybeans

Red crown rot yellowing a field, a few examples of what the fungus looks like on soybeans.
Red crown rot yellowing a field, a few examples of what the fungus looks like on soybeans.

A new fungus is becoming more widespread in the Midwest and threatening soybean crops.

Red crown rot, or calonectria iliciola, is a fungus characterized by its dark red color where the root and stem meet. It infects the whole root system and eventually kills the plant, causing a loss of half or more of its pods.

Darcy Telenko, an extension plant pathologist at Purdue, said that while researchers estimate the rot will only affect less than one percent of yields in the state, it can still harm individual fields.

“Some of the fields I was in this summer, there were patches 15 to 20 percent of the field that were yellowed, and those areas are going to lose a significant yield loss to those areas,” she said. “It's going to be field by field basis on how much yield loss we see.”

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Red crown rot isn’t new to the country; traditionally it’s been found in the south. Telenko said changes in environmental conditions could be to blame. A warmer, wetter spring may have helped the already present pathogen take hold.

Red crown rot has been identified in eight Indiana counties: Bartholomew, Decatur, Rush, Knox, Spencer, De Kalb, Allen and Adams.

“Moving forward, first, is identifying it, and then trying to look at our other management tools that our growers can implement,” Telenko said. “So like seed treatments, variety selection, you know, maybe down the line, maybe it's a planting day shift. … All that research has got to be initiated again for the Midwest.”

Telenko also said the movement of infected soil, tillage, equipment and water movements all help it move from field to field.

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Clayton Baumgarth is a multimedia journalist for Indiana Public Media. He gathers stories from the rural areas surrounding Bloomington. Clayton was born and raised in central Missouri, and graduated college with a degree in Multimedia Production/Journalism from Drury University.