Fungus Seen in Eight Indiana Counties Threatens Soybeans

By Clayton Baumgarth

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.”

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.