Red crown rot makes way to Indiana fields

WEST LAFAYETTE, Ind. — Red crown rot, a fungal disease that primarily affects soybeans and other legumes, has been discovered in Indiana fields, Purdue University experts confirmed.

The disease has appeared in several Indiana counties.

Symptoms

The primary indicators of red crown rot include yellow speckling on the soybean leaves and interveinal necrosis and chlorosis, where the tissue between leaf veins turns yellow or brown while the veins remain green.

Leaves may remain attached to the soybean plant instead of dropping off, as they do with sudden death syndrome.

The disease is named for its hallmark symptom: the crown of the plant — the stem area close to the soil line — turns red.

Although fungal structures may sometimes appear on the red tissue, they aren’t always visible.

Management

As a soilborne pathogen, red crown rot can spread through the soil, making it difficult to control once established.

Purdue experts recommend crop rotation with non-legume plants, such as corn, to help limit the spread. However, a long-term strategy will be essential to protect soybean crops.

“There’s nothing farmers can do now to manage the disease this season,” said Darcy Telenko, associate professor of botany and plant pathology at Purdue.

“What’s important now is to understand if they have the disease in their field so that they can make disease management decisions in the future.”

The Spread

First detected in Indiana in 2022, red crown rot has now been confirmed in several counties, including Adams, Bartholomew, Rush, Decatur and Spencer, as of Aug. 23.

While the disease has long been present in southern states, its emergence in Indiana and other Midwestern states is more recent.

“We need farmers’ help to track the disease across the state,” Telenko said. “Collecting samples helps us do that.”

Sampling

To assist in tracking the disease, farmers are encouraged to submit soybean samples suspected of having red crown rot to the Purdue Plant and Pest Diagnostic Laboratory. The testing is offered at no cost, but proper sample handling is essential.

Submit samples to: Plant and Pest Diagnostic Laboratory, Purdue University, 915 Mitch Daniels Blvd., LSPS 116, West Lafayette, IN 47907-2054.

Farmers should send samples early in the week and ensure they are properly labeled. Including the collection date, soybean variety, field location, ZIP code or county and the previous crop grown is crucial for accurate diagnosis.