By Blake Jackson
Red crown rot, a significant threat to soybean production, has been confirmed in several Kentucky counties. First identified in the state in 2021, this disease, caused by the fungus Calonectria ilicicola, has the potential to severely impact soybean yields.
Historically prevalent in the southern U.S., red crown rot has recently spread north, with cases reported in Illinois and Kentucky.
The disease primarily affects soybean roots, lower stems, and leaves, causing substantial plant damage and yield reductions.
Carl Bradley, a plant pathology professor at the University of Kentucky Martin-Gatton College of Agriculture, Food and Environment, expressed surprise at the appearance of red crown rot in Kentucky. He noted that affected fields could experience up to a 50% loss in crop output.
"It was quite a shock when red crown rot appeared in Kentucky three years ago," Bradley said. "We've been actively surveying for it and have now confirmed cases in Graves, Calloway, and Carlisle counties."
Symptoms and Spread
Red crown rot symptoms include yellowing and necrosis between leaf veins on soybean plants, often appearing during the reproductive stages.
While its symptoms may resemble other common soybean diseases, the distinctive red discoloration on lower stems and roots helps differentiate red crown rot.
Infected plants tend to occur in patches within fields, which can expand over time. In severe cases, yield losses can exceed half in heavily affected areas.
Researchers are actively investigating red crown rot management strategies. With grant support from the Kentucky Soybean Promotion Board, Bradley and his team have been conducting field trials to evaluate seed treatments and planting dates.
For Kentucky farmers, early detection and proper management are crucial. Farmers who suspect the disease should contact their local county extension office and submit samples for confirmation.
While there are currently no in-season rescue treatments, farmers can focus on long-term management strategies, such as crop rotation, to reduce the fungus presence in the soil. "Rotating to a non-host crop like corn for two or more years can help decrease the inoculum levels in the soil," Bradley advised.
Future research aims to identify more effective seed treatments and explore potential differences in susceptibility among soybean varieties.
Red crown rot is a growing concern in Kentucky and neighboring states. As the disease spreads, farmers must remain vigilant and implement appropriate management strategies to minimize its impact on their crops.
Photo Credit: gettyimages-gilaxia
Categories: Kentucky, Crops, Soybeans