UK scientists warn of red crown rot in soybean crops

Soybean yields may be affected this season by red crown rot, a fungal disease. During the week of Sept. 13, red crown rot in soybean crops was discovered in Graves County. Katie Pratt and Carl Bradley suggest taking samples for diagnosis to the University of Kentucky Plant Disease Diagnostic Lab in Princeton if the disease is suspected or found.

It was discovered in mid-September that Kentucky soybean crops were diseased by red crown rot, according to tests done at the University of Kentucky Plant Disease Diagnostic Lab in Princeton.

Katie Pratt and Carl Bradley of the UK Research and Education Center in Princeton have concluded the red crown rot may affect local soybean yields. The first — and only — case is in Graves County, however.

Pratt said the first case of red crown rot was discovered during the week of Sept. 13, according to a news release.

She said the fungus produces the fungus Calonectria ilicicola, causing stem and root fungus and discoloration. It also creates a toxin that causes leaf discoloration.

“At this point in the growing season, this disease will have the most impact on double-crop soybeans,” Bradley said in a news release.

He noted red crown rot may potentially be misidentified as sudden death syndrome and southern stem canker when examining the shared, similar symptoms.

He said the disease has been observed for years in neighboring states like Louisiana, Mississippi, and Illinois, but never in Kentucky.

“It will likely be too late for growers to observe red crown rot symptoms in full-season soybeans, as many of those fields are close to harvest,” Bradley said.

As Pratt and Bradley outlined, effective management practices are “done through rotating to non-host crops, planting less-susceptible varieties, and delaying planting in fields known to be infested with the red crown rot fungus.”

{p dir=”ltr”}They recommend contacting UK Cooperative Extension Service agents to help submit diagnosis samples to UK’s Plant Disease Diagnostic Lab in Princeton if red crown rot is suspected or found.

On Sept. 1, the Kentucky soybean production forecast was 6% — 98.5 million bushels — down from the 2020 August forecast. Yields fared better, up 1% from last month, as reported by the United States Department of Agriculture National Agricultural Statistics Service.