Red Crown Rot (RCR), caused by the fungus Calonectria ilicicola, is a soil-borne disease that causes crown and root rot in soybean. The disease is most prevalent in fields that experience wet conditions near planting. Yield losses from RCR have been measured as high as 20 to 30% in Louisiana and Mississippi, where the disease has been a problem for quite some time.

Red Crown Rot (RCR), caused by the fungus

, is a soil-borne disease that causes crown and root rot in soybean. The disease is most prevalent in fields that experience wet conditions near planting. Yield losses from RCR have been measured as high as 20 to 30% in Louisiana and Mississippi, where the disease has been a problem for quite some time.

Later in the season, if favorable environmental conditions persist for disease development, the leaves of the soybean plant will exhibit small yellow blotches that eventually lead to interveinal necrosis. Most foliar symptoms will be evident late in the season, at the R3 growth stage or later. Another diagnostic characteristic of RCR is the distinct color and location of the reproductive structures of the disease. Infected soybean plants can exhibit red/orange/rust-colored reproductive structures called perithecia. These perithecia will be located at the base of the stem, slightly above the soil line. Injury to the roots below the soil line can also be observed. Severely infected plants may die or senesce before maturity resulting in yield loss.

Rotted roots and grey discoloration of the pith will be present in the advanced, later stages of the disease. These stem symptoms can resemble symptoms of other common diseases like Charcoal Rot, Rhizoctonia Root Rot, and Phytophthora Stem Rot. It is important to remember that RCR can be present in fields without the expression of foliar symptoms. Many of the foliar symptoms consistent with RCR can resemble those of other soybean diseases like Sudden Death Syndrome, Brown Stem Rot, and Southern Stem Canker. Due to these similarities, it is important to actively scout fields to properly identify the pathogen causing the injury.

Currently, foliar fungicides are not known to provide protection against RCR. There are cultural and management practices that will reduce the incidence of the disease. 

 overwinters as microsclerotia, which allows it to survive in the soil for several years, even in the absence of a host crop. Delayed planting into warmer soil conditions, along with improved field drainage, can assist in the reduction of the disease by helping to create an environment less favorable for infection to occur. Also, rotation away from soybeans for two years may help. Management of nematodes and reducing other causes of root injury may help reduce infection by 

. For those in peanut-growing regions, rotation away from soybeans and peanuts can be beneficial because the pathogen can infect and reproduce on both crops.

Illinois Field Crop Disease Hub - http://cropdisease.cropsciences.illinois.edu/?p=1220
Crop Protection Network - https://cropprotectionnetwork.org/encyclopedia/red-crown-rot-of-soybean University of Kentucky Martin-Gatton College of Agriculture, Food and Environment- https://news.ca.uky.edu/article/new-soybean-disease-could-impact-some-kentucky-yields