Distinguishing Between Red Crown Rot and SDS

As Red Crown Rot begins showing up in soybean fields in parts of the Midwest and Kentucky, it can get mistaken for other diseases, including sudden death syndrome (SDS). Phil Krieg, an agronomic service representative with Syngenta, talks about what to watch out for.

Red crown rot can sometimes be observed on the lower stems near the soil line. Look for small, pinhead sized brick red balls. A hand lens is helpful for this purpose. Photo S. Geisler, courtesy

“Red Crown Rot is a relatively new disease that we’re seeing in the Midwest. We’ve seen a pretty good uptick in it in the last four years. Foliar symptoms are going to show up in that R3 to R5 reproductive mode in the soybeans. And the stem symptomology will show some red brick discoloration of the lower stem at the soil line moving up the stem just a little bit. Below-ground symptoms can show some red organisms growing on those lower roots. However, the foliar symptoms mimic those symptoms that we see in Sudden Death Syndrome. So, this is a little bit of an issue in that you have to do your due diligence in the field, that when you see those foliar symptoms, you don’t confuse it with sudden death syndrome.”

He talks about the similarities and differences between Red Crown Rot and SDS.

“We’ve been dealing with SDS for probably in the area of 30 years now, whereas red crown rot is somewhat new, and it is spreading relatively slowly. The infection occurs in the seedling at and about emergence time, so that’s a major similarity between the two. The leaf symptoms can be very similar when you first see the initial onset of the disease. The key difference is that SDS tends to infect that seedling in cooler, wetter conditions at emergence time, while Red Crown Rothrives a little bit better when the soil is warm. So, there are some distinct differences between the two, and very important that when we do see these foliar symptoms, we do our due diligence to make sure that we are diagnosing the correct disease.”

Krieg has a recommendation for protecting against those yield-robbing diseases.

“Saltro fungicide seed treatment appears to have some effect on Red Crown Rot as well as Sudden Death Syndrome. Now, we know was Salto we get very good Sudden Death Syndrome protection and robust nematode protection. And with Saltro seed treatment, we do not see the crop injury that we see with some of the other products that are similar in the marketplace. Also, we’ve been able to get what’s known as a Two-Double-E label for the suppression of red crown rot throughout the Midwest. So, you can see we have a nice big footprint with Saltro seed treatment for red crown rot throughout the Midwest and do have the appropriate labeling for the suppression of that disease. My recommendation to folks is to, first and foremost, if you see the symptomology, diagnose it properly. And for both diseases, along with cyst nematode protection, use Saltro seed treatment on your soybeans.”