Soybean Disease Management Gets More Complex as Red Crown Rot Spreads

What was once considered a regional soybean disease is becoming a broader concern across parts of the Midwest and South.

As red crown rot (RCR) continues to expand into new soybean production areas, growers who haven’t previously dealt with the disease may need to add it to their management checklist for 2027.

In 2026, red crown rot was reported in at least 14 states, including first-time confirmed detections in Iowa and Alabama.

(Crop Protection Network)

The disease’s growing footprint is adding to concerns about its economic impact. According to the Crop Protection Network, estimated soybean yield losses attributed to red crown rot climbed from 121,000 bushels in 2024 to 7.7 million bushels in 2025.

“RCR showed up in areas this season where many growers have not dealt with it before,” says Dale Ireland, technical product lead at Syngenta, in a release. “There’s no rescue treatment for RCR, so identification, management and containment are key to reducing yield loss risk and protecting future soybean productivity.”

A Disease That’s Easy to Misidentify

One of the biggest challenges with red crown rot is recognizing it in the field. Above-ground symptoms can look remarkably similar to sudden death syndrome (SDS), another destructive, soilborne soybean disease.

Both diseases can cause interveinal leaf chlorosis, stem discoloration and root rot. That similarity raises the possibility that some fields diagnosed with SDS may actually have red crown rot.

“RCR is more widespread than you may realize because it’s often confused with SDS,” Ireland says. “As agronomists and growers are looking closer, fields that were assumed to have SDS are sometimes turning out to be RCR. If you suspect RCR in your fields, collect a sample and send it to your local diagnostic laboratory for analysis and confirmation.”

There are some important differences growers and agronomists can look for when evaluating affected plants.
Red crown rot produces distinctive brick-red fruiting structures on the lower stem, just above the soil line. SDS-infected plants typically have a normal white pith, with tan-to-brown discoloration in the lower stem and upper root.

Leaf retention also can provide clues. As SDS-infected plants die, leaflets often detach and fall, leaving the petioles attached to the stem. Red crown rot-infected plants, by comparison, typically retain their dead, crisp brown leaves.

When symptoms are difficult to distinguish, laboratory confirmation is the best way to determine which disease is present.

The Time to Manage Is Before Symptoms Appear

Unlike foliar diseases that can sometimes be addressed with an in-season fungicide application, red crown rot infections begin below ground early in the soybean plant’s development. The pathogen infects plants shortly after germination, with root infections progressing throughout the growing season.

By the time above-ground symptoms become apparent, the infection is already established. There is no in-season rescue treatment to reverse the damage.

Yield losses can vary considerably depending on disease pressure and environmental conditions. Field observations have documented losses ranging from 15% to 80%, with typical losses reported at 20% to 50% in affected areas of the Midwest.

“With diseases like RCR, waiting until symptoms appear means it is too late to protect your soybeans,” Ireland says. “Understanding what occurred in your fields this season can help you make better-informed decisions before planting next spring.”

That makes the post-harvest period an important opportunity for growers to review field performance, identify areas where plants showed symptoms and document potential disease problems.

Knowing where red crown rot occurred can help growers and their agronomists develop a more targeted management strategy for the next growing season. It also can help guide seed-treatment decisions before planting.

Seed Treatment Offers Suppression

For fields with a history of red crown rot or an identified disease risk, seed treatment is one consideration in a broader soybean disease management program.

Syngenta’s Victrato seed treatment is the first federally registered seed treatment labeled for suppression of red crown rot. The product also targets plant-parasitic nematodes and sudden death syndrome.

In replicated field research conducted at nine locations under moderate to heavy red crown rot pressure during 2024-2025, Victrato delivered an average yield advantage of 11.9 bu./acre compared with another leading seed treatment, according to Syngenta.

During a recent Syngenta media event, Alex Russell, soybean seedcare product lead, emphasized the importance of recognizing the disease’s potential severity.

“Although this feels like a new pest to us, I think we’ve probably had it for longer than we realize, and we’re either misdiagnosing it or not getting out of the truck and looking closely enough,” Russell says.

For growers who haven’t encountered red crown rot, she cautions that the disease can be devastating in affected fields.
Russell also stressed that suppression is an intentional distinction in describing the product’s performance.

“Red crown rot is a bear of a pest out there,” she says. “We still don’t have full control of that disease, but we’re doing the best that we can for growers that are impacted by it.”

As the disease moves into new soybean-growing areas next season, identifying it accurately will be an increasingly important first step, Russell adds.