Red Crown Rot in Soybeans
Red Crown Rot in Soybeans
Understanding Red Crown Rot
Red crown rot, caused by the soilborne fungus Calonectria ilicicola, is a persistent and damaging disease affecting soybeans. Characterized by red lesions on the plant’s lower stem and crown, as well as yellowing and defoliation of leaves, this disease can lead to significant yield losses. The fungus thrives in warm, wet conditions and is particularly prevalent in fields with a history of peanuts or other susceptible crops.
GREEN = RED CROWN ROT REPORTED
Source: https://cropprotectionnetwork.org/maps/red-crown-rot-map
Why Red Crown Rot Could Be More Prevalent This Year
Several factors suggest an increased risk of red crown rot for the 2025 growing season:
Weather Conditions: Regions experiencing above-average rainfall and warm temperatures, such as parts of the Midwest and Southeast, create ideal environments for fungal growth.
Geographical Spread: According to the Crop Protection Network’s Red Crown Rot Map, the disease is recognized in high-production areas such as Virginia, Maryland, Delaware, Pennsylvania, and parts of the Midwest, including Indiana, Ohio, and Michigan.
Crop Rotation Challenges: Fields with a history of peanuts, which are also susceptible to Calonectria ilicicola, may see increased disease pressure, particularly if crop rotations do not adequately disrupt the pathogen’s lifecycle.
Nematode Damage: Fields with nematode pressure often experience exacerbated red crown rot infections, as nematode damage provides entry points for the fungus.
Regional Observations
Feedback from farmers and agronomists highlights the disease’s uneven impact:
Midwest: Limited but growing concern in Indiana, Ohio, and Michigan. Southern Ohio growers reported cases in 2024.
Mid-Atlantic: High-production areas in Virginia, Maryland, and Pennsylvania are experiencing notable issues.
Western Nebraska: No confirmed cases as of now, but vigilance remains essential.
Photo credit: Darcy Telenko and John Bonkowski. Source: https://extension.entm.purdue.edu/newsletters/pestandcrop/article/red-crown-rot-of-soybean-what-to-do-if-you-suspect-it-is-in-your-field/
Defending Against Red Crown Rot
While there is no cure for red crown rot, integrated management practices can help reduce its impact:
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Crop Rotation: Avoid planting soybeans after peanuts or other susceptible crops.
Drainage Improvement: Ensure proper field drainage to reduce soil moisture levels, which limit fungal growth.
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Use nematicides or resistant soybean varieties to minimize root damage, reducing fungal entry points.
One we recommend? BioSt Nematicide 100
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Advanced seed treatments like UAS N-Compass Soybean Blends offer a proactive defense against red crown rot. These treatments combine:
Fungicides to target early fungal infections.
Insecticides to protect against pests that damage roots.
Plant Growth Regulators like biologicals to enhance root development and stress tolerance.
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Plant resistant soybean varieties where available, focusing on those bred for tolerance to red crown rot and nematodes.
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Adjust planting schedules to avoid conditions that favor fungal growth, such as prolonged wet periods during early development.
Red crown rot is a growing concern for soybean farmers, particularly in regions with conducive weather patterns and a history of susceptible crops. While the disease is not yet a major problem in all areas, proactive management—including seed treatments like UAS N-Compass, nematode control, and strategic crop rotation—is essential to prevent its spread and minimize yield losses. Stay informed and take action to protect your fields this season.