Red Crown Rot Emerging Issue in Illinois Soybeans

Tuesday, August 22, 2023

Farmers in Illinois are reporting concerning cases of soybean plants displaying yellowing patches in their fields. While various factors like root rot, phytophthora, soybean cyst nematodes, and Septoria brown spot have been identified as potential culprits for the leaf discoloration, a new problem has arisen, adding to the complexity.

Red Crown Rot:

• A soil-borne fungus has led to the emergence of red crown rot in parts of Illinois, southern Indiana, and Missouri.

• This disease, while not new to soybeans, is new to the region and has been spreading since its first detection in Pike County in 2018.

• Symptoms include chlorosis and necrosis of leaves, along with reddish coloration on the lower stem, resembling other diseases like sudden death syndrome or brown stem rot.

• An identifiable trait of red crown rot is the appearance of small spherical structures on affected soy plants. Localized Impact:

• Current findings indicate that its impact has been concentrated in specific parts of fields.

• These localized "hot spots" have not yet caused widespread damage, and most fields remain unaffected. Management and Prevention:

• Some seed treatments, particularly fungicides like Saltro, offer protection against red crown rot.

• This disease seems to pose a higher risk for later-planted and double-crop soybean fields.

• Accurate diagnosis and management decisions are crucial, prompting the need for farmers to send plant samples to appropriate labs if red crown rot is suspected.

Corn Rootworm Concerns:

• Corn rootworms' adult forms are emerging across the state, causing concern for farmers.

• Rootworms aren't a major issue in areas with diverse crop rotations, but continuous corn fields, especially in northern Illinois, are experiencing notable outbreaks.

• Continuous corn fields require vigilant monitoring and potential use of insecticides due to resistance issues with some strains. Managing these emerging challenges requires careful monitoring and informed decision-making on the part of farmers.