Mar 3, 2025, 3:00 PM
Managing Anthracnose in Corn
Anthracnose is a fungal disease that can significantly impact corn fields by affecting standability, plant health, and overall yield. This pathogen targets both the leaves and stalks of corn, causing a range of symptoms above and below the ear. The infection typically enters the plant through the roots and stalks. There are three primary phases of anthracnose: leaf blight, top die-back, and stalk rot.
Phases of Anthracnose:
- Leaf Blight: Typically appears in early to mid-June as lesions that are long, irregularly shaped, and can spread across large areas of the leaf.
- Top Die-Back: This occurs 3 to 5 weeks after tasseling, starting at the top of the plant and moving downward. It causes a black discoloration on the stalks.
- Stalk Rot: The infection leads to node discoloration, which is noticeable when the plant stalk is split open.
Factors to Consider:
The impact of anthracnose on corn yields can vary based on the severity of the infection and the stage of plant growth. Grain fill and test weight can be significantly affected, with yield losses ranging from minimal to as much as 40%. Several key factors influence the severity of this disease:
- Weather Patterns: Anthracnose thrives in warm, humid conditions.
- Corn Residue: The pathogen overwinters in corn residue, leading to a higher risk of infection in following seasons.
- Hybrid Selection: Some corn hybrids are more susceptible to anthracnose than others.
Management Steps:
- Proactive Fungicide Application: If weather conditions are conducive to anthracnose, applying a fungicide early can help prevent plant stress. Reducing stress on the plant can make it less susceptible to anthracnose and other yield-reducing fungi.
- Reducing Overwintering Pathogen Sources: Minimize the amount of corn residue left in the field by rotating crops and utilizing conventional tillage methods. This will help reduce pathogen buildup and disease pressure in future seasons.
- Hybrid Selection: Choose hybrids with strong stalks and good late-season plant health to reduce the risk of anthracnose. Selecting the right hybrid for your field’s disease pressure is a key step in protecting yields. Consult your Legend Seeds team for hybrid recommendations that suit your needs.
- Early Harvest: If anthracnose symptoms are severe, early harvesting may be necessary to prevent yield loss from lodging or dropped ears. If more than 10% of the plants in a field show stalk rot symptoms during late-season scouting, prioritize that field for harvest.
Summary:
Anthracnose is a visually recognizable disease that can severely impact corn yields. Regular scouting is essential to assess the extent of the outbreak and take appropriate actions. Crop rotation, proper hybrid selection, and timely harvest are critical strategies to minimize yield loss. For further advice and hybrid recommendations tailored to your acres, reach out to your Legend Seeds team.
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