July 15, 2024

Effective strategies for managing fungal diseases in corn

Channel Field Check Up Series

Zak Swanson

Fungal diseases pose a significant threat to corn crops, affecting their health and productivity. Understanding the factors contributing to fungal infections and implementing effective management practices are crucial for safeguarding your harvest.

Here, we provide expert recommendations for managing fungal diseases in corn. Several factors influence the susceptibility of corn seeds, seedlings and mature plants to fungal diseases.

Genetics, use of fungicidal seed treatments, environmental conditions, timeframe of the growing season and the presence of causal agents such as fungal or bacterial pathogens, viral vectors and nematodes all play pivotal roles.

Upon planting, corn seeds are immediately exposed to pathogenic fungi and bacteria present in the soil. These pathogens thrive in wet and cold soils, although some prefer warm conditions.

Infected seedlings exhibit symptoms such as damping off, stunting, yellowing leaves or deformities. Prompt detection and management are essential to mitigate the impact of fungal diseases.

Tar spot, northern corn leaf blight and gray leaf spot are some examples of prevalent fungal diseases affecting corn crops.

While practices like tillage, crop rotation and fungicide use can help prevent some instances of these diseases, treatment may still be necessary depending on seasonal weather trends.

Management options may include:

• Cleaning equipment when leaving infected fields as the fungal spores can be transported via organic matter to uninfected fields.

• Planting corn products with higher ratings for fungal pathogen resistance.

• Planting corn products that are characterized with quicker emergence.

• Ensuring your corn products are treated with a systemic fungicide and are rated to control the fungal disease in question.

• Maintaining a well-balanced fertility program.

• Using in-furrow fungicide treatments, which can be effective; however, they may not be economically feasible in areas with sporadic incidences of fungal diseases.

Expert Recommendations

In most cases, we recommend that fungicides be foliar applied at or after tasseling. A general guideline for susceptible or moderately susceptible corn products may be to spray when disease symptoms have developed on the third leaf below the ear leaf or higher leaves on 50% of the plants at the tasseling stage.

If fungicide application is warranted, generally the greatest benefit comes from a single application at the tasseling, or VT, through silking, or R1, growth stages.

In conclusion, fields should be scouted to frequently and correctly diagnose fungal diseases. It’s important to note that fungicides are not effective against bacterial and viral infections.

Understanding when and how often to apply fungicides is crucial for effective disease management. Using multiple modes of action can provide comprehensive control and help prevent resistance issues.

Be sure to read the label and follow instructions of the fungicide that best suits the disease and agronomic situation. Remember to always apply fungicides using the appropriate equipment at the recommended application rate.

Channel brand offers its full support to you throughout the growing season and beyond. Our Channel SeedPros partner with their local agronomist to provide tailored support and agronomic knowledge to farmers to evaluate your fields’ needs along with disease pressure.

Your SeedPro can document progress in the Climate FieldView platform and help look ahead by prioritizing fields and areas of concern.

As the growing season gets underway in Illinois, farmers can consider these tips to avoid loss of their yield potential due to fungal diseases:

• Scout for disease early and often. While scouting, you can capture notes within FieldView to track progress and analyze performance.

• Utilize historical knowledge of disease pressure in your fields and local area.

• Manage aggressive pathogens like southern rust and tar spot in-season to reduce potential yield loss.

• Think about timing of crop development, severity and incidence if a disease is found and confirm the genetic resistance rating of the disease with your Channel SeedPro.

Channel® and the Channel logo are trademarks of Channel Bio, LLC.

Always read and follow pesticide label directions. Performance may vary, from location to location and from year to year, as local growing, soil and environmental conditions may vary. Growers should evaluate data from multiple locations and years whenever possible and should consider the impacts of these conditions on their growing environment.

The recommendations in this material are based on trial observations and feedback received from a limited number of growers and growing environments. These recommendations should be considered as one reference point and should not be substituted for the professional opinion of agronomists, entomologists or other relevant experts evaluating specific conditions.

Channel® and the Channel logo are trademarks of Channel Bio, LLC. Services and products offered by Climate LLC are subject to the customer agreeing to our Terms of Service. Our services provide estimates or recommendations based on models. These do not guarantee results. Consult with your agronomist, commodity broker, or other industry professional before making financial, farming or risk management decisions. More information at www.climate.com/legal/disclaimer. FieldView is a trademark of Climate LLC. ©2024 Bayer Group. All rights reserved.