Field Facts: Eyespot
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Eyespot, a fungal disease normally found in the northern regions of the Midwest, poses a significant threat to susceptible corn hybrids. Disease transmission through residue can lead to yield loss of up to 9%, so it’s important to safeguard corn from this disease.1
- Common name: Eyespot
- Scientific name: Aureobasidium zeae
- Symptoms: Affected leaves are covered with numerous small round spots. Spots are about ⅛ inch in diameter, are oval to circular and initially appear water-soaked. The central area of the spot soon dies, leaving a tan center surrounded by a distinct brown to purple border. The border is frequently encircled by a yellow halo.
- Spots can appear as early as the V3 and V4 growth stages.1
- Conditions for development: Eyespot is favored by long periods of cool, wet weather during the growing season, making the disease more prevalent in the northern regions of the Corn Belt.
Fast Facts on Eyespot
- Eyespot is a residue-borne, fungal disease that can overwinter and survive between corn crops.
- In the spring, the fungus produces spores that are carried to the new corn crop.
- The fungus also may be seed-borne, but this source of fungal inoculum is insignificant when compared with the number of spores produced on infested crop residues.
- High disease levels that result in yield loss usually occur in seed production fields, under no-till conditions, and when corn is planted sequentially for two or more years.
- Lesions can appear quickly under favorable weather conditions, in as little as four to 10 days. 2
- The appearance of lesions may differ depending on the hybrid variety; generally, lesions first appear on lower leaves and then can spread to cover the entire plant.
Control Tips
There are numerous management practices to reduce the incidence of eyespot disease. Encourage customers to implement the following practice to mitigate disease risk:
- Rotate crops. Consider rotating with nonhost crops to reduce the buildup of eyespot pathogens in the soil.
- Manage residue. Customers should practice good residue management to reduce disease pressure and limit early season spread of eyespot.
- Select a fast-acting fungicide. Aproach® Prima provides uptake that’s nearly twice as fast as other fungicides on the market. Aproach Prima can be applied on corn between V10 and R3 growth stages for preventive disease management. Customers should begin application prior to disease development for best results.
- Choose resistant hybrids. Your customers may want to consider hybrid or variety selection as a first step in disease prevention next season.
- Prioritize scouting. Regularly scout fields for early signs of eyespot. Corteva Agriscience advises scouting during tasseling for diseases like eyespot, especially if the field fits into this description:
- Has eyespot history
- Has had a susceptible corn hybrid planted
- Has ideal weather conditions for eyespot development
- Has irrigation
Consult your local Corteva Agriscience representative and check out our Corn & Soybean Disease ID Guide for more-detailed management recommendations for eyespot and common Midwest crop diseases.
1Malvick, D. 2018. Eyespot on Corn. https://extension.umn.edu/corn-pest-management/eyespot-corn
2Jackson, T., and A. Ziems. 2009. Corn Disease Update: Eyespot Confirmed. https://cropwatch.unl.edu/corn-disease-update-eyespot-confirmed
Aproach® Prima is not registered for sale or use in all states. Contact your state pesticide regulatory agency to determine if a product is registered for sale or use in your state. Always read and follow label directions.