9/4/2020

Field Facts: Northern Corn Leaf Blight

Caused by the fungus Exserohilum turcicum, northern corn leaf blight is an infection commonly found in corn. The disease is prevalent in the Midwest region of the United States and is more destructive when it gets a hold early in the growing season.

Symptoms — Elliptical, gray to tan lesions on leaves. Lesions can be anywhere from 1 to 6 inches long. Symptoms tend to start on lower leaves. 

Geography — Midwest region of the United States, specifically Illinois, Indiana, Iowa, Kansas, Michigan, Minnesota, Missouri, Nebraska, North Dakota, Ohio, South Dakota and Wisconsin. 

Timing — June through September. 

Conditions for development — Heavy dew, frequent rains, high humidity and moderate temperatures ranging from 65 F to 80 F. 

Scouting tips — Plants are most susceptible post-pollination, but disease can take hold any time in development. Scout often and check lower leaves first. 

Effect on yield — Early season infection can have a serious impact on yield, with losses up to 30%. 

Management tips — Choose resistant corn varieties with your retailer, rotate crops, till fields to encourage decomposition of infected residue, and apply a fungicide preventively or, if necessary, curatively. DuPont Aproach® Prima fungicide is very effective at controlling stripe rust with preventive and curative modes of action. Visit the Aproach Prima webpage to learn use rates of the fungicide in corn.

Aproach Prima is not be 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. Contact your local Corteva Agriscience sales representative for details and availability. Always read and follow label directions.