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Kentucky IPM Pest Information Pages

Northern Corn Leaf Blight: Kentucky Corn IPM

Northern Corn Leaf Blight (NCLB)


Symptoms of NCLB can often be confused with symptoms of bacterial wilt, especially late in the season. Lesions are long (1" to 6") elliptical in shape with pointed ends, grayish-green or tan in color and develop first on lower leaves. NCLB lesions differ from bacterial wilt lesions in that they are generally definite in shape, have greater width and do not follow leaf veins for extended lengths. The disease progresses upward.Northern Corn Leaf Blight

During damp weather, greenish black fungal sporulation is produced in NCLB lesions. On hybrids carrying an Ht2 resistance gene, long yellow to tan lesions with wavy margins and no sporulation have been observed on infected leaves. These resistance-reaction lesions can be easily confused with Stewart's Wilt (bacterial wilt).


Symptoms of NCLB are caused by the fungus Setosphaeria turcica (Exserohilum turcicum, Helminthosporium turcicum). Look for this disease developing first on lower leaves when corn plants are from waist to shoulder high. Development of the disease is favored during periods of wet weather with moderate temperatures during the growing season.

The fungal mycelia and conidia can overwinter in plant debris, and the disease is later tranferred by wind to new plants. Severe yield loss can occur when leaves become blighted during early grain fill. NCLB will be more severe in fields with corn following corn under reduced tillage. Other hosts include sorghum, johnsongrass, and some other grass species.

IPM Techniques

References and Additional Information

  • IPM-2 Kentucky IPM Manual for Corn

  • PPA-10a Kentucky Plant Disease Management Guide for Corn and Sorghum by P. Vincelli and D.E. Hershman, Extension Plant Pathologists

  • Compendium of Corn Diseases. M.C. Shurtleff. The Amer. Phytopathol. Soc. 1980

This site was created and is maintained by Pat Dillon, Department of Entomology, University of Kentucky, S-225 Agricultural Science Ctr North, Lexington, KY USA  40546-0091 (phone: 859/257-3571). Please send questions or suggestions to: pdillon@uky.edu