Northern Corn Leaf Blight is caused by the fungal pathogen Setosphaeria turcica.  Northern Corn Leaf Blight is a large, elliptical or cigar shaped lesion on the corn leaf, which is typically tan to brown in color. The infection is favored by wet, cool conditions with water that has been present on leaf surface for 6-18 hours. This fungal pathogen can lead to stalk rot in the corn plant as well.

Development of the fungus during silking or grain fill can lead to a yield loss of over 30 percent. Development before silking can lead to a 50 percent loss in grain yield. Losses are minimal if it is delayed until dent stage. Fungicide may be necessary if there is one or more lesion present on 50 percent of plants at tasseling. A rotation to soybeans or alfalfa is beneficial because the fungus survives in the infested crop debris until next crop. So far Northern Corn Leaf Blight has not been a concern in Minnesota this year but has been prevalent in Central Iowa.  It is important to scout for this damaging corn disease now.

-Matt Johnson
Ag Partners Agronomy Intern