Northern corn leaf blight

Northern corn leaf blight (NCLB) is a destructive fungal disease of maize caused by the pathogen Setosphaeria turcica (anamorph Exserohilum turcicum). It is a significant concern for corn growers worldwide, particularly in areas with humid and temperate climates where the disease can cause major economic losses.

The fungus survives primarily in corn debris left on the soil surface. During the growing season, conidia are produced and spread to the lower leaves of the plants through wind and splashing rain. Once the infection is established, the cycle of sporulation and re-infection can occur repeatedly throughout the season.

The disease is characterized by distinct, cigar-shaped, gray-green to tan lesions that appear on the leaves. As the infection progresses, these lesions lengthen and can merge to cover the entire leaf surface, resulting in significant necrosis and the loss of photosynthetic tissue, which ultimately stunts grain development.

Development of the disease is highly favored by moderate temperatures (18–27°C) combined with high humidity, dew, or frequent light rainfall. These conditions allow the fungus to thrive and produce massive amounts of spores, leading to rapid spread of the blight throughout the field during the mid-to-late vegetative stages.

The impact of NCLB is most severe when infection occurs early in the development of the plant, specifically before or during pollination. Yield losses can be substantial due to reduced grain filling and the overall decline in plant vigor, which can also make the stalks more susceptible to lodging and stalk rot diseases.

• Planting resistant or tolerant corn hybrids.
• Implementing crop rotation with non-host crops.
• Tillage practices that bury crop residue to speed up decomposition.
• Applying labeled fungicides when conditions are favorable for disease.
• Scouting fields regularly to detect early signs of infection.