Northern corn leaf blight

Setosphaeria turcica (anamorph Exserohilum turcicum) is a destructive fungal pathogen responsible for Northern Corn Leaf Blight (NCLB). It is a major threat to maize production, particularly in regions with humid and temperate climates, causing significant economic losses.

The host range of the pathogen primarily includes maize (corn), sorghum, and sudangrass. The disease is characterized by long, cigar-shaped, necrotic lesions on the leaves. As the infection progresses, these lesions merge, leading to extensive tissue death, which effectively reduces the photosynthetic capacity of the plant.

The life cycle of the pathogen begins with inoculum surviving on crop debris. During favorable conditions, conidia are produced and dispersed by wind or splashing rain to the leaves of new host plants. Moisture and mild temperatures are required for the germination of spores and the initiation of the infection cycle.

Environmental conditions play a crucial role in disease development. High humidity and temperatures ranging from 20°C to 28°C favor rapid conidia production and secondary infections. Under these conditions, the disease can spread throughout an entire field within a few weeks, especially if susceptible hybrids are planted.

The economic impact of NCLB is significant, as it leads to reduced grain fill and lower yield quality. Effective management requires an integrated approach to reduce the inoculum load and protect the crop during vulnerable growth stages:

• Selecting and planting resistant or tolerant corn hybrids;
• Implementing crop rotation to break the pathogen's life cycle;
• Tillage practices that promote the decomposition of infected crop residue;
• Timely application of foliar fungicides when the disease threshold is reached.