Turcicum leaf blight

Exserohilum turcicum:

Exserohilum turcicum, previously known as Helminthosporium turcicum, is a fungal pathogen that causes Northern corn leaf blight (NCLB), a significant disease affecting corn (maize) crops. Here's an informative description:

Symptoms:

1. Leaf Lesions: Initial symptoms appear as long, elliptical lesions on corn leaves.
2. Lesion Color: Lesions often have a tan to grayish color, with a darker border.
3. Linear Arrangement: Lesions may be arranged linearly along the leaf veins, giving a characteristic appearance.
4. Coalescence: In severe infections, lesions may coalesce, leading to large necrotic areas on leaves.

Identification:

1. Lesion Characteristics: Identify the characteristic lesions on corn leaves, considering their shape, color, and arrangement.
2. Presence of Dark Borders: Recognize the presence of darker borders around the lesions.

Disease Cycle:

1. Survival: The fungus can survive in infected debris and residues.
2. Spore Production: Conidia are produced in lesions during the growing season.
3. Spread: Wind and rain can disseminate conidia to new corn plants, initiating new infections.

Management:

Cultural Practices:

1. Resistant Varieties: Planting corn varieties with genetic resistance to Northern corn leaf blight is an effective strategy.
2. Crop Rotation: Rotate crops to reduce the buildup of the pathogen in the soil.

Fungicide Application:

1. Foliar Fungicides: Application of fungicides, especially during periods conducive to disease development, can help manage NCLB.

Regular Monitoring:

1. Field Scouting: Regularly monitor corn fields for early symptoms of Northern corn leaf blight, especially during periods of high humidity.

Post-Harvest Practices:

1. Residue Management: Remove and destroy infected crop residues after harvest to reduce overwintering sites for the pathogen.