Tobacco leaf spot

Ascochyta arida:

Ascochyta arida is a fungal pathogen that causes Ascochyta blight, a common disease affecting various legumes, including chickpeas (Cicer arietinum). Here's an informative description:

Symptoms:

1. Leaf Lesions: Circular to irregular-shaped lesions appear on leaves, starting as small, water-soaked spots.
2. Tan Centers: Lesions develop tan to grayish centers with reddish-brown margins.
3. Stem Lesions: The fungus can also infect stems, leading to lesions and cankers.
4. Pod Lesions: In advanced infections, lesions may develop on pods, affecting seed quality and yield.

Identification:

1. Lesion Appearance: Identify characteristic lesions on leaves, stems, and pods.
2. Tan Centers: Recognize the tan centers with distinctive margins.

Disease Cycle:

1. Survival: The fungus can survive in infected crop residues and seed.
2. Spore Production: Conidia are produced in lesions, serving as primary inoculum.
3. Spread: Rain and wind can disseminate conidia to nearby plants, initiating new infections.

Management:

Cultural Practices:

1. Crop Rotation: Rotate crops to reduce the buildup of the pathogen in the soil.
2. Resistant Varieties: Plant chickpea varieties that are resistant or less susceptible to Ascochyta blight.

Fungicide Application:

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

Regular Monitoring:

1. Field Scouting: Regularly monitor chickpea fields for early symptoms of Ascochyta 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.