Barley stripe

Pyrenophora graminea

Causal Agent: Pyrenophora graminea is a fungal pathogen that causes leaf spotting diseases in various grasses, including cereals like barley and wheat.

Symptoms:

  1. Leaf Lesions:

    • Circular to Oval Lesions: The primary symptom is the development of circular to oval-shaped lesions on the leaves.
    • Dark Borders: Lesions often have distinct dark borders.

  2. Leaf Blighting:

    • Lesion Coalescence: In severe infections, lesions may coalesce, leading to widespread blighting of the leaves.
    • Reduced Photosynthesis: Severe infections can impact photosynthesis and overall plant health.

  3. Culm and Sheath Infections:

    • Extended Infections: The fungus can extend its infection to culms (stems) and sheaths, affecting the entire plant.

Identification:

  1. Distinctive Lesions:

    • Circular to oval lesions with dark borders on leaves, stems, and sheaths.

  2. Favorable Conditions:

    • Humidity and Moisture: Pyrenophora graminea thrives in humid conditions, and moisture facilitates spore dispersal.

Conditions Favoring Disease:

  1. Humid Conditions:

    • Moisture Facilitates Spore Production: The fungus produces spores in the presence of moisture, and high humidity favors disease development.

  2. Moderate Temperatures:

    • Optimal Growth Conditions: Moderate temperatures, typically ranging from 15 to 25 degrees Celsius (59 to 77 degrees Fahrenheit), are conducive to the growth of Pyrenophora graminea.

Management:

  1. Resistant Varieties:

    • Plant Resistant Cultivars: Select grass varieties, especially barley and wheat, that exhibit resistance or tolerance to Pyrenophora graminea.

  2. Fungicides:

    • Foliar Applications: Application of fungicides may be considered in cases of severe infections. Consult with local agricultural extension services for appropriate recommendations.

  3. Crop Rotation:

    • Reduce Inoculum Buildup: Practice crop rotation to reduce the buildup of the pathogen in the soil.

  4. Sanitation:

    • Remove Infected Debris: Promote sanitation by removing and destroying infected plant debris.

Note: Leaf spotting diseases caused by Pyrenophora graminea can lead to yield losses in grass crops. Implementing integrated disease management strategies, including resistant varieties, fungicides, and cultural practices, is crucial for effective control.