Eyespot disease

The fungus Herpotrichia herpotrichoides (formerly Pseudocercosporella herpotrichoides) is the causal agent of eyespot disease, a significant foot rot infection in cereal crops. The disease directly targets the stem base, interfering with water and nutrient transport throughout the plant's vascular system.

The primary hosts of this pathogen include winter wheat, winter barley, rye, and triticale. The fungus persists in the soil on crop residues and stubble, making continuous cereal production a major risk factor for disease outbreaks. Proper field management is essential to break the survival cycle of the pathogen.

Symptoms are most visible at the base of the stems, where characteristic eye-shaped lesions with dark margins appear. As the infection progresses, the stem tissue weakens, causing the plant to lodge. In severe cases, the entire stem may collapse, leading to premature ripening and the formation of empty or stunted grain heads.

Development of the fungus is favored by cool, moist conditions with temperatures ranging from 5 to 15°C. High humidity and rainfall facilitate the spread of conidia from the soil surface onto the base of the stems. Dense crop stands with excessive nitrogen fertilization create a microclimate that is highly conducive to disease progression.

The economic impact of eyespot disease is significant, often resulting in substantial yield losses due to lodging and poor grain filling. Reduced stem integrity makes the crop prone to breaking, which complicates harvest operations and leads to massive grain losses in the field, further reducing the overall grain quality.

Integrated pest management strategies are crucial for controlling the disease. Key measures include:

• Implementing a crop rotation cycle with at least a two-year gap between cereal crops.
• Selecting resistant or tolerant cereal cultivars.
• Ensuring optimal seeding rates to prevent overcrowding.
• Applying systemic fungicides at the early tillering stage when infection thresholds are met.