Eyespot of cereals

Eyespot, caused by the fungus Pseudocercosporella herpotrichoides, is a chronic disease that affects the base of the stems in various cereal crops. It is widely recognized as one of the most destructive soil-borne fungal diseases in temperate climate zones, significantly impacting yield and crop stand stability.

The disease primarily infects winter wheat, rye, barley, and triticale. The pathogen survives as mycelium on crop debris within the soil and can persist for several years if susceptible hosts are continuously grown in the same field, making it a persistent challenge for continuous cropping systems.

Early symptoms appear during the tillering stage as oval-shaped eye-like lesions on the leaf sheaths. As the infection progresses, the fungus penetrates the inner stem wall, leading to the formation of necrotic lesions. The affected stems become weak, brittle, and prone to lodging, which is the most distinguishing characteristic of this disease.

The development of eyespot is favored by cool, moist conditions with temperatures ranging from 5°C to 15°C. Prolonged wet periods during the late autumn or early spring provide the ideal environment for the spread of spores. Cultural factors such as high seed density, early planting dates, and excessive nitrogen application create a canopy environment conducive to the disease.

Economic losses arise from reduced nutrient uptake, stunted growth, and severe lodging, which makes harvesting difficult and results in significant grain loss. Effective management strategies focus on preventing the buildup of inoculum through crop rotation (avoiding cereals for 2-3 years), using resistant cultivars, and applying fungicides when threshold levels are reached during the stem elongation stage.

• Implement a 2-3 year break between cereal crops.
• Select resistant cereal varieties.
• Avoid early sowing in heavily infested fields.
• Apply systemic fungicides at the early stem elongation stage.
• Manage crop residue to speed up decomposition.