Sharp eyespot

Sharp eyespot is a fungal disease caused by the pathogen Ceratobasidium cereale (anamorph Rhizoctonia cerealis). This disease predominantly affects the stem bases and root systems of various gramineous crops, leading to restricted nutrient uptake and structural weakness of the plants.

The primary hosts of this pathogen include winter wheat, winter barley, and oats. Ceratobasidium cereale is a soil-borne fungus that can survive as sclerotia or mycelium on crop debris, making it a persistent threat in continuous cereal cropping systems.

The characteristic symptoms appear as distinct, sharp-edged lesions on the leaf sheaths and stem bases. These lesions are typically oval or elongated with a dark brown border and a light, straw-colored center. As the infection progresses, the fungal growth can penetrate the internal tissues of the stem, resulting in lodging, shriveled grains, and reduced overall crop vigor.

The development of Sharp eyespot is favored by cool, moist environmental conditions, particularly during the early spring vegetative growth phases. High humidity at the soil surface and dense crop canopies facilitate the spread of the mycelium between plants. Poor drainage and low-lying fields often exhibit higher infection rates.

Effective management strategies require an integrated approach to reduce inoculum levels and protect developing plants:

• Implementing diverse crop rotations to break the disease cycle.
• Using high-quality seed treatments to protect seedlings during the early stages.
• Managing crop residues through appropriate tillage practices to encourage decomposition.
• Maintaining optimal seeding rates to ensure airflow and reduce humidity levels at the base of the crop.