Powdery mildew of buckwheat

Pathogen and disease type. The causative agent of the disease is the fungus Erysiphe polygoni, a highly specialized obligate biotroph. It belongs to the order Erysiphales and is responsible for typical powdery mildew symptoms, primarily affecting the aerial parts of buckwheat throughout its growth cycle.

Host plants and infection. The primary host for this pathogen is buckwheat. The fungus typically colonizes the leaf blades, stems, and floral parts. By extracting nutrients directly from the host cells, the parasite interferes with the plant's metabolic processes, often causing localized tissue stress and severe chlorosis in affected areas.

Symptoms and signs. The characteristic sign of the infection is the appearance of white, mycelial patches on the upper surface of leaves. As the colony expands, it takes on a powdery or dusty appearance due to the formation of abundant asexual spores (conidia). Eventually, small black fruiting bodies called cleistothecia appear within the mycelium.

Development and spread. The development of the fungus is favored by warm, humid conditions, typically ranging from +18°C to +25°C. Rapid spread of the disease occurs when favorable weather alternates with high humidity or heavy dew, facilitating the dissemination of conidia via wind across fields and neighboring areas.

Damage and control measures. The disease significantly reduces the photosynthetic leaf area, leading to stunted plant growth, reduced grain filling, and lower yields. Integrated management includes crop rotation, destruction of crop residues, and the use of resistant varieties. When conditions favor severe outbreaks, systemic fungicides are required to protect the crop.

• Utilizing resistant or tolerant buckwheat cultivars.
• Managing nitrogen fertilization to avoid excessive vegetative growth.
• Implementing wide crop rotation patterns.
• Applying systemic fungicides at the onset of symptoms.