Rice curvularia blight

Pathogen and disease type: Curvularia blight is a serious fungal disease caused by the pathogen Curvularia lunata. This fungus belongs to the class of mitosporic fungi and is characterized by the production of dark-pigmented, multicellular conidia. It induces necrotic lesions on various plant parts, significantly disrupting physiological functions.

Host crops: While the primary economic impact is observed in rice cultivation, Curvularia lunata is a polyphagous pathogen with a wide host range. It affects a variety of cereal crops including maize, wheat, sorghum, and millet. It can also colonize several grass species, making it a persistent threat in agricultural ecosystems.

Symptoms and signs: The infection manifests as small dark brown or black spots on leaves, stems, and panicles. In infected rice heads, the disease causes "black kernel" or spikelet sterility. A characteristic olive-black velvety fungal growth (conidiophores and conidia) is typically visible on the surface of the lesions during humid weather.

Conditions for development and spread: High relative humidity (exceeding 85%) and warm temperatures (ranging from +25°C to +30°C) are critical for the rapid development of the fungus. The pathogen survives in soil, infected plant residues, and contaminated seeds. Spores are dispersed through wind currents, water splashes, and irrigation practices, facilitating quick field colonization.

Economic impact and protection: The disease leads to significant yield losses, reduction in grain weight, and poor seed quality. To mitigate the risk, producers should implement integrated pest management strategies.

• Use resistant or tolerant cultivars;
• Treat seeds with effective fungicides;
• Practice systematic crop rotation;
• Remove and destroy crop residues;
• Avoid excessive nitrogen fertilization to maintain plant vigor.