Curvularia leaf spot

The causal agent of the disease is the microscopic fungus Curvularia crepinii (syn. Bipolaris crepinii), which belongs to the class Ascomycetes. It is a pathogenic microorganism that causes leaf spot, a common fungal disease affecting mainly cereal crops, including wheat, rice, and millet.

The primary symptoms of infection include the appearance of specific spots on leaves, leaf sheaths, and glumes. These spots usually have an elongated or irregular shape and are colored brown, dark brown, or black, often with a distinct lighter margin. Under high humidity, a dark velvety layer of mycelium and conidia of the pathogen frequently forms on the surface of the infected tissues.

The development and spread of the pathogen are directly dependent on climatic conditions. High relative humidity (over 85%) and temperatures ranging from +22°C to +28°C are optimal for spore germination and active infection of plant tissues. The infection can persist in the soil on crop residues and can also be transmitted through infected seed material.

The harmfulness of the disease lies in the premature death of the leaf assimilative surface, which leads to a decrease in photosynthetic intensity. As a result, the grain filling process is disrupted, reducing both grain weight and seed quality. In epidemic years with severe outbreaks, yield losses can be significant, negatively impacting the overall quality parameters of the grain harvest.

The complex of control and prevention measures includes the following methods:

• Use of healthy, treated seed material for sowing.
• Adherence to crop rotation, ensuring that susceptible crops do not return to the same field for at least 2-3 years.
• Thorough destruction of plant residues and deep autumn plowing.
• Application of fungicides during the growing season upon detection of the first symptoms to prevent mass spread.
• Balanced application of fertilizers to improve overall plant resistance to pathogens.