Angular leaf scorch

Angular leaf scorch is a fungal disease caused by the pathogen Pseudopezicula tetraspora. It is a specific condition affecting grapevines, impacting the health of foliage and potentially reducing the overall vigor of the plant during the growing season.

The disease primary targets cultivated grapevines (Vitis vinifera). It is classified as an ascomycete fungus and is known for its ability to persist in the vineyard environment, specifically on plant debris and overwintering tissues, which serves as a reservoir for annual re-infection.

Symptoms are identified by the appearance of angular, vein-limited lesions on the leaf blades. As the infection progresses, these spots become necrotic, turning brown or reddish-brown, which resembles a scorch pattern. This tissue death significantly reduces the area available for photosynthesis, impacting plant productivity.

Environmental conditions play a critical role in the development and spread of Pseudopezicula tetraspora. High humidity levels, prolonged rainfall, and moderate temperatures are the most favorable factors for spore dispersal and infection establishment. Spores are typically spread through rain splashes or wind, targeting susceptible young tissues in early spring.

Effective management requires an integrated approach. Cultural practices such as removing infected leaves, ensuring proper vine canopy management to improve airflow, and maintaining vineyard hygiene are essential. Chemical control, including the application of fungicides during the primary infection periods, helps to keep disease pressure under control and protect the yield.

• Monitoring for early signs of lesions on leaves.
• Sanitation by removing old leaves and debris.
• Maintaining optimal canopy density for better aeration.
• Applying fungicides as a preventative measure during wet periods.