Scab

The genus Venturia encompasses a group of pathogenic ascomycete fungi that cause the dangerous plant disease known as scab. The most prominent species include Venturia inaequalis, which affects apple trees, and Venturia pyrina, which targets pear trees. Systematically, these fungi belong to the Venturiaceae family within the Venturiales order.

The primary crops affected by these pathogens are pome fruit trees. The fungus attacks leaves, fruits, petioles, fruit stalks, and occasionally annual shoots, leading to significant yield losses and a drastic reduction in the commercial quality of the produce.

The pathogen's life cycle consists of primary and secondary infection phases. The fungus overwinters as mycelium or pseudothecia in fallen leaf litter. In the spring, during wet weather conditions, ascospores are released and infect young tissues. Throughout the growing season, the fungus spreads via conidia, which initiate new infection sites whenever free moisture is present.

The symptoms appear as circular spots with an olive-colored, velvety fungal growth. On leaves, these spots can coalesce, leading to premature defoliation. Affected fruits become deformed, develop cracks, and form corky tissue, rendering them unsuitable for storage or fresh market sales.

• Selection and planting of scab-resistant fruit tree cultivars.
• Timely sanitary pruning and removal of fallen leaf debris.
• Maintaining proper tree canopy aeration to reduce humidity.
• Preventive fungicide applications during critical growth stages.
• Use of copper-based products and systemic fungicides during active development periods.