Scab and leaf spots Venturiales

The order Venturiales consists of several significant fungal pathogens belonging to the Ascomycota phylum. These fungi are primarily recognized for causing various types of scab diseases and leaf spots on economically important horticultural and agricultural crops. Their life cycle often involves both sexual and asexual stages, allowing them to adapt efficiently to host plant environments.

These pathogens predominantly infect pome fruits such as apples and pears, but their host range can extend to other trees and ornamental plants. The fungi typically invade the surface tissues of leaves, fruits, and occasionally shoots, where they establish colonies beneath the cuticle, drawing nutrients directly from the host cells.

Symptoms often manifest as dark, olive-green to black velvety spots on the foliage, which can lead to yellowing and premature leaf drop. On fruits, the infection causes corky scabs, surface cracking, and severe deformities, which dramatically lower the market value of the produce and increase susceptibility to secondary storage rots.

Development and spread are strongly correlated with periods of high humidity, frequent rainfall, and mild temperatures. The fungus overwinters in infected leaf litter on the orchard floor, producing spores during the spring that are dispersed by water splashes or wind, initiating the primary infection cycle of the season.

Effective management strategies require an integrated approach to minimize fungal pressure:

• Sanitation, including the removal and destruction of fallen leaves and infected fruit.
• Application of protective and systemic fungicides aligned with critical phenological stages.
• Pruning techniques to promote canopy aeration and reduce leaf wetness duration.
• Deployment of disease-resistant cultivars in commercial and domestic orchards.
• Regular scouting for early symptoms to optimize the timing of defensive treatments.