Pleurostoma

Early symptoms are often subtle, manifesting as a general decline in vine vigor and reduced shoot growth during the spring months.

A hallmark of the disease is the presence of distinctive dark, necrotic streaks or patches visible on the cross-section of woody trunks and cordons.

In hot summer conditions, heavily infected vines may show symptoms of sudden wilt, commonly referred to as apoplexy-like decline.

Foliage on affected vines often appears stunted, chlorotic, or scorched, reflecting the plant's inability to maintain sufficient water supply.

• Stunted growth of new shoots and sparse canopy.
• Dark wood discoloration visible in internal cross-sections.
• Sudden wilting of leaves and shoots in warm weather.

The fungus Pleurostoma richoniae is the causal agent of this serious grapevine wood disease, which affects the internal vascular system.

As a vascular pathogen, it colonizes the xylem vessels, gradually obstructing the upward flow of water and essential nutrients throughout the vine.

The disease belongs to the group of grapevine trunk diseases, characterized by a long latent phase before obvious external symptoms appear.

Spore dispersal occurs primarily through wind and rain, which transport the fungus to fresh wounds caused by pruning or natural environmental damage.

Once inside the woody tissues, the fungus establishes a perennial mycelium that persists within the vine's structure for many years.

The development of the disease is favored by moderate to high temperatures combined with moisture, which facilitates the production of fungal spores.

Pruning activities without subsequent protective treatments create ideal entry points for the pathogen to colonize the exposed woody tissues.

The movement of contaminated pruning tools between vines is a major factor in the rapid dissemination of the fungus throughout a vineyard.

Vines stressed by extreme weather conditions, nutrient imbalances, or prior mechanical damage show significantly higher susceptibility to infection.

Orchard sanitation is critical, as neglected, dead wood serves as a continuous reservoir for fungal inoculum within the planting.

Pleurostoma represents a significant long-term threat to viticulture, as it causes irreversible damage to the structural integrity of the grapevine.

The disease leads to progressive yield loss and eventually renders the infected vine non-productive, necessitating its total removal.

The economic impact is severe, particularly in older vineyards where the cumulative effect of the disease reduces the overall lifespan of the planting.

Because the infection is systemic and hidden within the wood, it is difficult to manage effectively once a vine is thoroughly colonized.

The slow progression makes the disease a silent killer, often causing unexpected gaps in the vineyard rows that are costly to replace.

Strict vineyard hygiene is the cornerstone of control, including the mandatory disinfection of pruning tools between every single vine.

Applying protective wound dressings, such as fungicide-containing paints, to all major pruning cuts is essential to prevent spore penetration.

It is recommended to schedule pruning during dry periods to minimize the risk of spores germinating on fresh, wet wounds.

Removing and burning symptomatic or dead wood helps reduce the overall inoculum load present in the vineyard environment.

Focusing on vine health through balanced fertilization and stress management helps maintain the natural resistance of the plant to wood pathogens.