Dothiorella viticola

This fungus survives as a latent pathogen within the xylem and cambium tissues of the grapevine. It is widely distributed across major viticultural regions worldwide.

The fungus produces pycnidia—small, black fruiting bodies—on the bark of infected wood. These pycnidia release spores that serve as primary inoculum for new infections during rain events.

Its biological strategy is to colonize the woody parts of the vine, progressively disrupting the plant's vascular system. It thrives by decomposing wood components such as lignin.

Molecular identification is the most reliable method to distinguish Dothiorella species from other fungi that cause similar symptoms, such as Botryosphaeria species.

Grapevines are the primary host for Dothiorella viticola. The fungus is particularly damaging to commercial vineyards, where it affects the longevity and productivity of the vines.

Infection leads to wood necrosis, which can result in stunted shoot growth, poor canopy development, and eventual death of the affected arm or the entire cordon.

Beyond grapevines, related species in the Dothiorellaceae family are known to affect various fruit crops, suggesting a broad ecological range for the genus.

The economic impact is significant due to the reduction in yield, the cost of replacing dead vines, and the potential need to shorten the lifecycle of a vineyard.

Infection often progresses slowly, making it a "hidden killer" in vineyards where visual symptoms on the leaves may only appear long after the wood is extensively damaged.

The most common internal symptom is a brown, wedge-shaped necrotic lesion visible when a vine trunk or cordons are cross-sectioned during pruning.

Leaf symptoms often appear as interveinal chlorosis and necrosis. These signs can be mistaken for nutrient deficiencies or water stress, making early field diagnosis difficult.

Cracking of the bark on the trunk is common. In wet conditions, the small black pycnidia may erupt through the bark, which are clearly visible upon close inspection.

Vines may show signs of "apoplexy," where a healthy-looking vine suddenly collapses and dies during peak summer heat due to the inability of the damaged wood to support water transport.

In severe cases, the infected wood becomes spongy or brittle, compromising the structural integrity of the vine and making it susceptible to breakage under heavy crop load.

Prevention is the primary strategy for managing Dothiorella viticola. Pruning should be performed during dry periods, as moisture is the main vector for spore dispersal.

Applying wound sealants or protective fungicides immediately after pruning is an essential practice to block the pathogen from entering fresh cuts.

Strict sanitation protocols must be followed: all infected wood and pruning debris should be removed from the vineyard and destroyed to reduce the inoculum pressure.

Tools used for pruning must be disinfected regularly, especially when moving between different blocks or when cutting into potentially infected, symptomatic vines.

• Utilize clean, certified nursery stock to prevent introducing the pathogen into new vineyard sites.
• Avoid over-fertilization, which can lead to rapid, succulent growth that is more susceptible to infection.
• Monitor vineyards for signs of wood decay and proactively remove symptomatic vines to limit the spread of spores.