Dothiorella grapevine decline

Dothiorella viticola is a significant fungal pathogen involved in the complex of grapevine trunk diseases. This fungus primarily affects the woody tissues of the vine, leading to vascular obstruction and progressive decline. It is recognized as an opportunistic pathogen that colonizes the permanent scaffold of the grapevine.

The host range is primarily focused on Vitis species, particularly commercial grapevines. The fungus gains entry into the plant host mainly through pruning wounds, cold injury, or structural cracks in the wood. Once the infection is established, the mycelium spreads within the xylem, disrupting the movement of water and essential nutrients.

Symptomatology involves severe internal necrosis, often appearing as wedge-shaped or circular staining in the cross-section of the wood. Externally, the disease may present as stunted shoot growth, chlorosis, and the sudden dieback of cordons or entire vines. In some cases, the bark may crack, and distinct cankers may develop around old pruning wounds.

The development and spread of Dothiorella viticola are highly dependent on environmental conditions, particularly high humidity and rainfall during the pruning season. Rain splashes facilitate the dispersal of pycnidiospores, which land on freshly exposed wood surfaces. The disease is more prevalent in older, stressed vineyards where the plant's natural defense mechanisms are weakened.

The economic impact of this disease is substantial, as it leads to the premature loss of vines and reduced yields.

• Sanitary pruning practices to remove infected wood.
• Application of protective wound sealants immediately after pruning.
• Strict disinfection of pruning tools between vines.
• Mitigation of environmental stress to maintain vigorous plant growth.