Phaeoacremonium decline of grapevine

The causative agent of the disease is the fungus Phaeoacremonium viticola, an ascomycete pathogen responsible for grapevine wood diseases. This fungus is a key member of the complex pathogens associated with Esca and Petri disease. It colonizes the xylem vessels, obstructing water flow and significantly stressing the host plant's physiological processes.

The primary host for this pathogen is the grapevine (Vitis vinifera). The disease affects plants at all stages of development, from nursery stocks to fully mature vineyards. Because the fungus resides deep within the woody tissues, it can persist for long periods, leading to systemic infection that is difficult to eradicate once it is established.

Symptoms of the infection include

• stunted shoot growth
• interveinal chlorosis of leaves
• dark streaks or spots in the wood tissue
• sudden wilting of canes or cordons in summer
• formation of cankers on the trunk
• general decline and dieback of the vine

The development of the disease is favored by mechanical wounds, such as pruning cuts, hail damage, or frost fissures, which serve as entry points for spores. Wind and water-borne spores are the main means of spread between vines. Warm and humid conditions following pruning operations are particularly conducive to the rapid colonization of fresh wounds by the fungus.

The economic impact of Phaeoacremonium viticola is significant, as it leads to the loss of vine productivity and the premature death of entire blocks in vineyards. Prevention is the primary control strategy. It includes maintaining vine vigor, disinfecting pruning tools, applying wound protectants immediately after cuts, and ensuring the use of pathogen-free propagation material to reduce the incidence of the disease.