Phaeoacremonium aleophilum

Phaeoacremonium aleophilum is an ascomycete fungus and a primary pathogen involved in the complex of grapevine trunk diseases (GTDs), most notably esca and Petri disease. As a vascular parasite, it colonizes the xylem tissue of the grapevine, causing systemic decline and vascular necrosis. It is a widespread fungus in viticulture regions globally, posing a major threat to vineyard longevity.

The disease affects Vitis vinifera, particularly older vines, though it also impacts nursery propagation material. Symptoms in the vineyard include interveinal leaf chlorosis and necrosis, often described as tiger-stripe, along with vascular browning and central wood rot. Affected vines may show sudden wilt, leaf drop, or a slow decline that leads to the eventual death of the entire vine or individual cordons.

The life cycle involves the production of conidia within pycnidia formed on dead or necrotic wood. These spores are dispersed by rainfall, wind, and irrigation water, facilitating the colonization of fresh pruning wounds. Once inside, the mycelium spreads throughout the vascular system, secreting enzymes and toxins that degrade the cell walls and obstruct the transpiration stream, leading to wood decay.

Environmental conditions such as high humidity and moderate temperatures are ideal for the release and germination of spores. Pruning is the most vulnerable time for infection, as large wounds remain exposed for long periods. The fungus can persist for years in woody debris and asymptomatic hosts, acting as a constant reservoir of inoculum within the vineyard environment.

Management of Phaeoacremonium aleophilum remains challenging as there are no curative treatments available for infected vines. Integrated disease management strategies are essential:

• protecting pruning wounds with fungicidal pastes or biological control agents;
• sanitizing pruning equipment to prevent cross-contamination;
• removing and destroying severely infected wood to reduce local inoculum;
• sourcing high-quality, certified nursery stock to ensure the vineyard starts disease-free.