Eutypa

Eutypa is a genus of fungi in the family Diatrypaceae. Species within this genus are plant pathogens that infect woody hosts. The most prominent member is Eutypa lata, the agent of eutypa dieback in grapevines (Vitis vinifera) and related trees.

Eutypa dieback is characterized by long-term decline, shoot dieback, stunted growth, yellowing leaves, and the development of perennial cankers on branches and trunks. Infected wood often shows a distinct wedge-shaped zone of necrosis and dark fruiting bodies in the cankers.

Biology: The fungus overwinters in cankers. In wet conditions, it produces reproductive structures that release spores; infection typically occurs through wounds, especially pruning cuts. Once established in the xylem, the pathogen disrupts water transport and gradually girdles branches, leading to dieback over several months to years. Fruiting bodies may appear on cankers in favorable weather.

Management: Effective control relies on sanitation and cultural practices. Prune out and remove diseased wood during dry weather, cutting beyond the visible canker margin, and promptly destroy material. Sanitize pruning tools between cuts. Avoid pruning during wet conditions or when symptoms are present. Fungicides can provide some protection against new infections but are not curative; their effectiveness is limited and depends on timing. Maintaining plant vigor and canopy management also helps reduce susceptibility.

Distribution and importance: Eutypa species occur in many regions with susceptible woody hosts, including vineyards. Eutypa lata is widely distributed and can cause substantial yield losses in affected plantings if unmanaged.