Togniniaceae

The Togniniaceae family comprises a group of ascomycetous fungi that are significant pathogens responsible for serious wood diseases in grapevines. The most notable species, Phaeomoniella chlamydospora, is widely recognized in viticulture as a primary agent associated with the complex of disorders leading to wood necrosis and systemic decline in vineyards worldwide.

These fungi are classified as systemic pathogens that colonize the xylem of the plant. They function by infiltrating the vascular system, where they actively spread and produce toxins, eventually obstructing the transport of water and mineral nutrients. This type of chronic infection leads to a gradual reduction in vine vigor and ultimate plant mortality over several seasons.

The primary host for Togniniaceae is the cultivated grapevine. These pathogens are particularly damaging in nurseries, where they can be disseminated via infected rootstocks or scion wood. While vitis species are the main victims, these fungi can occasionally impact other woody plant species, making them a subject of intense phytopathological research globally.

Symptoms often appear as stunted growth, chlorotic leaves, and distinctive necrosis patterns on foliage. A hallmark of the infection is the internal browning or streaking of the wood, which is visible upon cross-sectioning the trunk or cordons. These necrotic spots represent the physical colonization of the vascular tissues by the fungal mycelium.

• using certified disease-free propagation material;
• disinfecting pruning tools between vines;
• applying wound protectants to pruning cuts;
• removing and destroying severely infected wood;
• optimizing vine vigor through proper nutrition and irrigation.

The development and spread of Togniniaceae are largely driven by environmental stress and mechanical injury to the vine. Pruning during wet periods allows spores to easily infiltrate open wounds. Given the persistent nature of these wood diseases, effective management relies heavily on preventative cultural practices, as there is currently no curative chemical treatment that can fully eradicate the pathogen from established vines.