Togninia

Togninia is a genus of fungi belonging to the family Togniniaceae, recognized as a primary agent involved in the complex and devastating grapevine trunk disease known as Esca. This fungal pathogen specifically targets the vascular tissue and internal woody structure of the vine, leading to severe decay and long-term decline.

This disease primarily affects grapevines (Vitis vinifera). The fungus enters the plant through wounds, such as pruning cuts or mechanical damage caused by cultivation. Once established, the pathogen grows slowly through the xylem, gradually destroying the hydraulic architecture of the grapevine.

Symptoms of Togninia infection are diverse and often unpredictable. The chronic form is characterized by foliar symptoms often referred to as "tiger-striping," where chlorotic and necrotic spots develop between the veins. In contrast, the apoplectic form results in the sudden wilting and total collapse of the vine, usually occurring during periods of high heat stress.

The development of the disease is highly influenced by climatic conditions and vineyard management practices. Warm temperatures and high humidity facilitate the production and dissemination of fungal spores. These spores are spread via rain splashes and wind, infecting new pruning wounds throughout the dormant and early growth seasons.

Management of Togninia-induced diseases is challenging because the fungus is protected within the wood. Prevention is the cornerstone of control: implement strict pruning hygiene, ensure wounds are protected with pruning sealants or biological control agents, and promptly remove heavily infected vines to prevent the accumulation of fungal inoculum within the vineyard environment.