Water regime and its possible impact on expression of Esca symptoms in Vitis vinifera: growth characters and symptoms in the greenhouse after artificial infection with Phaeomoniella chlamydospora

Impact of abiotic factors has been recently discussed in grapevine trunk diseases such as Esca. Emphasis of the present study lies on the relation between different water regime ("normal" and "stress") on one side and growth characters as well as Esca-related wood symptoms on the other side. Trials were conducted in the greenhouse with cuttings of the cultivars 'Müller-Thurgau' and 'Riesling', part of which artificially infected with Phaeomoniella chlamydospora. During a 12 month incubation period the following characters were evaluated: shoot length, weight of stem, expression of wood symptoms, and survival rate of plants. For evaluation of wood symptoms a numerical system was developed that is applied here for the first time. The obtained results indicate that water supply plays a statistically significant role, with plants under "stress" regime shown to be more affected. No strict spatial correlation was found to exist between wood symptoms and physical presence of the pathogen.