Effects of Surrounding Forest Cover and Stand Characteristics on Grapevine Trunk Disease Symptoms and Vine Mortality

Grapevine trunk diseases (GTD) are a major threat to grape growers worldwide, since there is no highly effective technology to mitigate the quality, yield, and plant losses. The GTD complex comes with hectically appearing chronic tiger strip leaf symptoms and plant loss caused by apoplexy. The disease complex can be caused by various polyphagous Ascomycota and Basidiomycota pathogens, which can be found in forest ecosystems. These fungi are capable of degrading woody tissues; some of them act as pathogens in forest trees, but they are important in dead wood mineralization as well.

Our studies were conducted in Hungary, in the Eger Wine Region, through the survey of 11 vineyards. The GTD chronic symptom expression, the historical and annual plant loss were assessed in the vineyards, while the measured parameters in the neighbouring forests were the slope, density, age, dominant tree species, elevation difference compared to the vineyard, deadwood quantity and ratio.

As a result, the vineyards with more neighbouring forest vegetation were more severely affected. With a model-based approach, the evaluated parameters were not found to significantly affect the chronic symptom expression, while plant loss was affected by the neighbouring forests' age, density, and deadwood ratio. Elevation differences propagation of the inoculum through water erosion can be an important predictor as well.