Evaluation of the efficacy of curettage and over-grafting in the control of esca disease complex

The domestication and cultivation of the vine required pruning techniques that expose the vines to trunk pathogens, thereby facilitating the spread of Grapevine Trunk Diseases (GTDs). Among these, the Esca Disease Complex (EDC), primarily caused by Phaeomoniella chlamydospora, Phaeoacremonium minimum, and Fomitiporia mediterranea, brings significant challenges to European viticulture. This study examines the effects of curettage and over-grafting as potential methods for containing the expression of the disease in three vineyards located in Tuscany and Veneto (Italy). For several years, symptomatic vines were treated with curettage (removal of necrotic wood) or over-grafting, and the manifestation of symptoms, recurrence, and mortality rates were compared with those of untreated controls. The results revealed that both techniques reduced the incidence of foliar symptoms and mortality from Grapevine Leaf Stripe Disease (GLSD), one of the diseases in the EDC, which was previously simply referred to as “esca”. In the long term, treated vines had a significantly lower probability of resuming symptoms or dying compared to the untreated ones. The effectiveness of over-grafting varied depending on the health status of the rootstock. Overall, both methods offer promising, yet context-dependent, strategies for managing GTDs, highlighting the importance of integrated and site-specific approaches in vineyard disease control.