Identification and characterization of fungi associated with esca in vineyards of the Comunidad Valenciana (Spain)

Grapevines sampled in the Comunidad Valenciana in Spain were examined for esca symptoms, and the different vine parts (trunk.. cane and young vine) were surveyed for the presence of esca-related fungi. The fungal species most frequently identified were the mitosporic fungi Diplodia mutila (Dmu), Phaeoacremonium aleophilum (Pal), Phaeomoniella chlamydospora (Pch) and Phomopsis viticola (Pvi) and the basidiomycetes Fomitiporia mediterranea (Fin) and Stereum hirsutum (Shi). PCR and sequencing using the universal pair primers ITS1-ITS4 confirmed the identification, these techniques proved very useful, particularly in cases where fruiting was not evident and/or pure cultures did not display enough diagnostic traits. Dmu and both basidiomycetes were the most frequent fungi associated with esca in this region. Dmu was the only fungal species found in all vine parts studied, being significantly more present in canes (82%) than in trunks (58%) or shoots (28%). Moreover, both basidiomycetes (50% Fin and 56% Shi) and Pch (32%) were most frequently found in trunks.