Morphological and molecular identification of Eutypa lata on grapevine in Serbia

During a survey from 2004 to 2016, symptoms of grapevine dieback were observed in six vineyards in Serbia. Symptoms initially appeared as small, chlorotic, and necrotic spots along the rim of the leaves, deformation of leafs, and the appearance of shortened shoots, often with the so-called zigzag internodes. Over time, partial or complete dying of the vines developed. Symptomatic samples were collected and submitted to laboratory analysis. Based on the morphological characterization, the isolated fungus was initially identified as belonging to Eutypa species. Pathogenicity tests showed that 47 selected isolates caused tissue necrosis around the site of inoculation, chlorosis, and deformation of the leaves, along with the appearance of tiny, necrotic spots on the periphery of the leaf that fall off over time. Inoculated cuttings were stunted, dwarf-like with zigzag internodes. Molecular identification was done with sequence and phylogenetic analysis of ITS, TUB, and RPB2 genomic regions. Based on the phylogenetic analysis, all isolated fungi were determined as Eutypa lata.