Flavescence dorée in Veneto.
Serious manifestations of yellowing and withering attributable to grapevine flavescence dorée were noted in various grape growing areas in Veneto, Italy. The causal agent of the disease, a phytoplasma, is transmitted by the cicadellid Scaphoideus titanus. Studies were initiated in Verona to investigate the occurrence of the disease in Veneto, the presence of similar pathogens such as those causing black wood (also caused by a phytoplasma), the areas and species of vines most affected by the disease, the role of S. titanus and other possible vectors in its spread, and the effectiveness of insecticide interventions and other agronomic practices for its control. Some of the samples analysed were affected by grapevine flavescence dorée or black wood, while others with similar symptoms were not affected by either. The importance of being able to distinguish between the 2 diseases is stressed; black wood is not transmitted by S. titanus, is present in endemic form and is found almost exclusively on Chardonnay. Specific directives have been issued on the collection of material for propagation to safeguard the health of the grapevines.