‘Flavescence dorée’: It sounds nice, but it isn’t. The name ‘golden yellowing’ gives a much better indication of what it is: the greatest threat to local wine since the phylloxera pest 150 years ago.
Flavescence dorée is a disease of grapevines caused by cell-wall-less bacteria known as phytoplasmas. These phytoplasmas depend on their host plants for survival. They rarely cause symptoms in wild plants – but they can kill a vine within a few years.
And it has an ally: the American grapevine leafhopper. This invasive leafhopper lives almost exclusively in vineyards. Above all, however, it can transmit the phytoplasmas from infected to healthy vines: The vine cicada feeds on an infected vine leaf, then moves or flies to a vine that is still healthy, feeds on a leaf there, and in this way transmits the phytoplasmas. In this way, Flavescence dorée can spread throughout an entire vineyard within a single growing season.