Detailed assessment of control measures against “flavescence doree” allows reduction of pesticide use

The wine industry plays important social and economic roles in the region of canton Vaud in Switzerland. Since 2015, “flavescence doree” (FD), a disease associated with a phloem-limited bacterium, has been present in the vineyards and represents a major threat to viticulture. The disease is propagated epidemically by its principal vector, the leafhopper Scaphoideus titanus. The “flavescence doree” phytoplasma is a quarantine pest, and is therefore under a national surveillance program. Control measures such as roguing infected stocks and insecticide treatments must be applied in affected perimeters. Regional phytosanitary services are responsible to organize the inspection of these areas. Each year, a systematic survey of S. titanus populations and symptomatic grapevines is conducted to assess that the actions are properly implemented. Here, a few examples from representative outbreaks are presented. The compulsory measures are efficient and, as expected, the pathway to disease eradication strongly depends on the initial severity of the outbreak. An adapted management strategy, based on individual risk analysis of each affected perimeter, to reduce the surface treated with insecticides was proposed.