Symbiosis Control

Flavescence dorèe (FD) is one of the diseases in the grapevine yellows disease complex. It was first described in the southwestern region of France in 1955. At the beginning it was thought to be a physiological disorder and then a virus. Only later, FD was associated to a phytoplasma [which belongs to the elm yellows (EY) group, known as the 16SrV group, subgroup C and D] and transmitted by a leafhopper vector in a circulative manner (must traverse the path from midgut through hemocoel to salivary glands before retransmission). In field conditions the phytoplasmid is vectored from infected to healthy grapevines by the cicadellid Scaphoideus titanus Ball.  

In 1973, a FD-like disease was first observed also in the North Italy. Until late eighties, FD was largely confined in France. Then in the nineties, an outburst of FD occurred in Northern Italy and Spain; it became a devastating disease and the pathogen was decreed a quarantine organism in the European Community (EC Directive 77/1993). Nowadays the FD is destroying several vineyards in the republics of Slovenia and Croatian of the former northern Yugoslavia.  

The FD has only been isolated from materials originating in the countries mentioned above. This fact does not exclude the possibility that Flavescence dorée occurs elsewhere, but the grapevine yellows from southern Italy (Sicily), central Italy (Emilia-Romagna), USA, Israel and South Australia is not FD. 

The diffusion of the disease is perfectly linked with the movement of the insect carrier (S.titanus) throughout the Europe; therefore, this insect appears to be the sole vector of the pathogen causing FD.