Contribution à l'étude des jaunisses de la vigne dans le monde. Prospection par test Elisa spécifique du mycoplasma-like organism (MLO) de la flavescence dorée

Grapevine yellows (GY) are a group of diseases with similar symptoms. The recent publication on the use of Elisa to detect the flavescence doree (FD) mycoplasma-like organism (MLO) in the grapevine itself has allowed the differentiation of FD from the other GY. In order to investigate the epidemiology of FD, grapevine canes or leaves showing GY symptoms were harvested from several areas in the world (France, 138 samples; Northern Italy and Sicily, 13; Switzerland, 39, Israel, 9, North America, 31; South Africa, 24, and Australia, 26) and tested by Elisa using specific polyclonal and monoclonal antibodies raised against FD. FD-MLO were specifically defected in various cultivars from the field and in rootstock cuttings grown in the greenhouse and showing mild symptoms. In this work, FD was found to be confined to grapevine stocks in 2 regions of Europe: southern France and northern Italy (Friuli). In France, these results have allowed clarification of a very confusing situation concerning FD and Bois noir (BN). All the symptomatic vines of north-east France reacted negatively, and hence probably belong to BN. Some samples from the south of the Rhone valley (Ardeche) reacted similarly. No positive FD reaction was obtained with samples showing GY symptoms from Sicily, Emilia Romagna (Italy), Switzerland (western part and Tessin), Israel, USA (New York State), South Australia or with Shiraz decline desease from the Republic of South Africa. These results suggest that no serological relationship exists between FD-MLO and the other GY. However this study does not exclude that FD could be present in some parts of these areas. This work shows the economic importance of the GY other than FD, the risk of epidemics and the necessity to promote protecion, cure and eventual quarantine measures.