SUMMARY
Bacterial necrosis of grapevine is caused by the quarantine bacterium Xylophilus
ampelinus. This disease is of difficult chemical control and is responsible for important
economic losses in Spain. Nowadays it is endemic in many areas in Aragón and Galicia, and
isolated outbreaks have been identified in La Rioja.
As no sensitive specific detection methods to use in routine analysis are available to
detect this bacterium, an extraction method and a protocol for serological detection of X.
ampelinus have been set up. The extraction method is based on internal washing of the
analysed shoots. The detection protocol is based on ELISA-DASI using specific monoclonal
antibodies. Both make the detection of this bacterium in plant material feasible at any time
during the year. The detection by immunoprinting in nitrocellulose membranes has also been
developed and can be used for rapid detection or for confirmation of doubtful symptoms.
A survey in the denominaciones de origen Campo de Borja and Somontano has been
carried out, using the method of internal washing and the ELISA-DASI technique. The
bacterium was detected in 4.7% and 0.9% of the analysed shoots. This is the first time that
this disease has been detected by using this technique in asymptomatic shoots and in the
Somontano area. In the survey an irregular distribution of the bacterium was observed inside
the analysed plants. The distribution of infected plants in a plot naturally infected was at
random.
A study of the susceptibility to bacterial necrosis was carried out using 19 Spanish
cultivars graffed on the rootstocks Rupestris of Lot, R-110 and 41-B. It was observed that the
first one conferred higher sensitivity to the grafted cultivars and that all the assayed cultivars
were sensitive to X. ampelinus. Among them, the cultivars Merseguera, Palomino, Airén,
Bobal, Juan Ibáñez and Granegro were proved to be very sensitive and Mazuela, Tinto basto
and Garnacha peluda showed low sensitivity.