Xylella fastidiosa Does Not Occur in Lebanon

Xylella fastidiosa has been reported as responsible for a devastating disease on olive trees in Apulia region (south-eastern Italy), characterized by a quick decline syndrome. In Lebanon, the pathogen was recently associated with leaf scorch symptoms on oleander, and reports on leaf scorch and dieback of olive trees branches by technicians and farmers have shown an increasing trend in the main agricultural areas. To assess the occurrence and distribution of the pathogen in Lebanon, samples of twigs from olive trees (82), olive seedlings (26), grapevine (30), oleander (32) and ornamentals imported from Italy (48) were analysed by isolation on four agarized media, serological techniques (ELISA and DTBIA) using Xylella fastidiosa -specific antibodies and by PCR, using three specific sets of primers. Results unequivocally demonstrated that all the collected samples were free from the pathogen. As well, both detection protocols and attempts at isolating the pathogen on agarized media demonstrated that oleander samples gathered from American University campus in Beirut, where X. fastidiosa was previously reported, were not infected. Nevertheless, continuous monitoring and rigorous control measures of propagative materials are necessary to prevent the introduction of Xylella fastidiosa in Lebanon.