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Poster: Diseases of Plants: New & Emerging Diseases


An invasive lethal phytoplasma disease threatening stone fruit production: detection, epidemiology and management.
Y. A. JAWDAH (1), M Jawhari (2), P. Tawidian (2), E. Choueiri (3), F. Quaglino (4), P. Bianco (4), A. Alma (4), M. Moilno-Lova (5); (1) American University of Beirut, Beirut, Lebanon, (2) FAFS, AUB, (3) LARI, (4) UNIMI, Milan, Italy, (4) IDISAFA, Univ. Di

Introduced into North Lebanon in the early 1990s, almond witches’ broom (AlmWB) disease spread rapidly in Lebanon killing about 200,000 almond, peach and nectarine trees. The disease is associated with ‘Candidatus Phytoplasma phoenicium’ that belongs to 16S rRNA subgroup IX-B. The major symptoms are proliferation, small chlorotic leaves, development of witches’ broom followed by dieback and death of almond trees. So far, AlmWB has been reported in Lebanon and Iran. In Lebanon, AlmWB was considered of quarantine importance and official containment measures were initiated in major stone fruit production areas. Specific, sensitive and reliable PCR and real-time PCR detection methods were developed. Preliminary data revealed that a leafhopper and planthoppers are vectors of the disease and two weed species are suspected to act as alternative hosts. An integrated disease management appraoch is considered for highly infested regions. Grafting experiements are in progress and preliminary results look encouraging, a recovery phenomemon was observed. Finally, regional and international cooperation are highly recommended to continue studies on the epidemiology of this invasive disease and to adopt phytosanitary control measures and strategies in order to contain the further spread of the disease.