A cixiid survey for natural potential vectors of 'Candidatus Phytoplasma phoenicium' in Lebanon and preliminary transmission trials

Almond witches'-broom (AlmWB) disease, associated with 'Candidatus Phytoplasma phoenicium', is an emerging threat with real risk of introduction in Euro-Mediterranean Countries. Its rapid spread over large geographical areas suggests the presence of efficient insect vector(s). In the present work, a survey on cixiids was carried out in Lebanon in the years 2010-2013 in AlmWB-infested almond and nectarine orchards. Insects were collected by means of different methods, identified with a stereo microscope, and analysed for phytoplasma identification through 16S rDNA PCR-based amplification and nucleotide sequence analyses. Preliminary transmission trials were performed with the most abundant species. A list of the cixiid genera and species present in the studied area is given as well as some information about their biology. 'Ca. Phytoplasma phoenicium' strains were detected in the genera Cixius, Tachycixius, Eumecurus and Hyalesthes. Preliminary trials revealed that Tachycixius specimens were able to transmit the detected strains to healthy peach potted seedlings. Further studies are required to better clarify the taxonomic status and the bio-ethology of collected planthoppers and deeply study their role as phytoplasma vectors.