Survey for Xylella fastidiosa and xylem-sap feeders in Lebanon

The emergence of Xylella fastidiosa in Europe and the report of some suspicious leaf scorching symptoms in Lebanon affecting oleander and olives prompted for further targeted surveys. Field inspections and sampling covered the main fruit tree growing areas in Lebanon (Bekaa valley, South Lebanon and North Lebanon). In summer 2018, more than 500 plant samples were collected from trees showing suspicious leaf symptoms. The majority consisted of olives (n. 298) followed by grapevine (n. 96), citrus (n. 72), stone and pome fruits, and walnut. Mature leaves from all samples were firstly screened by ELISA and then a group of 100 randomly selected and re-tested by PCR following the procedures recommended in EPPO diagnostic standard 7/24(3). None of the samples tested yielded positive reactions either in ELISA or PCR tests. Surveys to characterise the entomofauna occurring in the olive orchards and vineyards (mainly in Northern Lebanon, Bekaa valley and Jezzin region) were periodically carried out from spring to summer 2018, collecting insects from the canopies of the trees or from the weeds or border plants by sweeping net. Based on the morphological identification, among the specimens collected none were xylem-sap-feeders while several species of leafhopper (Hemiptera: Cicadellidae) and planthopper (Hemiptera: Fulgoroidea) were identified. Field surveys and inspections at the port of entry are in place to prevent inadvertent introduction of plant propagating materials infected by X. fastidiosa.