Studies on potential vectors of ‘Candidatus Phytoplasma phoenicium’ in Lebanon
In Lebanon, almond witches’ broom (associated with ‘Candidatus Phytoplasma phoenicium’ - formerly EPPO Alert List) is a lethal disease of almond (Prunus dulcis), peach (P. persica) and nectarine (P. persica var. nucipersica). The disease has rapidly spread from coastal areas to altitudes above 1200 m, killing more than 150;000 trees during the last 20 years. Transmission experiments have recently shown that the leafhopper, Asymmetrasca decedens (Hemiptera: Cicadellidae) is a vector of the disease. During these studies, it has also been found that the incubation period of the disease in plants could exceed one year. It is noted that further research is needed on the mode of transmission of ‘Ca. P. phoenicium’ by A. decedens, and more generally on the epidemiology of the disease (e.g. to investigate the existence of other vectors). It is also concluded that international cooperation and IPM strategies are needed to contain this lethal disease of fruit trees (Abou-Jawdah et al., 2014).
In another survey about potential vectors of ‘Ca. P. phoenicium’ conducted in Lebanon from 2011 to 2013, preliminary transmission experiments have shown that some Tachycixius species, T. viperinus and T. cf cypricus (Hemiptera: Cixiidae), could transmit the phytoplasma to healthy peach plants. It is stated that further studies are needed to clarify the taxonomic status and biology of these insects, as well as their potential role in disease transmission (Tedeschi et al., 2015).
Sources
Abou-Jawdah Y, Abdel Sater A, Jawhari M, Sobh H, Abdul-Nour H, Bianco PA, Molino Lova M, Alma A (2014) Asymmetrasca decedens (Cicadellicae, Typhlocybinae) ,a natural vector of ‘Candidatus Phytoplasma phoenicium’. Annals of Applied Biology 165(3), 395-403.
Tedeschi R, Picciau L, Quaglino F, Abou-Jawdah Y, Molino Lova M, Jawhari M, Casati P, Cominetti A, Choueiri E, Abdul-Nour H, Bianco PA, Alma A (2015) A cixiid survey for natural potential vectors of 'Candidatus Phytoplasma phoenicium' in Lebanon and preliminary transmission trials. Annals of Applied Biology 166(3), 372-388.