Potential Auchenorrhyncha vectors of Xylella fastidiosa in Crete (Greece): Survey, identification, seasonal abundance and vector management tactics

Abstract: The pathogenic bacterium Xylella fastidiosa is currently causing major crop losses in Italy and recently in Spain, but has not been reported in Greece to date. However, the risk of disease expansion is very high for the nearby olive producing countries. For this reason, the Region of Crete in collaboration with research institutions and universities is performing actions within the frame of a research program that will be enhancing the readiness of the authorities to eradicate the pathogen when required. A survey of Auchenorrhyncha, which could potentially act as vectors of X. fastidiosa, is carried out in several olive groves in Crete, a major olive growing region in Greece. Adult populations of Auchenorrhyncha species have been monitored fortnightly since June 2017 using Malaise traps and sweeping net. The most abundant subfamily found is Typhlocibinae followed by Deltocephalinae (Hemiptera: Cicadellidae). The species Philaenus spumarius and Neophilaenus campestris have been recorded in very low numbers. Finally, a wide range of chemical insecticides are currently screened for their efficacy against different Auchenorrhyncha, using a leaf-dip laboratory bioassay protocol. More than eight insecticides tested so far at the maximum recommended label rate exhibited mortality levels over 95%, suggesting that they could be used to vector control in a pathogen eradication scheme. This study offers valuable results for developing rational and efficient strategies against the spread of X. fastidiosa as well as important information on species diversity and the bio-ecology of Auchenorrhyncha vectors in the olive-grove environment.