First data on the flight activity and distribution of the ambrosia beetle Xylosandrus compactus (Eichhoff) on carob trees in Sicily

The factors influencing the entry and the spread of the black twig borer,Xylosandruscompactus(Eichhoff), in the Mediterranean environment have not yet been characterized.Following its first report in Sicily (southern Italy) in 2016, and due to the high level ofdamage it causes on one of its host plants (Ceratonia siliquaL.), the flight activity of thepest was studied there. Monitoring was performed from spring 2017 to summer 2018 byexposing red cross-shaped sticky traps combined with ethanol-baited bottle traps. The threemonitored sites were selected at different altitudes, representing the southern Mediterraneanenvironment where the carob tree is widely present. The results showed that the pest popu-lations are influenced by climatic factors. In particular, the first adults were caught whenthe maximum daily temperatures were stably higher than 20°C over several continuousdays.Xylosandrus compactusoccurred widely in the monitored territory and was continu-ously caught from spring to autumn. Furthermore, the traps used proved to be effective forintercepting the spring flight of the overwintering females. Moreover, the ability of the bee-tle to spread from a new infested area was also studied. It seems that the pest can spreadmore than 8 km from the last infested site of the previous flying season. It was not presentabove altitudes of 400 m in the conditions of the present study. This study represents the firststep to better understand the behaviour ofX. compactusin a newly colonized environment