Investigations on dispersal capability of Philaenus spumarius by mark-release-recapture method

Philaenus spumarius is the vector of the CoDiRO strain (subsp. pauca) of X. fastidiosa in the Apulian olive orchards (Saponari et al. 2014). Dispersal capability of the vector is of capital importance to predict future spreading of the pathogen, thus representing a research priority (EFSA 2016). Mark-release-recapture (MRR) is the method of choice to study movement of vector insects, including Homalodisca vitripennis, the main vector of X. fastidiosa in South California (Northfield et al. 2009, Blackmer et al. 2006). Although few information on the flight distance covered by P. spumarius are available (Halkka et al. 1971, Putman 1953, Weaver and King 1954), none have been obtained with a scientifically sound experimental plan. An experiment was conducted in Piedmont Region, with 650 adult insects marked by a solution of albumin, and released in a single point in a meadow. Spittlebugs were recaptured by sweeping net in 8 directions radiating from the release point up to 200 m, for a total of 92 collection points. Recaptures were conducted up to 15 days after the release. Marked insects were identified via an indirect ELISA. Twenty marked individuals were found within a maximum distance of 60 m. Two similar experiments were conducted in an olive orchard in the Apulia Region, with a total of 2500 marked insects released. Insects were then collected up to 30 days after, by sweeping net on the canopy of olive trees around the point of release up to 120 m in 170 collection points. Five marked insects were recaptured, with the most distant specimen at 100 m. Studies are ongoing during 2017