First finding of Drosophila suzukii (Matsumura) (Diptera: Drosophilidae) in Apulia, Italy, and its population dynamics throughout the year

Drosophila suzukii Matsumura (Spotted Wing Drosophila, SWD) is a pest that has been in- dicated as a major threat to European and Mediterranean fruit production. Its finding in Southern Italy offers interesting data to elaborate an efficient and sustainable control strategy. Materials and methods. The fly was collected during the “overhead” survey of an IAMB organic table grape vineyard by apple vinegar/wine/brown sugar bottle traps placed in and around the field. Once the presence of this pest was confirmed, traps were also hung on different host plants sur- rounding the vineyard, namely fig (Ficus carica L.), jujube (Ziziphus jujuba Mill.), pomegranate (Punica granatum L.), wild bramble (Rubus fruticosus L.) and rough bindweed (Smilax aspera L.). Collected Drosophila adults were identi- fied via morphological parameters by comparison with published descriptions and drawings. The SWD adult population was monitored per month throughout the year and related to the average values of the temperature (◦C) and minimum relative humidity (mRH%). The survey was carried out from September 2012 to August 2013. Results and discussion. We report the finding of Drosophila suzukii in Southern Italy, Apulia Region, and its population dynamics throughout the year in the area. In addition to D. suzukii, D. melanogaster (Meigen), D. simulans (Sturtevant) and similar species were also scored. The D. suzukii dynamics appeared to be strictly correlated with the temperature and relative humidity changes throughout the year, with a great summer population decrease. This behaviour is quite different from that of other indigenous drosophilas, both pest and non-pest. Conclusion. D. suzukii has, at present, a prominent pest status and may represent a key pest of soft fruit orchards in the South-Eastern part of Italy and, namely, in Apulia. However, further investigation on the marked decrease in the SWD summer population is needed to support effective pest con- trol strategies, which include baited-lure mass trapping in Mediterranean and other warm climate areas. Such strategies should also take into consideration pest reservoirs such as secondary and semi-wild fruit species bred in the areas tested.