Following the pest outbreak: preliminary fndings on the landscape efect on Dasineura oleae and its parasitoids in central Italy

Dasineura oleae (Angelini, 1831) (Diptera: Cecidomyiidae), the olive leaf gall midge, is a pest of olive crops that was not problematic in Italy until 2016 when a massive infestation of this pest was reported in a small region in central Italy. We identifed infested olive orchards using farmers’ reports and quantifed the pest infestation level and parasitism rate in each feld. We also explored the efect of the landscape on both the pest and parasitoids using the abundance of olive crops and semi-natural habitats and the Shannon index, estimated at four diferent scales (250 m, 500 m, 750 m and 1000 m bufers around the sampling points). The results showed a small-scale efect on the parasitism rate and a large-scale efect on leaf infestation mediated by the Shannon Index. Moreover, some preliminary results showed that the parasitism rate was high in sites where plants associated with D. oleae parasitoids were present in the adjacent semi-natural habitat. Further studies are needed to validate our fndings on the efect of landscape and vegetation on the natural enemies of D. oleae in order to develop new suppression strategies.