Ground Cover Management in Olive Groves Reduces Populations of Philaenus spumarius (Hemiptera: Aphrophoridae), Vector of Xylella fastidiosa

Philaenus spumarius (Linnaeus, 1758) (Hemiptera: Aphrophoridae) is considered the main vector of Xylella fastidiosa (Wells Raju et al. 1986) (Xathomonadales: Xanthomonadaceae), agent of the Olive Quick Decline Syndrome in Southern Europe. To limit the spread of the disease, it is of primary importance to identify effective control measures against the vector. Besides chemical control, cultural practices could potentially help reducing vector activity and population density. Here, we tested the effectiveness of three different ground cover management practices in controlling vector populations in olive groves in the Abruzzo region (Central Italy). We compared tillage (two tillage operations in spring followed by two cuts in summer), frequent mowing (four cuts from spring to summer) and a control (two cuts in summer) by sampling vectors both in the ground vegetation and in the tree canopy. In late spring, after the peak of the population, tillage reduced P. spumarius density by 60%, while frequent mowing only reduced the density by 20% compared to control plots. The differences tended to disappear with time. The treatments had the same effect on the vector density in both the ground vegetation and tree canopy. The vectors were more concentrated in the ground cover at the beginning of the season while in summer both the canopy and ground vegetation had the same vector density. Our findings suggest that tillage is a viable option for the containment of P. spumarius, as frequent mowing did not achieve sufficient control efficacy.