Influence of regulated deficit irrigation and partial rootzone drying on leafhoppers infestations on grapevine

(RDI) and partial rootzone drying (PRD) with two restoration volumes: 80% and 40% of the crop evapotranspiration (ETc). The irrigation strategy and the restoration volume significantly affected xilematic potential trends, but treatments did not show values over a moderate stress level. Water use efficiency was influenced by the irrigation strategy only in 2009, whereas it was affected by the restoration volume and was higher in 40% ETc treatment in all three years. PRD-80% ETc showed the highest J. lybica density, whereas the RDI-40% ETc was the least infested. Z. rhamni was very abundant only in 2009, but showed no differences among treatments. The 3-years trial demonstrates that the lower restoration volume (40% ETc) allow a better water use efficiency and lower J. lybica infestations.