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

Abstract: A field trial was carried out from 2009 to 2011 to investigate the influence of twoirrigation methods on the productivity of Vitis vinifera (cv Vermentino) and population density ofthe leafhoppers Jacobiasca lybica and Zygina rhamni. The trial was set up in a commercialvineyard in Southern Sardinia to compare two irrigation strategies: regulated deficit irrigation(RDI) and partial rootzone drying (PRD) with two restoration volumes: 80% and 40% of the cropevapotranspiration (ETc). The irrigation strategy and the restoration volume significantly affectedxilematic potential trends, but treatments did not show values over a moderate stress level. Wateruse efficiency was influenced by the irrigation strategy only in 2009, whereas it was affected bythe restoration volume and was higher in 40% ETc treatment in all three years. PRD-80% ETcshowed the highest J. lybica density, whereas the RDI-40% ETc was the least infested. Z. rhamniwas very abundant only in 2009, but showed no differences among treatments. The 3-years trialdemonstrates that the lower restoration volume (40% ETc) allow a better water use efficiency andlower J. lybica infestations.