Susceptibility and sensibility of grape cultivars to the leafhopper Empoasca vitis

The leafhopper Empoasca vitis (Goethe) (Homoptera: Cicadellidae) is a serious pest in European vineyards. The assessment of economic damage caused by E. vitis was associated with no definite results probably because of a different susceptibility and sensibility of grape cultivars to the pest. Empoasca vitis abundance and symptoms associated with the activity of this pest were evaluated during three years on 10 grape cultivars grown in collections located in north-eastern Italy. Empoasca vitis densities were estimated from May-June to September by sampling leaves every 7-10 days. At vintage time, the percentage of leaf surface with symptoms caused by E. vitis feeding was estimated. Carménère, Sauvignon Blanc and Tocai Friulano showed to be very susceptible and very sensible, whereas Cabernet Sauvignon, Chardonnay, Verduzzo Friulano and Pinot Gris showed an opposite behaviour. However, such correspondence was influenced by meteorological conditions and plant stress factors. These results may be useful for establishing economic thresholds and sampling plans for E. vitis in vineyards.