The grape phylloxera in Tuscany: an old or a new problem?

The resurgence of the grape phylloxera, Daktulosphaira vitifoliae (Fitch), as a vineyard pest is a quite huge problem in several Italian regions. A three-year survey (2017-2019) on the biology and population dynamics of the grape phylloxera has been carried out in some vineyards in Tuscany. Observations concerned mainly the distribution pattern of the species in the most relevant wine districts of the region, the relationship between leaf and root populations, and the effects of the leaf-galling population density on the plant physiology and grape qualitative parameters. In 2019, a field trial to control leaf-galling population has been performed comparing different chemical treatments combined with a cultural practice. In Tuscany, D. vitifoliae showed a noticeable variability in the foliar population density in relation to the microclimatic factors, seasonal trends, grapevine varieties, training and planting systems. Densities of the leaf gall population were more variable and unpredictable than those of the root population. Preliminary results showed how the increasing of the leaf infestation can affect some grapevine important physiological parameters. Concerning the control trial, no significant differences were highlighted between the treatments, confirming the importance of agronomic practices, such as the removal of infested leaves (shoot topping), as an excellent method of sanitation.