Assessment of the first spring wandering of asexual grapevine phylloxera hibernating on rootstock roots in vineyards–pilot monitoring in Austria

Abstract

Grapevine phylloxera (Daktulosphaira vitifoliae Fitch), controlled by grafting, has re-emerged due to climate change, with shorter hibernation phases, earlier hatching and migrating of hibernales towards the leaves of the vines, and increased reproduction cycles within one season. The life cycle of grape phylloxera is cyclically parthenogenetic and comprise up to 4-8 asexual generations in one season. Sexual reproduction under Austrian climate conditions has not been found recently. It is the number and timing of the first wandering hibernales from the overwintering populations that induces the leaf galling population. We aim to assess the spring migration of overwintering asexual crawlers in a pilot vineyard to gather population and climate data over several years to develop predictive statistical models for viticulturists.

The first migration of phylloxera from roots to vine surfaces in spring was monitored weekly over two seasons (2023 and 2024) and correlated with environmental factors (air and soil temperature, photoperiod, and precipitation events). Data were collected using emergence traps in different cultivars at the experimental vineyard of the institute of viticulture and pomology, BOKU University in Tulln, Austria.

The preliminary findings from the pilot study suggest that soil temperature and moisture play a pivotal role in phylloxera migration. In 2023, the initial migration of asexual grapevine phylloxera was detected on DOY 116. Subsequently, a correlation analysis was conducted to ascertain the relationship between this migration and the prevailing environmental conditions throughout the seasons. Following the acquisition of pertinent data and in accordance with extant literature, it was determined that the temperature threshold of 8.7 °C is required for the development of phylloxera aphids.

Acknowledgements

We express our gratitude to the colleagues from several Institutions across Europe who contribute to increase the data set: Luxembourg Institute of Science and Technology, Fruit Research Station Haidegg and IMC Krems University of Applied Sciences (Austria), Slovak University of Agriculture, Mendel University Brno (Czech Republic), WBI in Freiburg and DLR Rheinpfalz (Germany) and University of Pécs (Hungary).