Degree-day model and applications for management of grape phylloxera in the Ozarks

Although grape phylloxera is native to the southeastern United States, most studies have been completed elsewhere such as in California and France. Non-native cultivars susceptible to grape phylloxera are becoming increasingly popular in the Ozarks due to the growing demand for wine. This could lead to problems in the near future, including but not limited to vine decline, vigor loss, decreased fruit yield or decreased fruit quality. Studying this pest in the Ozarks will be beneficial to the future of wine production in the Ozarks. Timing insecticide sprays against the crawlers can be improved if a degree-day model is available. Toward this goal, grape phylloxera populations were monitored in multiple vineyards. Sticky tape traps wrapped on trunk and canes and soil surface box sticky traps were used to monitor crawler and alate presence and density on the vine and emerging from the soil. WatchDog loggers recorded at half hourly intervals the soil and air temperatures and soil moisture. These trap and microhabitat weather data were compared and a cumulative degree-day (base 50°F accumulated after 21 March) model was developed for the grape phylloxera and will be validated.