title: Estimation of feeding threshold for Homalodisca vitripennis (Hemiptera: Cicadellidae) and its application to prediction of overwintering mortality.
abstract: The glassy-winged sharpshooter, Homalodisca vitripennis (Germar), vectors the bacterium Xylella fastidiosa that induces Pierce's disease of grape. This study determined the effect of temperature on the feeding activity of H. vitripennis adults and the resulting  production of excreta. The Logan type I model described a nonlinear pattern that showed excreta production increased up to an optimal temperature (33.1°C), followed by an abrupt decline near an estimated upper threshold (36.4°C). A temperature threshold for feeding, at or below which  adults cease feeding, was estimated to be 10°C using a linear regression model based on the percentage of adults producing excreta over a range of constant temperatures. A simulated winter-temperature experiment using fluctuating thermal cycles confirmed that a time period above the temperature  threshold for feeding was a critical factor in determining adult survival. Using data from the simulated temperature study, a predictive model was constructed by quantifying the relationship between cumulative mortality and cooling degree-hours. In field validation experiments, the model accurately  predicted the temporal pattern of overwintering mortality of H. vitripennis adults held under winter temperatures simulating conditions in Bakersfield and Riverside, California, in 2006-2007. Model prediction using winter temperature data from a Riverside weather station indicated  that H. vitripennis adults would experience an average of 92% overwintering mortality before reproduction in the spring, but levels of mortality varied depending on winter temperatures. The potential for temperature-based indices to predict temporal and spatial dynamics of H. vitripennis  overwintering is discussed.
authors: Department of Entomology, University of California, Riverside, CA 92521, USA.
authors: Youngsoo
authors: Y
authors: Son
authors: Russell L
authors: RL
authors: Groves
authors: Kent M
authors: KM
authors: Daane
authors: David J W
authors: DJ
authors: Morgan
authors: Rodrigo
authors: R
authors: Krugner
authors: Marshall W
authors: MW
authors: Johnson
mesh_terms: D000818:Animals; D005247:Feeding Behavior; D005260:Female; D006430:Hemiptera / Q000502:physiology*; D008297:Male; D008954:Models, Biological; D013696:Temperature