Monitoring of xylem fluid feeding insects (Hemiptera) with potential to transmit Xylella fastidiosa was conducted from April 2004 to May 2006 in the Hill Country grape growing region of Central Texas. This bacterium causes Pierce’s disease of grapevine, the most limiting factor to grape production in the United States. The glassy-winged sharpshooter, Homalodisca coagulata, a known vector of Pierce’s disease, represented a third of insect captures. An additive Poisson regression model allowing for overdispersion was used to test for significant differences between trap counts. Glassy-winged sharpshooter adults were caught inside the vineyards throughout the grape vegetative season, with higher populations observed between June and August. Adults were caught in the habitat surrounding the vineyard throughout the year. Residual populations overwintered near vineyards on native vegetation and have been the focus of additional studies. These observations provide critical information to vineyard managers for timely applications of insecticides prior to insect feeding and vectoring of the disease to susceptible grapevines.