Strains of the bacteria Xylella fastidiosa cause serious diseases in various perennial plants and are a threat to California agriculture. One X. fastidiosa strain causes Pierce’s Disease in grapes, and its incidence in California has been exacerbated following the introduction and continued geographical spread of the glassy-winged sharpshooter (GWSS), Homalodisca coagulata (Say), an effective vector of X. fastidiosa. Distribution of X. fastidiosa causing Pierce’s disease is restricted in the USA to areas with mild winters. Similarly, GWSS populations appear to be constrained by climatic factors that limit their establishment and population growth. Thus, the spatial distribution of GWSS may be limited by a specific temperature threshold, below which feeding may stop and survival decreases dramatically.

The temperature-dependent survival and feeding of GWSS adults were measured by exposing them to seven constant temperatures. In the absence of plant hosts and with only water available, temperatures above 20^oC reduced adult longevity drastically, whereas young adults survived more than 1 week at 10 and 15^oC. When a plant host was available (i.e., citrus), temperatures ≥ 15^oC did not cause a significant mortality up to 3-weeks exposure, but survival was greatly reduced at temperatures ≤ 10^oC. Monitoring of feeding activity (based on electro-penetration graph waveform and xylem excreta collection) revealed that frequency and duration of feeding activity was reduced dramatically at temperatures ≤ 10^oC. Findings from our study, coupled with climatological data, would potentially permit estimation of the geographical range for GWSS where greater risks for Pierce’s disease would exist.