Cicadellinae leafhoppers and other Auchenorrhyncha in coffee and citrus farms in Puerto Rico were surveyed five times over 18 mo. We frequently collected four of the seven species of Cicadellinae previously found in Puerto Rico, yet only one species (Caribovia coffeacola Dozier) fed directly on coffee; no species was observed to feed directly on citrus. Populations of C. coffeacola were higher during the rainy season and were more common at higher elevations. Feeding preference and performance experiments established that C. coffeacola preferentially fed, and could survive exclusively, on coffee and the common shade host Inga vera. Within-farm distribution of C. coffeacola was examined at a site with high populations, and abundances were higher with proximity to I. vera. Lastly, sets of novel sites were selected in four municipalities to test hypotheses concerning effects of season, elevation, and host plant assemblages on Cicadellinae populations. These tests confirmed that C. coffeacola was the only species that frequently fed on coffee and no species fed on citrus. Populations of C. coffeacola were higher in the rainy season and at higher elevations. Abundances were also higher when Inga vera was interspersed in coffee plantings compared to when other shade species were present or when coffee was grown as a monoculture (sun coffee). Cicadellinae were our focus, as within this study this subfamily is the predominant potential vector of the bacterium Xylella fastidiosa (Wells). Xylella fastidiosa has yet to be confirmed in Puerto Rico, but both citrus and coffee are susceptible to X. fastidiosa diseases.