The progression of Pierce’s disease (PD) in vineyards and across a landscape is dependent upon factors related specifically to four components; the vector (in this case the glassy-winged sharpshooter (GWSS)), the pathogen (Xylella fastidiosa causing PD), the host (grapes), and the environment. When conditions in all four of these areas are optimal, disease spreads with devastating consequence. We have studied the spatial distribution of PD within infected grapevines, within infected vineyards, and across large agricultural areas. Studies at the landscape scale, in two diverse agricultural areas, have determined that vineyards infected with PD are found in close proximity to citrus, a favored host for GWSS. In one of the areas, research also has determined that diseased grapevines are found adjacent to dead, replanted, or missing grapevines. We are evaluating whether this putative signature of PD infection can be combined with aerial photography to locate areas in vineyard with a high probably of being infected with PD. In other work, we have developed a GWSS-reduction strategy based on the spatial distribution of GWSS. This strategy prioritizes citrus groves for application based on the proximity to sharpshooter traps (which can be modified depending on accepted levels of risk) and the abundance of GWSS (which can be adjusted to various threshold levels).