Pierce’s disease (PD) management employs the same general set of tools as for other vector-borne plant pathogens. Because there are currently no truly PD-resistant grapevine varietals available, management relies on a combination of efforts to control vectors and reduce pathogen supply. Vector control can take the form of biological control, chemical control, and other methods of reducing vector abundance or activity in vineyards. Reducing pathogen supply can include removing infected grapevines (i.e. “roguing”), non-grape X. fastidiosa-infected “reservoir” hosts in vineyards, or reservoir hosts in adjacent habitats.
Xylella fastidiosa transmission is a relatively generalized phenomenon, meaning that several species of xylem-sap feeding insects play a role in pathogen spread (read more about transmission). Some of these vectors, notably the glassy-winged sharpshooter (GWSS), have a broad range of plants that they use in addition to grapevines. Moreover, X. fastidiosa has an extremely broad range of host plants that it can infect. Such diversity in the PD pathosystem makes management a challenge because it means there are potentially many “targets” for control, whose importance varies geographically.
Here we describe the key elements of PD management for the three main grape-growing regions in California that have had to contend with significant outbreaks.