To visualize phytoplasmas at early stages of vector infection, an immunofluorescence assay was developed. The chapter provides experimental details on dissection of salivary glands, incubation of the dissected organs with phytoplasma suspension, fixation, embedding, sectioning, labeling, and final visualization with confocal microscopy. All the procedure will be described for the leafhopper Euscelidius variegatus, natural vector of "Candidatus phytoplasma asteris" and laboratory vector of Flavescence dorée phytoplasma.