Fig 4. Epifluorescence micrographs showing salivary sheaths (arrows) of D. citri adults that have been recorded by EPG while feeding on mature (A-C) or young (D-J) citrus leaves, on the adaxial side (D) or the abaxial side (A-C & E-J).

Panels C, I and J show sheaths in smaller veins, while the rest of the panels show sheaths in the midrib. Note that the fibrous ring (fr) around the phloem (ph) in the midrib is thicker, and showing more blue color similar to the xylem (xy), in mature leaves (A-C) than in young leaves (D-J). Panel A shows a salivary sheath that apparently terminated very close to fibrous ring. The asterisk in panel B indicates a salivary sheath passing into the phloem through a small gap in fibrous ring. Double arrows indicate branched sheaths (in D, E, G, H & J). Panels E and F show multiple sheaths (representing multiple probes) from the same adult male, while panels G to J show multiple sheaths from an adult female. Low transmitted light (in addition to UV light) was used in panels D-F to show mesophyll cell boundaries. Abbreviations: fr, fibrous ring; pc, palisade cells, ph, phloem; sm, spongy mesophyll; xy, xylem.