Update on the tomato/potato psyllid- Ca. Liberibacter transmission pathway

Observations between the fastidious bacterial plant pathogen, Ca. Liberibacter solanacearum, and the tomato/potato psyllid vector in the transmission pathway fall into two categories- anatomical and non-anatomical. The former involve accumulation of biofilms on the outer (hemolymphic) surface of the midgut, the esophagus, the salivary gland exterior and pericellular space, and inside the oral box- an endoskeletal frame that holds the collective components of the mouthparts, and provides the muscle attachment sites for them. Non-anatomical aspects involve temporal and spatial acquisition exposures to infected source plants and the inoculation access period on test plants inoculated with the bacterium during psyllid feeding.  Together, these observations provide a compelling estimation of the route and the latent period in the psyllid. Ingestion into the midgut, exit through the midgut wall, and association with the esophagus en route to the salivary glands and oral box appears to constitute a tentative routing of bacterial cells.  Observations at the fine level do not permit closure of the elucidation of the transmission pathway. TEM and SEM have not yet rendered micrographs that indicate transcytosis through, or pericelllular passage through, the midgut wall.