Plant-parasite-interaction
Guides
Pachypsylla
hackberry gall psyllids, hackberry psyllids
Pachypsylla is a genus of North American psyllids (jumping plant lice) in the family Aphalaridae. All known species are specialized gall-formers on hackberry trees (Celtis spp.), with each species producing a distinct gall type on leaves or petioles. The genus is notable for its intimate association with the bacterial endosymbiont Carsonella ruddii, which has the smallest known cellular genome of any bacterium. Adults are tiny (3.5–4.5 mm), resembling miniature cicadas, and overwinter in concealed locations before emerging to lay eggs on new hackberry growth in spring.