Hackberry nipple gall psyllid

Typically found on and around hackberry trees (Celtis occidentalis); often seen on cars or windows near these trees.

Sap-sucking insects that feed on the juices of hackberry tree leaves.

Adults emerge in late summer and fall, often swarming in large numbers. They seek winter shelter in bark crevices or structures like houses and vehicles. They cause the formation of nipple-like galls on tree leaves where the larvae develop.

They are harmless to humans and pets, but can be a nuisance when they swarm or enter homes. While they distort leaves, they rarely cause significant long-term harm to the health of the host tree.