Carya-specialist
Guides
Phylloxera caryaecaulis
Hickory Gall Phylloxera
Phylloxera caryaecaulis is a small, soft-bodied, gall-forming insect closely related to aphids. It induces distinctive globular galls on hickory leaves and petioles, primarily affecting mockernut hickory (Carya tomentosa) and other hickory species. The species overwinters as eggs deposited on bark or near old galls, with nymphs emerging during bud break in spring to initiate gall formation. Unlike some related phylloxeran species that attack pecan shoots and nuts, P. caryaecaulis is primarily a leaf-gall former and is not considered economically damaging to its host trees.