White-oak
Guides
Acraspis quercushirta
jewel oak gall wasp
Acraspis quercushirta, the jewel oak gall wasp, is a North American cynipid wasp that induces distinctive, detachable galls on white oak leaves. The species exhibits a complex life cycle with alternating sexual and asexual generations, each producing morphologically different galls. The sexual generation forms the namesake "jewel" galls—oval, faceted structures ranging from white to brown that detach and fall with leaves in autumn. Molecular studies have confirmed its conspecific status with A. macrocarpae, which was previously considered a separate species.
Andricus chrysolepidicola
Irregular Spindle Gall Wasp, irregular-spindle gall wasp
Andricus chrysolepidicola is a cynipid gall wasp that induces distinctive stem galls on several oak species in western North America. The species exhibits a complex heteroecious life cycle with alternating generations: first-year unisexual wasps produce irregular spindle-shaped stem galls, while second-year bisexual wasps induce bud galls. The species is primarily documented from California but has been recorded elsewhere along the Pacific coast and eastward to Nevada.
Andricus dimorphus
Clustered Midrib Gall Wasp
Andricus dimorphus, commonly known as the clustered midrib gall wasp, is a cynipid wasp that induces distinctive galls on oak leaves. The species forms clusters of up to 50 globular, red-brown galls along the midrib on the abaxial (underside) surface of white oak leaves, beginning in late summer. Adults emerge from galls the following year. The species was first described by William Beutenmuller in 1913 as Cynips dimorphus and later transferred to Andricus via the genus Adleria.
Burnettweldia washingtonensis
fuzzy gall wasp
Burnettweldia washingtonensis is a cynipid gall wasp that induces distinctive stem galls on white oaks (Quercus sect. Quercus) along the Pacific coast of North America. The species was originally described as Cynips washingtonensis in 1894 and later transferred to Disholcaspis before its current placement in Burnettweldia. It is locally common and among the more frequently observed oak gall wasps in its range, with over 1,400 citizen science records.
Callirhytis quercusfutilis
Oak Wart Gall Wasp
Callirhytis quercusfutilis is a cynipid gall wasp known for inducing distinctive wart-like galls on white oak group oaks. The species exhibits a complex life cycle with alternating generations: an asexual generation that develops in scurfy bark at the base of host tree trunks or roots, and a sexual generation that produces leaf galls. The species is restricted to central and eastern North America and is specifically associated with oaks in the Quercus section Quercus (white oaks).
Callirhytis seminator
Wool Sower, Wool Sower Gall Wasp
Callirhytis seminator, commonly known as the wool sower, is a gall wasp that induces distinctive cotton-like galls on white oak trees. The species exhibits a complex alternating life cycle involving two different gall types, though the alternate gall form remains unidentified. Adults are small, dark brown wasps approximately 3 mm in length. The species poses no threat to humans or oak tree health.
Druon ignotum
Druon ignotum is a gall wasp that induces galls on white oaks in central and eastern North America. The species exhibits a complex life cycle with alternating sexual and asexual generations, each producing morphologically distinct galls. First described as Cynips ignota in 1881, it has undergone several taxonomic revisions before its current placement in Druon.
Philonix
oak gall wasps
Philonix is a genus of oak gall wasps in the family Cynipidae, restricted to North America (Canada, United States, and Mexico). Species in this genus induce spherical, soft, fleshy galls on white oaks (Quercus sect. Quercus), typically on the undersides of leaves. The genus was first described by Asa Fitch in 1859. Unlike many cynipid wasps, alternate sexual and asexual generations have not been documented in Philonix.
Phylloteras volutellae
conical oak gall wasp
Phylloteras volutellae is a cynipid gall wasp native to North America that induces distinctive conical galls on the leaves of white oaks (Quercus section Quercus). The species is best known for the detachable, clustered galls formed on leaf undersides, each housing a single larva. Adults emerge in early January, though adult morphology remains undescribed.