California Oak Galls Wasps in the family Cynipidae are gall inducers on plants, or inquilines of gall inducers (living inside the galls made by other cynipids). The majority of species occur on oak trees (Quercus sp.). Galls range in size from 1 mm to 6 cm or more and come in many shapes and colors, as depicted on this page. Different cynipid species occur on specific oak species, and the galls themselves occur on specific locations on the trees (leaves, stems, buds, roots, etc.) depending on the species and which generation it is. Some species have two generations per year, a sexual and an asexual (female only) generation, each producing completely different types of galls on different parts of the host. The adult wasps are generally around 1-4mm in size. The wasps support a community of other insects that feed on them, their parasites, and their galls. Regarding the generic names I'm using on this web site, please read this page. See also the undescribed or unknown oak gall page.

White oak group: Quercus berberidifolia (inland scrub oak), Q. cornelius-mulleri (Muller's oak; desert scrub oak), Q. douglasii (blue oak), Q. dumosa (Nuttall's scrub oak) Q. durata (leather oak), Q. engelmannii (Engelmann oak), Q. garryana (Oregon oak), Q. john-tuckeri (Tucker's oak), Q. lobata (valley oak):
Andricus albobalani	Andricus atrimentus Asexual, fall generation	Andricus atrimentus Bisexual, spring generation	Andricus bakkeri	Andricus brunneus
Andricus confertus	Andricus coortus (syn: Callirhytis coortus)	Andricus chrysolepidicola	Andricus crystallinus	Andricus discularis
Andricus fullawayi	Andricus gigas	Andricus kingi	Andricus opertus	Andricus parmula
Andricus pattersonae	Andricus pedicellatus	Andricus quercuscalifornicus	Andricus stellaris	Andricus stellulus
Andricus wiltzae	Antron douglasii Asexual, fall generation (syn: Cynips douglasii)	Antron douglasii Bisexual, spring generation (syn: Cynips douglasii)	Antron quercusechinus (syn: Cynips quercusechinus)	Besbicus conspicuus (syn: Cynips conspicuus)
Besbicus heldae (syn: Cynips heldae)	Besbicus maculosus (syn: Cynips maculosus)	Besbicus mirabilis (syn: Cynips mirabilis)	Besbicus multipunctatus (syn: Cynips multipunctata)	Burnettweldia conalis
Burnettweldia corallina	Burnettweldia plumbella	Burnettweldia washingtonensis	Disholcaspis canescens	Disholcaspis eldoradensis
Disholcaspis mamillana	Disholcaspis mellifica	Disholcaspis prehensa	Disholcaspis simulata	Neuroterus fragilis
Neuroterus saltatorius Asexual, fall generation	Neuroterus saltatorius Bisexual, spring generation	Neuroterus washingtonensis	Phylloteras cupella	Sphaeroteras trimaculosum (syn: Atrusca trimaculosa)
Trichoteras californicum (syn: Andricus californicum)	Trichoteras tubifaciens (syn: Andricus tubifaciens)	Xanthoteras clavuloides (syn: Atrusca clavuloides)	Xanthoteras teres (syn: Trigonapsis teres)

Red (black) oak group: Quercus agrifolia (coast live oak), Q. kelloggii (California black oak), Q. wislizeni (interior live oak):
Callirhytis apicalis (syn: Andricus apicalis)	Callirhytis carmelensis (syn: Andricus carmelensis)	Callirhytis congregata (syn: Andricus congregata)	Callirhytis eldoradensis	Callirhytis perdens (syn: Andricus perdens)
Callirhytis perfoveata (syn: Andricus perfoveata)	Callirhytis quercusagrifoliae Asexual, summer generation (syn: Andricus quercusagrifoliae)	Callirhytis quercuspomiformis Asexual, summer generation (syn: Amphibolips quercuspomiformis)	Callirhytis quercuspomiformis Bisexual, spring generation (syn: Amphibolips quercuspomiformis)	Callirhytis quercussuttoni (syn: Andricus quercussuttoni)
Callirhytis serricornis Asexual, summer generation (syn: Andricus serricornis)	Callirhytis serricornis Sexual, spring generation (syn: Andricus serricornis)	Dryocosmus dubiosus Asexual, fall generation	Dryocosmus dubiosus Bisexual, spring generation	Dryocosmus minusculus
Melikaiella flora Asexual, summer generation	Melikaiella flora Bisexual, spring generation

Intermediate or golden oak group: Quercus chrysolepis (canyon live oak), Q. palmeri (Palmer's oak), Q. vacciniifolia (huckleberry oak):
Andricus chrysobalani	Andricus projectus	Disholandricus chrysolepidis	Disholandricus lasius	Disholandricus reniformis
Disholandricus truckeensis	Dryocosmus asymmetricus	Grahamstoneia humboldti	Heteroecus dasydactyli	Heteroecus flavens
Heteroecus lyoni	Heteroecus melanoderma	Heteroecus malus	Heteroecus pacificus Asexual, fall generation	Heteroecus pacificus Bisexual, spring generation
Heteroecus sanctaeclarae	Heteroecus sp.	Holocynips hartmani	Paracraspis guadaloupensis (syn: Acraspis guadaloupensis)	Paracraspis insolens (syn: Acraspis insolens)
Paracraspis patelloides (syn: Acraspis patelloides)	Protobalandricus spectabilis	Trichoteras burnetti (syn: Andricus burnetti)	Trichoteras coquilletti (syn: Andricus coquilletti)	Trichoteras frondeum (syn: Andricus frondeum)
Trichoteras perfulvum	Trichoteras rotundula	Trichoteras vacciniifoliae (syn: Andricus vacciniifoliae)

Non-native oaks growing in California: Quercus virginiana (southern live oak)

Andricus quercuslanigera This gall has been seen on Q. virginiana in Manteca, Stockton, Brentwood, and Sacramento. It has also been seen in Los Angeles County.