Oak moths are the adult stage of the California oakworm. These moths may be abundant in late spring/early summer and again in the fall, and can be observed fluttering around coast live oak trees (Quercus agrifolia) in the late afternoon.
It is the larval (caterpillar) stage of this insect that feeds on oak leaves (not the adult moths). Oak moths emerge from distinctive, colorful pupal cases (second picture) that are typically attached to twigs, branches, or objects near the host tree. This species produces 2-3 generations per year, and their abundance may vary markedly from year to year.
Click here to view the University of California's management guidelines for California oakworms.