Oak Bark Beetles – Pseudopityophytorus spp.

Oak Bark Beetles (Pseudopityophytorus spp.)

Latin Name: Pseudopityophthorus pubipennis

Common Name: Oak bark beetle/ Western Oak Bark Beetle


  • Adult bark beetles are tiny, cylindrical insects with rigid bodies approximately the size of a grain of rice. The majority of species are dark red, brown, or black. Their antennae are elbowed under magnification, with the outer segments more significant and clublike.
  • Most larvae are off-white, robust, and grublike, with a dark brown head.
  • For eating, bark beetles have potent mandibles (jaws). An area of concentration pattern of holes may be seen on the bark surface of afflicted branches or trunks.

Host plants:

The oak beetle appears to have oaks as a host plant exclusively. In the eastern United States, these beetles attack the branches of life, dying, and fallen oak trees. They don’t commonly infest the thicker bark of oak trunks. The oak bark beetle prefers it stressed, dying, or dead twigs to infest.

Damage caused by Oak bark beetle:

The oak’s bark has a distinctive texture. The beetle penetrates under the bark of coast live oak trees, mainly drought-stressed or recently injured oaks, constructing small tunnels beneath the dinghy across the grain of the wood and laying their eggs in the tunnels. They spend the winter under the bark. Damage is indicated by bleeding, foamy, boiling holes with drilling dust. They typically target trees that are stressed.

Life history and Habits:

Female bark beetles deposit little, round, pale eggs just beneath the surface of the outer bark. The tiny larvae mine tunnels that branch from the egg-laying gallery after the eggs hatch. Adults can emerge at any time of year, although late spring and early summer are the most usual times. The larval mines are relatively narrow initially, but as the larvae grow, their width increases. Pupation occurs in larger chambers at the ends of the larval tunnels, either within or beneath the bark. Pupae are typically plump and white in appearance. In California, most bark beetle species have two or more generations every year, depending on the climate.