Cedar Bark Beetles – Phloeosinus spp.

Cedar Bark Beetles (Phloeosinus spp.)

Latin Name: Phloeosinus spp.

Common Name: Cedar Bark Beetles


  • Feeding of newly emerged adults causes discolored leaves on the tree or ground (yellow-green to red-brown).
  • Adults eat little twigs, girdling them several inches back from the tip. The adults are reddish-brown to black glossy bark beetles with a distinctive oblong form 1/8 inch long.
  • The wing covering is covered with long rows of minute puncture wounds. Once the bark is removed, larvae, pupae, and adult life stages will be visible in the larval galleries.

Host plants: Rocky Mountain, Utah junipers, and Arizona cypress

Territory: it is found throughout in United States.

Damage caused by Cedar Bark Beetles:

Adults feeding on twigs cause a yellow-green, then red-brown staining of portions of the tree crown (flagging) or the whole crown. Although this leaf damage may not influence a tree’s overall health, it may signal the presence and activity of adult beetles. When adults attack living but stressed trees to generate brood, they cause significant host damage or death. Typically, only stems with a diameter of 34 inches are attacked, posing little harm to seedlings and young junipers. They eat under the bark of the bole and branches of stressed, dying, or fallen trees and are generally peaceful.

Description about Leaf chewers:

Insect chewing damage to plants can take several forms. Foliage or flowers may vanish when certain insects eat them. Occasionally, the plant will appear ragged and, upon closer inspection, will reveal bitten edges or cores. Plants can be cut at the root and topple over, or twigs can be girdled and die as a result. Mining or boring is the process of causing harm to a plant through chewing. Only the upper or lower portions are sometimes destroyed, producing a brown, burned look or skeletonization (openings between the veins).


Life history and Habits:

In the Rocky Mountain area, little is known about the life cycle of cedar bark beetles. The larvae discovered under the bark are the overwintering stage. Adults feed on twigs and emerge in late spring or early summer. However, substantial late-summer flights have been seen from mid-July to early September, indicating that two generations are the norm for some species. The egg gallery narrows into an arrowhead form at the bottom and then continues upward for a few inches parallel to the trunk’s long length. Larvae girdle the branch or trunk by feeding perpendicular to the central egg gallery. There might be one or two generations every year, depending on the weather.