Bark Beetles

Over 600 beetles in the family Scolytidae are commonly referred to as bark beetles. Nearly all bark beetles are black or brown, hard-shelled and between 1/8 and 1/3 inches long. Species determination is not necessary due to similarities in their life cycles. Adult bark beetles bore through the bark to the cambium layer of suitable host trees. Females excavate a tunnel between the bark and wood, along which they lay their eggs. When they hatch, they burrow away from the egg tunnel and feed on the live bark tissue and outer cell layers of wood (xylem).

The “shot hole” appearance of the bark in infested trees indicates beetles have matured, chewed exit holes and flown off to find new breeding sites. Once bark beetles are established in a tree, they emit pheromones, which attract other beetles to the same tree. Bark beetles usually attack trees that are weakened or dying due to other stress factors such as drought, disease, smog, mechanical injury, etc. They are also attracted to recently cut wood.

To Species Commonly Affected; Pine and Oaks, once a tree is infected, trees almost never recover and usually die rapidly. Control efforts at this point are futile. Healthy, vigorous, well-maintained trees have a stronger chance of resisting beetles and other disease and insects. City Arborist Tree Care recommends protective trunk applications to repel beetles throughout the growing season in addition to fertilization and proper watering.

Please call or email City Arborist Tree Care to discuss your tree’s disease and pest control needs.