How do bark beetles harm living trees?

Bark beetles, which belong to the subfamily Scolytinae within the order Coleoptera, harm living trees primarily by boring into them to create egg chambers and tunnels.1

As these beetles feed just beneath the bark, they construct intricate networks of channels that disrupt the tree's ability to transport food to its roots, which often results in the death of the tree. In addition to this physical damage, bark beetles can negatively impact trees in the following ways:2

• Disease Transmission: Some species act as vectors for harmful pathogens. For example, certain elm bark beetles transmit the fungal spores responsible for Dutch elm disease, which has devastated elm populations in Europe and the United States.13
• Structural Damage: By boring into the tree, they compromise its protective tissues, which can leave the tree more vulnerable to other infections or environmental stressors.2

While healthy forests often possess natural defenses, overmature or weakened trees are particularly susceptible to infestation, which can lead to population buildups that threaten surrounding healthy timber.2