Cedar Bark Beetles: Signs, Prevention & Treatment Insects, Mites & Diseases Cedar bark beetles are small but destructive insects in the Phloeosinus genus that can have a big impact on the health and appearance of your property. They typically target stressed or weakened trees by boring into the cambium layer to lay eggs and disrupt the tree’s nutrient and water transport. While infestations often start subtly, they can quickly lead to thinning foliage, branch dieback, and overall decline, making early detection and proactive care essential. Cedar bark beetles target trees in the cypress family (Cupressaceae), including junipers (Juniperus), arborvitae (Thuja), cypresses (Cupressus), false cypresses (Chamaecyparis), and true cedars (Cedrus), which belong to the pine family but are still attacked by several Phloeosinus species. Signs of a cedar bark beetle infestation Early identification is critical to help limit widespread tree damage. Key signs to watch for include: Thinning or reddish crown beginning at the top of the tree. Small, round exit holes about 1 to 2 millimeters wide) in the bark that can look like shotgun holes. Fine boring dust in bark crevices or at the base of the tree. Loose or flaking bark. Branch dieback, especially in the upper canopy. If you notice any of these symptoms, contact your SavATree arborist to assess the situation and recommend the right treatment plan. Where and when to look for cedar bark beetles Cedar bark beetles are native across much of North America and are found throughout the United States, with damage most often reported in the western U.S., especially in regions experiencing drought or other environmental stress. An invasive Mediterranean species, Phloeosinus aubei, has also been expanding its range in recent years. Adult beetles are most active during the warmer months, typically from late spring through late summer, when stressed trees are more vulnerable. Timing varies by species and region. Generally, one generation of beetles is produced per year, but this can vary depending on species. The larvae overwinter beneath the bark, and as they mature into adults, they emerge to attack new trees, continuing the cycle. The cedar bark beetle life cycle Cedar bark beetles operate across two phases: Phase 1 — adult maturation feeding (the “twig phase”) After emerging in spring, adult beetles don’t immediately move into stressed trees to reproduce. First, they feed on the tender bark and nutrient-rich tissue of healthy branch tips, typically small twigs in the upper canopy, as part of their maturation process. This feeding can cause twig dieback, which is often mistaken for drought stress or disease. At this stage, the damage is usually minor and mostly cosmetic, and the tree is otherwise healthy. These symptoms can also serve as an early warning sign. Dying or cleanly clipped twig tips with small feeding wounds may indicate adult beetles are active in the area, even before breeding galleries are present. Phase 2 — breeding galleries (the “bark phase”) Once mature, adults move to stressed or weakened trees to reproduce. They bore into the trunk and larger branches, creating egg galleries beneath the bark. This is the stage where significant damage occurs. As galleries expand, they disrupt the tree’s ability to move water and nutrients, weakening the tree and potentially leading to decline or failure if left untreated. How Cedar Bark Beetles Damage Your Trees Cedar bark beetles damage trees primarily by tunneling through the bark into the phloem and cambium to construct egg galleries. This severs the tissue that transports water and nutrients, disrupting the tree's vascular system. Damage from this tunneling often causes infested trees to resemble drought-stressed trees. Because these issues can also occur at the same time, it’s important to consult with SavATree’s ISA Certified Arborists® for expert tree insect identification. Over time, this can lead to branch dieback, thinning foliage, and tree death under high infestations. Trees already stressed by drought, overcrowding, compacted soils, or mechanical injury are especially vulnerable. Trees weakened by root rot pathogens such as Armillaria or Phytophthora are more susceptible to attack. Cedar bark beetles themselves are also known to vector fungi, including Seiridium/Coryneum cardinale (the cypress canker fungus) and Geosmithia species, which can accelerate tree decline. How to Prevent a Cedar Bark Beetle Infestation The most effective defense against cedar bark beetles is maintaining overall tree health, as strong, vigorous trees are naturally better equipped to resist insects. Keeping trees properly watered and prioritizing soil care supports healthy root systems, particularly during drought or environmental stress. Proper pruning and adequate spacing will reduce overcrowding, improve airflow and sunlight penetration, and also help limit problematic insect activity. Avoiding mechanical injury from lawn equipment, construction, or improper pruning further protects trees from opportunistic beetle attacks. In addition to these cultural practices, SavATree’s ISA Certified Arborists® can apply soil treatments such as ArborHealth® and ArborKelp® to support nutrient availability and overall tree vigor. In some cases, protective treatments may also be applied to the trunk to help deter bark beetles, or systemic injections may be used preventively when trees are at risk. By combining consistent care with these preventive treatments and regular inspections, you can help your trees become more resistant to cedar bark beetle infestations and improve the quality of your property. Where to Find Cedar Bark Beetle Treatment Near You Cedar bark beetle populations can spread quickly, and even a small infestation can compromise the health of your trees if left unmanaged. Early action is especially important, as adult beetles feeding on nearby twig tips are an early warning sign that stressed trees on your property may be at risk, even before breeding galleries form in the bark. SavATree's ISA Certified Arborists® have the experience and knowledge to identify both phases of beetle activity, distinguish bark beetle damage from lookalike conditions like drought stress or disease, and apply tailored solutions designed for your specific property and tree species. Using a combination of targeted insect management strategies and proactive tree care, including supportive soil treatments such as ArborHealth® and ArborKelp®, our team works to address active infestations while strengthening tree resilience against future stress and attack. Contact SavATree today to schedule a complimentary consultation and protect your trees from the damaging effects of cedar bark beetles. Contact us today to schedule a consultation with an expert arborist.