TREE PEST CONTROL

Colorado’s unique climate creates challenges for trees, where dry soils and nutrient loss make proper care—and effective tree pest management—essential to longevity.

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Advanced Tree Pest Control and Management in Denver, CO

Great Western Tree Care provides comprehensive tree pest control and disease management for residential properties across the Denver metro area. Colorado's Front Range supports a specific set of destructive insects and pathogens, from emerald ash borer and mountain pine beetle to cytospora canker and fireblight, each requiring precise identification and targeted treatment to prevent tree loss. Our ISA-Certified Arborists diagnose pest and disease issues using field examination and laboratory analysis, then prescribe treatments based on the specific organism, tree species, infection severity, and seasonal timing. Combined with proper fertilization and supplemental watering to maintain overall tree vigor, integrated pest management keeps your trees healthy and your property protected. Call (720) 535-8769 to schedule your free tree health evaluation.

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What Does Integrated Pest Managment (IPM) Look Like?

Integrated Pest Management (IPM) focuses on protecting your trees by understanding the entire ecosystem they live in — not just the pests that threaten them. Rather than relying on aggressive chemical treatments as a first step, IPM strategies for your landscape include:

To Treat or Not To Treat?

Should action be taken? If pests are identified, we look at the long-term economic threat and environmental conditions that could potentially be threatened. Spraying pesticides is not always the answer.

Control

By determining action thresholds, creating a specific plan for your property, and continual monitoring of control methods we can effectively decrease numbers of unwanted pests on your property.

Create A Plan

If it is determined that preventative measures need to be taken, GWTC will work with you to create a plan through a variety of different methods that best suit your landscape’s needs.

Monitor

We will visit your property numerous times throughout the year to ensure that, if preventative or targeted action was taken, is it working? Are there other means of Biological, Cultural, or Mechanical control methods that may better suit your landscape?

Tree Insect Control

Emerald Ash Borer (EAB) Treatment

The emerald ash borer, confirmed in Boulder County in 2013 and now present across the Front Range, kills untreated ash trees within 3–5 years of infestation. EAB larvae feed beneath the bark in the cambium layer, creating serpentine galleries that sever the tree's nutrient and water transport system. Early symptoms include canopy thinning starting at the top, D-shaped exit holes in bark, and increased woodpecker activity. We treat vulnerable ash trees with systemic insecticide injections, primarily emamectin benzoate (TREE-äge), delivered directly into the trunk vascular system. Trunk injections provide 2–3 years of protection per treatment cycle and are the most effective delivery method for EAB control in established trees. Treatment must begin before infestation reaches approximately 30% canopy loss; beyond that threshold, tree health cannot be reliably recovered.

Mountain Pine Beetle and Ips Beetle Management

Bark beetles target stressed conifers throughout the Denver metro area, particularly ponderosa pine, lodgepole pine, and spruce species in communities at higher elevations like Larkspur, Castle Rock, and Castle Pines. Mountain pine beetle attacks produce pitch tubes on the trunk surface, while Ips beetle infestations cause rapid top-down browning of needles. Preventive trunk sprays using carbaryl or bifenthrin-based products applied before beetle flight season, typically April through June, create a contact barrier that kills beetles before they can bore into the bark. Once beetles have successfully entered the tree, preventive sprays are ineffective and removal may be necessary to prevent spread to adjacent trees.

Scale Insects and Aphid Infestations

Oystershell scale, pine needle scale, and various aphid species affect ornamental and shade trees throughout Denver metro landscapes. Heavy infestations weaken trees by extracting sap from leaves, needles, and bark, producing honeydew deposits that promote sooty mold growth. We use horticultural oil applications timed to the crawler stage for scale insects, and systemic neonicotinoid treatments for aphid control when populations exceed damage thresholds. Treatment timing is critical; crawler emergence windows last only 2–3 weeks and vary by species and annual weather patterns.

Borers and Wood-Destroying Insects

Beyond EAB, several borer species target Front Range trees. Lilac/ash borer attacks ash and lilac trunks, producing frass-filled exit holes and bark swelling. Bronze birch borer targets stressed birch trees, causing branch dieback from the crown downward. Zimmerman pine moth larvae bore into pine branch junctions, creating pitch masses at wound sites. Treatment strategies vary by species: trunk injection for systemic borers, targeted spray applications for surface borers, and cultural practices including proper pruning to reduce stress that attracts these insects.

Tree Disease Treatment

Cytospora Canker

Cytospora canker is the most common disease affecting spruce trees along the Front Range, particularly Colorado blue spruce over 15 years old. The fungus enters through wounds or stressed branch tissue, producing resinous cankers that girdle branches from the lower canopy upward. Infected branches show needle browning and characteristic white resin deposits on bark. There is no chemical cure for cytospora canker; management focuses on removing infected branches with proper pruning cuts, reducing tree stress through watering and fertilization, and improving air circulation within the canopy.

Fireblight

Fireblight, a bacterial disease caused by Erwinia amylovora, affects apple, crabapple, pear, mountain ash, and other rosaceous trees common in Denver landscapes. Infected branches develop a characteristic "shepherd's crook" bend with blackened, water-soaked leaves that appear scorched. The bacteria spread rapidly during warm, wet spring conditions through blossoms and pruning wounds. We prune infected branches 12–18 inches below visible symptoms during dry weather, sterilizing tools between cuts. Preventive copper-based bactericide sprays applied at bloom stage reduce infection risk in high-value specimens.

Dutch Elm Disease and Elm Bark Beetles

American elms throughout Denver's established neighborhoods remain susceptible to Dutch elm disease, transmitted by elm bark beetles that carry the Ophiostoma fungus between trees. Symptoms include flagging branches with yellowing, wilting leaves, often starting on one side of the canopy. Preventive fungicide injections using propiconazole protect high-value elms for 2–3 year treatment cycles. Prompt removal of confirmed infected trees prevents beetle-mediated spread to adjacent elms.

Needle Cast and Rust Diseases

Rhizosphaera needle cast causes progressive needle loss on spruce trees, starting from the interior and lower branches, producing a thin, sparse appearance over 2–3 years. Dothistroma needle blight targets Austrian and ponderosa pines with distinctive reddish-brown banding on needles. Western gall rust produces spherical galls on pine branches that weaken structural integrity. Fungicide treatments using chlorothalonil or copper-based products applied during spring needle emergence provide effective control when timed to the specific pathogen's spore release window.

Unique To Colorado

Colorado’s stressed, drought-prone trees are more vulnerable to insects and disease—making proactive pest control essential to keep them healthy and protected.

How Much Does Tree Pest Control Cost in Denver, CO?

Tree pest and disease treatment costs vary based on the organism, treatment method, tree size, and number of trees requiring treatment. Here are general ranges:

Emerald Ash Borer Trunk Injection (per tree): $150–$500 per treatment cycle (2–3 year protection) depending on trunk diameter

Bark Beetle Preventive Spray (per tree): $100–$300 per application depending on tree height and trunk diameter

Systemic Insecticide Treatment (scale, aphids, borers): $100–$350 per tree depending on size and delivery method

Fungicide Application (needle cast, fireblight prevention): $75–$250 per tree per application

Comprehensive Annual Pest Management Program: $500–$2,000+ per property depending on tree inventory and active pest issues

Cost factors specific to the Denver metro area include:

Properties in Larkspur and Castle Rock with significant pine and spruce populations face higher bark beetle pressure requiring preventive programs
Ash tree inventories in Aurora, Centennial, and Englewood require EAB treatment planning before infestation reaches critical levels
Properties with multiple high-value specimens benefit from annual integrated pest management programs that combine preventive and curative treatments at reduced per-tree rates

Tree Pest Management by Property Type

Residential Properties with Mixed Species

Most residential landscapes across Highlands Ranch, Lone Tree, and Parker contain a mix of deciduous shade trees, ornamental species, and evergreen conifers, each with distinct pest vulnerabilities. Our integrated approach monitors the entire tree inventory and prioritizes treatments based on threat severity and tree value rather than treating every issue with equal urgency.

Properties with Significant Ash Tree Populations

Denver-area properties with multiple ash trees face a time-sensitive decision as emerald ash borer expands across the Front Range. We conduct canopy health assessments to determine which ash trees are viable candidates for treatment and which have declined beyond the recovery threshold. This evaluation helps property owners allocate pest management budgets effectively, treating healthy specimens and scheduling removal and replacement planting for trees that cannot be saved.

Properties at Higher Elevations

Communities along the foothills, including Roxborough Park, Castle Pines, and Larkspur, experience elevated bark beetle pressure due to larger conifer populations and drought stress at elevation. Preventive bark beetle spray programs for ponderosa pine and spruce are essential on these properties, particularly following drought years when beetle populations surge.

FAQs About Tree Pest Control in Denver, CO

How do I know if my ash tree has emerald ash borer?

Early signs include thinning canopy starting at the top of the tree, D-shaped exit holes approximately 1/8-inch wide in the bark, S-shaped larval galleries visible under loose bark, increased woodpecker activity, and epicormic sprouting (water sprouts) along the trunk and major branches. If you notice these symptoms, contact an ISA-Certified Arborist immediately; early treatment significantly improves survival outcomes.

When should I treat my pine trees for bark beetles?

Can a tree recover from a severe pest infestation?

Are tree pest treatments safe for children and pets?

What is the difference between tree pest control and tree disease treatment?

Pest control targets insects, including emerald ash borer, bark beetles, scale, aphids, and borers, using insecticides delivered through trunk injection, soil drench, or bark spray. Disease treatment addresses fungal and bacterial pathogens, such as cytospora canker, fireblight, needle cast, and Dutch elm disease, using fungicides, bactericides, or cultural practices like pruning and sanitation. Many tree health issues involve both pest and disease components that require integrated treatment approaches.

How often do trees need pest treatment?

Frequency depends on the specific pest and treatment method. EAB trunk injections provide 2–3 years of protection. Bark beetle preventive sprays require annual application before flight season. Fungicide treatments for needle cast may need 2–3 consecutive spring applications to achieve control. Our arborists design programs with the minimum effective treatment frequency to protect your trees while managing costs.

Why Great Western Tree Care for Tree Pest Control

3 ISA-Certified Arborists on Staff: Accurate pest and disease identification is the foundation of effective treatment. Our ISA-certified team diagnoses issues based on field symptoms, seasonal timing, host species, and laboratory confirmation when needed, ensuring treatments target the actual problem.

3 Colorado Department of Agriculture Plant Health Care Qualified Supervisors: State-recognized credentials specifically covering the diagnosis and treatment of tree pest and disease issues in Colorado's unique environment.

Family-Owned Since 2018: Headquartered in Larkspur, Colorado, we monitor regional pest trends, including EAB expansion, bark beetle flight patterns, and disease outbreak conditions, that affect properties across Douglas County and Arapahoe County.

2 TRAQ-Certified Professionals: Tree Risk Assessment Qualification training includes evaluating how pest damage compromises structural integrity, informing decisions about treatment viability versus removal.

1 Certified Treecare Safety Professional (CTSP): Ensures safe handling and application of pesticide products, including proper PPE usage, environmental protection measures, and compliance with Colorado Department of Agriculture application regulations.

Our Tree Pest Management Process

Step 1: On-Site Inspection and Diagnosis: We examine your trees for pest and disease symptoms, including bark condition, canopy density, foliage discoloration, exit holes, frass, fungal fruiting bodies, and other diagnostic indicators. We identify the specific organism causing damage.

Step 2: Treatment Recommendation: Based on diagnosis, we prescribe targeted treatments specifying products, application methods, timing, and expected outcomes. We discuss treatment options including cost-benefit analysis for trees where treatment viability is uncertain.

Step 3: Scheduling and Preparation: We schedule treatments during optimal application windows, which vary by pest species and treatment method. Some treatments require specific temperature ranges, phenological timing, or pre-treatment watering.

Step 4: Treatment Application: Our licensed crew applies treatments using calibrated equipment: trunk injection systems, airblast sprayers, soil drench applicators, or targeted bark sprays depending on the prescribed method. We document every application with product names, rates, and environmental conditions.

Step 5: Monitoring and Follow-Up: We monitor treatment effectiveness at subsequent visits, check for new pest activity, and adjust ongoing management programs based on results. Annual re-evaluation ensures evolving pest pressures are addressed proactively.

Additional Tree Care Services

Great Western Tree Care offers comprehensive tree and plant health care services that support integrated pest management:

Greater Denver Metro Service Areas

Our tree pest management crews serve residential properties throughout Douglas County and Arapahoe County from our Larkspur, Colorado headquarters:

Schedule Your Tree Pest Control Consultation

Early detection and treatment make the difference between saving a tree and losing it. Great Western Tree Care provides expert diagnosis and targeted treatment programs for every pest and disease threatening trees in the Denver metro area.

Call (720) 535-8769 to schedule your free on-site tree health inspection, or use the form below to request an estimate.

Get a Free Tree Pest Control Estimate