Emerald Ash Borer Treatment in Denver
Targeted EAB Protection for Denver-Area Ash Trees
Monster Tree Service of North Metro Denver provides emerald ash borer treatment as part of a broader approach to tree and soil health, not as a one-time insecticide visit. Our trained crews handle EAB alongside the full range of factors that affect whether an ash tree survives a regional infestation.
If you have ash trees on your property, don’t wait for symptoms to appear. Call us at (303) 835-9403 or request a free, no-obligation estimate online to schedule an evaluation.
How EAB Has Spread Across the Denver Metro
The emerald ash borer (Agrilus planipennis) first reached Colorado in Boulder in September 2013. From there, the pest moved steadily into the surrounding communities: Westminster confirmed it in September 2019, Arvada in 2020 near the Homestead Park neighborhood at 64th Avenue, and Thornton in 2022, becoming the first city east of I-25 to confirm EAB. Both Denver and Wheat Ridge added confirmed detections in 2025.
That timeline matters because untreated, infested ash trees typically die within two to four years. EAB larvae feed beneath the bark, cutting off water and nutrient flow, and canopy dieback progresses from the crown downward. With an estimated 1.45 million ash trees in the Denver metro area, representing roughly 15% of Colorado’s urban forest, the scale of the risk is significant. Only true ash trees in the genus Fraxinus are susceptible, including green ash and white ash. Mountain ash is not a host species.
Recognizing a Possible EAB Infestation
Detection is genuinely difficult in the early stages. Symptoms may not appear until two to four years after a tree is first infested, which is one reason preventive treatment matters in an area with confirmed EAB activity. When signs do appear, they include:
- D-shaped exit holes: Roughly 3 mm wide, left in the bark when adult beetles emerge in summer
- Canopy thinning and dieback: Starts at the crown and works downward through the tree
- S-shaped larval galleries: Visible under the bark when it splits or is peeled back
- Epicormic shoots: New sprouts pushing from the trunk or base, a response to severe stress
- Woodpecker activity: Increased feeding on a tree often signals larvae beneath the bark
If you notice any of these signs on an ash tree, prompt evaluation gives it the best chance of responding to treatment.
Professional EAB Treatment: Methods & Timing
Effective treatment requires more than applying a product. Timing, application method, and the overall condition of the tree all affect how well a systemic insecticide performs.
How Treatment Is Applied
Professional EAB treatment is typically delivered through trunk injection or soil injection, placing the product where it can move through the tree’s vascular system. Trunk injections using emamectin benzoate can provide control for approximately two years. Follow-up treatment is commonly recommended every two to three years depending on the product and the tree’s health.
When to Schedule Treatment
Optimal timing for trunk injections is generally after ash trees leaf out in spring, typically mid-May through mid-June. Our crews use state-of-the-art equipment and eco-friendly methods, and all work is performed in accordance with the ANSI Z133 tree care safety standard. Colorado requires commercial pesticide applicators to be licensed through the Colorado Department of Agriculture to apply EAB treatments, and our team is fully licensed and insured.
Why Denver Property Owners Trust Monster Tree Service of North Metro Denver
We treat emerald ash borer as part of a complete picture of tree health. Our approach connects pest management to soil quality and other conditions that determine whether a treated tree can sustain its recovery. Experienced crews, state-of-the-art equipment, and environmentally responsible practices are standard on every job. Our teams are professional, courteous, and arrive on time because we respect your schedule as much as your trees.
As a locally owned and operated company, we’re committed to the health of Denver’s urban tree canopy, not just individual jobs. Transparent pricing, free, no-obligation estimates, and honest assessments are how we build lasting relationships with property owners who count on us for the long term.
Serving Denver, Arvada, Thornton, Westminster & Wheat Ridge
Monster Tree Service of North Metro Denver provides emerald ash borer treatment and tree health services throughout Denver, Arvada, Thornton, Westminster, and Wheat Ridge. Each of these communities has confirmed EAB activity, and our team is familiar with the spread patterns and conditions property owners in each area are facing.
Get a Free EAB Evaluation for Your Ash Trees
Acting before visible decline gives an ash tree the best chance of responding well to treatment. Our team can assess your trees, explain your options, and provide straightforward pricing with no hidden fees.
Call Monster Tree Service of North Metro Denver at (303) 835-9403 or schedule your free emerald ash borer evaluation online. Don’t wait until the damage is visible.
