Common Pests & Tree Diseases in Colorado: Fall Treatments

As the growing season winds down, your trees and shrubs may look like they’re ready for winter, but insect and disease activity isn’t over just yet. In fact, many pests and tree diseases in Colorado begin their most damaging work in fall, when they prepare to overwinter in bark, soil, or branch wounds. Without intervention, these problems can explode come spring.

What Are the Most Common Pests in Colorado?

From sap-sucking crawlers to wood-boring beetles, some of Colorado’s most damaging insects include:

• Aphids and scale insects, which leave sticky residue and can stunt growth
• Borers, like the invasive emerald ash borer, which tunnel into wood and kill trees from the inside
• Mites, which thrive in dry, dusty conditions and cause leaf discoloration and drop

These Colorado insects often go unnoticed until damage is severe. In fall, they find shelter under bark or lay eggs in soil, making early sick tree treatment essential for control.

Watch for These Common Tree Diseases

Colorado’s climate also fosters a range of fungal and bacterial infections. The most common tree diseases include:

• Fire blight, a bacterial infection common in apple and pear trees
• Dutch elm disease, which spreads quickly and is often fatal
• Powdery mildew, seen as a white film on leaves, which weakens overall tree vigor
• Ink spot disease and Rhizosphaera needle cast, both of which affect foliage and photosynthesis
• Tree cankers, localized dead patches that indicate deeper tree canker disease problems

Without proper diagnosis, these diseases can persist through winter and flare up aggressively in spring.

Why Fall Treatment Matters

Fall is one of the most effective times to address tree diseases in Colorado and prevent pests from overwintering. If you wait until spring, infestations may already be well-established.

At Affordable Tree & Shrub Experts, our ISA-certified team offers thorough inspections, customized environmental pest control through safe, effective sprays that target overwintering pests and spores. Treatments can include:

• Emerald ash borer treatment to slow or prevent internal decay
• Fire blight treatment to prune and stop bacterial spread
• Powdery mildew treatment to clear fungal residue and reduce spore loads

This seasonal attention strengthens your trees heading into winter and helps reduce costly removals or emergency calls next year.

Prevention Is the Best Cure

Early intervention is the smartest way to manage Colorado pests and tree diseases. That means:

• Monitoring for symptoms like sap oozing, bark cracks, early leaf drop, or unusual spotting
• Scheduling annual fall health assessments to catch problems before they spread
• Using professional-grade treatments that are safe for pets, people, and pollinators

Our sick tree treatment plans are tailored to your landscape, tree species, and local pest pressures. Whether you’re in Colorado Springs, Denver, or elsewhere in the Front Range, our team is equipped to help your trees resist disease and bounce back stronger next season.

Defend Your Trees Before Winter Strikes

Don’t let hidden threats linger. Fall is the perfect time to protect your trees with smart, proactive care. Contact Affordable Tree & Shrub Experts for expert diagnostics, pest control solutions, and preventive treatments designed specifically for Colorado insects and the common tree diseases that impact our state’s landscapes.