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How Do I Stop Insects from Damaging My Trees? Calgary

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Urban trees in Calgary are critical to our city’s health and livability. They provide shade, reduce pollution, and increase property value, but they also face real threats. One of the most persistent? Insect infestations. Aphids, leaf beetles, spider mites, and borers like the bronze birch borer can cause serious damage or even kill trees if left unchecked.


At Evergreen LTD, our ISA-certified arborists specialize in protecting Calgary's trees using proven, science-based strategies. Here's how homeowners and property managers can stop insect damage before it becomes irreversible, and how our team can help.


Insect Pests to Watch Out for in Calgary

Insects threaten Calgary’s trees in a few key ways: they feed on sap, leaves, and bark, weaken structural integrity, and introduce disease. Some of the most common culprits include:

  • Aphids – Sap-sucking pests that cause leaf curling and reduce tree vitality

  • Spider Mites – Thrive in dry conditions and cause stippling and discoloration

  • Elm Leaf Beetles – Skeletonize leaves, weakening elms over time

  • Cottony Psyllids – Especially harmful to ash trees

  • Spruce Budworms – Feed on new growth, weakening spruce over time

  • European Elm Scale – Often goes unnoticed until dieback is visible


Early detection is key to managing these pests effectively. If you notice curling leaves, sticky residue, discoloured foliage, or unexplained branch dieback, it’s time to act.


Need a professional tree inspection? Contact Evergreen LTD to schedule a pest assessment today.


Integrated Pest Management (IPM): Calgary’s Best Defense

Integrated Pest Management (IPM) is a multi-pronged strategy used by professionals across Canada. It combines proactive monitoring with a tiered response system: biological, cultural, mechanical, and chemical controls. Here’s how we implement it in Calgary.


1. Monitoring and Early Detection

Regular inspections of leaves, bark, and branches are essential. Sticky traps and visual signs, like leaf distortion or bark damage, can help detect pests before populations explode. For instance, cottony psyllids produce visible white deposits on ash leaves. Catching infestations early allows for low-impact treatment.



2. Biological Controls

Nature offers some of the best pest control tools. Predators like:

  • Ladybugs – Consume large numbers of aphids

  • Lacewings – Prey on scale insects and psyllids

  • Parasitic Wasps – Control beetles and caterpillars naturally


Biological controls work best when combined with other IPM methods and are especially effective in moderate infestations.


Protect your trees without harsh chemicals. Evergreen LTD can help introduce natural pest solutions.


3. Cultural and Mechanical Practices

Healthy trees are naturally more pest-resistant. Calgary’s dry climate makes proper care even more important:

  • Water trees regularly during droughts

  • Apply mulch to protect roots and conserve moisture

  • Prune dead or infested limbs during dormancy

  • Use water sprays to knock off small insects like mites or aphids


Removing heavily infested branches or even full trees may be necessary to prevent the spread of pests to neighboring trees.



4. Responsible Chemical Use

When infestations are severe, chemical treatment may be required. In Calgary, systemic insecticides like imidacloprid or acephate are sometimes used against pests like elm leaf beetles and bronze birch borers.


That said, chemical applications:

  • Must follow Alberta regulations

  • Should be applied during times of low pollinator activity

  • Must be handled by a certified professional to avoid overuse or environmental harm


The City of Calgary advises residents to consult ISA-certified arborists before using any pesticide products on trees.



Diversify to Protect: Plant Smarter in Calgary

Another long-term solution? Tree diversity. Tree monocultures are more vulnerable to rapid pest outbreaks. After cottony psyllids heavily impacted ash trees in Calgary, the city shifted to more varied tree planting strategies.


Use the “right tree, right place” principle to reduce pest stress:

  • Choose species suited to Calgary’s climate

  • Avoid overplanting a single species on your property

  • Replace pest-prone trees with hardier alternatives when necessary


Ask Evergreen LTD for help selecting and planting tree species that thrive in Calgary’s environment.


Public Education and Community Involvement Matter

Insect damage prevention is more effective when the whole community participates. The City of Calgary’s Pest Management Awareness Program encourages residents to:

  • Learn to recognize pest signs

  • Report issues via 311

  • Consult professionals for treatment


Homeowners play a vital role in protecting the city’s urban forest.


Don’t go it alone, partner with Evergreen LTD to manage tree health the right way.


Protecting Calgary’s Trees Starts with You

Insect damage is a serious and growing concern for Calgary’s trees, but with the right approach, it’s manageable. By adopting Integrated Pest Management, keeping trees healthy, diversifying species, and acting early, homeowners can protect their trees for the long haul.


At Evergreen LTD, we bring ISA-certified expertise, local knowledge, and environmentally responsible practices to every job. Whether you're dealing with aphids on your maples or borer damage on your birch, we’ve got a solution.


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