How Do I Stop Caterpillars From Eating My Trees?
- Sprig The Tree Geek
- 2 minutes ago
- 4 min read
If you've noticed leaves disappearing from your trees, clusters of fuzzy caterpillars crawling across trunks, or piles of tiny black droppings collecting beneath the canopy, you're not alone.
Calgary and Foothills County are experiencing a significant outbreak of forest tent caterpillars this year, leaving many homeowners wondering if their trees are dying and what they can do to stop the damage.
The good news is that caterpillar infestations can often be managed successfully when caught early. The key is understanding what you're dealing with and taking steps that support the long term health of your trees.
What Are These Caterpillars?
The insect responsible for much of the defoliation being seen throughout Southern Alberta this year is the forest tent caterpillar.
Despite their name, forest tent caterpillars do not build tents. They feed heavily on deciduous trees including:
Trembling aspen
Poplar
Birch
Crabapple
Fruit trees
Other ornamental hardwoods
They are easy to identify by the row of white, footprint shaped markings running down the center of their backs.
As they feed, leaves develop irregular holes before eventually being stripped entirely from branches. Homeowners may also notice caterpillars gathering on trunks, fences, decks, and buildings as they move throughout the property.
Wondering if your trees are affected?
Evergreen LTD can help identify the species involved, assess the severity of the infestation, and recommend a treatment plan designed specifically for your landscape.
Will Caterpillars Kill My Trees?
In many cases, healthy trees can survive a single year of defoliation.
However, repeated years of leaf loss place trees under significant stress. Trees weakened by drought, compacted soils, poor nutrition, or previous insect damage have a much harder time recovering.
Over time, this stress can lead to:
Reduced growth
Branch dieback
Increased susceptibility to disease
Greater vulnerability to other insect pests
Premature decline
This is why simply waiting for the outbreak to pass is not always the best approach, particularly for mature shade trees and valuable ornamental specimens.
What Can Homeowners Do?
There are several management strategies available depending on the size of the tree, the severity of the infestation, and the overall condition of the landscape.
Remove Egg Masses During Winter
Forest tent caterpillars spend the winter as eggs attached to small twigs.
These egg masses appear as dark, shiny bands wrapped around branches. Pruning and disposing of infested twigs before spring can help reduce populations before they hatch.
Remove Caterpillars By Hand
For smaller trees, caterpillars can be knocked into a bucket of soapy water or removed manually.
Sticky barriers installed around tree trunks may also help intercept caterpillars as they travel between feeding and resting sites.
While these methods can be effective for minor infestations, they often become impractical when dealing with larger properties or mature trees.
Encourage Natural Predators
Birds, parasitic wasps, spiders, and beneficial insects all help suppress caterpillar populations naturally.
Outbreaks often collapse over time as predators, parasites, and diseases begin reducing numbers.
Still, homeowners dealing with severe infestations may not want to wait several seasons while trees continue to lose foliage.
Why Tree Health Matters More Than Most People Realize
Healthy trees are better equipped to withstand environmental stress and recover from defoliation. Unfortunately, Alberta's heavy clay soils can make this challenging. Clay particles bind tightly to many of the micronutrients trees need to thrive, making them less available for root uptake. Over time, nutrient deficiencies can contribute to declining vigor and make trees more susceptible to pests, drought, and disease.
To help trees recover from caterpillar feeding and improve overall health, Evergreen LTD utilizes a proprietary fish fertilizer application treatment designed to replenish essential nutrients and support long term tree vitality.
Rather than focusing solely on eliminating caterpillars, this approach works to strengthen the tree itself, helping it better tolerate stress, produce healthy foliage, and recover more effectively from defoliation.
For many properties, improving tree health can be just as important as reducing caterpillar populations.
Concerned about a tree that has already lost most of its leaves? Contact Evergreen LTD to learn whether our fish fertilizer application treatment may help support its recovery.
When Is Professional Treatment Recommended?
Professional intervention may be worthwhile when:
Multiple trees are being defoliated
Valuable mature trees are affected
Defoliation has occurred for more than one year
Trees already show signs of stress
Homeowners are unsure which caterpillar species is present
Every property is different.
Some trees may only need monitoring and supplemental nutrition, while others may benefit from a more comprehensive management strategy.
Protect Your Trees Before The Damage Adds Up
Caterpillar outbreaks are a recurring reality in Calgary and Foothills County, but they do not have to become a long term problem.
If your trees are losing leaves, covered in caterpillars, or simply looking less vigorous than they once did, now is the ideal time to act.
At Evergreen LTD, we help homeowners understand what is happening, identify the underlying causes of tree stress, and implement solutions that support healthier landscapes for years to come.
Whether that means monitoring an infestation, improving soil conditions, or applying Evergreen's proprietary fish fertilizer treatment, our goal is always the same: preserving the health and longevity of your trees.
Not sure if your trees will recover on their own? Reach out to Evergreen LTD for a professional assessment and personalized recommendations before this season's caterpillar damage turns into next year's tree health problem.
Comments