Tree Spraying & Pest Control

Arbortec Tree Service offers tree spraying and chemical application services to save your trees from tree pests and insect infestations.

We all love our trees in the Denver-area urban forest. Maintaining their integrity and ensuring they survive anything Mother Nature and human intervention throws at them makes us all tree preservationists in some form or another. Sometimes that means chemical application is necessary for pest control situations.

Plant Health Care specialist sprays red-leafed trees for pests

Some tree and shrub pests like to live in the upper stories of their host plants. To the untrained eye, they appear like a webby netting or spaghetti-like strands, funny mushroom or unsightly gall. Not all are pests, but when they are, tree spraying may be a solution to mitigate the tree parasite problem.

At Arbortec Tree Service in Denver, we focus on the nature of a tree or shrub problem, only using sprays that are specific to the cause and in safely applied amounts. How can you tell if what’s on your tree is a problem in the first place? You need an expert to know for sure.

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Why Pests Take Up Residence


A coalition of forest industry specialists, including Colorado State University Extension, Colorado Tree Coalition, Colorado Nursery & Greenhouse Association, and the American Society of Landscape Architects, developed an extensive evaluation of over 250 tree species and varieties grown in our region. Their study noted critical cultural factors and cautionary climate, exposure and lifecycle influences creating plant vulnerability to pests, and that list is just the beginning of what can go wrong.

Arbortec welcomes opportunities to offer advice on pest control mechanisms and methods for the Denver urban forest property owner. We find pests are often a symptom of a larger problem. Addressing those first helps the chemical solutions do their job effectively.

Plant Health Care Specialist kneeling next to a tree, using trunk injection equipment to treat the tree

Tree and shrubs can be vulnerable to insects, fungi, and viruses and bacteria. Here is a sample of what we typically find:

Use of non-native species: Plants that are not suited to the region, whether because of soil nutrient needs, climate and water requirements, or seasonal and sunlight variations are more likely to be attacked by pests.

Trees planted outside their comfort zone: Putting a low-water native tree in a lawn that receives water daily causes stress, which in turn can create vulnerability.

Soil conditions in extremes: Some trees are better suited for low alkaline soils, and some are salt tolerant.

Pruning outside growth habit: A shrub with multiple stems that someone attempts to prune to a single, tree-like standard will require multiple, frequent cuts, leaving open wounds with little time to heal.

Transplant shock: Some varieties prefer to be planted where their roots will never be disturbed.

Lack of proper TLC: Running into any tree repeatedly with a mower or weed eater leaves it with open wounds.

This is not an exhaustive list. Complicating matters, many of the symptoms could be caused by multiple sources. This is why having a professional assessment of what’s going wrong is so important.

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Protecting Leaves and Needles


Leaves and needles convert sunlight into energy for the plant through a process called photosynthesis. While a broadleaf has a larger surface area, needles often grow in denser clusters. Both provide food for the tree or shrub to thrive.

However, if those conversion engines are coated with a pest or light is blocked, any ability to create energy is weakened. Translate that into less food for the plant, and you’ll understand why it’s important to keep an eye on what’s growing far above you. Here are some common problems, courtesy of the Colorado State Forest Service.

Fungus among us: Fungi take many forms on trees and shrubs, from powdery mildew (looks exactly like its description) to wilt and rot. The latter can be colorful at certain times of the year. Not all are bad for the host tree, such as moss and lichen. In fact, the presence of moss and lichen are indicators of healthy air quality!

Resident insects: Insect pests come in many shapes and sizes. Aphids and mites secrete sugars. Caterpillars may eat the leaves or needles. Borers and beetles drill into stems or trunks and excavate under bark. Beneficial bees may use openings in wood for hives. Some damage the tree’s structure, and others only use it as an incidental home.

Nonresident insects: If ants are running up and down a trunk or stem, examine the area above for an aphid infestation. Spiders build intricate webs, sensing their prey will not move far from the tree. Trees and shrubs become temporary nurseries during times of the year, carrying harmless cocoons or nests.

Parasitic plants: These plants use the tree or shrub’s energy and food as their own. Examples include mushrooms, dodder (spaghetti strands in various colors), wild morning glory, and ivy varieties. Some of these have their roots in the soil at the tree’s base but hurt the tree by suffocating the upper story.

As you can tell by reading these lists, good guys and bad actors can be hard to tell apart. That is why it is best to call a professional arborist in Denver, CO to determine if you have a pest problem that requires spraying.

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Targeted Tree Spraying Solutions


Our Certified Arborists do not recommend broad applications of multi-purpose sprays when you suspect a pest problem. They are rarely effective and often result in over-spraying, which means chemicals end up in water supplies and places where humans, pets and wildlife can be impacted.

Our process begins with a detailed assessment of what pest or disease is causing the problem. In some cases, the tree or shrub will survive the invasion for the current season without intervention. Problems can have non-pest causes too, like overwatering, over-pruning, and over-fertilizing.

When treatment is called for, we take a targeted approach, applying chemicals only where the problem lives and only when it is safe to spray. That rules out windy days and rainy days. We consider the lifecycle of the pest, so your landscape receives the maximum benefit from our spraying.

Finally, we leave you with instructions on how to avoid the problem reoccurring in the future. This may mean pruning and trimming to open air circulation, changes in watering patterns, and watching for indicators that could be early warning signs.

Call Arbortec, the professional tree service in Denver, to ensure any spraying is done safely to preserve your landscape and your environment. Our estimates are free, and we are happy to share our knowledge about how to maintain a balanced urban forest.

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