Insect & Disease Control

Keeping Seattle area trees healthy isn't just good for the trees, it's good for home values, wildlife, enjoying outdoor activities, and much more!

The Tree Doctor Is In!

When your trees look sick, insect pests are infesting your shrubs, or strange growths appear on leaves, who should you call?

Tree diseases and insect infestations call for the services of an ISA Certified Arborist with deep experience in the unique pathogens and pests that affect trees in the Pacific Northwest. That means it's time to call the tree health management experts at Seattle Tree Care!


Registered Tree Service Provider: LIC-TSP-18512


Registered Tree Service Provider: 104

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Is Your Tree Safe

Do trees really need a "tree doctor"?

The Puget Sound area is a hot spot for several highly destructive tree diseases and insect pests, including Bronze Birch Borer, anthracnose, and European canker. Plus, we have the usual problems with apple scab, fire blight, needle drop, and other diseases that disfigure but don’t necessarily kill your trees.

Our Certified Arborists help you develop and maintain your landscape to achieve optimum health while having it look its best. We will conduct an inventory and analysis of your property to identify existing conditions and potential threats to the trees prior to planning any tree care or maintenance strategy.

We provide maintenance, tree and shrub care programs, and solutions to disease and other tree problems that are specific to the landscaping needs of your property.

We look forward to meeting with you and developing a tree care and maintenance strategy to suit the specific needs of your property.


Signs That Something's Wrong With Your Tree

Signs and symptoms of tree disease and insect infestation aren't always obvious to the untrained eye. That's where a Certified Arborist makes a big difference in determining what's really going on with your trees. Still, there are some common things to look for that usually indicate that there's a problem.

If you see any of these symptoms on your trees, give us a call for a quick inspection, diagnosis, and treatment recommendation.

  • Brown, dead, crispy leaves
  • Dying needles on conifers
  • Yellowing or curling leaves
  • Leaves or needles dropping in spring or summer
  • Holes or ragged edges on tree leaves
  • Lines or "squiggles" just under the leaf surface
  • Spots, speckles, or blotches on leaves
  • White, grey, or black fuzzy areas
  • Wet areas or oozing sores on the trunk or branches
  • An unusual number of wasps or other flying insects around the tree
  • Soft areas in the ground around the tree or mushrooms growing at the base
  • Silk webs, threads, or "tents" on branches
  • Holes in the tree bark (especially on ash trees)
  • Bumps or balls growing on stems and small branches
  • Sticky substance (and maybe black mold) on leaves or under the tree
  • Rotting or spotted fruit
  • Dying branch ends
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Sick Trees?

We make house calls! Phone Seattle Tree Care for a timely visit by your friendly and knowledgeable local arborist. We'll diagnose the problem and recommend the best treatment options to get your trees back to full health.




"Seattle Tree Care kicked off our experience with the incredible Andrea S., who assessed our trees through a free consultation. We knew we needed to get ahead of any Birch Borer issues, so STC sent out the stellar crew of Russell, Keaton, & Emma. All of them were considerate, knowledgeable, and professional. A fantastic experience all around from scheduling with Mary to finishing up the experience with the on-site crew. I highly recommend Seattle Tree Care."

Tristan Fields


"Thank you Seattle Tree Care for great service. Employees were knowledgeable, professional, and hardworking. Very good outcome and we recommend them highly."

Steve R.


"The team was great and spent time describing the health of the trees, what was needed now, and working with them for ongoing maintenance. Highly recommend Seattle Tree Care!"

Kym Michela


Our Approach to Insect & Disease Problems in Trees


What's Harming Seattle's Trees?

There are many common insects and pathogens that affect trees and shrubs in Seattle, Bellevue, & Puget Sound. Some are barely noticeable, while others often cause extensive (and sometimes fatal) damage. Below are some of the worst bugs and diseases in our area.

  • Apple scab
  • Anthracnose
  • Powdery mildew
  • Bacterial canker
  • Brown rot
  • Rust
  • Leaf curl diseases
  • Codling moth
  • Apple maggot
  • Spotted wing drosophila
  • Aphids
  • Bronze birch borer
  • Dothistroma needle blight
  • Armillaria root disease
  • Laminated root rot
  • Sooty bark disease
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Whenever possible, the arborists at Seattle Tree Care use a process called Integrated Pest Management (IPM).

We don't just spray everything with pesticides and fungicides according to a calendar-based schedule. Instead, we thoroughly inspect your trees to positively identify which pests are causing (or have caused) the problems and to diagnose any bacterial, viral, or fungal diseases affecting your tree's health.

We then carefully select the right times and types of treatments based on the insect's life cycle and/or disease progression. This allows us to use the least toxic treatments with minimal impact on surrounding plants, wildlife, and beneficial insects.

This approach, called Integrated Pest Management (or IPM), is better for the environment, more efficient, and uses fewer potentially dangerous chemicals. As a result, it ensures safety for people, animals, and the environment, as well as saving you money that would otherwise have been spent on ineffective pesticide applications.

How Does IPM Work?

Implementing an IPM program means monitoring your trees and landscape on a regular basis to identify when pest numbers have escalated to the point of needing to be managed or when environmental factors are putting your trees at risk of illness. That's why we advise you to have your trees inspected once a year.

We apply pest and disease controls at the time when they are most likely to be effective. This means that pesticides won’t be used when they are not really needed and that the right kind of targeted pesticide will be used.


Call Seattle Tree Care for Tree Health Management

We recognize that you have many options when it comes to caring for your trees. Here are some of the reasons why we could be the best choice for you.

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Properly licensed by Washington state to apply chemicals used to treat tree and landscape problems.

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ISA Certified Arborists on staff to ensure that treatments are used appropriately

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All treatments are applied by specially trained and certified tree health technicians

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A free estimate and detailed proposal so you know exactly what's wrong and what we'll do

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Locally owned and operated since 2007. If it affects trees in the Seattle area, we've dealt with it.

Set Up Your Tree Health Management Program

Have you noticed any signs of insect infestation? Are you concerned about an unhealthy-looking tree? Want to ensure the longevity and safety of your trees? Speak to one of our staff members to schedule a tree inspection and set up your Tree Health Management Program!

Looking for More?

We've got you covered with tips, resources, updates, how-to's, and other helpful information about trees and landscapes in Seattle, Puget Sound, and King County, WA. Join the thousands of smart local residents who get the monthly newsletter from Seattle Tree Care for helpful information you won't want to miss!

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