Tree Disease and Insect Control

Unsure if your tree is a city tree?
CLICK HERE for the City of Denver tree inventory site

  • Enter your address into the search box at the top left of the page
  • Blue triangles indicate a city tree that belongs to the Forestry Department
  • Green Circles indicate a parkway tree that belongs to the Parks and Recreation Department
  • Clicking on the triangles or circles will open a window that shows the species, address, ID # and size range of the tree
  • If the blue tree is an ash, it will include a line for “treatment cycle” (ash trees only)

Key of Terms:

  • N/A means the tree has not been selected for treatment by the city
  • Cycle1 means the tree was selected for treatment in 2016
  • Cycle2 means the tree was selected for treatment in 2017
  • Cycle3 means the tree was selected for treatment in 2018
  • Note: Ash trees that are a green circle will not show if they were selected for treatment


Tree disease and insect control year-round

Scales, mountain pine beetle, spider mites and ash borers can cause high levels of damage and tree disease can be fatal in some cases. Swingle offers a variety of treatment and protection plans to control these pests.

Treat and Inspect Program

Our “Treat and Inspect” program is designed to protect your valuable trees and shrubs from aphids, spider mites and caterpillars. We recommend three to four applications per year to ensure protection during the infestation period. Tree and shrub insect control is a two step approach, providing the utmost in plant protection with minimum environmental impact.

The “Treat” phase: We treat “primary” trees and shrubs that are most likely to be damaged by aphids, spider mites and caterpillars surrounding the time frame of each treatment. Two application methods (foliar and soil injection) are utilized to protect your plants.

The “Inspect” phase: The remaining trees and shrubs will be inspected for aphids, spider mites and caterpillars every time. Any trees or shrubs that are infested will be automatically treated AT NO ADDITIONAL CHARGE*. Fruit trees on your property will also be inspected, but will not be treated unless we have your prior permission.

Tree Disease and Insects:

  • Borer
  • Japanese beetle
  • Leaf miner
  • Scale
  • Canker
  • Fire blight
  • Leaf spot
  • Aphids
  • Spider mites

Environmental Damage:

  • Dry
  • Freeze
  • Hail
  • Salt
  • Wet
  • Chlorosis
  • Broken branch
  • Dead branch
  • Mechanical injury

Soil injections are used to control a wide variety of problem insects including aphids, elm leaf beetles, leaf miners, birch borers and more. Recommended frequency of treatment depends on the size and other characteristics of the tree and may range from every two months to over a year.

Mountain Pine Beetle / Ips Control – Preventative sprays are the solution to bark beetles. Swingle recommends one spray for mountain pine beetle and up to two sprays for the Ips engraver beetle. In addition, watering is essential during all seasons including winter. Fertilization recommendations may also be necessary.

Disease Control – Swingle’s proven Dutch elm disease program has protected American elms in Colorado since 1972. We offer both fungicide injections as well as natural biological pesticide for disease control.

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