Tree Diseases in Calgary

Royal Dutch Tree Services cares for the health of your trees; our arborists see a lot of sick trees in Calgary yards infected by insects, fungus and bacteria. It is very important to detect a diseased tree in early stages of infection as most tree diseases can be treated or even be cured.

Listed below are the most common insect, fungal, and bacterial tree infections that occur in Calgary.


  • Cytospora Canker (can affect any tree, most often spruce trees)
  • Apple Scab (affects fruit-­bearing trees such as apples and pears.)
  • Armillaria Mellea Root Disease (can affect any tree)
  • Oak Leaf Blister (affects Oak trees)
  • Hawthorn Leaf Spot (affects hawthorn trees)
  • Spruce Needle Rust (affects Spruce trees)
  • Needle Cast (affects spruce, fir & pine trees)
  • Black Knot (affects trees in the cherry family)
  • Sun Scald Complex (mainly affects mountain ash and chokecherry)
  • Elm Wilt
  • Hypoxylon Aspen Canker(affects columnar and trembling aspens)
  • Leaf Bronzing (affects columnar and trembling aspens)
  • Septoria Canker (affects poplars)
  • Nectria Canker (affects cotoneasters and mountain ash)
  • Silver Leaf (affects many deciduous trees)
  • Trunk Rot (affects mature trees)
  • Western Gall Rust (affect pines)
  • Apple/Cedar/Hawthon Rust (affects (Crab)Apple,Cedar, Hawthorn and Juniper)


  • Spruce Budworm (affects spruce trees)
  • Pine Weavil
  • Pine Beetle
  • Spider Mites (affects spruce & pine trees)
  • Elm, Lilac and Birch Leaf Miners
  • Bronze Birch Borer (affects birch trees)
  • Oystershell Scale (affects apple trees & cotoneasters)
  • Pear Leaf Blister Mite (affects pear, apple & mountain ash trees)
  • European Elm Scale (affects elm trees)
  • Gall Adelgid (affects spruce trees)
  • Aphids (affects many species)
  • Leaf Roller Catepillars (affects deciduous trees)
  • Spruce Sawfly (affects spruce trees)
  • Satin Moth (affects poplar and willows)
  • Tent Catepillars (affect deciduous trees – often seen on Calgary golf courses)
  • Emerald Ash Borer (affects Ash trees)


  • Fire Blight (affects apple & mountain ash trees)
  • Crown Gall (affects many species including juniper)

If your tree appears unhealthy, please call us for a free tree health consultation to diagnose the underlying problem and suggest treatment options.