Category: Tree Diseases

Aspen Trunk Rot

What is it? Aspen trunk rot is a wood decaying fungus happens on aspen exclusively. Symptom Damages What to do? Other resource: https://tidcf.nrcan.gc.ca/en/diseases-caused-by-pathogens/factsheet/1000008

Powdery Mildew

What is it? Powdery Mildew is a fungal disease of trees, shrub and grass. It thrives in shade and humid condition, where spores can be spread by rain and wind in warm and humid weather. Damages What to do? Other resource: https://agriculture.canada.ca/en/agricultural-production/crop-protection/diseases-and-pests-agroforestry/powdery-mildew

Cytospora Canker 

What is it? Cytospora canker is caused by the fungus Leucostoma kunzei, which attacks conifers such as Colorado spruce, Norway spruce, Douglas-fir, and white pine. The spores can be spread via birds, insects, rain, and wind. This fungus is often present in healthy branches, but the disease typically begins in stressed trees. Symptoms What to […]

Dutch Elm Disease (DED)

What it is? Dutch Elm Disease (DED) is a devastating disease that affects all elm species. It is caused by a fungus primarily spread by three species of elm bark beetles. The disease obstructs the tree’s ability to transport water, ultimately leading to its death. Alberta was free from Dutch Elm Disease for the past […]

Bronze Leaf Disease

What is it? Bronze leaf disease is a fungus that infects various poplar species including Swedish columnar aspens, trembling aspens and tower poplars. Symptoms Damages What to do? Other resources: https://www.calgary.ca/parks/pests/bronze-leaf-disease.html https://agriculture.canada.ca/en/agricultural-production/crop-protection/diseases-and-pests-agroforestry/bronze-leaf

Hypoxylon Canker

What is it? Hypoxylon canker is a fungus that occurs mostly on trembling aspen, also on other poplars and various hybrid poplars like balsam poplar, columnar aspen. It causes trunk cankers, which can eventually girdle and kill the tree. Symptoms Damages What to do? Other resource: https://tidcf.nrcan.gc.ca/en/diseases-caused-by-pathogens/factsheet/15

Spruce Broom Rust

What is it? Spruce broom rust is a native fungi that alternates its life cycle between two hosts: spruce and bearberry(kinnikinnick). It weaken the tree and also affects the aesthetic of the tree. Symptoms Damages What to do? Other resource: https://tidcf.nrcan.gc.ca/en/diseases-caused-by-pathogens/factsheet/1000053

Cedar Rust Diseases

What is it? Cedar apple rust, cedar hawthorn rust (juniper hawthorn rust), and cedar quince rust are the most common cedar rust diseases. They are rust fungi that require two different hosts, one evergreen and one deciduous, to alternate and complete their disease cycles. Evergreen hosts include red cedar or juniper, while deciduous hosts include […]

Fire Blight

What is it? Fire blight is a destructive bacterial disease of fruit trees in North America. It is often seen in crabapple, apple, mountain ash, hawthorn, plum, cotoneaster, raspberry, flowering almond, and saskatoon. Fire blight can spread through rain, wind, insects, birds, and contaminated pruning tools. Symptoms Damages What to do? Other resources: https://tidcf.nrcan.gc.ca/en/diseases-caused-by-pathogens/factsheet/176 https://www.calgary.ca/parks/pests/fire-blight.html

Black Knot Fungus

What is it? Black Knot Fungus is a very common disease in Prunus family (common cherry trees, mayday tree, schubert choke cherry tree, plum trees in calgary). It is a fugus called Apiosporina morbosa. It will affect the look and the health of your tree. Symptoms Damages What to do? Other resources: https://www.calgary.ca/parks/pests/black-knot-fungus.html https://tidcf.nrcan.gc.ca/en/diseases-caused-by-pathogens/factsheet/4 https://www.alberta.ca/black-knot