Information Calgary Tree Problems

Possible Tree Problems in the Calgary Area


These insects attack new growth on many plant species including Maples, Birch, Maydays, Elms, Honeysuckles and several types of shrubs. They suck plant fluids from the young leaves and new stems. The leaves then develop a shinny appearance and will be sticky to the touch.

Smaller plants can be washed with an insecticidal soap but infestation of full sized trees may require the attention of an arborist.

Aphids - Tree Problems Calgary

Cottony Ash Psyllid

When the buds of Black or Manchurian Ash open, they can be eaten by the nymphs of this species. This causes the leaves to curl. Inside the curled leaf is a cottony substance with the insect inside. This infestation causes leaves to drop early in season and a general dieback of the tree.

Cottony Ash Psyllid - Tree Problems Calgary

Cooley Spruce Gall Adelgid

This insect infestation is common to spruce trees growing in the Prairie Provinces. The damage is first evident in late May when new growth is disfigured by a cone-shaped gall containing adelgids that feed on the spruce sap. The galls start out green then turn red or purple as they dry out. The damage is mainly cosmetic. Old galls stay on the tree for a couple years until they fall off or are displaced by newer growth. With heavy infestations the growth and vigor of a tree may be affected but the parasite rarely kills the host.

Cooley Spruce Gall Adelgid - Tree Problems Calgary

Fire Blight

This is a serious bacterial infection that affects such trees as apples, pears, cotoneasters, hawthorns and saskatoons. Generally the flower and tip of the branch turns red and curls. Later cankers will appear on infected areas leaves that don't drop off during the winter months. Control requires that the infected wood is pruned from the tree and burned or disposed of in a landfill. Inadequate pruning can actually spread the disease.

Fire Blight - Tree Problems Calgary

Black Knot Fungus

This air borne fungus affects Saskatoons, Chokecherries and Maydays. It forms a distinct black growth on the branches that will eventually kill the host tree if there is no intervention. Treatment requires meticulous and aggressive pruning 12 inches below infected areas at all parts of the tree.

Black Knot Fungus - Tree Problems Calgary

Bronze Leaf Disease

This is a fungal disease that can affect some Poplar and Aspen species. Because Calgary has a high concentration of Tower Poplar and Swedish Aspen, urban areas have a high risk for this wind-borne infection. Generally seen in August, the leaves of affected plants will turn red-brown. Pruning the infected wood and keeping the site clean is the best way to control this problem.

Bronze Leaf Disease - Tree Problems Calgary

Birch Leaf Miner

This is a common insect infection of birch trees. The main symptoms are brown patches on the leaves. On closer examination, the inside of the leaf is seen to have been eaten by the insect. Unfortunately the best treatment is a pesticide but an integrated pest management scheme may be effective.

Birch Leaf Miner - Tree Problems Calgary