Tree pests and diseases
There are many different pests or diseases that can infest Calgary's urban forest. Some are beneficial to the trees, but many are not.
Below is a list of the more common pests and diseases that can occur in Calgary's trees:
- Aphids - small pear shaped insects that feed on plant sap.
- Ash leaf cone roller - caterpillar/moth like insect that rolls tree leaves.
- Ash psyllid - small insects on tree leaves, resulting in curling leaves.
- Black knot fungus - large knots (abnormal growths) of bark that encircle the branch.
- Bronze leaf disease (BLD) - effects certain poplar and aspen trees.
- Elm scale - tiny crawling insects on leaves, twigs and branches.
- Fire blight - a bacterial disease that browns and kills leaves, flowers and branches.
- Oystershell Scale - small clusters of oyster-shaped “shells” that cover bark on shrubs and trees
- Satin moth - feeds on poplar tree leaves.
- Yellow-headed spruce sawfly - caterpillar like insect on spruce needles.
Dutch elm disease is a fungus spread in elm trees by the elm bark beetle. Alberta is DED-free and works diligently to stay that way.Learn more about common pests in Calgary