Download fact sheet - City of Airdrie

FACT SHEET
Most Airdrie residents understand the important benefits trees provide to people and our
community. However, basic knowledge of tree care is less widely known.
The following information will help you understand some basic tree care with regards to tree
diseases commonly found in Airdrie as well as your responsibility in helping care for our trees.
It is your responsibility to care for trees on your private property as per the Parks Bylaw (No. B13/2009). This includes prevention, maintenance and treatment with regards to pests or
diseases considered to be contagious that could affect the health of any City Tree. Should you
become aware of a contagious pest or disease, it is your responsibility to treat, remove, and/or
dispose of it in accordance with the direction of the City of Airdrie.
TREE DISEASES
Diseases can be prevented by planting trees that are adapted to the site you plant on (I.e.
Willows prefer wet sites etc.). Avoid susceptible species, plant the tree correctly, follow proper
maintenance practices and avoid mechanical injury.
More information on tree care can be found at http://treesaregood.org/.
Black knot
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Black knot affects Schubert Chokecherries, May Days, Saskatoons etc.
Black knot is a highly contagious fungal disease and can cause branch die-back or even
kill your entire tree is left unchecked.
To get rid of this unpleasant looking disease prune the infected branch 20-30cm below
the ‘knot’ pictured above.
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Sterilize pruning tools with hand sanitizer or rubbing alcohol between each cut.
The diseased wood must be pruned & either burned, buried or put in a tied plastic
garbage bag.
Fireblight
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Fire blight is a bacterial disease that affects members of the Rosaceae family, including
Cotoneaster, Apple, Crabapple, Pear, Rose, Hawthorne, Mountain Ash etc.
Flowers and leaves turn brown/black and twigs curl in to a ‘Sheppard's hook’. Leaves
will remain on the tree well into the winter. Cankers appear as discoloured/sunken
patches on branches or trunk. (If cankers appear on the main trunk of your tree it may
need to be removed)
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Remove infected tissue and healthy tissue back along branch at least 30-45cm. *Sterilize
all pruning tools between each cut. (Bleach:Water = 1:9)
All diseased material must be burned or sealed in a garbage bag and discarded.
Fire blight transmits very easily from plant to plant by contaminated pruning tools, hail
wounds, birds, or rain splashes.
Bronze leaf disease
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Bronze leaf (BLD) is a fungal disease that currently affects Swedish columnar aspen and
Tower poplar. There is concern that it could jump to our native Trembling aspen which
could be devastating to the Aspen parkland region that we live in.
BLD enters through the leaves an becomes systemic after that, meaning it can spread
very quickly.
Affected branches turn a reddish/bronze colour, while the veins of the leaves remain
green. Those leave will remain on the tree well into the winter. They contain the spores
that will spread to new hosts the following spring.
Affected branches should be removed back to the truck of the tree and pruning tools
should be sanitized with bleach: water 1:10 solution between each cut.
The diseased wood and leaves should be bagged and disposed of.
Dutch elm disease
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Dutch Elm Disease (DED) is a fungal disease that is carried by the insect vector the elm
bark beetle which is native to our area. Beetle bore into the bark of American Elm trees
and spread the fungus.
DED can be first noticed by yellow dying branches in the canopy and can quickly kill
entire stands of Elm trees.
DED is not currently in Alberta but can be easily spread here through fire wood
transportation as is it is currently wreaking havoc to the East (Saskatchewan) and in the
States South of us.
DED containment is legislated by the Government of Alberta through the Agricultural
Pests Act. More information can be found at
http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/prm1043?opendocument
Needle Rusts
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Rusts are fungal infections that affect conifers like spruce or pine.
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Needles will appear covered in an orange powdery substance and may drop.
Prune all affected parts, and ensure good clean-up of all needle drop around trees.
Powdery Mildew
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Fungal disease that affects caragana, aspen, hawthorn, current, turf grass etc.
Powdery mildew favors cold, moist shady conditions and can be controlled but
eliminating those conditions. E.g. Pruning to increase air flow, reduce watering
Ensure leaf litter is cleaned up well & consider spraying a fungicide for large infestations.
The mildew does not actually kill the plant shades the leaf and doesn’t allow sunlight in
thereby starving the plant.
Cytospera Canker
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Cytospera is a fungal infection that affects Spruce trees
It is identified by dead branches that always die-back from the bottom of the tree up.
When close up you will notice pale mauve oozing lesions.
Known as the slow killer, it can take many years to completely kill a spruce but the tree
will eventually die if the disease is not managed.
Prune out and remove and dead or infected wood. Good sanitation in your yard will
prevent the spread.
Hypoxylon Canker
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Hypoxyln canker is a fungal disease that affects Aspen and Balsam Poplar
The spores are active during late summer and fall so avoid pruning in August and
September
Swollen distorted areas on branches or on the trunk will be discoloured and show a grey
and white camouflage pattern.
Prune and affected areas which may include entire trees if the canker is in the trunk.
A canker left on a trunk creates a weakened area that is prone to breaking.
Wood Decay
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Wood decay is a fungal infection that can be identified by the fruiting bodies growing off
the trunk or branches of the tree or up from the soil over root zone of the tree.
Decay enters through poor pruning cuts and bark damage from mowing, trimming or
planting too deeply. By avoiding any unnecessary bark damage you can largely prevent
decay fungi.
It is important to call in an arborist to identify the type of wood decay present because
conks can often indicate the tree or part of the tree is likely to fail.
Slime Flux
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Slime flux is a bacterial wetwood disease that commonly affects Poplar and Elm. It is
characterized by smelly ooze dripping out down the bark.
It is spread by wind, insects, pruning tools etc. to a point of entry. (i.e. a pruning or hail
wound)
While slime flux is unsightly is rarely causes any real damage to a tree.