Leduc County

Pest control (animal, insects and diseases)

Leduc County provides programs, advice and rental equipment to aid awareness and control of specific pests. From agronomic advice to assistance in controlling predation on livestock, Agricultural Services has knowledgeable staff to aid Leduc County residents.

Pest control rental equipment

Leduc County landowners may rent an assortment of pest control equipment from Agricultural Services for use on private land. Please contact the department for more information. 

Animal pests

Leduc County's full-time pest control officer enforces the Government of Alberta's Agricultural Pests Act and Regulation, providing advice and assistance to residents. The pest control officer works with property owners to help remove nuisance animals such as beavers, coyotes, Richardson's Ground Squirrels and Northern Pocket Gophers. The pest control officer's priorities are protecting Leduc County's valuable assets such as roads and bridges as well as assisting agricultural producers by preventing the predation of livestock and preventing the flooding of agricultural lands. 

For nuisance animals such as skunks, porcupines and magpies, a variety of humane live traps are available for rent to Leduc County residents. For the proper removal of nuisance animals after live capture, and issues with wildlife such as deer, bear or cougars, contact the Fish and Wildlife district office at 780-361-1250.


Coyotes are highly motivated scavengers possessing an inborn ability to recognize and take advantage of distressed or defenseless animals. Being opportunists, they will prey on the weak (newborn calves and lambs, or cows in difficult labour). Coyotes rarely attack and kill healthy livestock, but they will readily take advantage of sick or injured stock. Calves and lambs less than two months old, particularly those in a weak or sickly condition, represent the majority of livestock prey.

Dead animals are coyotes’ main winter diet. The presence of carrion on farms attracts coyotes and teaches them to return to the site looking for the same and other prospects. Improper disposal of carrion by one neighbour can cause problems for others in the area. It is imperative that livestock owners employ quick disposal of all dead livestock, stillborns, and afterbirth to reduce attractants to the calving and cattle feeding areas.

The Alberta Livestock Diseases Act requires dead animals to be disposed of within 48 hours. Under the Livestock Diseases Act, acceptable methods of disposal include rendering, composting, burial, and burning. Special direction is required for an animal suspected to have died from an infectious or reportable disease. Copies of the Alberta Livestock Diseases Act or Livestock Mortality Management (Disposal) can be obtained from Alberta Agriculture and Food Publications by calling 1-800-292-5697 or visiting agric.gov.ab.ca.

What can I do?

Engage in responsible management practices including proactive supervision of animals during calving will help producers reduce the threat of predation.

Livestock owners concerned about nuisance coyotes can shoot them on their own property, or may give permission to permit holders of trapping licenses to trap, snare, or shoot coyotes on their property. For more information about trapping licenses, please contact your local Fish and Wildlife office by calling 310-ESRD (3773).

Leduc County Agricultural Services department can provide guidance to assst livestock producers with management choices as well as aiding in the removal of coyotes where permissible. You can contact Leduc County’s Pest Control services through the Agricultural Services department by phone at 780-955-4593 or 1-800-379-9052.

Northern Pocket Gopher

To manage the population of Northern Pocket Gopher's, Leduc County offers residents a trapping incentive of $1 per tail, to a maximum of $150 per program participant. Leduc County residents may submit tails (dried or frozen) to the Agricultural Services department to apply for the $1-per-tail trapping incentive. Residents must provide the legal land location as confirmation that the pocket gophers were trapped from lands within Leduc County boundaries. Payment of incentive will be based on the verified number of Northern Pocket Gopher tails counted and will be made on a monthly basis, as funds remain available.


About Porcupines

  • Porcupines are primarily nocturnal and often rest in trees during daylight hours.
  • The bulk of their diet consists of plants, leaves and inner tree bark.
  • Porcupines cannot throw their quills. A quilling happens when a porcupine embeds its quills into the intruder with a quick slap of its tail.

Porcupines do not normally quill intruders without advanced notice. Porcupines will communicate when they are feeling threatened by vocalizing, displaying their quills and clattering their teeth. Be cautious if you see these signs, and back away slowly, as they mean a quilling may be imminent.

What's the problem?

  • Porcupines can cause significant damage to personal and public property by feeding on trees.
  • Porcupines are rodents that need to sharpen their teeth, so they may chew on wood in your backyard.
  • Porcupines feed on salt and salt residue, and have been known to chew on leather items and even the brake lines of vehicles.

What can I do?

  • Fence off valuable orchards, gardens and anything else that may be susceptible to porcupine damage. To protect individual trees, wrap the trunks in aluminum flashing.
  • Keep all your tools and leather goods locked away in a shed or garage.
  • Keep your dog on a leash when outdoors, especially if you suspect that there’s a porcupine in the area. Dogs are often unable to resist investigating nearby porcupines and may suffer for their curiosity with a nose full of quills.


If you see a porcupine that is too sick or injured to move or if you need specific advice about the porcupine on your property contact the Fish and Wildlife Office.

Richardson's Ground Squirrel

The Pest Management Regulatory Agency has approved registration of 2-per-cent liquid strychnine concentrate (LSC) to agricultural producers experiencing "economically significant" infestations of Richardson's Ground Squirrels on croplands and rangelands. The 2-per-cent LSC product is available only through municipal offices and its use requires training. The product is registered for use on Richardson's Ground Squirrels only and cannot be used in residential or public areas.

Yellow Bellied Sapsucker

Size / Shape

Yellow-bellied Sapsuckers are fairly small woodpeckers with stout, straight bills. The long wings extend about halfway to the tip of the stiff, pointed tail at rest. Often, sapsuckers hold their crown feathers up to form a peak at the back of the head.

Color pattern

Yellow-bellied Sapsuckers are mostly black and white with boldly patterned faces. Both sexes have red foreheads, and males also have red throats. Look for a long white stripe along the folded wing. Bold black-and-white stripes curve from the face toward a black chest shield and white or yellowish underparts.

Adult male

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Adult female

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Yellow-belled Sapsuckers perch upright on trees, leaning on their tails like other woodpeckers. They feed at sapwells—neat rows of shallow holes they drill in tree bark. They lap up the sugary sap along with any insects that may get caught there. Sapsuckers drum on trees and metal objects in a distinctive stuttering pattern.


Yellow-bellied Sapsuckers live in both hardwood and conifer forests up to about 6,500 feet elevation. They often nest in groves of small trees such as aspens, and spend winters in open woodlands. Occasionally, sapsuckers visit bird feeders for suet. 

On a walk through the forest you might spot rows of shallow holes in tree bark. This is the work of the Yellow-bellied Sapsucker, an enterprising woodpecker that laps up the leaking sap and any trapped insects with its specialized, brush-tipped tongue. Attired sharply in barred black-and-white, with a red cap and (in males) throat, they sit still on tree trunks for long intervals while feeding. To find one, listen for their loud mewing calls or stuttered drumming. 

Insect pests

Helpful identification of common insects found in the Leduc County area and information on how to control them.



All trees and shrubs along with other common plants.

Appearance and life cycle

Aphids, commonly known as plant lice are small, pear-shaped, fragile insects. They can be black, red, green, yellow or colorless, with some species being covered with long, white, waxy threads. Aphids may be winged or wingless and measure 1 to 3 millimetres (mm) in length. They can usually be identified by a pair of short, tube-like projections near the rear of the abdomen. Aphids have long antennae and slender legs and are equipped with piercing/sucking mouthparts. The life cycle of most aphids is complicated with many variations and exceptions.


Aphids cause damage by piercing the tender plant tissue and drawing large quantities of plant sap. They may be found feeding on any part of the host including the foliage, buds, flowers, fruit, twigs and roots. They often feed in groups. Aphids can cause galls, curled leaves, swollen branches, and discolored or wilted leaves. They usually do not cause permanent damage to forest, shade and ornamental trees. Some aphids excrete excessive amounts of a sticky substance called honeydew. This honeydew can be extremely annoying when it is deposited on sidewalks, cars and other objects. Honeydew attracts insects such as ants, bees, flies and wasps, whose presence may be the first sign of an aphid infestation.


Aphids have many natural enemies including lady beetles and birds. Weather conditions such as heavy rains or cold temperatures are major factors in reducing aphid populations. However, under favourable conditions, aphid populations can rapidly increase and may require chemical control. Insecticides registered for control of aphids include: malathion, diazinon, dimethoate, or permethrin. Before applying any insecticide check for predators, the amount of aphid damage and make sure the insecticide is not toxic to the plant

Apple Maggot

What is it?

Apple maggot (Rhagoletis pomonella) is a pest fly native to North America, and has been a serious pest of apples in Canada for over 100 years.

What's the problem?

The apple maggot larva burrows in all directions through the flesh of ripening apples feeding on the pulp and leaving brown channels. Pitting, dimpling and black spots on the fruit can mark the puncture sites where female flies have laid eggs in the fruit.

The apple maggot mainly attacks apple and hawthorn. They will also sometimes attack sweet cherry, sour cherry, plum, peach, pear and cotoneaster.

What can I do?

Pick up any fallen fruit as soon as possible and place it in tightly sealed plastic bags for regular garbage pickup. Fruit infested with apple maggot larvae tend to fall from the tree sooner than uninfested fruit, and larvae may remain in the fallen fruit for several days before they mature. Timely disposal of the fallen fruit prevents mature larvae from emerging to overwinter as pupae in the soil under the tree.

Home composting of infested fruit is not recommended, as it may provide ideal conditions for the larvae and pupae to develop. If you wish to compost the material, make sure the maggots are dead first by cooking (> 70°C/160°F), freezing, or pureeing the fruit in a blender.

Commercially available traps are intended primarily for monitoring the presence of apple maggot, but may work as effective control measures in small scale (backyard) settings. They consist of a round red ball coated in apple scent and an adhesive glue to trap the flying adults.

Quarantine information

Fresh fruit must not be brought into British Columbia from other provinces or countries without a movement certificate or phytosanitary certificate that shows the produce is free of apple maggot. There are also regulations governing movement of plant material that can host apple maggot.


What is it?

Ants most regularly encountered are native field ants (Formica species) nesting under sidewalks or creating mounds in lawns. If your house is not well sealed, workers can wander in foraging for food, but they seldom do any real damage. Many kinds of ants can be found in the area.

The Pharaoh ant (Monomorium pharaonis) and other exotic species of ants (fire ants, argentine ants, crazy ants, thief ants, etc. ) will nest in apartments and other buildings, where they are potential pests year round. These exotic species, usually imported with plant material, will feed on many household foods such as meats, grease, sweets, fruits, vegetables and liquids.

The most damaging ants in our area are native carpenter ants (Camponotus species) which can excavate their galleries in wood. Like termites, these insects can cause serious structural damage if left unchecked. There are no termites in the County.

Several other ant species collectively known as "moisture ants" have also been found associated with rotting wood in buildings. One of these ants (Lasius pallitarsis) is sometimes recovered from homes that have experienced water damage.

Before attempting to control an ant problem, it is best to have the workers (wingless ants) identified.

What's the problem?

Although most ants are at worst a nuisance, some species can become serious pests in the house, even causing structural damage.

What can I do?

Field Ants

To prevent field ants from wandering into your house, repair cracks and crevices with a silicone sealant. Before sealing the cracks, blow a drying absorbent dust (diatomaceous earth or silica aerogel) into wall voids and other inaccessible places to provide long-term control.

Strategic placement of sticky insect barriers can also deny ants access to certain areas. Exercise good housekeeping practices and seal all food and organic waste in tightly sealed containers so as not to provide attractive food sources for ants.

Pharaoh Ants

The pharaoh ant is one species of exotic ant that can survive in homes year round. It is important to seal food and garbage properly. Food that the ants have swarmed over should be assumed to have been exposed to organisms causing spoilage, and should be discarded. Typical insecticides cannot be used against these ants as they will undergo a process called budding, whereby the colony will fragment and spread to other areas.

It will take time, but baiting is the only sure way of eliminating these persistent pests.
Ant bait stations (small plastic discs containing a food attractant mixed with an insecticide, usually boric acid or hydramethylnon) are available at hardware stores and garden centres.

Carpenter Ants

Carpenter ants prefer to nest in moist decaying wood but they will tunnel through dry timbers. In addition to causing damage to trees and buildings, carpenter ants will also bite if provoked.

To help prevent carpenter ants from coming into your house, remove all stumps, logs and wood debris from your yard. Wood in contact with the soil, such as deck supports and fence posts, should be treated. Store any firewood away from the house and off the ground.
Destroy any colonies within 100 metres of your home by setting out ant bait stations and spraying or dusting the nest with a residual insecticide.

Finding carpenter ants indoors at any time of the year indicates the presence of a nearby colony or colonies. Locating the nest usually is the most difficult step in control. Swarms of large, black, winged ants in the house, usually in the spring, indicates that you likely have a serious infestation in your home.

Piles of sawdust are also indicators of carpenter ant activity in your home, but they may not always accumulate in evident locations. Sometimes a nest can be located in walls by listening for a dry rustling sound that will get louder if you disturb the ants by pounding on the wall.

Control of carpenter ants in a building is best left to a professional exterminator. When searching for an exterminator, look for a company that guarantees its work.

Moisture Ants

This group of ants are common, native insects. These ants are not a primary structural pest, but they can speed the deterioration of wood that is already in a state of decay.
They are secretive insects and often go undetected in homes until the colony is mature enough to produce winged, reproductive swarmers. They will excavate water-damaged wood in walls, often worsening matters by filling wall voids with soil.

The presence of these ants in a building is usually a symptom of a leakage or condensation problem. Correct the moisture problem and replace all damaged wood with sound material. Ants in wall voids should be treated with dust formulations, as liquid sprays may damage insulation or cause electrical shorts.

Ash Borer

What is it?

The ash borer or lilac borer (Podosesia syringae) is a day-flying clearwing moth native to North America. The larvae feed on the bark and wood of ash trees and lilacs.

What's the problem?

Tunnels made by the larvae provide access to moisture and fungi which can result in further tree decline. Extensive tunneling weakens stems and can increase breakage during storms.

Trees that are stressed or damaged are the most susceptible to borer attack and dieback. Tunneling by this insect can also weaken or kill young trees, especially during prolonged dry periods.

What can I do?

The ash borer targets open-growing trees, so avoid planting ash in exposed locations. Young trees are susceptible to attack, so if you're living in a neighbourhood that already has many ash trees, it would be a good idea to select a different type of tree to plant.

Since the insect prefers to feed on trees that are drought stressed or mechanically injured, keep your ash tree protected, healthy and well watered. Ash borer eggs are almost always laid in or near wounds, so avoid pruning ash trees when the egg laying adults are present (June and July in our area).

Additional information

Ash borers spend 2 years in the larval stage to complete development this far north. Pupation occurs in the spring of the third year and adults emerge shortly thereafter.

The moths have dark transparent wings, yellow stripes on the abdomen and about a 30 mm wingspan. Females live about 1 week, during which they lay eggs in bark crevices or tree wounds.

Once hatched, larva feed within the bark for the first summer. Larvae bore into the wood during the second year. Sawdust is visible outside the tree as larvae clear their tunnels of debris.

After spending the 2nd winter in the heartwood, larvae tunnel close to the bark surface and pupate. The pupae push through the bark just before emergence. When the adults emerge, the distinctive pupal skin is left sticking out of the exit hole.
Are you curious?

The adult ash borer is a harmless moth that resembles a stinging wasp. Such mimicry is thought to offer the insect protection from predators.

Ash Leaf Cone Roller

What is it?

The adult of the ash leaf cone roller (Caloptilia fraxinella) is a small gray moth with a 12 mm wingspan. This insect is native to North America.

What's the problem?

Early stages of the caterpillar are leafminers, feeding on the tissue between the upper and lower surfaces of the leaflet. In early to mid June, the caterpillar migrates on a silk line to a different leaflet. Once on a new leaflet, the caterpillar folds the leaflet into the characteristic cone, and spins its cocoon inside.

What can I do?

Spraying is not required as this rolling up of leaflets appears to have little effect on the health of the ash trees. The rolled leaflets remain attached to the tree. While a small part of a rolled leaflet will rot, most of it appears to remain undamaged.

Birch Leafminers

What is it?

Three species of sawflies (Fenusa pusilla, Profenusa thomsoni, Heterarthrus nemoratus) introduced from Europe in the early 1970s can be responsible for the premature browning of birch trees.

What's the problem?

The larvae feed on the inner green tissues of the leaf, causing a discoloured spot. Feeding over several weeks causes the blemish to take on a blister-like appearance.

A single leaf can contain many larvae whose blisters may merge to destroy much of the leaf. Heavy attacks repeated over several years will cause stress, making the tree more susceptible to other problems.

What can I do?

To support the biological control of birch leafminers, we do not recommend chemical birch leafminer treatments. Since 1990, populations of a tiny wasp (Lathrolestes luteolator) which selectively attacks the most damaging birch leafmining pest (Profenusa thomsoni) have developed and drastically reduced the problem.

The following tips will help you maintain a healthy birch tree will be more resistant to any birch leafminer attack:

  • Roots of birch trees need a cool, moist, shady location. Proper site selection is crucial for a long, healthy existence.
  • Fertilizing is best done in early spring at the onset of the growing season. Lawn fertilizer applications around the tree may be sufficient.
  • Prune any dead wood and remove the smaller of any branches that rub 1 another. Birch tree pruning is best done after the leaves are fully developed (June to July).
  • During the growing season, provide water during prolonged drought conditions. Thoroughly soak the area under and around the tree at least once a week if there is little rainfall.
  • To reduce the risk of mechanical damage from lawn mowers, weed eaters etc. , do not have any sod immediately surrounding the tree trunk.

Bronze Birch Borer

What is it?

This beetle (Agrilus anxius), native to North America, is 7-11 mm in length and dark green-bronze in color.

What's the problem?

This insect is often considered a secondary pest that attacks birch trees already stressed by things like drought. If populations build high enough on stressed trees, however, the beetle may move on to attack healthy trees.

Attacks result in progressive dieback of the crown and death of the tree within a few years. Injury is caused by the larvae feeding under the bark.

What can I do?

A healthy birch tree is most resistant to borer attack. Proper and frequent tree care including watering should be maintained.

If a tree exhibits top dieback symptoms, dead branches should be pruned out in the fall 30-50 cm below the dead wood or any signs of successful beetle attack (D-shaped emergence holes). All pruned material should be destroyed to prevent any beetle emergence the following spring.

Bruce Spanworm


Fruit trees, native trees and shrubs including willow, poplar, maple and alder.


Buds - Large areas chewed from buds, petals and flower parts.
Leaves - Large areas chewed from leaves before bloom; severe infestations can almost defoliate trees.
Fruit - Holes in small fruit resulting in small russeted scars in mature fruit.


Larva - Yellowish-green to dark green with light to dark brown head; larger larva with cream to white lateral stripes and moves with looping motion.
Adult - Wingless female; male moth with thin, semitransparent wings banded with brown and gray.

Life history

Bruce Spanworm overwinters as eggs laid singly on twigs. The eggs hatch near the green tip stage of apple. Most larvae mature and drop to the ground by petal-fall. Larvae remain in the soil until pupation in the fall. Adults appear in October and November. Wingless females crawl up the tree, mate and lay overwintering eggs.


Examine fruit bud and blossom clusters for larvae and feeding damage. Limb taps can also detect larvae.


There are many natural enemies that affect Bruce spanworm populations. It is thought that parasites are important in controlling populations between outbreak, though they seem ineffective in regulating populations once an outbreak has begun. For the most recent information on insecticides available for control of this pest, call Agriculture and Agri-Food Canada's Plant Industry Directorate in Ottawa (toll-free) at 1-800-267-6315.

Cooley Spruce Gall Adelgid


Colorado spruce, Douglas fir and White spruce

Appearance and life cycle control

The cooley spruce gall adelgid has a very complex life cycle which is not fully understood. Adelgids are a small group of insects that are closely related to aphids. The normal life cycle of this adelgid consists of 6 different forms of the insect over a 2-year period on 2 hosts; spruce and Douglas fir. In Saskatchewan and Manitoba where there is no native Douglas fir, the adelgid has the capability of completing its life cycle entirely on spruce. Only the first form of adelgid causes a formation of galls, whereas, the remaining forms feed openly on needles. Another form of the cooley spruce gall adelgids produce white, cottony protective covers for their eggs. These cottony covers appear as white specks early in the spring and continue throughout the summer, and can cover an entire tree during a severe infestation.


Damage first occurs in late May when the new growth of the branch tips form into cone-shaped galls. Galls vary in length from 25 to 75 mm and 12 to 18 mm in diameter. The galls are green at first but later turn a reddish-purple color. The old galls dry out and turn a reddish-brown color and may remain on the branches for several years. During a heavy infestation, young spruce may be severely deformed because the buds die on the gall-infested twigs. On established spruce, the growth and vigor may be reduced but trees are rarely killed.


Some control may be achieved by picking the new galls off as they form and burning them. This will improve the tree's appearance and reduce the aphid population. Chemical control of the cooley spruce gall adelgid can be achieved by applying carbaryl or malathion in early spring just as the buds begin to open.

Forest Tent Caterpillars

What is it?

Egg bands should be removed from trees before the caterpillars hatch.

The forest tent caterpillar (Malacosoma disstria) is a pest of broad-leaved trees and shrubs. Young caterpillars are black, hairy and about 3 mm long. They cluster together on the trunk or branches when they are not feeding.

Mature caterpillars are about 50 mm long and are characterized by wide blue bands along the sides of the body and a row of whitish keyhole shaped spots running down the back.

What's the problem?

Although this species prefers trembling aspen, it is also found feeding on the foliage of birch, ash, maple, fruit trees and cotoneaster. During severe infestations the caterpillars will feed on almost any green leaves, including garden crops.

Heavy defoliation for 2 or more years can result in a decline in the health of a tree which makes it more susceptible to attack by other pests.

What can I do?

Cultural control is the first line of attack against forest tent caterpillars. This consists of the removal of egg bands from infested trees and shrubs. The egg bands are easily detected between fall and leafing out in spring when the leaves are absent from the trees. Once discovered they can simply be scraped off with a dull blade.

Laboratory analysis of egg bands shows a significant impact of parasitic wasps on the hatching of forest tent caterpillar eggs. So rather than discarding those egg bands, leave them somewhere outdoors above the winter snow levels where the caterpillars will starve, but the tiny wasps can complete their development.

If some egg bands are missed or are inaccessible, clusters of caterpillars can be removed by pruning or washing down with a strong jet of water. Small caterpillars will rarely manage to recover from this, while larger ones can be controlled individually by physical means.

Keep in mind that light defoliation has little effect on tree growth.

Indian Meal Moth

What is it?

The Indian Meal Moth (Plodia interpunctella) is a commonly encountered pest in the home year round. The adults are about 12 mm (0. 5 inches) long and are distinct from other moth pests in homes by having a reddish-brown forewing with a light grey basal area. The moths fly around erratically, mostly at night.

The mature, creamy coloured caterpillars are about 12 mm (0. 5 inches) long with a brown head, and are often seen crawling up walls a week or so before they change into the moth stage.

What's the problem?

This insect pest is commonly introduced into the home through infestations in raw sunflower seeds, dried fruits, pet bird food and in chocolates which contain nuts.

What can I do?

  • Improved storage of dry foods in sealable glass or polythene containers protects against these and other pantry pests.
  • Watch for incoming infested food materials. These should be immediately frozen to control the pest before returning the product to the store.
  • Similarly, before disposing of any infested container contents, freezing for a few days will usually kill off any living stages.
  • Spraying is not required or recommended.

Larch Sawfly

What is it?

  • Order: Hymenoptera
  • Family: Tenthredinida
  • Latin: Pristiphora erichsonii (Hartig)
  • English: Larch sawfly Damage, symptoms and biology

The larch sawfly can be detected by looking for the slits on new shoots in which females have deposited their eggs or checking for groups of larvae crawling on the branches.

What's the problem?

Egg-laying in young shoots causes them to dry out and curl, which stops them from growing, reduces the number of buds and eventually results in crown deformation. The main damage is caused by feeding groups of larvae, which defoliate the tree. Moderate defoliation reduces growth and weakens the tree. Larch is deciduous and can withstand defoliation better than most conifers. However, repeated severe infestation over many years may result in a reduction in growth, tip dieback, branch mortality and tree mortality.

Larch sawfly larvae live in colonies (groups) during their initial larval stages and then scatter throughout the crowns of trees. Larvae feed heavily on needle clusters from mid-May to September, stripping the foliage from entire branches. Mature larvae drop to the ground between June and July and spin cocoons in the duff. The larvae overwinter in cocoons and transform into pupae the following spring. A few individuals may diapause for more than a year. When they emerge from the cocoon in the spring, the females lay approximately 75 eggs in small slits along 1 side of an elongating shoot.

What can I do?

The larch sawfly is considered the most damaging pest of larch in North America. An outbreak was reported in Alberta in 1996-1999 in the northwestern part of the boreal forest and large tracts of larch were defoliated. Since the 1970s, the larch sawfly has remained at an endemic level in Quebec, except in seed orchards, where populations are more abundant. The species can be controlled on small ornamental trees and isolated trees by shaking infested branches and destroying the larvae that fall to the ground.

Larder Beetle

What is it?

The most familiar stage of the larder beetle (Dermestes lardarius) is the adult. These beetles are up to 9 mm (a third of an inch) long, dark brown to black with a prominent greyish-yellow band roughly across the middle of the body. Although they are capable of flight, adults are commonly found trapped in a cooking pot or a sink, where the sides are too slippery to escape.

The worm-like larval stages grow up to 13 mm (half an inch long), are dark brown on top with spiky hairs and a pair of short spines at the tail end.

What's the problem?

Larder beetle females fly in from outdoors during May and June and lay their eggs on or near available food items which may be provided by fat splashed from the back of the stove, grease deposits in a fume hood, spilled food, a bag of dog food, a dead mouse or an accumulation of dead flies in a ceiling light fixture.

Adult beetles eat similar food materials as their young, preferring animal protein, fats and animal skins including dead insects, feathers and woollen materials.

What can I do?

Beetles that are seen can be easily caught by hand and killed. Cheese can be used as a bait.

The most effective way to control these insects is to eliminate food sources, including the removal of old bird nests close to the home and cleaning dead insects from light fixtures, baseboards and windowsills.

Sealing insect entry points into the house will help. Vacuum often.
If infestations persist, consider the use of crack and crevice applications of diatomaceous earth, a low toxicity insecticide dust that provides effective long-lasting control of these insects.

Larder beetles in dry pet foods can be killed by heating to 50 degrees Celsius for at least half an hour or by freezing for several days.

Large Aspen Tortrix

What is it?

  • Latin name: Choristoneura conflictana (Walker)
  • French name: Tordeuse du tremble
  • Order: Lepidoptera
  • Family: Tortricidae
  • Micro-habitat(s): Leaf

The large aspen tortrix is one of the main insects associated with the trembling aspen. This species occurs throughout the geographic range of the trembling aspen, its preferred host. The population of this boreal pest species periodically swells and remains at a high level for 2 to 3 years, then suddenly crashes. In Eastern Canada, Ontario is the region most affected by the large aspen tortrix, followed by Quebec, where there have been 3 major outbreaks since 1938. In the 3 Prairie provinces and southern Northwest Territories, outbreaks are known to have occurred in virtually all areas where trembling aspen grows. Sudden outbreaks of the insect occur over hundreds of square kilometres of aspen forests, often in association with infestations of forest tent caterpillars.

What's the problem?

The defoliation caused by the large aspen tortrix does not affect tree survival since it occurs early enough in the summer season to allow the trees to produce new foliage.

The signs that can be used to identify the insect on trees are as follows:

  • Delayed budbreak in the spring;
  • Presence of deformed leaves, which are rolled up into a cone or attached together by silk threads, which contain caterpillars or frass;
  • Thin crowns, which may sometimes be completely defoliated

What can I do?

Chemical control is not recommended, primarily because of the effective action of the many parasitoids associated with the large aspen tortrix. On ornamental trees, however, control can be achieved by placing a sticky strip around the trunk about 1 metre above the ground to intercept the larvae as they make their way toward the buds in May or toward their overwintering sites in August.

Diet & feeding behaviour

  • Phyllophagous: Feeds on the leaves of plants.
  • Leafroller: Hides and feeds inside a leaf or the tip of a leaf that it has rolled up into a cigar-shaped tube. 

Large Boxelder Leafroller

What is it?

The larger boxelder leafroller (Archips negundana) is a green caterpillar found on Manitoba maple (boxelder) trees during spring and early summer. The caterpillar feeds on the leaves, webbing them together with silk. If disturbed, the larva quickly drops from the tree, suspended by a silken thread.

What's the problem?

Caterpillar webbing and feeding damage looks unsightly. Dead foliage often bleaches, giving the tree a whitish appearance. Heavy infestations can result in complete defoliation of the tree.

What can I do?

In most situations, intervention is not required as little tree mortality has been observed. Established Manitoba maple trees that are completely defoliated over several consecutive years appear to recover and continue to grow normally. These trees have the ability to compensate for the caterpillar attack by producing a second set of leaves so that they appear nearly normal by the end of the summer.

If control is desired and the tree is small enough, you can spray for this insect in the spring as soon as you notice damage to the leaves.

Less toxic insecticides registered for the control of leafrollers are bacterial formulations containing BTK (Bacillus thuringiensis sub-species kurstaki).

Linden Looper


American plum, Apple, Birch, Elm, Oak, Linden pine, Maple and others.

Appearance and life cycle

The linden looper overwinters in the egg stage on host trees. In May, or as soon as the buds begin to open, the larvae emerge and begin feeding on the new foliage. Larvae are light brown to yellow, with a broad, bright yellow stripe along each side, and ten, wavy, narrow black lines along their back. The head may vary from yellow to rusty-brown. By late June or early July, the larvae are approximately 37 mm long and are full grown. They crawl or drop to the ground and tunnel into the soil to pupate. 

Adult moths emerge in October or November. Male moths have a wingspan of 37- 42 mm. The forewings are a light buff colour, marked with two, brown, wavy, transverse bands. The forewings also have a sprinkling of brown dots, and at times, a diskshaped spot. The hind wings are lighter in colour and are marked with a faint, disk-shaped spot. Females are wingless and are approximately 13 mm long. They vary in colour from light grey to brownish and have two rows of large, black spots on their back. After mating, the females crawl up the tree and deposit eggs singly or in clusters under loose bark or in crevices on the trunks and limbs. Overwintering eggs are oval and yellowish-brown. In Canada, there is only one generation a year of the linden looper.


The linden looper causes damage by defoliation during the larval stage. Large scale control measures have never been required because of natural control by parasites and diseases.


When populations of linden loopers grow because of an insignificant amount of natural enemies, other control methods can be used. One method to control the pest on a small number of trees is by banding. Banding prevents the wingless females from crawling up the trees to lay eggs. 

In late September, before adult emergence, a 10 cm band of paper-backed insulation or cotton batting and tar paper (paper side out) is attached to the tree at a one meter height. A thin layer of sticky adhesive (Tanglefoot®) is applied to the band. Linden loopers on a large number of trees or in a shelterbelt can be sprayed with Bacillus thuringiensis during the early larval stage. Bacillus thuringiensis is a bacterial insecticide that is non-toxic to beneficial insects. Recommended chemical insecticides are carbaryl and methoxychlor.

Pine Webworm


Eggs: Females lay eggs on needles.
Larvae: After hatching, pale green larvae mine the needles. Older larvae live in silk tubes hidden inside a mass built of silk and frass. Mature larvae have brown bodies and yellowish brown heads and can grow up to 18 millimetres long.
Pupae: After maturing, larvae pupate in cells formed in the soil.
Adults: Adult moths emerge during the summer and are black and grey in colour. Their wingspan is about 25 millimetres.

Identifying infestations

Silken masses of needles and frass: As larvae eat, they build a large mass of frass and silk among the needles of the tree branch.

Preventive tools

Follow a regular watering, fertilizing, and pruning schedule to keep your trees as healthy as possible to resist attack.

Physical tools

Remove masses from infested branches.

Pitch Moth

What is it?

The sequoia pitch moth, Synanthedon sequoiae, occurs from California north through British Columbia. This clearwing moth (family Sesiidae) infests Douglas-fir and most pine species, especially Monterey pine in urban coastal areas of Northern California, from Monterey Bay to the San Francisco Bay Area. The Douglas-fir pitch moth, Synanthedon novaroensis, infests Douglas-fir, pines, and spruces from Northern California to Alaska. Its appearance and biology is similar to that of the sequoia pitch moth.


Pitch moth larval feeding causes infested conifers to produce copious amounts of resin that form globular masses on bark. Larvae cause very little injury to cambium or wood; this damage usually does not cause girdling of the trunk and rarely kills trees. Larval feeding sometimes causes one or more limbs to die or break, especially if infested trees are young. Sequoia pitch moth is the more common of these Synanthedon spp. and is usually the only one that is managed. It frequently attacks pines with pruning wounds or other injuries, and its damage is most prevalent in planted Monterey pine (Table 1).


Infestations are recognizable by the gray, pink, reddish, or yellowish pitch masses that protrude from infested trunks and limbs. Pitch masses initially are small, soft, glistening, and reddish brown to pink. As the larva feeds and grows beneath each mass, the gummy exudate enlarges, hardens, and becomes darker gray. A brownish pupal case may protrude from the mass after the larva has matured and emerged as an adult. Old pitch masses can remain on bark for several years. Abandoned pitch masses are often reinfested because egg-laying females are attracted to these injury sites.

People unfamiliar with the damage sometimes confuse pitch moth pitch masses with bark beetle pitch tubes. Bark beetle pitch tubes are usually less than 1/2 inch in diameter, often have a distinct round hole near the center made by an adult beetle, and may resemble the end of a large gummy drinking straw protruding from bark. Sequoia pitch moth masses ultimately become much larger, vary in shape from roundish to an elongated oval, and often lack a distinct emergence hole.

Resinous ooze from pine bark can have other causes, including Diplodia canker, western gall rust, injuries such as pruning wounds, and pitch canker, caused by the fungus Fusarium circinatum. Unlike the distinct pitch protrusions of bark beetles and pitch moths, if injuries or pathogenic fungi are the cause, bark usually becomes coated with a thin layer of resin resembling thick syrup. In addition, bark discolors due to pitch canker, while bark around beetle and pitch moth attacks is not discolored.

Pitch canker can infect pine tissue of any age, including young branches and terminal shoots the diameter of a pencil; bark beetles and sequoia pitch moth attack primarily the main trunk, although they sometimes attack large limbs several inches in diameter. Unlike the natural shed of older (inner branch) needles throughout the tree during late summer and fall, pitch canker can cause dying, yellow and red needles to appear at any time of year. Pitch canker causes dead branches scattered throughout the tree, and it can eventually kill the entire pine tree. When bark beetle feeding causes foliage color to fade to yellowish green, then to tan and red-brown, this tree decline and dieback typically appears first only at the tree top (due to Ips beetles). Sometimes the entire tree fades and dies (from Dendroctonus species and others) without being preceded by scattered branch dieback. However, these symptoms of tree decline and death can also be due to other causes. For more information, see Pest Notes: Bark Beetles and Pitch Canker, and Pests of the Native California Conifers.

Pitch moth adults are day-flying moths, distinguished from other moths by their mostly clear wings with blackish margins. The Sequoia pitch moth’s head, legs, and thorax are blackish and yellow. The abdomen is covered with blackish and yellow hairs in alternating bands, resembling a paper wasp or yellowjacket wasp. Females are somewhat larger and plumper than males. The adult’s body is about 3/4 inch long with a wingspan of 3/4 to 1 1/4 inches. Although the colors and erratic flight behavior of adults resemble those of paper wasps, clearwing moths (including pitch moths) are not wasps: they do not sting and are harmless to people and pets.

The adult Douglas-fir pitch moth is orange and black, instead of yellow and blackish as with sequoia pitch moth. Douglas-fir pitch moth biology, life history, and management methods are similar to those of sequoia pitch moth, but Douglas-fir pitch moth usually is not managed in landscapes.

Life Cycle

Most pitch moth individuals require two years to develop from egg to adult. Because not all pitch moths emerge from pupae at the same time, adults can be present anytime from May through early September. Adults emerge earlier at warmer inland sites and later at cooler sites near the coast. Peak emergence occurs in June and July.

Adults live only a few days, during which they mate, and females lay eggs individually on bark, usually in crevices around pruning wounds and other injury sites. Eggs are 1/16 inch in diameter, reddish brown, oval, and somewhat flattened. They hatch in about two weeks.

The insect spends most of its life in the larval stage. The dirty white, grayish, or pink larva feeds for months, excavating a shallow cavity that penetrates the inner bark to the cambium surface of wood. After feeding as a larva, the pitch moth develops into dark brown pupa that is about 3/4 inch long. The pupa sits in a chamber within the pitch mass for about a month, then moves to the surface just before the adult emerges. After the adult has emerged, the brown, thin-walled pupal case remains protruding from the surface of the pitch mass, or drops and lands in a bark crevice or on the ground.

Satin Moth

What is it?

The satin moth (Leucoma salicis) was introduced to North America from Europe in the early 1920s. Satin moth was likely introduced (probably from British Columbia) before 1991 but went unrecognized until 1994, allowing the population to spread.

Mature satin moth caterpillars grow to be 38 mm long. Their backs are black with a central row of white or light yellow markings. 

The adult moths have pure white wings with a satin-like lustre. They are heavy-built moths with a wingspan ranging from 35 to 50 mm and can be distinguished from other local white species by narrow alternating black and white bands on the legs.

What's the problem?

The caterpillars feed principally on the leaves of poplar and willow trees and less commonly on oak. In new outbreaks, satin moth is often seen to prefer hybrid poplar species such as the Northwest, Griffin, Silver and columnar types which are planted here as landscape ornamentals. Successive heavy attacks over 3 years will likely result in the dieback of branches, or even whole trees.

What can I do?

A small parasitic wasp (Cotesia melanoscela) attacks and for the most part now suppresses satin moth populations in the area. Typically spraying is no longer required.

There are a couple of cultural practices a homeowner can use to help control satin moth on a tree. The greenish egg masses concentrated on the lower areas of the tree can be easily scraped off in July with a dull blade and destroyed before they hatch.

A sticky band can be used to intercept much of the upward movement of young caterpillars that overwinter in bark crevices on the lower trunk area. Such a sticky band trap should be established by the end of April and monitored throughout the month of May to ensure the sticky surfaces do not become saturated with emerging caterpillars.


What is it?

Sowbugs (Oniscus asellus) are an introduction from Europe. Although they live on land, they are crustaceans and are related to shrimp and lobsters. Sowbugs have 7 pairs of legs, a series of armour plates covering the back and may be up to 15 mm (half an inch) long.

What's the problem?

Sowbugs are a common sight in yards and homes in the Edmonton area. They usually cause the most concern when found crawling in the home, especially in large numbers.

What can I do?

Sowbugs typically live in damp areas and feed on decaying plant material. Removing any grass clippings, mulch, rotting wood and leaf litter around the foundation of your house will help keep the area dry.

Removing logs, boards or boxes under which sowbugs hide will also help.

Basements and crawl spaces should be kept dry and free of any food material for sowbugs. Foundations, doors and windows should be properly sealed to prevent entry. Sweep or vacuum any sowbugs that may still wander in. Spraying is not usually required.

Spruce Beetle

Spruce beetles (Dendroctonus rufipennis (Kirby)) occur in endemic populations in white spruce stands throughout Alberta. Outbreaks of the spruce beetle often originate from areas with blowdown, logging slash, or damaged standing timber. Spruce beetles breed in these areas and may attack and kill healthy trees.

Primary hosts and distribution

White spruce (Picea glauca (Moench) Voss)
Engelmann spruce (P. engelmannii Parry).
Spruce beetle is common throughout Alberta, especially in areas with abundant mature spruce trees. 

Life Cycle

The spruce beetle usually has a 2-year life cycle in Alberta.

Stout dark brown adults (about 4.5-7.0 mm long) overwinter in the tree, then emerge and attack new hosts from late May through June. The female beetle tunnels egg galleries along the wood grain in logs, stumps or standing trees. The female beetle mates with a male in the gallery and then lays eggs.

The female lays white eggs along the gallery walls.

Larvae and Pupae
The eggs hatch in 2 to 4 weeks and the young larvae tunnel under the bark away from the gallery. The larvae are white grubs with brown heads and are about 3-7 mm long. In the 2-year life cycle, spruce beetles overwinter as larvae. By the following summer the larvae pupate and become adult beetles. In late summer, the adults come out of the galleries, and reenter the tree at the base and spend the final winter there.

Detection and Damage

Look for the following signs and symptoms:
  • Entrance holes bored into the bark of the lower stem in late May and June.
  • Boring dust and resin (pitch tubes) on the tree trunk, and boring dust at the tree base.
  • Straight egg galleries (6-23 cm long) under bark that follow the wood grain.
  • Woodpecker predation, leaving a reddish tree trunk.
  • Yellowish-green to reddish colored needles throughout the crown.

The spruce beetle can seriously damage large-diameter spruce during outbreaks, which can last 2-5 years. Larval feeding within the bark can lead to colonization of blue stain fungi and other associated fungi. Fungi disrupt the water transportation within the tree and kill the tree.
For more information about aerial or ground survey standards, data or initiatives, click here. In Alberta, the spruce beetle management program can include:

  • Aerial surveys, especially of mature spruce stands that surround an outbreak, blowdown areas or storm-damaged stands;
  • Using Lindgren® funnel traps baited with pheromones (3-component lures) during the summer, if necessary to predict the population trends;
  • Ground surveys to detect and assess current year infestations;
  • Felling beetle-susceptible healthy trees (trap logs) to trap beetles in outbreak areas before spring. After beetle attack, trees are removed from the area and processed before the beetle completes its development;
  • Sanitation logging of infested stands. Infested trees are cut and processed quickly or if required, burned before the beetles emerge.

Spruce Spider Mite

What is it?

The spruce spider mite (Oligonychus ununguis) is a common pest found on spruce trees. Adult mites are green-brown, have 4 pairs of legs and are scarcely visible to the unaided eye.

What's the problem?

These mites suck sap from the tree's needles, causing them to turn yellow, then brown and eventually drop off. Damage on a tree usually starts appearing on inner portion of the lower branches.

If an infestation persists, twigs and branches may die. During periods of drought, extremely severe attacks may kill the tree.

Spruce spider mites also spin a fine webbing that traps debris between the needles and makes the tree look dirty.

What can I do?

Spruce spider mites survive best during hot, dry conditions. Heavy rain, high winds and high humidity usually control mites naturally. 

Regularly washing a spruce tree down over the summer with a hard stream of water from the garden hose will control mite populations and remove unsightly webbing and trapped dirt.

Strawberry Root Weevil

What is it?

The strawberry root weevil (Otiorhynchus ovatus) is a dark brown to black beetle with elbowed antennae and a blunt snout. The adult insect is about 6 mm (1 quarter-inch) long.

What's the problem?

Most complaints about this beetle occur because of their abundance in homes during late spring and late summer. The beetles cannot fly but can be found crawling on walls, floors, ceilings, and items in the home.

What can I do?

Although their presence can sometimes cause concern, they do not feed and are harmless.

The best way to control strawberry root weevils around the home is to prevent access by sealing cracks with caulking compound and installing weather stripping.

If some insects still manage to enter your home, use a broom or vacuum cleaner to remove them. Spraying with insecticide is not recommended.

Ugly Nest Caterpillar


Choke cherry, Hawthorn, Rose, Wild black cherry and other hardwoods.

What is it?

The insect is named after its untidy, nest-forming characteristics. Larvae of the ugly nest caterpillar hatch from overwintering eggs in the spring and may be found feeding throughout May to September. The larvae are yellowish to greenish-yellow with black heads and thoracic shields and range from 20-23 mm in length when full grown. The larvae pupate within the nest during mid-June to September. The pupae move to the outer wall of the nest just before the adults emerge. Adults are orange moths with wingspans of 18-25 mm. The forewings are speckled and spotted with dark, reddish-brown markings. The hind wings are a solid, bright orange colour. The moths may be present from early July to September, depending on the climatic region. The females deposit their overwintering egg masses on the stem near the ground of host trees. There is only one generation a year of ugly nest caterpillar.

What's the problem?

In the spring, the larvae construct a nest of leaves and branches that are tied together with dense webbing. The larvae feed as a group within the nest, enlarging the nest when necessary. The nest is often filled with excrement and bits of leaves, resulting in an unsightly mass. Damage caused by the ugly nest caterpillar has no lasting effect, but the presence of the nests reduces the aesthetic value of the tree. In severe cases, whole shrubs have been entirely covered by unsightly webbing. Outbreaks of the ugly nest caterpillar are sporadic and may be absent for several years.

What can I do?

Chemical control of the ugly nest caterpillar is rarely required. In most cases, control can be achieved by cutting out and destroying the nests containing the larvae.

Yellowheaded Spruce Sawfly

What is it?

The yellowheaded spruce sawfly (Pikonema alaskensis) is native to North America. Mature larvae are about 20 mm (3/4 of an inch) long. They look like hairless green caterpillars with a series of darker stripes running along the body. They have a distinctive dark yellowish head.

What's the problem?

This pest attacks spruce trees, especially young, open-grown trees. The larvae eat all the new needles before moving onto older ones. Feeding damage starts near the top of a tree and moves downward.

This stripping of the needles can seriously weaken a tree. Moderate attack 2 or 3 years in a row can kill a spruce tree.

What can I do?

If the spruce trees attacked are small and few in number, this pest can be controlled by hand picking and destroying the larvae when they first appear mid to late June. Young larvae may also be controlled by hosing them off with a strong jet of water. 

Unfortunately, damage to spruce trees is generally not noticed by homeowners until later when the larvae are quite large and have already started eating entire needles. These insects can be difficult to spot among the needles so careful, timely inspections are required. 

Insecticide can be applied mid to late June to protect larger spruce trees under attack.

Yellow Jacket Wasp

What is it?

Several colony-forming species of stinging wasps and bees live in the County of Wetaskiwin. Probably the most troublesome are the yellowjacket wasps (Vespula & Dolichovespula species). There are no true hornets in County of Wetaskiwin.

These wasps commonly build their grey paper nests in dry sheltered sites. Around the home, hollow doorsteps commonly provide ideal nesting sites. The nest colonies die off each winter.

What's the problem?

Yellowjacket wasps can be a nuisance around food at a backyard picnic. A nest close to your home can be a safety hazard, especially later in the season when the risk of stings increases.

What can I do?

Call an exterminator for nests on private property. You can find a list of exterminator companies in the yellow pages under the heading "Extermination". Get a written guarantee for their services in case the initial treatment fails.

In the event that a honey bee swarm lands on your property, contact the Alberta Beekeeper's Association and they will send out a beekeeper to remove the swarm at no cost.
You may choose to attempt to manage yellowjacket wasps yourself. Here are some suggestions:

Watching flight patterns of yellowjacket wasps will often reveal the whereabouts of nests. Since wasps become more aggressive as colonies get larger, early detection and control of nests reduces the risk of being stung. To prevent access to the hollow under a doorstep, seal all entrance cracks early in the spring (April), before the queens begin searching for suitable nest locations. 

Since wasps and bees are attracted to nectar and fruit juices, they may swarm around flowers, ripe fruits and pop and juice containers. Certain yellowjacket wasps species scavenge meat or hunt flies associated with human food and garbage.

Proper management of attractive foods and drinks or their open containers is especially important during summertime. This includes making sure that all outdoor garbage receptacles are properly covered.

Simple traps baited with sugar water and containing liquid soap to promote drowning, will reduce wasp activity. Such traps, however, should only be considered supplemental to nest control. 

Large or hidden nests are best left to the professional exterminator, however, if a yellowjacket nest is small and easily accessible, you may wish to control the nest yourself.

If you are willing to take that risk, consider the following points of advice, as any mistake in handling the situation could lead to a life threatening mass attack:

  • Control measures should be attempted during cool conditions after dark, when the whole colony is settled down in the nest for the night. 
  • Wear protective clothing such as heavy coveralls, boots, heavy gloves and veiled headwear, and use tape to seal off all cuffs.
  • Be sure to wear goggles or eyeglasses, since the wasps may attempt to spray venom through the veil into your eyes.
  • For better night vision, you might want to set up a spotlight focused on the nest from a distance. Wasps are attracted to light, so do not pass between the light source and the nest, and do not hold a flashlight.
  • It is advisable for another person to watch from a protected location in case a serious accident occurs.
  • The nest entrance, which is usually on the lower side of the structure, should be thoroughly soaked with a residual insecticide. Specially designed insecticide products for wasp control are available through seed-store, garden centre and hardware insecticide retail outlets.
  • When you are satisfied that mid-day nest activity has ceased, it should be safe for you to return at dawn to remove, bag and completely crush the nest to ensure total mortality before disposal.
  • Remember to follow all precautions and rates of application listed on the product label to avoid injury to yourself, others, and the environment.

Additional information for sting treatment

If you are stung, carefully inspect the site for the presence of a stinger. The barbed stingers of honey bees will usually remain in your skin, complete with a venom sac that continues to pump venom into the wound even after being torn from the bee's body. Quick removal of the stinger is therefore recommended. Be careful to scrape the stinger from the wound without squeezing the venom sac.

Wasps and bumble bees have smoother stingers that usually will not lodge in your skin, allowing each insect to sting you repeatedly. The stings will cause pain and swelling and can be dangerous depending on the number, body location and your immunity.

Seek immediate medical attention if reaction to the sting causes breathing difficulties, shock symptoms, or severe swelling in the head or neck regions. Sting kits or antihistamines are available if you find out that you are highly sensitive to insect venom. If your symptoms are minor, ice or a paste made from baking soda or mud applied to the stung area will provide some relief of the pain.


Agricultural Services staff enforce the Government of Alberta's Agricultural Pests Act and Regulation, providing advice and assistance to residents. The pest control officer monitors the potential for developments of crop pest infestations and works with property owners to help prevent crop pest infestations.

Black Knot

What is it?

Black knot (Apiosporina morbosa) is a fungal disease that causes greenish brown to black swellings in the stems of cherry trees (Prunus spp). It's spores are released following periods of warm, wet weather and are spread by splashing water, wind, birds, and insects.

What's the problem?

Black knot deforms branches and reduces their growth. Heavily infected trees often become stunted and may eventually die from the disease.

What can I do?

Regularly monitor your cherry tree(s) for symptoms of black knot. Early on, the disease appears as small light brown swellings, usually found on the succulent green stems. As the knots mature, the swellings will appear olive green with a velvety texture. Eventually the knots darken and harden. If you detect black knot, follow the guidelines below:

  • Prune out the infected branches between late fall and early spring when the plants are dormant and the knots are easier to see.
  • Remove the infected branches to at least 25 cm (10 inches) below the knot.
  • It is best to prune an infected branch further back to a suitable location, such as a healthy collar, rather than leave a stub.
  • For knots on the trunk or scaffold branches (main branches growing directly from the trunk) that can’t be removed, cut away the diseased material down to good tissue and at least 1 cm (1/2 inch) beyond the edge of the knot.
  • Sterilize your cutting tools between each cut using a disinfectant to prevent further spread of the disease.
  • Destroy infected prunings immediately by burning or burying, as they can continue to produce spores for months after being removed.

Bronze Leaf Disease

What trees does this disease affect?

Swedish Columnar Aspen, Tower poplar, any aspen hybrid with Swedish Columnar genes

What is the disease cycle?

Spores are released from mature preithecia (spore producing structures that develop on overwintered leaves). The spores are then spread during the spring to infect leaves on the same tree and other nearby trees. The disease will develop over the summer and infections will spread internally to other parts of the trees. Symptoms typically appear in later summer (early-mid August) or early fall (September). You will begin to see individual branches or a few leaves suddenly show symptoms.

What conditions help to spread the disease?

Rain and moderate to warm temperatures (18 degrees Celsius) lead to spore dispersal.

What are the symptoms?

Leaf tissues turn orange-brown to reddish-brown, starting from the edges of the leaf, moving inward towards the base of the leaf. Leaf veins and petiole remain a bright green colour. All leaves on a branch may be affected. Discolouration deepens to a bronzy, reddish-brown colour as the season progresses.

Infected leaves will often remain attached to the tree over the course of the winter (they do not fall off). Branches may dieback as the disease progresses systemically. Leaves that overwinter may have a pebbly surface texture (like the surface of a curling rink), reflecting the development of spore-producing structures (perithecia).

What can you do?

Prune affected areas of the tree. Cut off leaves and branches, place in a sealed garbage bag and dispose of in your black waste cart or take to the landfill. The sealed plastic bag will help prevent spores from spreading the disease.

Please do not burn, compost or dispose at a recycle centre. Monitor your trees and prune out any infected branches. If trees are heavily infected it is best to remove the entire tree.

Cottony Psyllids on Ash

What is it?

The cottony psyllid (Psyllopsisdiscrepans) belong to the family of insects sometimes called jumping plantlice.

Attacks by this psyllid on black ash trees can be very noticeable. Natural control of this insect in our area seems to be largely lacking at this time.

What's the problem?

These cottony psyllids attack black and Manchurian ash, but not green ash. These insects suck sap from the leaflets. This feeding causes ash leaflets to become shriveled and discoloured. The leaflets curl under from the sides to enclose the psyllids and a white, cottony material they produce.

What can I do?

Trees that are kept healthy and in optimum growing conditions are better able to sustain insect attacks. Insecticidal soap is a less toxic product registered for the control of psyllids.

The best time to treat is just after budbreak when the young psyllids hatch. Homeowners also have the option of hiring the services of a certified tree spraying company if a serious outbreak persists.


Clubroot is considered a pest under the Agricultural Pests Act and it is Leduc County's policy to identify cropland within the county that has a clubroot infestation in an effort to limit the spread of the disease. Positive confirmation of clubroot in a field requires landowners to develop a management plan to limit the spread of the disease, by using some of the methods outlined in in Alberta Agriculture and Forestry's Clubroot Management Plan. The county is striving to work with the agricultural community to develop measures to deal with this disease and has developed a Control of Clubroot Disease in Canola Policy and Code of Practice for Control of Clubroot in Canola.

Dothiorella Elm Wilt

What is it?

Dothiorella elm wilt is a disease involving a fungus (Dothiorella ulmi) that causes the wilting and progressive die-back of American and Siberian elm trees. Symptoms of the disease are:

  • Wilting, drooping, curling and yellowing of leaves, branch dieback, and browning of sapwood.
  • Evident soon after leaf out and brown leaves persist on dead branches throughout the fall and winter.
  • Impossible to visually distinguish from Dutch Elm Disease (DED).

What's the problem?

The disease attacks elms under extreme stress, a condition that impairs the trees' defences.

What can I do?

Prevention of Dothiorella wilt starts by keeping elm trees healthy. Watering trees during periods of drought will help lower their stress levels and increase their resistance to infection.

Additional information

Unlike Dutch Elm Disease, Dothiorella wilt requires no insect or other organism to spread the disease. Studies elsewhere have shown that Dothiorella fungus is spread as microscopic spores by water or wind.

The disease begins in weakened elms when spores enter natural wounds, cracks, pruning wounds or tiny pores in the bark called lenticels.

Infected elm trees that exhibit extensive canopy die-back should be removed and replaced with non-elm species to promote diversification of the urban forest. To reduce the spread of the disease, any wood removed from a hazard tree or stump must also be disposed of.

Dutch Elm Disease

What is it?

Dutch Elm Disease (DED) is a deadly disease caused by a fungus (Ophiostoma ulmi) that can affect any elm tree. Since its introduction from Europe about 1930, it has destroyed millions of American elm trees across North America.

An isolated case of DED was discovered in Wainwright, Alberta in 1998.

What's the problem?

Although Alberta is still disease free, the beetles, which carry the disease, have been found in Edmonton and St. Albert (since 1995), Calgary (since 1994), and Vauxhall (since 1996).

On average, DED arrives 3 to 7 years after the first detection of elm bark beetles.

What can I do?

Keeping Track of Elm Trees

Monitor the condition of the your elm trees.

Watch for these symptoms of Dutch Elm Disease:

  • Drooping and yellowing leaves in summer
  • Branches with smaller leaves than rest of the tree
  • Branches with no leaves
  • Brown wilted leaves that remain on the tree

Apart from being ideal breeding material for the beetles, elm firewood is especially problematic as it is easily and often transported from place to place. It is in this way that the beetles and DED are most readily transported long distances.

Because DED can be carried on elm firewood, provincial regulations prohibit storage, transport and sale of elm firewood. So if you go camping, please do not transport firewood.

Pruning and disposing of Elm wood

Prevention of Dutch Elm Disease starts by keeping elm trees healthy. Prune all dead wood that provides beetle habitat. Pruning of healthy elms, however, should only be done during the winter season when the beetles which are attracted to fresh tree wounds are not active (October 1 to March 31).

Did you know?

Edmonton has one of the largest concentrations of uninfected American elms left in the world.

Elm Scale

European elm scale (EES) is a pest that normally attacks fruit and ornamental trees.

Controlling Elm Scale

There are several ways we can control elm scale populations. Early and late season control involves applying dormant or horticultural oil in order to suffocate active nymphs. Early season control is applied shortly after tree bud-break, prior to the production of elm scale adults and crawlers. Late season control is undertaken just prior to leaf drop as nymphs move back to the branches. During peak crawler numbers, applying a soap and permethrin mix known as Trounce® will significantly reduce crawler numbers.

About Elm Scale

In order to understand how elm scale affects trees, it’s important to understand the lifecycle of the insect. Elm scale eggs begin to hatch in late June and early July each year. The early stages are known as nymphs and the first nymphal stage are crawlers. Crawlers begin feeding on leaves and crawler numbers peak in mid-July. By the beginning of autumn, they move onto branches and twigs where they prepare to overwinter - nymphs are forced to initiate overwintering prior to leaf drop. Elm scale feeds by piercing plant tissue (leaves and bark) and utilizing plant juices.

Elm trees are particularly affected by both the nymph and adult stages that inflict damage to the tree.

Fusarium Graminearum

Fusarium graminearum is a fungal disease that can cripple wheat, barley, oat and corn crops. This cereal disease can pop up in regions unannounced and disappear when weather conditions are not favourable. Fusarium graminearum is not currently established in leduc County and allowing this disease to get a foothold in the Leduc County area could cause significant negative impacts to the agriculture industry. Fusarium graminearum is considered a pest under the Agricultural Pests Act and Regulation and Leduc County encourages producers in the region to be aware of the disease and take necessary measures to prevent the establishment of Fusarium graminearum within the municipality. 

Western Gall Rust

Endocronartium harknessii



Distribution and disease cycle

Current year's shoots are infected when spores are dispersed in May and June from galls on branches and stems. Galls form in the summer following the year of infection, with sporulation not occurring until the subsequent spring. Galls can weaken stems, increasing the incidence of wind breakage. Extensive gall formation can cause tree stunting or mortality.

Symptoms and signs

Infection by western gall rust results in round or pear-shaped galls on branches or stems of susceptible pine hosts. In spring, the gall surface ruptures, releasing bright orange spores. Cankers sometimes form on main stems near galls; in some cases infection can result in production of witches'-brooms.


Prune branch galls or remove trees with main stem galls. Avoid planting susceptible pine near diseased, natural stands. There are no chemical controls registered for Western gall rust.