This article about the "Invasive Insects of Canada" gives you a snapshot into some of the nastiest bugs that are threatening our forests, cities, gardens and ecosystems. Below you you will find 10 insects, fungi and diseases. Each is presented in alphabetic order. You may also wish to read about the "Invasive Plants of Canada" in this blog. These plants are aggressive and relentless. Links with additional information, resources, maps and reporting sites can be found at the bottom of this article.
Asian Long-horned Beetle
The Asian Long-horned Beetle (Anoplophora glabripennis), also known as the Starry Sky, Sky Beetle, or ALHB, is native to eastern China, Japan and Korea. It is a very serious pest of hardwood trees. In 2003, ALHB was first discovered in Canada near Vaughan Ontario. This became a serious threat to urban and natural forests in the area, which has a large component of maple and other vulnerable trees. The loss of these trees would have considerable impact on urban and natural landscapes and ecosystems causing billions of dollars of lost revenues in the forest, maple syrup and tourism industries.
The Canadian Food Inspection Agency (CFIA) led an eradication program aimed at eliminating the beetle. After removal of many host trees in the area, followed by intensive monitoring for several years, the beetle was declared eradicated from Ontario in 2013. Unfortunately later that year, ALHB was found again, this time in an area near Pearson Airport in Mississauga Ontario. The CFIA is again leading eradication attempts and has established a regulated area in Toronto and the GTA in order to prevent the spread of the beetle. The movement of tree materials through the infested area is prohibited.
Adult females lay 40–60 eggs in their lifetime by chewing a small hole through the bark of the host tree and lay one 5–7 mm long egg underneath the bark in each hole. The eggs hatch in 10–50 days depending on the temperature. Eggs, larvae or pupae can overwinter within the tree. They resume their life cycle when temperatures are above 10 °C. Most adult beetles emerge between late June and late August but continue to emerge into the fall.
Larvae are cylinder shape and elongated. They can be 50 mm long and 6 mm wide. Mature larvae tunnel to the heartwood as they feed. Larvae go through at least five stages over 1–2 years, which varies due to host and temperature conditions. A larva can consume up to 1,000 cubic cm of wood in its lifetime. This feeding eventually kills the tree by destroying its vascular tissue.
Adults typically lay eggs on the plant they developed on during immature stages rather than moving to new plants unless the population density is high or the host plant is dead. When they do disperse, they can travel up 2.5 km from their host tree in a growing season in search of a new host.
What you can do
The ALHB is confined to a small area in northwest Toronto and northeast Mississauga. The approach is to eradicate it. Early detection is essential for eradication. If you think you have found Asian Long-horned Beetle, contact the CFIA Plant Health Surveillance Unit or call 1-800-442-2342 or 647-790-1012.
Beech Bark Disease
Beech Bark Disease (BBD) is caused by the combined actions of an insect, the Beech Scale (Cryptococcus fagisuga), and a fungus (Neonectria faginata). The insect attacks the bark on the tree creating a wound or canker stressing the tree and decreasing its resistance to the subsequent fungal infection. The Beech Scale, probably along with the fungus, arrived in Nova Scotia around 1890. It arrived from Europe on infested beech seedlings. The disease was first noticed in Halifax in 1920 and by the early 1930's was found through the Maritime Provinces. It has since moved southwestward and was first detected in 1965 in Quebec and in 1999 in Ontario. Beech Bark Disease is now found through most of the natural range of beech in Canada.
Beech Scale is a tiny insect (up to 1 mm long) that feeds only on beech tree sap. There are only female scale insects, which reproduce without mating. The adult scale lays her eggs on the trunk of the tree in mid-summer and nymphs hatch from the eggs later that summer or fall. Each nymph crawls to find a location to feed and inserts its mouthparts into the bark to suck sap from the inner bark of the tree. Once the scale begins feeding, it becomes immobile, and eventually secrets a distinctive woolly white covering. The nymph becomes an adult the following spring. Scale insects are spread by wind, by animals or with infested wood.
Two fungi common to North America are important to the Beech Bark Disease process. These fungi infect the tree through the wounds caused by the Beech Scale insect and then begin to produce spores. The spores are red, lemon-shaped fruiting bodies that form in clusters on the bark. These spores mature in the fall and once they have become sufficiently moist, they each release eight spores that are carried by the wind to other beech trees.
Beech Bark Disease is now found through most of the natural range of beech in Canada.
What you can do
Since BBD is widespread; the approach is to manage it. If you have beech trees in your woodlot, read about management recommendations for Beech Bark Disease.
Beech Leaf-mining Weevil
The Beech Leaf-mining Weevil (Orchestes fagi), also known as the Beech Flea Weevil, is a common pest of beech foliage in Europe. It was first detected in Canada in 2012 in Halifax, Nova Scotia. There it was causing severe defoliation on American beech trees (Fagus grandifolia). Subsequent surveys detected the presence of the insect near Sydney, Nova Scotia as well.
Both the larvae and the adults cause damage to beech foliage. The larvae feed inside the leaf, creating tunnels. The adults create holes resulting in a very distinctive damage. American beech trees are dying after many successive years of defoliation by the weevil. In Europe, the adults feed on a variety of alternate hosts, including cherry (Prunus spp.) and apple (Malus spp.). Feeding on alternate hosts has not yet been observed in Nova Scotia, which is important to fruit growers concerned that that their crops could be threatened by the species.
Weevils overwinter under scales and in the bark of trees. Movement of logs and firewood from infested areas may contain overwintering weevils capable of infesting new areas. Protection of urban trees is being tested with stem injections of TreeAzin, a systemic insecticide that kills larvae and reduces damage to foliage, but treatment in the natural forest is not a viable option. Natural enemies, such as wasp parasitoids, help control weevil populations in Europe, but natural controls have not yet been observed in Nova Scotia.
Female weevils lay eggs in the mid-rib of beech leaves in the centre of the leaf and typically one per leaf. The hatched larvae are white with a black head and up to 5 mm long feed within the leaf. They devour a linear mine from the mid-rib toward tip of the leaf for 4-5 mm before moving off to the side of the leaf where they make a blotch shaped mine. The larva pupates within the mine and adults (2-3 mm long) emerge from the pupae in June. They feed on beech leaves before finding an overwintering site in July. After the winter, adults feed on newly emerging beech leaves.
What you can do
If you think you have found Beech Leaf-mining Weevil, contact the CFIA Plant Health Surveillance Unit.
Brown Spruce Long-horned Beetle
The Brown Spruce Long-horned Beetle (Tetropium fuscum) (BSLB) is an invasive forest insect native to north and central Europe and western Siberia. It was first detected in Canada 1999 in Point Pleasant Park in Halifax, Nova Scotia. They likely arrived 10 years or more before that in solid wood packaging material. It is of concern because it can kill healthy trees, though prefers those that are already stressed. It spreads slowly but there is a risk of the beetle's range expanding to other areas of Canada.
The adult beetle, which looks somewhat flat, is a dark brown colour, with its head and thorax a dark brown or black. It is up to 2 cm long, with reddish-brown antennae that are approximately one third of the length of its body. Due to its colour, it blends in well on the tree's trunk where they hide during the day under scales of bark.
Adult beetles emerge from spruce trees from late May to mid-August. The female lays eggs in crevices in the bark, and larvae hatch about 12 days later. Larvae consume the phloem that transports food to the roots, weakening the tree.
In the fall they excavate pupal chambers either between the inner bark and the sapwood, or in the sapwood (up to 4 cm deep); they pupate the following spring. In the insect's current range, its life cycle usually takes one year to complete.
The insect has been under regulatory control by the Canadian Food Inspection Agency (CFIA) as a quarantine pest since 2000. The CFIA surveys eastern Canada for BSLB, using pheromone-baited traps developed by the Canadian Forest Service (CFS) of Natural Resources Canada at the Atlantic Forestry Centre. The CFIA also regulates the movement of high-risk spruce products from infested areas to reduce the artificial spread of BSLB, and supports Natural Resources Canada (NRCan) research on BSLB ecology and mitigation.
What you can do
If you suspect signs of BSLB infestation within Nova Scotia contact the Federation of Nova Scotia Woodlot Owners for advice. Outside of Nova Scotia contact CFIA Plant Health Surveillance Unit.
Emerald Ash Borer
The Emerald Ash Borer (Agrilus planipennis) or EAB, native to Asia, is a wood-boring beetle that arrived here accidentally in solid wood packaging material. It is an invasive species attacking native ash (Fraxinus) tree species and is a highly effective and destructive tree-killer in North America. It has already killed millions of ash trees since it was first detected in Canada in 2002, and is expected to kill billions more.
Females lay eggs in bark crevices on ash trees. The larvae feed underneath the bark of ash trees to emerge as adults in one to two years. After hatching, the young larvae tunnel through and feed under the bark creating an S-shaped gallery. Since the tissue they consume is the tree's vascular tissue, larval feeding damages the tree and eventually kills it. After developing through the pupal stage, the adult beetle bores its way out of the tree leaving a distinctive D-shaped exit hole in the bark. Adult beetles can be seen from May until late summer, depending on weather and climate.
Adult beetles are typically bright metallic green and about 8.5 millimeters (0.33 in) long and 1.6 millimeters (0.063 in) wide. Their wing covers are typically a darker green, but can also have copper hues. Emerald Ash Borer is the only North American species of Agrilus with a bright red upper abdomen when viewed with the wings and elytra spread. The species also has a small spine found at the tip of the abdomen and antennae. Adult beetles of other species can often be misidentified by the public
EAB is established throughout southwestern, central and eastern Ontario, and southwestern Quebec.
What you can do
If you think you have found EAB in Canada outside of the EAB regulated area in Ontario and Quebec, contact the CFIA Plant Health Surveillance Unit or call 1-866-463-6017
Hemlock Woolly Adelgid
The Hemlock Woolly Adelgid (Adelges tsugae), or HWA, is an invasive aphid-like insect that is a serious pest in eastern North America, damaging and killing eastern North American hemlock species. Importation of infested Japanese nursery stock is thought to be the source of HWA in the eastern United States. It was found in isolated locations in Etobicoke, ON in 2012 and in Niagara Gorge, ON in 2013. All infested trees were removed and destroyed, and the region continues to be monitored for new infestations. A different strain of HWA has been in western Canada for thousands of years. These populations of HWA rarely cause significant damage likely due to the combined effects of tree resistance to HWA and predator insects that eat HWA.
The adelgid is tiny insect, less than 1.5 mm in length and oval shaped. The tiny brown-colored insect has four thread-like stylets that are bundled together and function as a mouthpart. In North America there are only female HWA, which reproduce asexually. There are two generations of HWA on hemlock each season, with the more fertile generation laying as many as 300 eggs per female. The newly emerged nymph, called a crawler, is the dispersing stage of the insect and can spread on their own or with the assistance of wind, birds and/or mammals. It can spread more than 12 km per year. Once the crawler finds a location to feed, it inserts its mouthparts into the twig and becomes immobile. The nymph feeds on the tree's stored starches, depleting its energy causing damage to the tree. The insect is inactive through much of the summer, resuming feeding and development in the fall. The presence of HWA can be identified by its egg sacs, which resemble small tufts of cotton clinging to the underside of hemlock branches.
What you can do
If you think you have found Hemlock Woolly Adelgid in Canada, contact the CFIA's Plant Health Surveillance Unit
Mountain Pine Beetle
The Mountain Pine Beetle (Dendroctonus ponderosae) (MPB) is a tree-killing bark beetle, native to western North America where its principle host is the lodgepole pine (Pinus contorta). Although MPB is native to Canada, the beetle can be considered invasive when it invades new regions. In Canada, its historic range was in British Columbia, with occasional isolated finds in Alberta. An extensive outbreak since the 1980's has resulted in an unprecedented population increase of the beetle resulting in a massive range expansion north and eastward. If conditions are favourable for the beetles, they could continue to expand eastward in range invading the boreal forest, impacting boreal forests in northern and eastern Canada.
The current outbreak of the Mountain Pine Beetle has destroyed wide areas of lodgepole pine forest, including more than 16 million of the 55 million hectares of forest in British Columbia.
Normally, these insects play an important role in the life of a forest, attacking old or weakened trees, and speeding development of a younger forest. However, unusually hot, dry summers and mild winters the last few years along with forests filled with mature lodgepole pine have led to an unprecedented epidemic.
It may be the largest forest insect blight ever seen in North America. Climate change, monocultural replanting, and a century of forest fire suppression have contributed to the size and severity of the outbreak. The outbreak may have significant effects on the ability of northern forests to remove greenhouse gas (CO2) from the atmosphere.
The Mountain Pine Beetle has a hard black exoskeleton measuring approximately 5mm, about the size of a grain of rice.
The female beetle excavates under the bark and lays her eggs. Healthy trees defend themselves by producing a toxic resin, flushing the beetle out of the tree. This defense works when a small number of beetles attack the tree, however, MPB can attack the tree en masse overwhelming the tree's defenses.
Larvae emerge and feed on the inner bark creating tunnels. After spending the winter in the larval stage, the beetle passes through the pupal and early adult stage under the tree bark, emerging in July and August. Newly emerged beetles disperse within and between forest stands, usually traveling downwind.
Adult beetles carry blue-stain fungi with them in special compartments in their mouth. These fungi are introduced into the tree by the beetle when it enters the tree. The joint action of larval feeding and fungal colonization kills the host tree within a few weeks of the successful attack. The fungus and feeding by the larvae girdles the tree, cutting off the flow of water and nutrients. Usually within a year of attack, the needles will have turned red. This means the tree is dying or dead, and the beetles have moved to another tree. On the tree exterior there are popcorn shaped masses of resin called "pitch tubes" where the beetles have entered.
What you can do
If you think you have found Mountain Pine Beetle outside of its current range please contact: In Manitoba: Forestry Branch at 204-945-7868. In Ontario: Invading Species Hotline at 1-800-563-7711 or report online at the Early Detection and Distribution Mapping System.
Insects not in Canada yet but pose a threat:
European Spruce Bark Beetle
The European Spruce Bark Beetle (Ips typographus) (ESBB) is native to Europe and parts of Asia. It is considered to be Europe's most destructive bark beetle. It is able to attack and kill healthy spruce trees when populations of the beetle are high. It has not been detected in North America; however, it has been intercepted with shipments of materials from Eurasia and is considered high risk for establishing in Canada if it arrives without detection. Our climate and host trees are suitable for the beetle and the beetle is very effective at locating host trees. The insect lives under the bark for most of its life cycle and is difficult to detect at early stages of establishment. This limits management options. The insect is effective at dispersing long distances both naturally and assisted by human activity. Suitable host trees are widely distributed across Canada. If it becomes established here, there is a risk it will become a serious pest of conifer species through the range of spruce.
Adults are usually 4.0–5.5 mm long, cylindrical and robust, black or brownish-black. The wing casing is slightly shiny, with 4 teeth on each margin side. The third tooth is the biggest and club like on its top. The egg is yellowish-white. The larva is white and legless. The pupa is also white.
Once air temperatures increase in the spring begin to disperse. The male beetle finds a suitable host tree initiates an attack on the tree and creates a nuptial chamber. The males produce pheromones, which attract more beetles (male and female) to the tree. Multiple beetles attacking the tree overwhelm the tree's defensive system. After mating, the female beetle excavates egg galleries under the bark laying eggs along them. In Eurasia, ESBB often carries fungi with it, some of which are virulent pathogens. European fungal pathogens arriving with the ESBB pose an additional risk to Canadian trees.
Tubes of resin may be seen extruding through the bark of vigorous trees attacked by ESBB. Trees decline and die within a few weeks of attack, with needles turning yellow and then red before falling from the tree. Many small exit holes can be seen where newly emerged adult beetles completed development and left the tree. Reddish-brown excrement can be seen in the tree's bark. Beetle galleries are seen when the bark is removed. They consist of a nuptial chamber with 2-5 longitudinal egg galleries. As with other insects that live under the tree's bark, evidence of woodpecker activity may be seen.
What you can do
ESBB is not known to be in North America at this time. Early detection of it provides the best chance to manage it effectively. If you think you have found European Spruce Bark Beetle in Canada, contact the CFIA Plant Health Surveillance Unit.
The Spotted Lanternfly (Lycorma delicatula) is originally native to parts of China, India, Vietnam and eastern Asia. The lantern analogy stems from the inflated front portion of the head that was thought to be luminous. It was detected in Pennsylvania in September 2014 and to date has not been found anywhere else in North America. It attacks a number of economically important tree species including fruit trees, grapevine, and conifers. If it were able to establish here in Canada it could pose a threat to viticulture and fruit growing industries.
The Spotted Lanternfly is a large 2-3 cm plant hopper. They have a black head and grayish wings with black spots. Their wing tips look like they are covered with tiny black bricks and grey mortar in between. In flight it displays red hind wings with black spots on its centre, a white wedge in the middle of the wing and a solid black wing tip. The abdomen is yellowish with black and white bands on the top and bottom. The lanternfly is a strong jumper and hops from location to location more than it flies
The adult female lanternfly lays her eggs in the fall in groups of 30-50, and covers them with a yellowish brown waxy deposit. They prefer tree of heaven for egg laying but other flat vertical surfaces including other plants and objects such as vehicles and yard furniture are also used. Eggs hatch in the late spring and early summer. Emerging offspring called nymphs go through four developmental stages before becoming adults in mid-summer. Nymphs feed on a range of tree species but adults prefer to feed on tree of heaven and grapevine. The adults and nymphs feed on sap in the tree's stems and leaves using their piercing-sucking mouthparts. The insect overwinters in the egg stage which is sensitive to colder temperatures. There is one generation per year.
What you can do
If you have tree of heaven in your yard, check it, and objects near it, for egg masses or for feeding insects. If you think you have found Spotted Lanternfly in Canada, contact the CFIA Plant Health Surveillance Unit.
Thousand Canker Disease
Thousand Canker Disease of walnut (TCD) results from the combined activity of the Walnut Twig Beetle (Pityophthorus juglandis) and a canker producing fungus, Geosmithia morbida. The beetle carries spores of the fungus on its body. The beetle is native to Arizona, New Mexico, Mexico and possibly to southern California. The origin of the fungus is not known - it was first detected in New Mexico in 2001. The geographic range has expanded within the western United States, and has recently been detected in the eastern U.S. in the native range of black walnut (Juglans nigra). It was found in Tennessee in 2010, Virginia in 2011, and Pennsylvania and Ohio in 2012. Widespread die-off of Juglans species is found throughout the range. This disease is expected to spread through the range of black walnut, which is quite susceptible to the disease, posing a serious threat to black walnut in eastern Canada.
The adult Walnut Twig Beetle is 1.5-2.0 mm long. It tunnels into the inner bark of walnut branches 1.5 cm or more in diameter. Under the bark, the beetles mate and the female constructs galleries along which she lays her eggs. When a beetle enters a branch it carries the fungus with it. The fungus is introduced into the tree during this wounding where it subsequently germinates and grows. The growing fungus kills the affected bark tissue, causing cankers in susceptible trees. The cankers grow and eventually merge, girdling the branch and impairing its vascular tissue, causing mortality of the girdled branches. As the tree declines, the beetle will attack larger branches as well as the main trunk of the tree. Susceptible trees die within three years of developing symptoms of TCD.
What you can do
TCD is not known to be in Canada yet. Early detection will allow broader management options. Monitor walnut trees for signs of the disease. If you think you have found TCD, contact in Ontario the Invading Species Hotline at 1-800-563-7711 or report online at the Early Detection and Distribution Mapping System.
Additional resources, maps and reporting sites:
For more information you can contact the following authorities
by clicking on the following links:
Canadian Food inspection Agency - Plant Pests & Invasive Species
Canadian Food inspection Agency - Plant Pest Surveillance
Natural Resources Canada - Top Forest Insects and Diseases in Canada
Canadian Wildlife Federation - Invasive Species in Canada Encyclopedia
iMap Invasives - Reporting System
Early Detection & Distribution Mapping System - Reporting System
Here is a list of "Tree Facts" you may also find interesting!
Did you know that trees…
You may find "The Importance of Trees" interesting as well!
- Mow regularly, removing too much of it at one time will cause stress to your lawn.
- Adjust cutting heights based on conditions: Never cut at a height less than 2.5 to 3 inches.
- Mulch the clippings returns valuable nutrients back to the soil. Be careful not to leave clumps on the lawn.
- More frequent mowing may be needed in spring and fall. Never remove more than 1/3 of the grass blade in one cutting. Removing too much of the blade length at one time stresses the grass and weakens your lawn. A longer cutting height results in a stronger, deeper root system, shading the soil, retaining moisture and preventing weed seeds from germinating.
- A sharp blade makes a clean precise cut which seals quickly and helps resist diseases. A crisp cut is also easier to achieve on a dry lawn rather than a wet one. A sharp blade also reduces wear and tear on your lawn mower engine and will increase your mowers gas efficiency.
- Do not to cut your lawn during the hottest part of the day.
- Your cutting pattern should be altered each time as this will keep the grass blades growing straight and strong.
- Grass clippings should be left on the lawn when mowing. It is a natural and environmentally friendly practice. Grass clippings are about 90% water by weight. They are high in protein and should be left to decompose which adds nutrients to the soil.
- The use of a mulching type mower is ideal for grass‑cycling as it cuts the clippings smaller and allows for quicker decomposition.
- Mulching reduces waste and conserves landfill space. It is only necessary to remove the clippings if they are long and will smother the lawn.