Gain new insights into your most difficult weeds and pests. Pests Addressed highlights a new pest or weed along with fun facts, product recommendations, and the most effective treatment techniques.
Like the Norway rat, the roof rat is an Old World rat native to Asia, specifically the forests of Southeast Asia. It also spread west through human migration, but it arrived in Europe and North America earlier than the Norway rat. Once the more aggressive Norway rat reached Canada, roof rats began to decline. Whereas Norway rats appear in every province, roof rats tend to dominate in coastal cities or along waterways in warmer climates. Although they generally don’t occur more than 100 miles inland, they may be transported inland and establish local infestations.
Common ragweed is a summer annual with origins in southwestern United States and northwestern Mexico and is common in the northeastern United States and southeastern Canada. This invasive weed highly pollenated flowers known to cause allergic reactions in humans, however, it is also notorious for causing crop loss in agriculture as well as growing in waste areas, roadsides, and gardens. The plant is highly resistant to drought and can grow in a wide variety of soil types with a preference to sterile soil. Common ragweed has ecological benefits to birds and insects within its habitat, attracting honeybees and birds to its oil-rich seeds and are especially valuable to birds during winter months as the spikes of seeds can remain above snow cover.
Bed bugs belong to a family of insects that are primarily human, bat and bird parasites. It is believed that the first bed bugs parasitized bats in ancient Mediterranean caves and began parasitizing humans as they inhabited caves along with bats. As cities were established and commerce between them followed, bed bug infestations became more permanent and spread to other areas. Now, the bed bug (often called the common bed bug) has a worldwide distribution and is the dominant bed bug in temperate climates.
Earwigs belong to their own small order of insects. Most are easily recognizable by having a pair of cerci at the end of their long abdomens. Immature earwigs have straight cerci that remain so in adult females but generally become curved in adult males. Earwigs use their cerci to defend themselves and for grasping prey or each other during mating.
Field bindweed is a perennial that was introduced to North America by Europe. The plant grows distinct white or pink flowers with five fused petals that form a trumpet shape, growing from the leaf axils and blooming from late spring to fall. Its arrowhead-shaped leaves grow on vines with hard green stems that wrap themselves around nearby plants, causing the weed to be invasive to crops and pastures, lawns, gardens, and roadsides. The plant can also be identified by the two small bracts that form just below the flower. The flowers develop brown seed pods that each contain up to four seeds and can have a long dormancy of up to 60 years.
The dandelion is an herbaceous, broadleaf perennial native to Eurasia that was introduced to many parts of the world by Europe. It’s hard to imagine this plant as an invasive weed as it’s valued for its nutritional and medicinal properties reducing inflammation, lowering blood pressure, boosting the immune system, and combating liver disorders and weak digestion, among many others. However, the design of the weed with its parachute-like bristles each containing a seed that can be carried over great distances by the wind suggests its intent to spread invasively.
Raccoons, in general, are New World animals. Of the three raccoon species that exist, the common raccoon is the largest and most widely distributed. It is native to North and Central America from southern Canada down to Panama. Originally from the tropics, the common raccoon is one of a few larger animals whose range increased along with human settlement. They have been introduced outside of their native range into Europe and Japan where they have become invasive.
The pavement ant is an introduced species from Europe that arrived in North America with settlers in the early 1800s. It is a significant pest on the West Coast, the Midwest to northeastern states and on into Canada. Because it prefers disturbed areas with little vegetation, it is common in urban areas where it often nests under concrete slabs. Colonies generally have one queen and one nest site. Nests near or under sidewalks, driveways, patios or building foundations are usually marked with displaced soil.
The Oriental cockroach is a worldwide pest with its origin most likely in the Middle East. It is a large cockroach that cannot fly. Adult males have short wings that do not cover the abdomen.
Adult females have wing stubs and may look like beetles before taking a closer look.
A biennial plant or short-lived perennial producing a rosette the first year and flowering the second. It is believed to have been accidently introduced from Europe in the late 1800s through contaminated alfalfa and clover seed and in soil used for ship ballast.
Subterranean termites form colonies and forage for wood in soil, which provides moisture and protection from extreme temperatures. As a result, subterranean termites are more widespread than drywood termites, which are more vulnerable to extreme cold. Also unlike drywood termites, subterranean termites don’t live in the wood they’re eating. Since their colony size is not limited by wood, one subterranean termite colony can cause more structural damage than one drywood termite colony. Subterranean termites occur in every US state except Alaska and in Canada are typically found in high density population areas in Eastern Canada and BC. Subterranean termites are limited by frozen topsoil in areas where winters are extremely cold, reducing the overall number of structural infestations in these areas.
Indigenous to Japan, this perennial was introduced to North America in the 19th century. Japanese knotweed forms dense stands spreading predominantly by extensive rhizomes creating a very persistent and hard-to-kill plant. Small pieces of rhizome can produce new plants very quickly. The species can be found in riparian areas, wetlands, roadsides, utility right of ways and fence lines. This invasive species can grow up to a meter in height in three weeks. There are similar species, including Himalayan, Giant and Bohemian knotweeds. Japanese knotweed is considered to be one of the world’s most invasive plant species.
Blacklegged ticks are also known as deer ticks because the white-tailed deer is the main host of their adult reproductive stage. The blacklegged tick is widely distributed across the eastern United States and has been expanding into southeastern Canada. The western blacklegged tick occurs along the U.S. Pacific coast into southern British Columbia. Both blacklegged ticks are vectors of Lyme disease.
Two mice belonging to the genus Peromyscus are collectively called “field” mice in pest management. The deer mouse occurs in most of Canada and the United States (except the southeastern states). The white-footed mouse overlaps the deer mouse in the eastern and central U.S. and extends into the southeast. Both have large eyes and are sharply bicolored with white along the bottom of their bodies. While they may be difficult to tell apart from each other, they look different from house mice, which have smaller eyes and are more uniform in color.
A native of Europe, Common Tansey was originally introduced to North America in the 1600’s. Common Tansey is considered a noxious weed in all prairie provinces and British Columbia. It can form dense stands and contain alkaloids which are toxic to both humans and livestock if consumed in large quantities. Common Tansy prefers sunny areas with well-drained soils, and often infests roadsides, pastures, and fence lines.
The fruit fly originated in tropical African rainforests and spread to all the major continents by ship transport. It was first reported in New York State in 1875. By 1915, it was reported from California and was common throughout northern America in 1920. The fruit fly is an effective colonizer due to its short life cycle, high offspring production and its ability to fly several miles per day. It is a frequent pest in food-handling establishments.
Originally native to Turkey and Georgia, Giant hogweed was introduced as an ornamental to North America likely due to its significant height of 2 to 5 meters. It is a biennial or short lived perennial and reproduced by both seed and tuberous root buds.
The common house spider is native to South America, but now occurs across the contiguous United States into southern Canada through transportation in plants. It mostly lives around humans, making it one of the most common spiders to build webs indoors. The common house spider belongs to a family of spiders that frequently abandons its web and builds another nearby. Dust settling on abandoned webs creates cobwebs, which accumulate if not removed often.
A deciduous short lived tree, reproducing by both seeds and spreading roots (suckers). Aspen popular can be considered a problem weed due to the multiple sucker plants feeding off the mother plant and have been known to penetrate even sewer lines. Plants are either male or female.
An annual, biennial or short lived perennial that originated in Eurasia but now common to Western Canada. The species is competitive in sheer numbers alone since it reproduces only by seeds. The seeds have no dormancy. Large populations and no dormancy increase the complexity of control options. Aliases of this weed are mayweed and scentless mayweed.
Twenty-four species of carpenter ants are structural or nuisance pests in North America, although each species may be found in different regions. All carpenter ants can be recognized by the evenly rounded thorax when viewed from the side. Color is variable amongst the species, from black, red and black, to even a yellowish-brown. The black carpenter ant (Camponotus pennsylvanicus) is the most common species in the East; the western black carpenter ant (Camponotus modoc) is most common species in the West.
Although named the German cockroach, the most widespread cockroach pest in the world probably originated in Southeast Asia and expanded to urban areas through human travel and commerce. The first specimens to be identified may have been from Germany and assumed to be German. However, the fact that cold is a major limiting factor to their survival points to their not being native to Europe.
Originally from Eurasia, it is a perennial with a strong pungent sage-like odor. It forms a shrub and the new growth emerges from an existing crown each spring. Often found in pastures or roadsides, it can be a difficult and troublesome pest.
A perennial with extensive underground creeping roots – which makes this weed a challenge to control. Canada thistle is a native of Eurasia but was introduced to North America in the late 18th century.
The house mouse probably originated around northern India and stowed away in grain supplies as people migrated around the world. It is now a worldwide pest and, in most cities, it is the top rodent pest. In addition to being transported to new areas as stowaways, house mice are able to enter smaller structural openings than rats and require very little living space. They also require less water than rats because, if necessary, they are able to meet their body’s moisture requirement by producing metabolic water from food. Once indoors and a food resource is established, they can breed throughout the year.
What do both of these weeds have in common? They originate from the same are - Eurasia. Both weeds have an extensive creeping root system which makes them difficult to control. Both weeds aggressively invade rangeland and have yellow flowers.
Raccoons in general are New World animals. Of the three raccoon species that exist, the common raccoon is the largest and most widely distributed. It is native to North and Central America from southern Canada down to Panama. Originally from the tropics, the common raccoon is one of a few larger animals whose range increased along with human settlement. They have been introduced outside of their native range into Europe and Japan where they have become invasive.
Native to Asia, kochia- a summer annual broadleaf - was introduced as an ornamental to North America. Today, it infests fields, gardens, roadsides, ditches, and waste areas. It is commonly known as summer cypress, burning bush, and goosefoot. Kochia has a unique seed dispersal method since a mature plant will roll with the wind leaving a trail of offspring in the following growing season. One plant can produce up to 25,000 seeds but they are short lived in the soil. Kochia is one of the very first to emerge early in the spring and can survive harsh soil conditions, including sandy or alkaline soils.
Today, rock pigeons are common in cities around the world. Originally, they were cliff-dwelling birds with a natural range from western and southern Europe through northern Africa to southwestern Asia. The earliest record of their domestication dates back to at least 5,000 years ago in the eastern Mediterranean, making rock pigeons the world’s oldest domesticated bird. They were the main bird eaten in Europe and the Middle East for many years. Due to their good homing ability, they were also used to send messages over long distances. European settlers first brought domesticated rock pigeons to North America in the early 1600s. All feral rock pigeons in North America are the result of escaped domestic birds.
Commonly known as common reed grass; originated in Eurasia. Invasive Phragmites are moving west from Eastern Canada; they've been identified as far as Alberta.
Norway rat is the official common name for a rat that is native to the eastern Siberia/China border and parts of Japan. This misnomer occurred because the English naturalist who classified the rat in 1769 thought the rat was introduced to the UK on Norwegian ships. Although not true, the name stayed and continues to be used today.