Creature Feature

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. Continue Reading

The house cricket, likely native to southwest Asia, was introduced to the United States and Canada in the 1700s through human migration. Now it lives outdoors in southern California and the eastern states, with the curious exception of the Florida peninsula for reasons still unknown. House crickets are popular feeder insects for reptile and amphibian owners, making them a common sight in their homes, pet stores, or facilities that house these animals. Continue Reading

The common house spider, native to South America, now thrives across the contiguous United States and into southern Canada, often hitchhiking in plants. These spiders frequently live near humans, making them a common indoor presence. Belonging to a family of spiders known for abandoning their webs to build new ones nearby, their deserted webs gather dust, forming the cobwebs we often see if not regularly cleaned. Continue Reading

The spotted lanternfly, despite its name, is not a fly but a type of planthopper native to China. Its preferred host is the tree of heaven, or Ailanthus, but it isn't picky—it can damage over 173 types of crops and ornamental plants. In its native habitat, parasitic wasps keep its population in check. However, in the United States, where it first appeared in Pennsylvania in 2014, the spotted lanternfly has become an invasive menace, spreading rapidly to 13 surrounding states. Interestingly, both tree of heaven and the spotted lanternfly are considered invasive species in several states, though they did not arrive together. Continue Reading

The yellow fever mosquito (Aedes aegypti) originated in Africa, where it evolved from an ancestor that still exists there today.  Its ancestor prefers to lay eggs in natural tree holes and to feed on non-human animals.  At some point, the yellow fever mosquito became domesticated, breeding in artificial containers close to humans and preferring human hosts.  This domestication allowed their introduction into the New World via European ships leaving West Africa with slaves and containers of drinking water also holding immature yellow fever mosquitoes. Continue Reading

This month we are addressing a pesky weed, Crabgrass. The two most common species of crabgrass in North America are large (or hairy) crabgrass (Digitaria sanguinalis) and smooth crabgrass (Digitaria ischaemum). They are native to Europe and Eurasia and were introduced to the United States in 1849 as a forage crop.  Both are now found across the U.S., in Canada, and almost worldwide. The main difference between them is the presence or absence of hairs on the leaf sheath. Continue Reading

Clover mites are a type of spider mite that feeds on grasses and weeds, such as clover. They are relatively large for a plant-feeding mite, and their front pair of legs are longer than the rest, which they hold forward like antennae. Eggs and newly hatched larvae are bright red, but, as they age, their bodies turn dark green. All clover mites are female and develop from unfertilized eggs. Clover mites use vertical surfaces, such as trees and buildings, to lay their eggs and molt. Continue Reading

Boxelder bugs are pests of the boxelder tree, a species of maple native to the Midwest. As the boxelder tree was introduced to other areas of the United States and Canada, boxelder bugs followed. The western boxelder bug is present from New Mexico, Utah and Idaho westward to the Pacific coast and up into British Columbia. The boxelder bug is present east of this region in Canada and the United States with some overlap between the two regions. These two boxelder bugs look similar except the western boxelder bug has more red veins on the upper membranous half of its forewings. Continue Reading

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. Continue Reading

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. Continue Reading

The cigarette beetle is a common stored product pest that has a history of being associated with humans dating back to Egyptian tombs. Although a tropical insect, it has a worldwide distribution considering stored products are normally kept in climate-controlled environments. It is closely related to the drugstore beetle, a temperate stored product pest with similar habits. The cigarette beetle has serrate antennae and smooth wing covers; the drugstore beetle’s antennae end in three-segmented clubs and their wing covers have pitted rows. Continue Reading

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 the United States, roof rats began to decline. Whereas Norway rats are found in every state, 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. Continue Reading

The European hornet was introduced to the United States in New York, between 1840 and 1860. Since then, it has spread to the other east coast states, across to the Mississippi River, and up into parts of North and South Dakota. Workers are brown with yellow markings and, being hornets, can reach up to one and a half inches in length. They do not look like northern giant hornets, also known as “murder hornets,” which are almost two inches long, making them the largest hornet in the world. While the European hornet is established in the United States, northern giant hornets are not, and were last seen in 2021 in Washington state. Continue Reading

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 common bed bug has a worldwide distribution and is the dominant bed bug in temperate climates. Continue Reading

Excluding the northeastern and upper midwestern states, scorpions are present across most of the US and just over the border into southwestern Canada. Although they can be found in a variety of habitats, many live in hot and arid deserts. Of the 90 or so species in the U.S., all but four naturally occur west of the Mississippi river with the highest concentration in the desert southwest. Most are terrestrial, living under objects on the ground or in burrows, but some are arboreal, meaning they live up in trees. Continue Reading

Two house mosquitoes (Culex spp.) are present in the United States: the northern house mosquito and the southern house mosquito. The northern house mosquito was introduced from North Africa and is present across the northern US; the southern house mosquito was introduced from Southeast Asia and is present across the southern US. There is a hybrid zone where these mosquitoes meet and are able to produce viable offspring, indicating they are probably subspecies instead of two separate species. Continue Reading

The Turkestan cockroach is native to much of the Middle East through Central Asia. It was most likely introduced to the United States in military equipment returning from the Middle East in the late 1970s. Since then, it has become common in southern California and across the southwestern states into Texas where it appears to be displacing the Oriental cockroach. It may occur in other states near military bases or due to its popularity as a live feeder insect for reptile pets. Continue Reading

Moles are small mammals (not rodents) that live underground in burrows and mostly eat earthworms and insects. They are active day or night, tunneling underground to find food. Sometimes, their tunnels breach the soil, especially in the spring and fall, or during rainy periods in the summer, when higher soil moisture pushes their prey up towards the surface. Shallow tunnels create ridges in turf and can injure grass roots, turning the surrounding turf brown. Moles also create hills of soil pushed up from deeper tunnels. Continue Reading

Blow or bottle flies are common around most of the world. They serve an important role by quickly consuming organic waste, such as animal remains, feces, and garbage, in the environment. Adults of some species arrive within minutes to the presence of animal remains, where they’ll lay their eggs that hatch into maggots to consume the body. Forensic entomologists are able to use the maggots’ developmental stages to determine a body’s time of death. Continue Reading

House centipedes are native to the Mediterranean. They are now found throughout the United States, living both indoors and outdoors. Outdoors, they live under mulch, leaf litter, rocks and logs. Cold weather can push them indoors, where they can survive year-round as long as there is access to moisture. They prefer cool, humid and dark places such as bathrooms, basements and crawl spaces. Continue Reading

The dark rover ant is one of several species of rover ants present in the United States, both native and introduced. It is native to South America, where it survives well in a variety of habitats, especially urban and suburban areas. Although introduced to the U.S. as early as 1976 in Louisiana, it didn’t become widely reported as a structural pest until the early 2000s. It is now mostly found in South Carolina, Georgia and the Gulf states, as well as some urban centers in Arizona and southern California. Continue Reading

Voles belong to a group of rodents containing many species collectively referred to as meadow voles. Although they look like mice, voles are generally stouter with shorter ears and tail. They behave differently from mice as well and usually stay outside of structures. Voles live underground in shallow burrow systems and are poor climbers. Continue Reading

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. Continue Reading

Odorous house ants (OHAs) belong to a subfamily of ants that use strong odors from anal glands as a chemical defense—there is no stinger. The odor isn’t unique to them, but comes in handy when identifying them against similar-looking pest ants. Although historically described as “rotten coconut”, pest management professionals (PMPs) didn’t always agree about what the odor smelled liked. A study in 2015 clarified the source of the odor as an organic compound also associated with blue cheese and rotten coconut. Penicillium molds that turn coconuts rotten are also used to make blue cheese, so PMPs that smell either are both correct. Continue Reading

There are several species of yellowjackets across North America. Most have a distinctive pattern on their abdomen that tells them apart from the others. While most yellowjackets are yellow and black, some are white and black. Yellowjackets belong to a subfamily that contains Vespula and Dolichovespula species. Vespula species tend to nest in the ground or in above-ground voids and Dolichovespula species tend to build aerial nests. Although the baldfaced hornet was given the name “hornet” because of its large size, it is a Dolichovespula species of yellowjacket. Continue Reading

The yellow fever mosquito (Aedes aegypti) originated in Africa, where it evolved from an ancestor that still exists there today. Its ancestor prefers to lay eggs in natural tree holes and to feed on non-human animals. At some point, the yellow fever mosquito became domesticated, breeding in artificial containers close to humans and preferring human hosts. This domestication allowed their introduction into the New World via European ships leaving West Africa with slaves and containers of drinking water also holding immature yellow fever mosquitoes. Continue Reading

House flies are the most common flies associated with humans and their animals. Originally from central Asia, they now occur in inhabited areas worldwide. Since house flies breed in feces and garbage, they can transmit diseases from these mediums onto food and food preparation surfaces. Studies have shown that community-wide fly management reduces cases of infectious diarrhea, which can be caused by various pathogens. House flies may carry these pathogens on their bodies or in their bodies and deposit them in their feces or regurgitated gut contents. Continue Reading

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. Although subterranean termites occur in every state except Alaska, structural infestations are more common in warmer climates. Subterranean termites are limited by frozen topsoil in areas where winters are extremely cold, reducing the overall number of structural infestations in these areas. Continue Reading

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. Continue Reading

Red and confused flour beetles are one of the most common stored product pests. Physically and behaviorally, they are practically the same and can be approached with the same management methods. The main difference between them is that adult red flour beetles fly (although not strongly) and adult confused flour beetles do not. Adults are up to ¼ inch long with flattened bodies that help them hide in tight crevices. They can also live from one to three years, are very active and cause feeding damage along with the larvae. Continue Reading

Moth flies are fuzzy little flies with wing veins that run parallel from base to tip. In nature, they breed in moist, polluted environments that sometimes flood, where their larvae feed on decaying organic material. In and around structures, moth flies are common in plumbing drains and sewage systems. Because moth flies develop in decaying organic material, they may carry pathogens in healthcare facilities or to food handling areas. They may also cause allergic asthma in sensitive people. Continue Reading

Conenose or kissing bugs are blood-feeding insects that have a history of biting around people’s faces. Eleven species have been found in the United States – in Hawaii and the lower 29 states from California across to New Jersey. Most are found in Texas, New Mexico and Arizona. Continue Reading

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. Continue Reading

Springtails are a group of organisms that have six legs (hexapods) like insects. However, springtails are not insects, mainly because their mouthparts are enclosed within the head, whereas insects have external mouthparts. Most springtails have a forked appendage (furcula) held under the abdomen that helps them escape predators by catapulting them into the air when sprung against the ground. Hence the name springtails. Continue Reading

The most common skunk in North America is the striped skunk, which is found across southern Canada down through the continental United States and into northern Mexico. Skunks have enlarged anal scent glands that produce an oily defensive fluid containing sulfur-based compounds that can be sprayed up to 10 feet away. If not surprised, skunks may warn before spraying by raising their tail and stomping their front feet. Continue Reading

Black Widow Spiders are one of the two groups of medically important spiders in the United States. Three species of black widow spiders are native to the U.S., but only two are common around structures – the southern and western black widow spiders. Adult females of both species have shiny black bodies and globular abdomens with a red hourglass marking underneath, except the western black widow has an additional red spot above the tip of the abdomen. Continue Reading

The pharaoh ant is native to Africa and was named in 1758 by Linnaeus using a type specimen from Egypt. In naming this ant, Linnaeus may have been under the impression that it was one of the ten plagues of Egypt. It has been a worldwide pest (or plague) for over 100 years and is historically well-known for infesting structures. Being a tropical ant species, it can nest outdoors in soil in subtropical areas. In temperate regions, it mainly nests inside heated structures because it cannot survive outdoors year-round. Continue Reading

Boxelder bugs are pests of the boxelder tree, a species of maple native to the Midwest. As the boxelder tree was introduced to other areas of the United States and Canada, boxelder bugs followed. The western boxelder bug is present from New Mexico, Utah and Idaho westward to the Pacific coast and up into British Columbia. The boxelder bug is present east of this region in Canada and the United States with some overlap between the two regions. These two boxelder bugs look similar except the western boxelder bug has more red veins on the upper membranous half of its forewings. Continue Reading

Although native to South America, the Indianmeal moth is now present in most of the world and one of the most common stored product pests. “Indianmeal” is another name for cornmeal, in which the American entomologist who named the moth found larvae feeding. Indianmeal moths attack a wide variety of both whole and processed seed products. They prefer coarse flours like whole wheat and cornmeal. In homes, bird seed and dry pet food are common infestation sources. Dried fruit, spices, powdered milk, and chocolate can be infested as well. Continue Reading

There are just over 20 species of paper wasp in North America. Like yellowjackets and hornets, they chew wood and mix it with saliva to create the paper with which they build their nests. Their nests consist of an open comb layer supported by a stem and often resemble an umbrella. A mature colony may contain up to 200 to 300 wasps, but colonies are usually smaller. Continue Reading

The common malaria mosquito (Anopheles quadrimaculatus) is actually a group of five species that are genetically different but look so much alike that it is difficult to tell them apart under a microscope. These mosquitoes are present in the eastern United States up into southeastern Canada, but are more prolific in the southeastern states, especially along the Gulf of Mexico. They are the main vector of malaria in North America. Although malaria outbreaks have not happened in the United States since the 1950s, local transmission does occur sometimes. Continue Reading

Phorid flies are small flies that mostly breed in decaying animal or plant material. Some are parasites, as in the genus Pseudacteon, which contains species that have been released in the United States to biologically control red imported fire ants. The larvae of these phorid flies decapitate worker ants by consuming the contents of the head and causing it to fall off. Continue Reading

Millipedes are multi-segmented arthropods that have two pairs of legs on most of their body segments. Most millipedes live outdoors in damp soil and feed on decaying vegetation. Some species defend themselves by producing noxious or irritating fluids that leave stains or cause blisters. Continue Reading

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. Adults females have wing stubs and may look like beetles before taking a closer look. Continue Reading

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. Continue Reading

The American cockroach is the largest pest cockroach in North America, averaging 1½ inches long. Being native to Africa, it is American in name only and was probably introduced to the United States on ships in the early 1600s. As one of the most common cockroaches on ships, it eventually spread to become a worldwide pest. Continue Reading

The Virginia opossum is the only marsupial (pouched mammal) native to the United States. It is found along the west coast and east of the Rocky Mountains. Even though it doesn’t survive well in extreme cold, its range has extended into parts of southern Canada, most likely due to the availability of shelter from man-made structures. Although the words “opossum” and “possum” are used interchangeably, opossums are found in the Americas while possums refer to unrelated marsupials native to Australia. Continue Reading

Bat bugs belong to an insect family that primarily contains human, bat and bird parasites, including bed bugs. Two bat bug species are present in the United States: the eastern and western bat bugs. Bat bugs are closely related to bed bugs and are very similar in size and appearance. Under magnification, bat bugs look harrier than bed bugs because the hairs on their bodies are longer. Continue Reading

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. Continue Reading

The Oriental rat flea is a primary vector of two human bacterial diseases, plague, and murine typhus. Although it is also known as the tropical rat flea, it is found in subtropical and temperate areas, especially in major cities. Studies have found Oriental rat fleas on Norway rats in Los Angeles (2007) and New York City (2015), although they were not infected with the bacteria that cause plague or murine typhus. Continue Reading

Two house mosquitoes are present in the United States: the northern house mosquito and the southern house mosquito. The northern house mosquito was introduced from North Africa and is present across the northern US; the southern house mosquito was introduced from Southeast Asia as is present across the southern US. There is a hybrid zone where these mosquitoes meet and are able to produce viable offspring, indicating they are probably subspecies instead of two separate species. Continue Reading

The West Indian drywood termite is the most widely and frequently introduced termite in the world. Although called West Indian, they are not native to the West Indies, but to the Pacific coastal deserts of southern Peru and northern Chile. In the United States, the West Indian drywood termite is common throughout Hawaii and Florida. In Florida, it is the most common drywood termite infesting structures. Heavy infestations also occur in coastal areas of southeastern and Gulf states. For example, New Orleans, Louisiana and Galveston, and Corpus Christi, Texas are major port cities where West Indian drywood termite infestations are common. Continue Reading

The house sparrow is the most common wild bird in the world. Originally from the Middle East, it spread to Asia, Europe, and North Africa following agriculture and was deliberately introduced to other places in the world. In North America, eight pairs were released in Brooklyn, NY in 1851. By 1910, house sparrows were established in California. Continue Reading

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. Continue Reading

The brown dog tick is unique in that it can complete its entire life cycle indoors. As a result, it is more of a domestic pest (occurring in and around structures) than other tick species. Other ticks can be brought indoors, but they are not able to build populations and infest structures like the brown dog tick. Because it is primarily an indoor parasite of the ever-present domestic dog, it is the most widespread tick in the world. It is usually introduced into a structure on an untreated dog that originated from or visited an infested location. Continue Reading

The West Indian drywood termite is the most widely and frequently introduced termite in the world. Although called West Indian, they are not native to the West Indies, but to the Pacific coastal deserts of southern Peru and northern Chile. In the United States, the West Indian drywood termite is common throughout Hawaii and Florida. In Florida, it is the most common drywood termite infesting structures. Heavy infestations also occur in coastal areas of southeastern and Gulf states. For example, New Orleans, Louisiana and Galveston, and Corpus Christi, Texas are major port cities where West Indian drywood termite infestations are common. Continue Reading

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 sending 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. Continue Reading