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Carpenter ant: Image by Mikhail Vasilyev

Pacific Northwest Pest Directory

In our years of experience, these are the most common pests we encounter, along with some tips on identification, treatment and possible hazards.

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Norway Rats

The Norway rat is an aggressive rodent with strong senses of hearing, smell, taste, and touch. They have incredible capabilities of gnawing through just about anything for food and water sources. Norway rats prefer to live in low lying areas such as crawlspaces and sewers where they can thrive regardless of unsanitary conditions. While they prefer dark and quiet spaces, these rambunctious rodents can be quite noisy when scavenging for resources, mating, and during territorial disputes.

Norway rats don’t need much room when attempting to infiltrate your home. About half an inch is all these rodents need to occupy your residence. Gaps in crawlspace entrances, torn vent screens, and holes around exterior piping are all examples of key entry points for the Norway rat.

Roof Rat

Roof Rats

Roof rats, also called black rats, and house rats, are smaller rats, usually black in color and possessing tails which are longer than their body.  Roof rats have larger eyes and ears relative to brown rats and are smaller overall in size. Known for climbing in walls and being difficult to eradicate, rats spread around the world as humans travelled and have become established almost everywhere humans live.  Roof rats spend most of their lives in elevated locations, and enjoy climbing in walls, attics, garages, above ceilings and in trees or around ventilation.    

Rats are a common pest worldwide, serving as destructive creatures both in residences and commercial, especially agricultural, settings.  Rats are known for carrying fleas which can spread a multitude of diseases, making them dangerous for humans.  Additionally, rats infest food stores, consuming and spoiling the contents, and make nests in inconvenient places around human habitations.  Nest sites can include inside stored boxes and packing materials, clothing, attics and inside walls.  Signs of roof rats include noises within walls, partially consumed food, and chewing on and around roof eaves or on wiring. 


House Mice

House mice, like rats, are small rodents found worldwide.  The house mouse is one of the most common examples of mice encountered,  widely taking up residence near humans and often kept as pets.  While they often spend warmer months outside, as weather grows colder they seek shelter and food in human residences. They gnaw on household objects and structures, and can cause significant damage to electrical wires.  

Mice are smaller and thus easier to catch then rats using a variety of lethal and nonlethal traps that are readily available.  However, due to their high breeding rates it can be very difficult to fully eliminate a mouse infestation. If homemade strategies are not successfully controlling your mouse population, you may benefit from contacting professionals to help!

Deer Mouse

Deer Mice

Deer mice are native to North America, and common across the United States.  Recognizable for their larger ears and eyes, deer mice also usually have brown fur except on their undersides, which are white.  Deer mice are notable for their ability to carry hantaviruses and Lyme disease, among other diseases, making them a serious pest that should be removed from your living spaces.

Like other mice, deer mice can be captured using various traps both commercial and homemade.  They are also difficult to eradicate fully due to their high breeding rates.  In addition to the challenge of removing an established population, if you cannot identify how they are getting into your house, it is possible that more could enter from outside after removing the established residents.  

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White Footed Mice

White footed mice are small mice, up to about four inches in body length, which distinctive white feet.  Common across the southeast of the country, they can rarely be found in Washington.  These mice are shy, and usually avoid humans where they can.  This makes  them uncommon pests in households, but as they can potentially carry disease they are still potentially quite damaging.  

White footed mice normally live in warmer, dry habitats but can adapt to live in urban settings.  These mice are omnivores, and excellent climbers, which contributes to their ability to travel and survive in many habitats. 

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Yellow Jackets

Though they are beneficial predators of many pest insects, the Yellow Jacket is an aggressive insect that is capable of stinging repeatedly. They can be extremely dangerous to anyone allergic. Yellow Jackets are social wasps and hunters that construct nests made from chewed wood fibers mixed with their saliva. These nests can contain thousands of workers with a single queen. While they are capable of pollination, Yellow Jackets only resemble bees in size and general color. Their thin waist, hairless bodies, and shiny yellow color distinct them from the bee.

Yellow Jackets prey on other insects but also have a liking for sweets, which is why you find them circling picnic tables and outdoor dining tables. These wasps are known to be ground nesters, establishing their nests under porches, between cracks, and at the base of trees. When they do build above ground, nests are typically built inside bushes, within eaves, and if capable of entering the home, behind and inside wall voids. 

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Paper Wasps

Paper wasps are boldly colored in black and yellow, more readily identifiable by their open-celled nests then by the wasps themselves, which look very similar to yellow jackets.  These wasps are one of the more significant insect threats to humans, though they are generally not as aggressive as yellow jackets.  If disturbed, these wasps can sting multiple times, and their venom can cause serious allergic reactions in some people.

Paper wasps are very common in western Washington.  They build the distinctive papery nests with open cells, and are frequently found under overhangs, on support beams, and the sides of buildings.  In nature, wasps serve as a form of organic pest control, hunting other insects and frequently undesirable pests near homes and gardens.  Despite this value, wasps are often considered pests due to their ability to sting and similarity to more aggressive insects. 

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Bald Faced Hornets

Bald faced hornets are common across southern Canada and the United States. Primarily carnivorous and hunting other arthropods, they favor flies which adds some value to their presence.  Though related to yellow jackets, bald faced hornets are usually slightly larger and more black and white rather than yellow in color. 

Bald faced hornets are a significant nuisance due to their protective behavior near their nests, attacking and stinging perceived intruders.  Unique among stinging insects, bald faced hornets can spray venom at intruders in addition to stinging, usually targeting eyes.  For these reasons, extreme caution is warranted when dealing with these insects, and for larger nests it is often best to obtain professional assistance for their removal. 



Bees is a generic term referring to pollinating insects, related to wasps which fill a crucial ecological niche.  Most readily recognized are the honeybees, small insects with the ability to sting which are central to pollination of both natural ecosystems and commercial crops.  The decline of the honeybees is a source of significant concern worldwide, and for that reason no pest control is recommended for bees.  As a bee will die after stinging someone, they are usually quite docile and only sting when they feel themselves or the nest are being attacked. 

If you feel threatened by the presence of bees nearby, it is best to take natural steps to discourage them from visiting your home.  They are attracted to bright colors, flowers, and sweet things, so avoiding keeping these things close to the home’s entrances can help discourage the bees.  Additionally, there are natural scents, like lavender, which bees dislike and avoid, which can help keep bees away from your residence.  We do not offer pest control services for bees.

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Common House Spiders

Common house spiders are the most frequently seen spiders near residences, building webs on the side of buildings, near light fixtures, and in gardens or outdoor structures.  These spiders will only bite if handled and aggravated, though accidental squishing increases the frequency of bites.  They are effectively harmless, with any bites producing little more than an irritated bump like a mosquito bite, despite widespread fear of spiders.  


With the largest specimens’ bodies measuring under a quarter inch long, these spiders are generally considered beneficial due to their predation on flies, mosquitoes, and wasps, among other pest insects. 

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Giant House Spiders

While intimidating at first sight, the Giant House Spider does not pose a threat to homeowners or their pets. These spiders would prefer to hide rather than bite, though they can and will bite if provoked. Formally holding the world record for top spider speed, this quick moving arachnid builds their nests in attics, crawlspaces, and between clutter. Males are typically seen more often as they actively search for mates, with their activity mostly occurring between the summer and fall months.

These spiders are known for their single flat and disarranged webs with a single funnel for refuge. A common spider to find within the home, the Giant House Spider prefers dry forests, rocks, and caves. Keeping a clean and organized home and garage will limit the amount of these spiders. Look near windows for entry points via small cracks. 

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Hobo Spiders

The hobo spider is a relatively large spider that commonly resides in fields and near structures in wood piles or brick walls.  These spiders build funnel shaped webs in which they hide and wait for potential prey to approach.  These spiders avoid areas with competition from other similar spider species and are uncommonly encountered in homes due to competition from giant house spiders. 

While there are historical anecdotes of hobo spider bites being toxic and causing necrosis, it is now believed that those were mistakenly identified and caused by other species.  Hobo spiders are classified as posing no threat to humans, though the bite can be temporarily painful.

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Wolf Spiders

Wolf spiders are large, primarily solitary spiders with worldwide distribution.  Notable for their excellent eyesight, wolf spiders are hunting predators which do not spin webs and prefer to stalk or ambush prey.  Wolf spiders are most notable for their method of carrying their eggs and spiderlings.  The female wolf spider carries the egg sac with it while moving around, and after the young hatch she continues to carry them on her back for a time until they can better fend for themselves.  

Wolf spiders are another species long associated with causing necrosis, but studies show that is most likely not an effect of wolf spider bites.  The bites do cause swelling, mild pain and itching though, which makes them unpleasant.  Despite this, wolf spiders can be seen as beneficial as they consume a variety of agricultural pests that otherwise could damage plants in a garden. 

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Black Widow Spiders

One of the most recognizable spiders in the world, the black widow is known by its small, beady shape, glossy black coloration, and red hourglass on its abdomen.  Building messy webs with no perceivable organization, black widows are found across western North America.  

These spiders are one of the few considered dangerous to humans, though no confirmed fatalities occurred in the past several decades the bites are extremely painful and frequently require hospitalization.  Black widows favor tall grass and dry firewood to hide in, so keeping the area around your house clean and orderly without buildups of undisturbed natural materials will help discourage black widow spiders. 

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Yellow Sac Spider

The yellow sac spider is a smaller spider species which also possesses venom reported to cause necrosis in victims.  While these reports are anecdotal and likely unreliable, the spider bites do cause localized swelling and are unpleasant.  The spiders are recognizable by their pale-yellow bodies.  

Yellow sac spiders will live in human homes as well as gardens or forests.  These spiders do not build webs to capture prey, relying on actively hunting and travelling to locate and capture small arthropods.  

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American Cockroaches

Not endemic to America, the American cockroach is believed to be native to Africa and the Middle East, introduced to the Americas in the seventeenth century. The largest of the cockroaches, American cockroaches can now be found across the world following the spread of human habitation and global trade.  Often about an inch and a half long, American cockroaches are reddish brown, and can fly for short distances. 

Not picky eaters, these cockroaches will consume a wide variety of things, including food scraps, beer, tea, decomposing organics, and starchy papers and book bindings.  They prefer to live in damp areas but can survive throughout a house if they can access water.  For this reason, they are common in basements, crawl spaces, hiding in walls and foundations or other concealed locations with access to potential food and water sources.  Aside from being gross and unpleasant, the cockroaches can potentially carry disease and contaminate food stores inside a home, and the dust they create can contribute to allergies and asthma in susceptible individuals.  If you think you have an infestation, it would be best to act fast to get rid of them!

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German Cockroaches

German cockroaches look relatively similar to American cockroaches, but are much smaller, usually roughly a half inch in length.  They are unable to fly well but can manage a short distance if they need to escape or reach something. These are arguably the most widespread pest cockroaches, appearing even far north and south in human structures where they could not survive outside for long due to cold climates.  They are notable for invading food establishments, including restaurants, and commercial structures that have food present, like hotels or care homes.

Not truly German, these cockroaches are of highly disputed origin, with historical theories identifying Europe or Ethiopia, but most recently speculated as emerging from Southeast Asia.  As scavengers, they will eat a wide range of foods including meats, sugars, and carbs, enabling them to survive in a multitude of settings. Facing a shortage of other foods, they may resort to consuming things like glue and toothpaste! These cockroaches have very resilient populations which can be extremely difficult to eradicate, as they mature quickly and even a few eggs escaping control measures can reestablish the population.  Control methods need to be consistent, sustained, and paired with measures to prevent reintroduction of the population from outside to be successful. 

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Brown Banded Cockroaches

With a maximum size of about a half inch, brown banded cockroaches are among the smallest common pest cockroaches.  Entering the Southeast United States through the Caribbean, these cockroaches have become recognized pests across the country.  They are somewhat harder to detect than other cockroaches, being smaller and more widely distributed.  They are not as water dependent as many other cockroaches and can be found in living rooms and bedrooms in addition to places with more consistent moisture.  Brown banded cockroaches eat almost anything, again contributing to their ability to live in a variety of locations. 

Due to their hiding abilities, it is important to assume that there may be an infestation even if you only find an occasional insect.  They can live in higher cabinets and in furniture and can spread pathogens to any food they come into contact with.  As with most cockroaches, the dust they cause can exacerbate allergy and asthma symptoms, and eradication of an infestation may require professional assistance due to the resilience and varied diet of the brown banded cockroach. 

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Oriental Cockroaches

These large cockroaches are originally from the region of the Black and Caspian Seas.  They are often about an inch long, shiny, dark brown in color and oval shaped.  These cockroaches will eat scraps of food but prefer decaying organic matter and most often come into houses in search of water.  For this reason, these cockroaches are most often found in basements, crawl spaces or near sinks and in bathrooms.  They usually live outside in warmer months but may seek refuge in homes as the temperatures drop in late fall and winter. 

Oriental cockroaches are flightless and possess only vestigial wings.  This contributes to them being slower and easier to catch than most cockroaches, but because they are not as dependent on human food scraps, they may be harder to find and eradicate.  Keeping surfaces clean and eliminating all standing water will help discourage their presence, as will sealing possible entry points around windows, pipes, and doors. 

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Carpenter Ants

The Carpenter Ant is a very beneficial insect that aids in the decomposition of fallen trees, but what they can’t do is distinguish the difference between decaying wood in the forest and wood damage in your home. Seeking out moist environments for refuge, these large ants cut tunnels into wood for passageways known as galleries. Unlike Termites, Carpenter Ants do not digest wood for food consumption. Known as “frass”, these ants will discard of wood shavings they removed when conducting their extensive tunnels.

These ants are known to forage in the darkness where they prey upon dead insect carcasses and honeydew nectar on plants produced by aphids. In addition to the food they find in nature, Carpenter Ants enjoy many of the sweets we humans indulge in like honey, juice, and syrup. Dusk would be the ideal time to spot these ants at work, but you can also look under windowsills, decks, and roof eaves. These ants gravitate to moist wood, so any areas of your home that meet water throughout the year are good spots to check for frass left behind.

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Odorous House Ants

This small species of ant, also known as the sugar ant, is a common household pest that can become a major nuisance. Odorous House Ants are extremely tough and difficult to remove from the home once they have established themselves. Large colonies contain multiple queens, therefore they breed quickly and have many chains of command in waiting. The Odorous House Ant is a scavenger and a predator that enjoys both the consumption of sweet foods containing sugar and other insects.

These ants are known to be social and tolerant of other ant species, creating nests diverse with multiple ant species. Odorous House Ants are invasive during the later winter and early spring months, particularly after it rains. Attracted to moisture, these ants are known to gravitate towards standing water. Materials stored close to the home such as firewood and plants making contact with siding are also easy paths for this intrusive ant. Crushing one of these tiny ants between your fingers will emit a smell similar to a rotting coconut. 

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Bed Bugs

Bed bugs are a common household pest, biting in the night and causing irritating rashes or allergic reactions.  Though they are not known to transmit disease, bed bugs are extremely irritating pests which are difficult to eliminate on your own.  If you miss just one pregnant female bed bug you can be re-infested by hundreds more within a couple months.
Bed bugs are troublesome household pests. They’re sneaky, hard to find, and can pose potential health risks for you and your family. More serious problems caused by bed bug infestations can include anxiety, stress and sleep difficulty.  For these reasons, it is best to allow professionals to eliminate the bed bugs for you and your family.  

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Brown Marmorated Stink Bug

These small, shield shaped bugs are under an inch long, and most often green and brown in coloration.  Native to east Asia, they were accidentally introduced to the United States and have become a serious agricultural concern.  As their populations are increasing across the US, if you see them around you may want to get rid of them!  Their impact on agriculture makes them particularly concerning if you grow plants, especially fruit.
Stink Bugs enter houses during winter to escape the cold, where they can live for months attacking house plants until winter has passed.  They are notable for the mildly offensive odor they release when crushed or aggravated, from which they get their name.



Crickets are small, grasshopper like insects with long antennae and round heads, often with very large back legs.  Many have front wings adapted to make chirping sounds, some species of crickets are entirely flightless with only vestigial wings.  They occur around the world, are primarily nocturnal and can often be recognized by the persistent sounds they make.  


Crickets often live in deadwood or on the ground in burrows and other hiding places.  They most often react to threats by fleeing, though some species are capable of biting humans they rarely do so.  



Houseflies are a very common fly species that frequently invades buildings and residences.  Adults are usually grey to black and have hairy bodies roughly a quarter inch in length.  These flies can hibernate in the winter and are a nuisance pest across the world.  They sometimes carry disease, and their tendency to land on food contributes to the spread of sickness.  Roughly a quarter inch long when full grown, flies process images much faster than humans, contributing to the great difficulty of catching or swatting them. 

A single fly can lay up to 500 eggs, usually on a food source.  Long associated with disease, the number of potential pathogens that houseflies can carry serves as a strong reason to control and eliminate them from households and living spaces.  While professional pest control is impractical for houseflies, there are some home remedies you can use to reduce their population.  Using screens over doors and windows, fly paper and bug zappers can help discourage or catch flies, while removing and cleaning potential food sources removes the fly’s incentive to come in.  We do not offer pest control services for flies.



Earwigs are small insects recognizable for the long pincers and narrow bodies.  Under two inches in length, they are primarily nocturnal and eat a variety of plants and insects.  Their consumption of plants makes them a recognized agricultural pest in many places, and their pincers make many people uncomfortable when found indoors.  Earwigs are especially prone to coming into structures and residences during winter, as they cannot survive outdoors in cold regions.  Large numbers of earwigs entering a home can be a frustrating nuisance to get rid of. 

Near people, earwigs are often found on walls, floors and ceilings looking for food.  Most will flee if approached, attempting to find a dark crevasse to hide in.  They can frequently be found in any dark cracks which they can hide in, such as tucked into plants, in furniture, or in window frames.  They pose no threat to humans beyond annoyance, and they certainly do not intentionally crawl into human ears, despite the urban legends. 



Recognized as the archetypical parasite, fleas are tiny flightless insects that survive on hosts and travel by jumping.  Known mainly for pestering dogs, historically fleas were responsible for the major outbreaks of bubonic plague in the Mediterranean killing sizable fractions of the world’s population.

There are many species of fleas, some of which are specific to certain hosts, while others are more generalists.  Fleas primarily cause itching, with bites resembling mosquito bites, and can lead to dermatitis.  The main health hazard fleas pose is spreading bacterial diseases, which vary around the world. 



A pill bug, or woodlouse, is a small bug that appears to have an armored shell and can roll into a ball when threatened, much like an armadillo.  They are usually under an inch long, and feed mainly on decaying plant matter, presenting no threat to humans.  They are sometimes prone to consume live plants, including agricultural crops, which makes them a nuisance to crop owners. 

Pill bugs are harmless and are even kept as pets in some areas.  They sometimes occur in exceptionally large numbers however, which can lead to the view that they are pests.  If you are finding them in your home, it is best to try and remove moisture and clean up any areas they may be using to shelter.  Pillbugs like water sources and dark spaces, so removing those elements will help discourage their presence. 

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Powderpost Beetles

Powderpost beetles, like their name suggests, are most widely known for reducing wood to powder as they bore holes in it in their larval stage.  These beetles are usually under a quarter inch long, and have jointed antennae, large heads, and straight wings.  The larva of these beetles feed mainly on trees but will also move into structural frames or any other wooden objects that are conveniently available such as furniture, wooden tools, or even toys and books. 

The larva bore holes, leaving small piles of fine dust in their wake, leading them to be a serious nuisance everywhere they occur.  The small holes and dust left by an emerging adult are often the first signs of an infestation.  



Silverfish are small, nocturnal insects, generally under one inch in length.  Somewhat similar in appearance to earwigs, silverfish usually have a more tapered body with long antennae and what look like pincers at its back.  Silverfish have no wings, and avoid light, making them somewhat difficult to find.  In a residence, they will most likely be located in highly humid areas that are rarely exposed to the light, such as in attics, basements, under sinks, or in crevasses and corners of bathrooms. 

Silverfish commonly damage to textiles and paper products, including books and clothing. They also are known to contaminate food, although they do not carry disease and are not considered any threat to humans. The destructive behavior they exhibit leads to them being very undesirable in a home, as they can cause significant damage over time and have long lifespans. 



Ticks are small parasites known primarily for biting and attaching to people and pets that pass through their forested homes.  Ticks can carry disease, most notably Lyme disease, and as such should be treated carefully and avoided wherever possible.  Awareness of the potential for ticks, most commonly found in underbrush, is key to avoiding them.  Checking clothing and pets for ticks after spending time in the habitats where they are common will help to avoid allowing the tick to become established. 

Discouraging ticks in your yard can include several steps.  Firstly, removing the kinds of underbrush and leaves that they like.  Maintaining the trees to allow sunlight to reach the ground as much as possible will help discourage ticks, as they dislike sunlight.  Finally, checking pets and keeping pets out of heavy underbrush helps prevent ticks from reaching the house in their fur.  

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Fruit Flies

The fruit fly is a very small fly common anywhere that people have food.  About an eighth of an inch long, fruit flies have red eyes and tan and black bodies. They lay their eggs on rotting or fermenting fruit, and are commonly found around garbage cans, garbage disposals in sinks, or aging fruit left out on counters or in grocery stores.  All that they need it a small amount of old fruit. Growing from an egg to an adult in about seven days, a population of fruit flies can explode if it remains unnoticed for even a short time. 

Getting rid of fruit flies is almost impossible unless you can eliminate their food sources.  As long as there is fruit present to consume and lay eggs, the flies will continue breeding and infesting the area.  Ensure that all fruit kept is not allowed to remain on the counter after ripening, and keep containers sealed.  Be aware of the potential for flies to live in garbage disposals, lost food under a refrigerator or in random garbage containers around the house.  Fruit flies are best controlled by eliminating their food sources, and pest control services are not available for fruit flies.  

Giant House Spiders
Yellow Jackets emerging from nest



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