Bees, Wasps, and Hornets can be nasty unwanted guests in the Portland area.

Honey Bees
In Spring, Honey Bees can swarm while looking for a new home.  While not dangerous unless disturbed, a nest of drones surrounding and protecting their queen can be disconcerting.

We will not exterminate Honey Bees.  They provide a necessary service for the area by pollinating the fruit trees and flowers to make our outdoor spaces bloom.  Honey Bees have been under pressure from Hive Collapse Disorder and an array of other parasites that have caused their numbers to dwindle.

If you see a swarm, there are trained experts that will respond quickly and relocate the nest to a safe place where they can provide their beneficial mission. Just search for Bee Keepers in your area.

Wasps and Hornets
Wasps and Hornets, on the other hand, have a well-deserved reputation for being aggressive.  We have no compunction about eliminating these threats.

Paper Wasps are noticeable by the nests that they build.  Typically, they will find an overhang or tree branch and build there.  A nest hanging from your eaves can bring them into close contact with doorways and windows where they will infiltrate your living areas.

Hornets are more solitary but like to nest under porches and behind shutters.  Have you ever experienced the fury of hornets interrupting your bar-b-que?  Not a pleasant experience.

Yellow Jackets have a habit of moving into your house, making a nest in your attic, and causing a variety of issues.  They can even chew through drywall and enter your living areas if not controlled.

We can help you to identify your problem bees and provide you the best solution to your problem.

Wasps make their first appearance in early spring after hibernating from their protected shelter that can be under tree bark, in stone walls, and sometimes attics.  Only a mated queen from the previous year’s colony will overwinter. She will begin the process of building a nest and starting a new colony.  After laying eggs she begins foraging for food to feed them.  In social wasps, after the first brood emerges as new adults her only duty is to continue laying eggs. The new adults take over caring for the eggs and expanding the nest.

Insect Classification Order

Wasps belong to the Hymenoptera order of insects and includes bees, wasps, ants, and sawflies.  This means that most in this category have two pairs of wings with the hind pair usually smaller than the front pair.  They have mouthparts that are adapted for chewing and the ability to drink liquids such as nectar.  Most have compound eyes and a thin pedicle or waist where it joins the thorax as if it were pinched together and develop through a complete metamorphosis.

Stinging Behavior

Often the first sight of these insects brings fear and apprehension to many.   Caution is justified as the sting from these insects is painful and dangerous for those who may have a life-threatening allergy that can send them into anaphylactic shock.  However stinging behavior generally results as a reaction to the colony or nest being threatened, or when an individual bee or wasp is trapped or threatened.  Some species may be more likely to sting during the latter part of their annual cycle in August or September as food they are foraging for becomes limited.

Are they Pests?

Wasps and bees can become pests when nests are located where people frequent such as our parks, homes, or other structures. Control measures are justified based on each given instance such as nests in poor locations relative to the safety, comfort, or other interests of people. Locations such as under the front steps of a home, in a school playground, or other areas that present an imminent hazard warrant control measures, especially if there is a health and safety risk to people or pets.  Nest locations such as a high shade tree or remote areas unlikely to be bothered by the activities of people or pets near ground level can usually be left undisturbed.

Various wasp species display different habits, some are social and live in colonies, while others are solitary.

Solitary Wasps

Solitary wasps do not have a colony group, even though they may nest in the same areas each female lives and breeds independently.  Many of these species raise their young by laying eggs in or on other insects during any part of its life stage from egg to adult. Most solitary wasps young are carnivorous, feeding on mostly insects and spiders while adults feed mainly on nectar. Adult females build a cell for each egg and provisions each cell with an insect or prey for the larva to eat.  Because of this behavior these wasps can be valuable in horticulture and sometimes as a biological pest control method for some insects.  Some species can effectively transport pollen and are in that sense pollinators of several plant species, however most species are predatory and play no role in pollination.  Wasps and bees are considered beneficial insects in most circumstances.

Characteristics of Social Insects

Caring for offspring from other individuals
Generations overlap within a colony of adults
Division of labor into reproductive and nonreproductive groups
Specialized behavioral groups within an animal society called castes.
Colony cast differences

Queens and reproductive males are the sole reproducers
Soldiers and Workers work together to create favorable living situations for the offspring.
Social Wasps

Social wasps do live in colonies like those of ants.  They have a queen that produces eggs, female workers and males called drones.   Some social wasps are omnivorous, feeding on fallen fruit, nectar and carrion such as dead insects.  Adult male wasps sometimes visit flowers to obtain nectar.  Many species are pollen vectors contributing to the pollination of several plants, while others are predators of pest insects.

Establishing the Nest

These social wasps build nests called a carton.  In northern regions, new colonies are formed each year with only the mated queen overwintering and hiding in protected areas.  In early spring, she will establish new nests and colonies by collecting material from exposed and weathered wood surfaces such as fences, siding, dead tree limbs and loose bark, combining this material with salivary secretions to form a paper like carton for her nest.  Each carton has a small number of cells and she places an egg in each one.

Division of labor

After the eggs hatch into larvae she forages for food to feed them until pupation occurs.  This food is usually caterpillars or other insects.  Adults feed on liquids such as nectar, honeydew and juices from the bodies of insects fed to larvae.  When the adults emerge, they are sterile female workers that will take over nest building and brood rearing while the queen stays on the nest.  There is only one egg producing queen in the colony, workers protect and maintain the nest, forage for food and water, and care for the eggs, larvae, and pupae.  Late summer to early fall adult males and newly produced queens leave the parent colony, colonies die off and newly mated queens find a protected location to overwinter. Population of future colonies may be diminished due to excessive rain or moisture, dryness, excessive cold or harsh winter conditions and competition with other queens.

Paper Wasps  sometimes referred to as umbrella wasps

Like yellowjackets and hornets, paper wasps are social insects.  They prey on caterpillars and other soft-bodied, leaf-feeding insects.  Adult paper wasps also feed on nectar, and can be see foraging on flowers.  Queens winter over, and build a nest in early spring, she places an egg in each cell and feeds them with the insects she captures.  Adult female workers emerge about one month after eggs are laid.  Like other social wasps, adult workers take over maintaining the nest, foraging for food, and tending to larvae.  The queen’s only job is to produce eggs and when early fall arrives males emerge, leave the nest then mate with newly developed queens.  Males then die and the queen finds a protected place for the winter. Paper wasps are similar in appearance to yellowjackets but have a slimmer elongated body shape and are long-legged.  Their paper nest resembles an open umbrella with individual comb cells open to view from below.  Usually found suspended beneath horizontal surfaces, such as eaves of a house, beneath window ledges or porch roofs.  It is a simple nest called a comb consisting of one tier or layer of cells and is rarely more than 6 – 8 inches in diameter and seldom more than 100 – 200 workers at any one time.  Paper wasps secrete a chemical that repels ants which protects the loss of eggs or brood.  Paper wasps can sting multiple times, although they may sting if unprovoked generally they attack if they themselves or their nests are threatened. They do however have a territorial area they will protect and their stings are painful so if a nest is in an inhabited area it could present a safety hazard.   There are many species of paper wasps and each have slight differences in relationship to their nest building materials and behavior. These wasps are pollinators also feeding on garden pests and are considered beneficial by gardeners.

One of the most fear-provoking social wasp’s nests is large grayish brown carton structures seen hanging from a tree or bush.  Resembling a very large, inverted tear drop or bloated soccer ball these nests belong to hornets, however; entomologists may consider them yellow jackets.  Like a paper wasp nest yet is has several tiers and a continuous paper envelope surrounding the whole nest with a single opening at the lower tip of the nest.  As new combs are added this opening will be positioned to the side of the nest.

Bald-Faced Hornet

With black and white markings on the thorax and abdomen, this is a moderately large wasp and may have whitish or yellowish markings on the front of the head between the eyes.  This species is a yellow jacket wasp, not a true hornet.  Distinguished from other yellow jackets by their white and black coloring.  Colonies may contain 400 to 700 workers.   It builds a characteristic large hanging nest found in forested areas or in vegetation around urban areas.  Usually located in trees and bushes but can occasionally be found under rock overhangs or the sides of buildings.  The queen collects cellulose from weathered and rotting wood chews the wood adding her saliva to make this papery material to construct the nest.  She creates a few brood cells within the nest and deposits eggs in them, she then feeds and cares for the larvae as they develop.   As with other social wasps, newly fertilized queens will overwinter and the rest of the colony will die shortly after the first hard frost. Bald-faced hornets are omnivorous, considered to be beneficial due to their predation of flies, caterpillars, spiders and other yellowjackets.  They will also help pollinate flowers when searching for nectar.  Their aggressively defensive nature makes them a threat to humans who wander too close to a nest or when a nest is constructed too close to human habitation.  They are known to vigorously defend the nest, with workers stinging repeatedly.  The bald-faced hornet has a unique defense in that it can squirt venom from the stinger into the eyes of nest intruders.  The venom causes immediate watering of the eyes and temporary blindness.  A pest control service is highly recommended for this type of nest.  They will have the necessary safety equipment and expertise needed to remove this nest without harm to themselves or others.

European Hornet

A European Hornet body is brownish with markings of orange, and the only true hornet present in the United States, it had its start along the Atlantic Coast and has spread to the mid-western states.

Nesting in natural cavities such as hollow logs or stumps and occasionally within a structure.  Female workers construct the nests into a paper-pulp mixture by chewing dead bark, trees or other plant matter, surrounding soil and combining these elements with their saliva.

Like other social wasp’s workers forage for food, feed the larvae, and collect cellulose to expand the nest and protect it from threats.  Colonies may reach 300 workers by September or October.  These workers are unique for their ability to forage at night.  In spring workers, actively forage for natural food sources and then in fall scavenge around garbage cans, picnics, and other areas.  They will aggressively defend their hive and food sources.  Their diet consists of large insects, such as wasps, large moths, or other bees.  They are larger than the common wasp and are known to eradicate the domestic honeybee hive.  They may even steal prey from a spider’s web.

Yellow Jackets

Yellow Jacket nests are normally underground and workers will come and go through a hole at the surface.  Nests may be formed in abandoned mammal burrows or similar underground cavity’s and then enlarged as the colony develops.  Yellow Jackets have built extensive nests within the voids of concrete block foundations or below railroad ties.  They prey on other pests such as caterpillars, aphids, flies or other garden pest and therefore are beneficial in garden areas.  However, they are aggressive in some situations and a nest located in or around a home is a concern.

German Yellow Jackets

Introduced in the Northeastern United States they are also found in Midwestern to the Western United States.  Nests can be in wall voids, attics or crawl spaces using available holes and cracks on the exterior of buildings.  Whether in the ground or within a wall void, Yellowjacket nests are made of a carton and resemble the bald-faced hornet nests.  Several thousand workers may be produced in one season.  Colonies in certain areas may persist for more than a year ultimately developing more workers than typical annual colonies.

Some species forage exclusively on live prey, such as flies, caterpillars, and other insects, while others forage strongly for meat from carcasses, garbage, and picnic tables.  They may also forage on sugar sources such as beer, fruit, and sweet beverages.  Workers may also forage on the honeydew of aphids to feed the Queens produced in the late summer.

Their tendency to scavenge human food sources puts yellowjackets in frequent conflict with people, particularly in late summer and early fall when the number of workers out foraging is at its peak, and food sources are declining.

Tending to be somewhat unpredictable in response to humans approaching the nest, they may completely ignore one person or sting someone simply walking by.  Most serious stinging incidents occur when the nest is accidentally disturbed.

Workers foraging away from the nest usually ignore humans and stinging incidents are usually caused by the accidental trapping of the worker against a body, such as between folds of clothing, under an arm or leg, or in the mouth when swallowing a beverage from a container.  Because of the insects nesting and foraging behavior and the potential for it to induce severe life-threatening allergic responses in certain sting victims, many experts consider yellow jackets to be the most dangerous of the social Hymenoptera classification.

Non-social, or Solitary Wasps

Sphecid wasps include only solitary nesting species.  Unlike the Vespidae family of social wasps, these wasps do not fold their wings, holding them separately they lay them one on top of the other in a flat position on top of their bodies.  Female workers build nests with several cells and may build more than one nest.  In each cell, she places live prey such as an insect or spider then lays an egg on the prey and seals up the cell, they will then develop and emerge as adults. Distinctive from true hornets, these wasps are known to excavate burrows in the ground sometimes placing several unsightly nests in a lawn.

Cicada Killer

The Cicada Killer is a large insect up to 2 inches long with a black body and strikingly yellow markings, it is often mistaken for a hornet.  Females will excavate large burrows leaving a mound of dirt at the entrance.  Paralyzing her prey and placing it in each cell then laying an egg on it, she seals the cell.   Each burrow is the result of a single female and the only real damage done by Cicada Killer wasps is to lawns or flower beds.  Most often female wasps will not sting unless handled however, their sting can be painful.

Mud Daubers

Mud Daubers a Sphecid wasp species, they build nests of mud and are frequently found visiting the edges of mud puddles in the summer.  Nests can often be found around rafters of attics, garages, outbuildings or on the sides of buildings.  They typically prey on spiders.  Chances of being stung by a mud dauber are remote, however, their nests should be approached with some caution.  Their nest is associated with Dermestid beetles, such as cabinet and carpet beetles that can infest homes.  Because of this nests should be removed and destroyed after control is achieved.

Bees (Families: Apidae, Xylocopidae and Bombidae)

Bees can become pests in and around homes due to their ability to inflict stings, some species may also cause structural damage because of their nest-building activities.

Honey Bees

Wild or domesticated European honey bees become a serious pest when they establish a nest in or on a structure such as when a swarm of honey bees locate a small opening in an exterior wall, down a chimney, or behind faulty flashing of a home, and then nest in a wall void or another interior area.  Large amounts of wax and honey may build up within the wall, if the bees keep this honey cool by fanning it the honey stays firm, however if the bees are collected without removing the nest it may be absorbed into the plaster or similar porous material leaving a permanent stain.  Neglecting to remove a nest is also an attraction for other pests such as flies, ants, or beetles to infest the structure.  Therefore, it is important to completely remove the nest as soon as possible after the colony is controlled, even if it requires carpentry and repairs to the structure.

Honey bees are a social species with queens, drones and workers, there is only one egg laying queen per colony and some larger colonies have been known to have 20,000 to 50,000 bees.  Like other social insects’ workers feed the larvae and maintain the nest.  Honey bees produce large supplies of reserve honey used as food by all the members of the colony during times of unfavorable conditions.  A colony can survive throughout the winter and bees do not need to establish a colony annually unless there is an unfavorable placement of the nest.

Honey bees are about 2/3 – inch long, may be various shades of yellow, black brown, or orange, with the head, antennae, legs and parts of the abdomen being dark.  The body is covered with light-colored hairs.  They can be aggressive at times and it is wise to call a beekeeper for advice and help if you have encountered a nest in an unfavorable or dangerous place.

In recent years, there has been a decrease in the Honey Bee populations.  Colony collapse disorder is thought to have many possible causes and research is still ongoing to find a cause and solution to this.  It is thought that there is not one cause but a mixture of elements contributing to the overall decrease in population.  Honey Bees are an important part of our ecosystem because of their pollination of plants used in agriculture and their decrease will influence many areas.  If possible leave a nest undisturbed, however if a nest location is a hazard and safety issue it is recommended that a beekeeper is contacted for help.

Carpenter Bees

Carpenter Bees are nonsocial bees; they bore long tunnels in wood and divide them into cells where individual larvae will develop.  While many females may be nesting in wood of the same structure or site, each is acting in a solitary fashion.  Sometimes confused for a bumble bee, this Carpenter Bee is black and may have areas of yellow hair but the dorsal sides of the abdominal segments have no areas of yellow hair. Some species of Carpenter Bees of other genera may have different coloring such as black, green purplish and have various markings of whitish, yellowish, or reddish hair with the dorsal surface of the abdomen generally bare.

The Carpenter bee bores a tunnel in the wood surface going inward for a short distance and then turning sharply upward and running in the same direction as the grain of the wood.  Unlike a wasp, she does not use live prey but places an egg on a ball of pollen before closing the cell with a mass of wood pulp.  She creates a series of cells while working backward out of the gallery.  Often using existing tunnels these can develop into a complex system over years and if enough tunnels are made in the wood it may reduce the structural strength of the timbers. Common sites for these bees may be in siding, window trim, eaves, wooden shakes, porch ceilings or similar areas.  Many types of wood may be used but softer woods are preferred.  A possible indication of a Carpenter Bee infestation may be galleries or tunnels found or a yellowish or brownish excrement stain on the siding below the entrance holes.

Carpenter bees take one year to complete a generation in most areas.  Tunnels are prepared and eggs laid in spring, larva and pupa develop in early summer.  Adult bees emerge in late summer and return to the same tunnels to hibernate for winter.  In the spring, adults mate and females lay eggs, completing the cycle.

Bumble Bees

Unlike Carpenter Bees, Bumble Bees are social insects and their nest is generally underground in abandoned mouse burrows, under piles of grass clippings and leaves, stones, logs or other similar locations.  There is rarely a conflict unless nests are established close to a sidewalk, near a foundation or another location where conflict with people or pets is inevitable.  Some species are more likely to sting people or pets than other species.  If the nest area is directly threatened they will attack and sting the intruder as a defensive reaction.


Horntail wasps infest dying trees or recently felled logs.  They are a medium to large-sized wasp and emerge from wood that has been in a building for only a few years.  The female wasp deposited eggs in the wood, the developing larvae bore tunnels 1 to 2 feet long, packing them with frass and cast skins from each larval molt.  Pupation occurs close to the wood surface and the new adult emerges using its strong jaws to chew out of the wood.  Emergence holes are about ¼ inch in diameter.  Most infestations are in softwoods although sometimes hardwood logs of firewood can be infested.  Normally horntails take 2 or 3 years to complete a life cycle.  Usually found in low-cost rough timbers salvaged from diseased or fire-damaged trees because such wood is seldom kiln dried, a process that would have killed any eggs or larvae. Horntail wasps do not infest lumber after it has been cut, and they usually occur in small numbers.  If a horntail wasp emerges it is ok to use a general-purpose household aerosol insecticide to destroy it as it will not re-infest.