Pest Control Ants – Carpenter Ants


Pest Control Ants is a common category and one of the featured pests is The Black Carpenter ant, Camponotus pennsylvanicus (DeGreer), which is a native species and the common species in the east. Camponotus modoc, Wheeler is the common western species. These ants get their common name from their habit of hollowing out galleries in pieces of wood for nesting purposes. This nesting habit can result in structural damage. Carpenter ants are found throughout the United States.

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Workers polymorphic are large (1/8–1/2″ or 3.5–13 mm) but vary greatly in size; the queens are about 1/2–5/8″ (1 3–17 mm) long. Their colors are black, combinations of red and black, or completely red or brown. The antenna is 12-segmented, without a club. The thorax lacks spines, and the profile is evenly rounded on upper side. The pedicel is 1-segmented. The gaster, with the anal opening being round, is surrounded by a circlet of hairs. The stinger is absent. Workers are capable of emitting a strong formic acid odor.

Camponottis pennsylvanicus, with workers about 1/4–1/2″ (6–13 mm), are long and completely black except for the top of the gaster, with long, pale yellowish hairs pressed against its surface. Camponotus modoc, with workers about 1/4–1/2″ (5–11 mm) long, are dull black with reddish legs and with golden hairs covering abdomen. The Queens are up to 5/8+” (17+ mm) long. Other species are black, various combinations of red and black, or completely red or brown. Although carpenter ants do not sting, their bites can be quite painful, especially when they inject formic acid into the wound.


(1) Dark Field (Formica spp.), larger yellow (Acanthomyops interjectus), and Allegheny Mound (F. exsectoides) ants have a profile of the thorax not evenly rounded, with distinct impressions; in addition, Dark Field ants have front and hind margins of node steeply or equally sloped. (2) Velvety Tree ants (Liometopum spp.) lack the circular anal opening and are surrounded by circlet of hairs. (3) Other medium to large dark ants have 2-segmented pedicel.

Ant wall walk


The only external indication of infestation other than the presence of workers and/or swarmers is the appearance of small openings or windows on the surface of the wood. Through these, the workers expel debris that consists of sawdust-like shavings and/or fragments of insulation and insect body parts. The accumulation of such debris below such holes is a good indication of an infestation. Inside, the galleries follow the softer spring wood with numerous connections through the harder/dark summer wood. The gallery walls are smooth, with a sandpapered appearance. The active galleries are kept clean of debris. They prefer to attack wood softened by fungus and are often associated with moisture problems.


Pest Control Ants

Black Carpenter ant colonies are of moderate size, usually containing more than 3,000 workers (up to 10–15,000 including satellite nests) when maturity is reached in about 3 to 6 years. The typical Western Carpenter ant’s (C. modoc) mature colony contains about 10–20,000 workers, with large colonies having up to 100,000 workers. Developmental time (egg to adult) for workers takes at least 60 days. Workers are polymorphic, with majors, minors and intermediates present. There is usually only one functional, wingless queen per colony. Swarmers are not produced until the colony is more than 2 years old, usually 3.5–4 years old for the C. pennsylvanicus, and often 6–10 years old for C. modoc. Swarmers appear from May until August in the east and from February through June in the west.


Most carpenter ant species establish their first nest in decayed wood and later expand or enlarge this into sound wood. Inside, nests are located in wood (preferably softened by fungus rot), in insulation, and/or in wall voids. Workers are a nuisance when out searching for food but are destructive to timbers utilized for nesting activities. Outside, nests are typically located in rotting fence posts, stumps, old firewood, dead portions of standing trees, and tinder stones or fallen logs. The presence of a carpenter ant nest is sometimes indicated by a rustling sound coming from wall voids or from wood where the colony is located. Otherwise, the emergence of swarmers indoors may be the first indication of an indoor colony. Carpenter ants feed primarily on insect honeydew, plant and fruit juices, insects, and other arthropods. Inside, they will also feed on sweets, eggs, meats, cakes, and grease. The workers forage for distances of up to 300 feet (91.4m) from the nest. They typically enter buildings around door and window frames, eaves, plumbing and utility lines, and shrub and tree branches in contact with the building. Although some workers are active during the day, most activity is from dusk till dawn, with peak activity between 10 p.m. and 2 a.m. The trail between the parent and satellite nest is usually about ¼–3/16″ (6–20 mm) wide and is kept clear of vegetation and debris. It usually follows contours but typically will cut across lawns.


The first step is to determine if the ants present are merely foraging inside or if there is a nest inside. The best indication of a nest is the presence of sawdust piles containing insect body parts. Another indication is the sound produced as the workers remove wood to expand the nest. Outside, check around the building’s perimeter for foraging trails, especially in the direction of trees and shrubs. It is easiest to locate between sunset and sunrise when the ants are most active.

Odorous House Ants 1outdoorant


The pungent, “rotten coconut-like” odor given off when this ant is crushed gives it its name. It is a native species and is found throughout the United States.


Workers monomorphic are about 1/16–1/8″ (2.4–3.25 mm) long. The body is brown to black. The antenna is 12-segmented, without a club. The thorax lacks spines, and the profile is unevenly rounded. The Pedicel is 1-segmented with small node segment hidden or concealed from view from above by the base of the gaster. The gaster with the slit-like anal opening, is lacking the circlet of hairs. The stinger is absent. Workers emit a disagreeable, rotten, coconut-like odor.



(1) Ghost ant’s (Tapinoma melanocephalum) head and thorax are dark, but the abdomen and legs are pale. (2) Argentine (Iridomyrmex humilis), Crazy (Paratrechina longicomis), Pyramid (Conomyrma insana), and Dark Field (Formica spp.) ants have a visible node, not hidden by the gaster; in addition, pyramid ants have a thorax with a single tooth on upper surface, the Field and Crazy ants have a circular anal opening surrounded by circlet of hairs and Crazy ants additionally have an antennae scape (Ist segment) at least twice the head length and very long legs in relation to body size. (3) Other small dark ants have 2-segmented pedicel and/or lack rotten coconut odor when crushed.



Colonies may be composed of several hundred to 100,000 ants. There are usually many queens in a colony. Developmental time (egg to adult) is 34–83 days, varying with temperature during summer months, and up to 6–7 months during the winter. Colonies typically produce 4–5 generations a year. Although they probably mate both inside and outside the nest, the first swarmers appear from May to mid–July. The workers and queens live for several years. Individuals from different colonies are not hostile to one another and workers normally move along trails.



Inside, these ants usually construct their nests in wall voids, especially around hot water pipes and heaters, in crevices around sinks, cupboards, etc. These ants prefer sweets but also eat foods with high protein content and grease such as meats and cheese.

Outside, they are often found in the nest of larger ants, in exposed soil, but mostly under objects. Workers feed on insects, seek honeydew and plant secretions, and even feed on seeds. They are extremely fond of honeydew and attend such honeydew-excreting insects as plantlice (aphids), scale insects, mealybugs, etc. They are most likely to enter buildings when their honeydew supply is reduced such as during rainy weather or with leaf fall in the autumn. When workers are alarmed, they run around in an erratic manner with their gasters/abdomens raised up.


Location of the nest(s) is crucial and can often be accomplished by following the trail of foraging workers back from the food source. Use of boric acid dust in the voids of outside ground-floor walls and infested interior walls along with barrier treatment is effective pest control. Baiting is often required.

Topic: Pest control Ants