Termites, Reticulitermes hesperus
The eastern subterranean termite is the most common termite species in Colorado. Termites are either blind or have poor vision and spend most of their lives under soil or within mud tubes. These soft-bodied insects live in colonies organized into a caste system, in which individuals are responsible for certain tasks such as protection, reproduction, and acquiring food. Colonies can have well over 1 million members with a foraging range over 0.5 acres.
The appearance of an individual termite depends on species and caste. Queen and king termites are the largest individuals in a colony. Queens are especially large with bloated bodies that limit their mobility. Soldier and worker castes of the east subterranean termite are about 0.6-1.9 cm (0.25-0.75 inches) long, unpigmented, and do not have wings. Soldiers have heads that are larger and often darker than the heads of workers. Kings, queens, workers, and soldiers are usually difficult to spot since they remain within the colony.
Winged (alate) termites are usually produced in great numbers in the spring or fall when they leave the parent colony to mate and establish a new colony. The wings are broken off once a new colony forms. When seen indoors, winged termites indicate that an infestation is present. While winged termites resemble carpenter ants, there are several characteristics that distinguish winged termites from winged forms of household ants. Termites have antennae that are straight and resemble beads on a string, a broad waist that is not constricted, and two pairs of wings that are the same size. For comparison, winged ants have elbowed antennae, a constricted waist, and a pair of wings that differ in size.
- The presence of winged termites indicates that an infestation is present. Winged termites have straight antennae, two pairs of wings that are similar in size, and a thick waist that is not constricted.
- To prevent infestations, avoid placing wooden structures in contact with soil. Remove all waste wood from the property and seal cracks in the building’s foundation or plumbing to reduce the availability of entry sites.
- It is recommended to hire a certified pesticide applicator for termite infestations. Chemical treatments are available as liquid barriers and baits. Termite infestations are slow to build, and treatments can be effective if applied as soon as the infestation is detected.
Worker of the eastern subterranean termite, the most problematic termite species in Colorado. Termites feed on decaying wood and live in colonies with a caste system. Over $5 billion is spent on termite management in the United States each year. Image credit: Joseph Berger, Bugwood.org
Soldier caste of eastern subterranean termite. Note the large, dark head in comparison with the image of worker castes. Image credit: Gary Alpert, Harvard University, Bugwood.org
Illustration of a winged termite (top) and winged ant (bottom). Winged termites have straight antennae, a thick waist, and two pairs of wings that are the same size. Image credit: USDA Forest Service, USDA Forest Service, Bugwood.org
Swarm of eastern subterranean termites on a tree. Image credit: Jeff Weidhaas, Bruce Terminix, Bugwood.org
Mud tubes constructed by eastern subterranean termites. Image credit: Terry S. Price, Georgia Forestry Commission, Bugwood.org
Life history and habits
Termites have three life stages: egg, nymph, and adult. After mating, winged males and females disperse to new locations in search of a suitable habitat to establish a new colony. These founders of the new colony begin foraging and prefer to construct nests in areas with decayed wood in soil. As eggs are laid and the colony grows, the queen begins to establish a caste system in which workers, soldiers, and secondary reproductive are produced.
Workers can construct mud tubes with a mixture of saliva, wood, and soil. These tubes are constructed to protect workers during exploration or foraging and can also be used to direct colony traffic. The tubes can be built over many surfaces, including concrete, plaster, brick, and metal. The presence of moisture inside indicates that the tube is active, while inactive tubes are dry and crumble easily.
Prevention can be an effective way to protect wooden structures from termites. When possible, wooden structures should not be in contact with soil. For example, wooden shingles or supports should be positioned a minimum of 8 inches above the soil. Cinder blocks, bricks, or other hollow masonry should not be kept in contact with wood and soil. All waste wood should be removed from the property, and any cracks or gaps in the foundation or plumbing should be sealed to prevent entry of termites into the building. Thick plastic sheeting can be placed over soil to provide a barrier under crawl spaces and porches.
Crawl spaces should be well ventilated since termites prefer environments with high humidity. Barriers of roofing paper can be installed to reduce moisture in structural wood if the soil below the building is very moist. Proper watering can help limit the amount of moisture in soil beneath wooden structures.
The exterior surface of slabs, sill plates, joists, garages, porches, crawl spaces, sidewalks, steps, roof eaves, gutters, windows, AC or fan units, wood piles, trellises, and other vegetation should be thoroughly examined for indicators of termite activity, which includes mud tubes, frass, and winged adults.
Indoors, areas with high moisture should be monitored for cracking or blistering paint. Additionally, basement supporting structures, plumbing units, heating units, drywall, baseboards, and window frames should be checked for termite activity. Baits can also be used for monitoring termite activity when they do not contain any insecticide.
Certain termiticides provide a chemical barrier that prevents termites from reaching wooden structures. They are liquid treatments that can deter termites for years and are most effective when applied during construction. This is best done through a professional pesticide applicator.
Baiting with insecticides is another method of treating termite infestations but is often more expensive than liquid treatments and does not provide immediate control.
Hodgson, E, and A. Roe. 2008. Subterranean termites. Utah State University – Extension. Available https://extension.usu.edu/pests/uppdl/files/factsheet/sub-termites09.pdf