Subterranean Termites


North American Subterranean Termites belong to the endemic genus Reticulitermes species and are found in every state in the United States, except Alaska.

You don’t need to remember the formal name of these buggers.  What you do need to know is how to identify, treat, eradicate, and the post-treatment for subterranean termites.

Subterranean termites live beneath the soil, under the surface of the wood, and in mud tunnels that they create.  This lifestyle allows them to penetrate our homes unseen, invading our structures from underneath the soil surface.  They forage in the wood, and we have no idea that they are present until they swarm.  Tiny discarded wings and dead winged termites are evidence of swarming.   Other indicators of infestation are weakened pieces of wood around door jams or windows and mud tubes.

Under the soil is a perfect place to live for subterranean termites.  Soil retains moisture that protects termites from drying out and it shields from predators.  Soil is used as building material for their shelter tubes, and they can excavate through it to get to their food sources.

Subterranean Termites are social insects.  They share resources, cooperate in raising their young, they divide the labor, and they live in a colony.  Some researchers view the termite colony as a single entity who work together for survival  With the majority of the population being immature workers cooperation is easy. The structure of the colony of subterranean termites is a mobile nest that is located close to a food source.  They excavate and populate rotted wood.

how Subterranean Termites enter your homeThey enter your home through tiny cracks in your concrete slab, through plumbing connections, utility passages, and expansion joints.  It may take you up to eight years to notice any damage to your home.  In most cases, they will eat the wood along the grain and leave the outer surface of the wood intact hiding any indication of their presence.

It can be difficult to determine where the colony is and how they got into your home.  Here are the first things you should check around the house if you believe you have termites.

  1. Any soil to wood contact
  2. Wood debris left in your yard or around your home
  3. Wood debris buried under your slab or porch
  4. Below grade Stucco or veneer siding
  5. Improper drainage or moisture around the foundation of your home
  6. Mulch or gravel that is against the foundation that can hold in moisture
Most people realize a termite infestation when the yearly flight of winged termites called Alates takes place – usually in the spring.  Alates are dark or yellowish brown and less than 0.4” long including wings.  If they swarm in your home flights usually occur at night.  In the morning most Alates are found dead near windows or around sinks and bathtubs.

Preventative measures include keeping any wood structure from direct contact with soil.  Keep foundation walls and siding clear of vegetation and mulch.  Subterranean termites need moisture to survive so any leaky plumbing, a collection of moisture around the foundation, air conditioning drip or condensation, pool runoff or overflow and rotting, or soggy branches or trees should need to be corrected.  Maintaining a dry environment around your home will discourage subterranean termites.

These small insects have been around for over 250 million years.  They go through their life cycle and do what is in their nature to do.  Procreation of the species – they eat and breed.  We mean very little to them, and if we were gone tomorrow, they would probably not even notice.  Their role in nature is to break down wood and other plant-based materials.  This process helps our ecosystem by disposing of rotting timbers and making the soil ready for new growth.

Unfortunately for us, we build our homes of wood.  So if you live in ‘This Old House’ or an older home you probably have termites, have dealt with termites, or will be dealing with them in the future.

identify Subterranean Termites“The alates of Reticulitermes flavipes and Reticulitermes virginicus are dark brown, while those of Reticulitermes hageni are yellowish brown. Alates of Reticulitermes flavipes are generally larger (approximately 0.4″ long including wings) than those of Reticulitermes virginicus or Reticulitermes hageni (approximately 0.3″ long). Alate wings of Reticulitermes species have two hardened and thickened veins that are visible along the entire front end, but lack the small hairs that are characteristic of the Formosan subterranean termite, Coptotermes formosanus Shiraki.”  – via.

  • f. alates seen in the picture is an eastern species of subterranean termites and found in the eastern region of the United States. They infest from Florida to Ontario.
  • h. is the western species encompassing the Pacific coast from California to Washington and R.t. The inter-mountain region of the West.
  • v. Florida region.

Classes or Castes of Subterranean Termites

There are three (3) classes or categories of subterranean termites:  reproducers which include (queen, king, alates), the soldiers, and the workers.  Alates and solders are used for species identification.

Subterranean Termites classesThe workers are the largest group in the colony.  They are white, immature, wingless termites.  Workers are the first termites seen when an infected piece of wood is breached.  They are blind and only perceive changes in light intensity.  These workers perform most of the labor associated with colony life.

Their tasks include finding food, excavating, building mud tubes, building and repairing shelters.  They also feed and groom the soldiers and reproducers, and they take care of the young.

The Solder termite’s primary function is defense of the colony.  They are identified by their elongated yellow- brown head and black mandibles.  Soldier termites are wingless, blind and soft bodied.  Soldier termites are not capable of feeding themselves, so worker termites provide regurgitated food.

Alates or Swarmers are winged adult termites.  They have eyes and two pairs of narrow wings which are functional.  They are dark brown – this color assists them in tolerating water loss.

Alates are sometimes confused with flying ants, but there are distinguishing characteristics such as:

  • Straight to slightly curved beaded antennae vs. the elbowed antennae of an ant
  • No waist vs. distinct differentiation between body regions of the winged ant
  • Two pairs of the same size wings vs. a larger front wing and smaller back wing

Most alates die after swarming, which is good news for homeowners.  They often succumb to dehydration or predators, and other environmental elements.

Subterranean Termites life cycle

Life cycle of Reticulitermes subterranean species. Graphic by Nan-Yao Su and Rudolf H. Scheffrahn, University of Florida.

If they survive soon after the swarm, they lose their wing and find a mate.  The pair that is successful in establishing a new colony are King and Queen and are known as the primary reproductives.

Distribution of Subterranean Termites

Subterranean termites are found in every part of the continental United States.  They thrive because they are protected from the environment by living underground, this enables them to live in a wider variety of climates.  Government organizations monitor the spread of termite species in the United States.  Recorded information includes sticky traps that trap swarming termites, monitoring stations, and relying on pest control companies to submit geographical information on the species they have encountered.

Zonal Creep is the migration of termites from one zone to another.  The zones are the regular planting zones across the United States.  Termites that are strictly Eastern termites will occur further north or west.

Types of Subterranean Termites

Formosan Subterranean Termite

Formosan Subterranean TermiteThe Formosan Subterranean Termite is the most aggressive termite in the United States it was discovered in the 1940’s after World War II.  The species is native to China.

The Formosan subterranean termite is often nicknamed the super-termite because of its destructive habits, due to the large size of its colonies and its ability to consume wood at a rapid rate.

Just one colony can contain several million of these pests vs. several hundred thousand of other subterranean termite varieties. This super-termite can forage up to 300 feet underground, and they wreak havoc in our southeastern states.  The timbers they infest are oak, cypress, pine and maple.  They are known to cause major damage to structures within a few months.  They also destroy railroad-ties, barges, and ships.

“Formosan termites can be found in Louisiana, Texas, Hawaii, California, Mississippi, Alabama, Georgia, Florida, North Carolina, South Carolina and Tennessee.”

The alates (winged reproducers) and soldiers are used to identify the species.  Alates are a yellowish brown and are up to 0.6″ long – with small hairs on their wings.  They swarm at dusk on humid and calm evenings from April to July.  Their swarms are massive, and they are attracted to lights (just like moths) and are usually found around windows, outdoor lights, and window sills.  Soldiers have a whitish body with an orange-brown oval shaped head, and curved mandibles.

One colony of Formosan Termites can produce over 70,000 alates.  They fly, shed their wings and find a mate to begin a new colony.  Within three to five years this new colony is hearty enough to cause severe damage.  Their large colony size is an indicator they can cause more damage in a shorter period.

These beasts build their nest in structure voids between walls and underneath sinks.  Wood that is infested will sound hollow or will be paper thin upon inspection or will look blistered.  Their nests are called ‘carton nests’ and are made up of soil, chewed wood and excrements.  They infest cargo pallets as well as sod and mulch, and the moving of this material transfers them from place to place increasing their breeding area.

People are the main cause of increasing the range of the Formosan termite, by moving wood, materials, and old railroad ties that are infested.  About 95% of buildings that are infested from colonies based on the ground and are infested from the ground up.

They enter your home primarily through wood to ground contact, but they can also fly onto your roof, and if the conditions are right (food and moisture) they can initiate a colony with no connection to the ground.  About 30% of infestations are from aerial colonies!  They also attack living plants, plaster, plastic, asphalt, and some soft metals in search of food.

Formosan Termites Picture Gallery

Arid Land Subterranean Termites

Arid Land Subterranean Termites prefer damp dirt and moist decaying wood that has been water compromised.  These termites prefer to live in the open sunny areas, which is peculiar for a subterranean species.

The range of this termite includes most states west of Mississippi, but they are most destructive in Arizona.  They have been found in sand dunes as well as high altitudes in mountain states, moist lowlands by streams, but mostly are found in deserts where they attack timber building structures.

“The arid-land subterranean termite is  located in sunny, dry areas from the Pacific Coast to Indiana, down to southern California and across to Texas and Mississippi.” They prefer hardy desert shrubs, so their damage to structures is minimal.  This termite is the most common and harmful termite in Arizona.

The Arid Land Subterranean Termite swarm between January and March, and in higher elevations between June and July. These termites swarm during the day in the spring and fall.  They are small 1/5” long with their wings and almost black in color.  Their soldiers have straight jaws and resemble the desert termite.

Arid Land Subterranean Termite Pictures

Arid Land Termites are found living in sand dunes in the low desert, as well as in high altitudes of the Rocky Mountains states.  They also like living in moist river canyons and streams.  The feed on creosote and greasewood bushes and of course buildings.  What they like the most are dry, sunny locations.

Evidence your home is infested will present as piles of wings around the windows and doors, mud tubes, weak wood, and soft bubbled or peeling paint.  They also attack untreated wood in utility poles, plant roots, and fence posts.

Desert Subterranean Termites

The Desert Subterranean Termite is found in the Arizona and Californian desert region.  They live in desert plants like dead cactus, dead and living desert plants, utility poles, and building timber.  Mud tubes also protect their workers who are in search of food.

The desert subterranean termite can be found in southeastern California and southern Arizona.

They thrive in high temperatures with lower humidity, and the desert climate is perfect for them.  The Desert Subterranean Termite is the most common and the most destructive of all the desert and dry climate termites.  Their area is limited to the southwest part of the United States.

Their Adults are 3/8” long including wings and have a pale yellowish body.  They swarm at night from July to September during the rainy season.  This termite is also attracted to posts, structural timber, fence, cow-chips, dead weeds and grass,  and utility poles.

Signs of an infestation are the same as for others – this includes swarming, weak wood, mud tubes.  In addition to mud tubes along walls they also produce free hanging tubes from roofs or ceilings, and overhangs.  Also, these termites like cardboard boxes left in the garage.  Look for signs of tunnels on cardboard boxes, especially if they are seldom moved or disturbed.

This small termite’s ability to thrive under dry conditions gives it a niche not used by other subterranean termites.   This species is not dependent on moisture and will attack dry wood.

They get into your home through cracks in concrete 1/32” wide or mortar joints in brick walls, or through roofing or decking timbers.  They can squeeze through cracks that are so minuscule other species cannot penetrate.

Desert subterranean colonies may contain up to 300,000 termites, and forage territory of up to an acre.  They build wide thin mud structures on wooden objects where they feed by scraping off the dead wood from the exterior of the surface.

Eastern Subterranean Termites

eastern Subterranean TermiteThe Eastern Subterranean Termite consumes anything that contains cellulose: (a long chain of linked sugar molecules that gives wood its remarkable strength.  It is the main component of plant cell walls and the basic building block for many textiles and paper. Cotton is the purest natural form of cellulose). Eastern Subterranean Termites establish their colonies underground, and the workers then use networks of tunnels located both above and below ground to search for cellulose.

Termite workers are constantly foraging for food and when a food source is located the workers communicate the food source location by depositing complex odors called pheromones along trails.

The eastern subterranean termite can be found from Maine down to Florida, across to Montana and down to the Gulf Coast in Texas.

Their colonies also have three classes or castes: workers, soldiers, and reproductives that work together for the success of the colony.  The workers are a cream color, and they are the ones that feed the colony.  Alates are dark brown or black, as are the kings and queens.  Soldiers have elongated yellow heads and large jaws, and are ¼” in length.

The only evidence of these termites is discarded wings.  They swarm during late winter or early spring and are attracted to light.  They drop their wings and find a mate, but what they need is moist wood in contact with soil to start a new colony.  Most do not succeed.  The presence of wings in your home may alarm you, but at this stage, no damage can be done by the winged form.

“Wood attacked by termites has runways or passages that are coated with an earth-like material glued to the wood. Where the wood has been infested for some time, it may be largely hollowed out with passages and may be rotten in appearance. Upon probing such wood with a screwdriver or similar tool, many of the hidden worker termites may spill out.”  – via.

Where to look for these termites in your home:

  • In the basement or cellar area
  • Wooden posts, steps, door frames
  • Studs, joists, and around trim that are embedded in earth or concrete
  • By wood siding and window frames

These termites especially prefer areas around chimneys, furnaces, hot water heaters, and hot water pipes that furnish warmth during winter months.  All wood you suspect infected should be probed with a screwdriver or small sharp instrument for soundness.  Look for any signs of mud tunnels.

Make your home as termite proof as possible by removing wood debris – firewood or old wood stacks, replace damaged wood with pressure treated wood, drain water away from your home (make sure the ground grades away), repair all cracks in your foundation with concrete.  These things are preventative maintenance for termites.

Western Subterranean Termites

Western Subterranean Termites are known as the ‘world’s best timber recyclers,’ and are one of the most damaging termites in North America.

“The western subterranean termite can be found from Washington to southern California and into Idaho and Nevada.”

Their destruction of wooden structural building materials occurs quickly; they cause millions of dollars of damage every year in these areas.

You can identify the damage by the hollowed out sections of wood in a honey-combed shaped pattern.   They particularly like the Douglas Fir and other common building materials, and damage across the wood grain.

Western Subterranean termite swarms in the spring in large numbers.  They find a mate, drop their wings and become the new king and queen of their new colonies.

Colonies consist of Queen, King, Workers, and Soldier Termites.  The queen is identified by her large bloated whitish body, the King is dark brown, the workers are translucent milky white – these are the ones that do the most damage, the soldiers have orange heads with pinchers.

srs.fs.usda.gov
Being subterranean they can enter your home through cracks in your concrete foundation, travel under tile flooring or through expansion joints.  They like moisture and build their nests inside wall cavities where moisture is allowed to collect.  They will shield themselves in mud tubes while passing over a solid object.  These mud tubes are a sure indication that you have termites. – source.

Dark Southeastern Subterranean Termite

The Dark Southeastern Subterranean Termite is in the Eastern states from New England, south to Florida and west to Texas.  They are up to 1/3” long and have a brown or black body.  This termite usually resides in the eastern part of the United States.  Swarming occurs in the summer during the day, and if there are multiple colonies swarming at one time, there can be millions in the air.

They can also live above ground if enough moisture is present.  If you have a roof or plumbing leak take care of it as soon as possible because these termites prefer wood with an over 20% moisture rate.

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