Subterranean Termites
Subterranean termites are by far the most common type of termite, and have been estimated to cause over 90% of all termite damage in the US. They are the most destructive insect pest of wood, causing more than $1.5 billion of damage each year in the United States. This variety of termite is found throughout the United States with the exception of Alaska and is especially common in the southern and pacific coastal states. While subterranean termites are often found in homes, they actually live in the soil, and return to the soil after feeding on a home. Subterranean termites require moisture to live and will always return to their colonies in the soil.
Wood damaged by subterranean termites is often not noticed because the exterior surface usually must be removed to see the damage. However, galleries can be detected by tapping the wood every few inches with the handle of a screwdriver. Damaged wood sounds hollow, and the screwdriver may even break through into the galleries.
The Subterranean Termite Colony
The subterranean termite colony is a highly coordinated sytem composed of three main varieties: workers, soldiers and reproductives. Each kind has specific responsibilities.
Worker Termites
Workers have creamy-white soft bodies and are appoximately 1/4 inch long. Worker termites are the type most often seen when active termite damage is discovered. Often they are found still eating on the wood. They have many responsibilities including tunneling, building, feeding and servicing the other termites (reproductives and soldiers). Because they are in charge of providing food to the colony, they constantly forage in search of wood based food, traveling as far as 250 feet from the colony. The other termites in the colony can't forage for food, so they depend upon the worker termites to feed them.
When worker termites find cellulose material, food, they leave a "pheromone," or scent trail to lead other worker termites in the colony to the food that they find. Worker termites enter a home through tiny cracks in the foundation or slab, through utility entry points or anywhere that soil contacts wood. If they can't find an easy entrance point near the ground, they will construct mud tunnels (also called shelter tubes) to access areas above ground. These tubes protect them from low humidity and predators. The tubes are usually 1/4-1 inch wide (about the thickness of a pencil). Homeowners will often find these coming up the side of the house or in the basement or crawl space.
Soldier Termites
The soldier's role is to protect the colony from predators, mostly ants. And they are much less common than the workers.
Reproductive Termites
Reproductive termites are shiny, dark brown to black in color and approximately 1/4 - 1/2 inch long.
A mature colony will produce new reproductive termites called "swarmers" or "alates." Following a brief flight, the swarmers come to rest, shed their wings and try to find a member of the opposite sex in an attempt to mate and begin a new colony in the soil. Homeowners often see these in the spring and/or fall on a wet, warm day.
Very few swarmers emerging indoors survive to initiate new colonies because they are unable to find a moist location below the soil. A swarm indoors does indicate however that an infestation of the home is present. If you witness a termite swarm in your home or find the small translucent wings, you should have your home inspected to determine the extent of the infestation, the species present in your home and other treatment options.
Formosan Subterranean Termites
The Formosan subterranean termite is the most destructive termite in the U.S. These termites live in the ground like common subterranean termites, but have colonies that are many times greater in size. A colony of Formosan termites may have millions of members and can consume hundreds of pounds of wood in a single year. Along with their native subterranean cousins, Formosans are currently found in Alabama, Arizona, Arkansas, California, Florida, Georgia, Hawaii, Louisiana, Mississippi, New Mexico, North Carolina, South Carolina, Texas and Virginia. Their colonies are growing, continuing to move inland and northward. When they do invade a home, they inflict more damage, at a faster rate than traditional termites. Formosans are especially prevalant in south Texas and Louisiana where they are eating their way through New Orleans' French Quarter.
Formosan colonies are larger and more voracious than native termite species. Formosan termites cost consumers more than $1 billion a year, including the cost of repairs. In New Orleans alone, it's estimated that the pest infests as many as 30% of the trees and can cost individual homeowners several thousand dollars a year in damage and control costs.
Native to mainland China, it is believed that Formosan termites were originally imported to the U.S. from Taiwan (formerly known as the island of Formosa) on U.S. military ships at the end of World War II. The termites entered the country through southern ports in Charleston, along the Gulf of Mexico, and the Pacific. At home in the warm, moist climate, Formosans quickly set up residence and began to spread. They adapt quickly, even to cooler climates, and have been known to tunnel through plaster, plastic and even asphalt to reach the wood they crave. Formosan termites can be found to a limited extent along the Southeast and Gulf Coasts and in Hawaii (these areas also contain subterranean termites). Formosan termites are especially prevalent in Louisiana.
Drywood Termites
The Drywood termite colony lives in undecayed wood with little moisture and does not have to maintain constant contact with the ground. Drywood termites can be found along the Southeast, Gulf and Southern California coasts of the US. Homes in one of these areas can have subterranean and Drywood termites living in its vicinity.
Often Drywood termites can be found in roof rafters and in door and window frames. Unlike subterranean termites, Drywood termites do not build mud tubes into a structure and they do not bring mud into their wood tunnels. A sign of Drywood termites are the smooth tunnels in the wood, vs. a tunnel with mud in it for subterranean termites. These tunnels will also have hard fecal pellets scattered in them, this looks like ground pepper.
Dampwood Termites
Dampwood termites are most often found in Northern California, Oregon and Washington in cool, humid areas. They attack homes located on moist soil, such as beach houses and forest cabins or even homes with leaky plumbing. A mature colony has several thousand Dampwood termites. They start their colonies in moist wood and do not build mud tubes or need contact with the soil.