House & Home

Formosan Termites: A Growing Threat

Posted June 11, 2008 9:29 a.m. EDT
Updated June 11, 2008 1:42 p.m. EDT

Formosan Termites: A Growing Threat

The Formosan subterranean termite (Coptotermes formosanus) strikes fear in the hearts of homeowners, particularly residents of Hawaii and the southern United States. According to a report by the Department of Agriculture, it is one of the most destructive pests in the country. Each year over $1 billion is spent in the U.S. for preventative and remedial treatment and to repair damage caused by Formosan termites.

Despite persistent myths to the contrary, Formosan termites can’t chew through concrete and aren’t able to leap tall buildings in a single bound. Even so, they’re often referred to as “super-termites” because they’re aggressive, able to build nests above ground, and form extremely large colonies. While native termite colonies often number in the hundreds of thousands, Formosan colonies include millions of individuals. One Formosan queen can live as long as 20 years and lay as many as 2,000 eggs a day.


Formosan termites are native to China and migrated to North America on military transports returning from World War II. They are now found in at least 11 states, including Alabama, California, Florida, Georgia, Hawaii, Louisiana, Mississippi, North Carolina, South Carolina, Tennessee, and Texas. Formosan termites are rarely found further north than 35° N latitude because their eggs can’t hatch below 68°F.


The best way to prevent an infestation of Formosan termites is to make your home uninviting by cutting off their access to food and water. To accomplish this goal:

  • Remove dead trees as well as scrap wood, paper, and cardboard from your yard.
  • Prevent wood from coming into direct contact with bare ground around your home.
  • Use pressure-treated wood for structures at or near ground level.
  • Anchor wooden posts for fences, decks, porches, and sheds in cement.
  • Eliminate wooden planters, tubs, trellises, and stakes.
  • Keep plants and landscaping materials at least a foot away from buildings.
  • Avoid using wood chips for mulch close to the house.
  • Install and maintain rain gutters to direct water away from the walls and roof of the house.
  • Add downspout extenders to deliver runoff at least a foot away from the foundation.
  • Repair leaks in outdoor faucets, indoor fixtures, water lines, drains, and appliances immediately.


Early detection leads to early treatment, which is critical. Entomologists at the University of Hawaii have found that a colony of Formosan termites can do significant structural damage in as little as six months. If you live in or near affected areas, inspect your home and property at least once a year for the following signs:

  • Shelter Tubes: Formosan termites don’t like to be exposed, so they build shelter tubes to travel between their nest and sources of food and water. Check the foundation, as well as any wood near the ground, for signs of tubes.
  • Water Source: Examine areas surrounding outside faucets and water lines. Inside, inspect areas where moisture is found, such as kitchens, bathrooms, and laundry rooms.
  • Damage: Look for pinholes in drywall and evidence of damage to wood in any location, even the tack strips under carpeting.
  • Nests: Formosan termites build large nests made of a rock-like mass. Most of these nests are built below ground, but not all nests have contact with soil. Probe any suspect areas with an awl or screwdriver, and check any wood that feels soft or hollow. Look for bulges or depressions, discolorations, and spongy wood. Check cracks in stucco or plaster, and knots in trees.


Should you discover an active colony of termites, try to gather several different looking specimens from the nest, since some members of the colony are easier to identify than others.

Another approach is to collect them when they swarm, which takes place at night from April through July. Like most insects, Formosan termites are attracted to light. To collect samples for identification, mix a little dishwashing soap in a container of water. Place it near a light source, and turn off all other lights in the area.

Put any suspect insects you find in small bottles filled with rubbing alcohol and take them to a trusted exterminator, county extension office, or university entomology department for identification.


If the samples you collect are identified as Formosan termites, it’s time to call an exterminator, since eradication is best left to professionals. Before selecting a pest control company, get at least three bids and make sure the exterminator you choose has plenty of experience in dealing with Formosan termites.

There are two basic types of control available: soil termiticides and bait. A reliable exterminator should consult you and discuss all the options before making a decision about treatment.