Common Signs of Termite Infestation

The Old House Web

If you're a homeowner, you probably had your house inspected for termites before you bought it. But even if no termites were found at the time of purchase, you still should watch for these pests, according to an entomologist in Penn State's College of Agricultural Sciences.


"To protect your investment and save yourself a lot of trouble, learn the signs of possible termite infestation," says extension entomologist Steven Jacobs. "One symptom of infestation, swarming termites, usually takes place in the spring."

In nature, termites perform a beneficial function by breaking down wood and cellulose for use by other organisms. In buildings, they may feed on structural wood, wood fixtures, paper, books, cotton and related products. "When structural damage becomes apparent, it usually is the result of years of infestation," Jacobs says. "Generally, termite problems only occur 10 or more years after construction."

Eastern subterranean termites can be found throughout Pennsylvania. These social insects live in colonies underground, where they feed mostly on old roots, tree stumps and fallen limbs.

Each colony consists of three castes: workers, soldiers and winged reproductives. The workers are creamy-white and are rarely seen unless infested wood is broken open. These quarter-inch-long termites are the ones that feed on wood and cause damage. The soldiers have elongated yellowish heads with large jaws and are about the same size as adult workers. They protect the colony in case of invasion.

The kings and queens, or reproductives, are dark brown or black, and reach up to one-half-inch long. They have two pairs of wings, which drop off shortly after they have "swarmed" to begin new colonies. "In Pennsylvania," says Jacobs, "swarms of winged termites usually emerge between February and June."

During this time, swarms may be found inside infested structures. Sometimes, their shed wings are the only evidence that termites are present. "Although the reproductives don't cause damage, swarming termites or their wings alone are sure signs that termites are working in a building," warns Jacobs.

Because winged termites often are confused with winged ants, it's important to know how to tell the difference. Ants have narrow, wasp-like waists, while termites have broad waists. Also, the wings of an ant are about the same length as its body, but a termite's wings are about twice the length of its body.

Termite tubes are another danger signal to watch for. Because they prefer dark, moist conditions, termites make these earth-colored tubes primarily as protected runways from the earth to the wood they feed on. They also may serve as swarming exits for winged termites.

"Look for these tubes on cellar walls, wooden posts, exterior masonry and trim around doors and windows," Jacobs says.

Wood attacked by termites has channels or passages coated with an earth-like material. Where the wood has been infested for some time, it may be largely hollowed out with passages and may look rotten. When such wood is probed with a screwdriver, many worker termites spill out.

Most infestations occur in basements and in the structural timbers just above cellar walls. Wooden posts, steps, door frames and trim embedded in an earthen or concrete floor are especially susceptible. Termites particularly favor areas around furnaces, chimneys and hot water heaters and pipes that provide warmth during winter.

Many houses in Pennsylvania are unlikely to ever have termites because they are located in low-risk areas or are constructed to resist infestations. "The less suitable the site is for termites, the less likely a colony will become established and flourish," Jacobs says. He offers several structural control recommendations:

  • Remove all wooden debris from around the building. Replace wooden posts, steps, trellises and other structures that contact the soil with noncellulose materials or pressure-treated lumber.
  • Replace badly damaged timbers with sound materials. Where possible, don't allow wood within 18 inches of the soil.
  • Provide adequate ventilation and drainage for basements, cellars and crawl spaces.
  • Fill all visible cracks and voids in the foundation with concrete or caulking compound.
  • Reduce soil moisture around the structure by directing run-off away from the foundation. Be sure gutters and downspouts are installed and working correctly.

If you find termites or suspect an infestation, Jacobs recommends that you find a reputable professional to inspect the building and implement control measures. "Contact at least three licensed pest control operators for estimates," he says. "Firms that are members of the National and Pennsylvania Pest Control associations have access to specialized training and materials."

Penn State Cooperative Extension offers a free publication titled "Eastern Subterranean Termites." To receive a copy, or for more information, contact the extension office in your county.

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