Formosan Termites: How to Handle this Growing Threat

Mud tubes on wood door
Formosan termites don’t like to be exposed, so they build shelter tubes to travel between their nest and sources of food and water. (DepositPhotos)

Detecting Formosan Termites

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.

Termite droppings, also called frass, found in the nest
To positively identify Formosan termites, you need to collect them and share them with an expert. (DepositPhotos)

Identifying Them

Should you discover an active colony of termites, 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.

Spraying termites with pest control on the ground
Before hiring an exterminator, make sure they’re qualified to treat Formosan termites. (DepositPhotos)

Exterminating These Pests

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.

Further Information


  1. I have found a bunch of dead formosans in my attic. I think that thye are comign in during outside swarms through my ridge vents.

    I find no sign of damamge anywhere.

    How concerned should I be? What action should I take?

  2. You are correct that the formosan termite alates can get into an attic during their swarm. If there are only a few dozen, I would not worry. As long as the house is sound and there are no roof leaks, anything entering the house will die. If there are hundreds, then they may be emerging from wood in the attic. They could also be drywood termite alates. They are both similar in appearance.
    Either way it is always a good idea to have your house under termite control contract. Make sure to schedule your annual inspection. Be there for the inspection and follow the technician around to make sure they are thorough.

    • Thanks for sharing your thoughts with the Today’s Homeowner community, Chris!
      TH community members helping other TH community members — we love it. 🙂


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