How Can I Tell If I Have an Asian Subterranean Termite Infestation?

The clearest sign of an Asian subterranean termite infestation is a swarm of dark brown winged termites at dusk or at night between February and April, especially if they come from inside the house. Mud tubes on the foundation, carton material in walls or hollow, soil-packed wood are the other telltale signs.

Asian subterranean termites are an invasive species from Southeast Asia that became established in South Florida after they were first found in Miami in 1996. UF/IFAS describes them as very common from Key West to West Palm Beach, and a 2026 University of Florida study found them established as far north as Brevard and Hillsborough counties. Because they work out of sight, most homeowners only learn about them from the few clues below. This guide shows how to read those clues, how to tell this species apart from look-alikes and what to do when you find them.

Why Asian Subterranean Termites Are Hard to Spot

Asian subterranean termites nest in soil, hollow wood, wall voids and even living trees. Workers move between the colony and their food inside mud tubes or inside the wood itself, and they rarely come out into the open. The EPA notes that many people only discover termites when a swarm appears or when damage turns up during construction.

According to UF/IFAS, the first signs are usually dispersal flights, foraging tubes or damage, and advanced infestations leave carton nest in hollowed wood or in structural voids. Colonies of these invasive termites can reach several million individuals, and the species can forage underground up to 100 feet from its central nest, so the colony that is feeding on your house may live under the yard or inside a tree.

Sign 1: Swarms at Dusk Between February and April

Swarming is when mature colonies release winged reproductives (alates) to start new colonies. It is the most visible sign and the one most homeowners notice first.

• When: In Florida, UF/IFAS has recorded flights from February to April. The season ends about when the Formosan termite season begins.
• What time: At dusk or at night, often on warm evenings.
• Where: Around porch lights, windows, light fixtures and TV or computer screens, since lights attract the swarmers indoors when doors or unscreened windows are open.

How many you see matters. Indoor swarmers rarely survive because they need moist wood or soil. A handful near an open door may have flown in from outside. UF/IFAS notes that hundreds to thousands of alates indoors usually indicate a structural infestation.

What the Swarmers Look Like

Asian subterranean swarmers are about 13 to 14 mm long including the wings, slightly smaller than Formosan swarmers. The head, the plate behind it and the top of the abdomen are dark brown, and two light “antennal spots” on the face are clearly visible. On Formosan swarmers those spots are faint or absent, and the body is orange to light amber-brown.

They can also be confused with flying ants. Termites have straight antennae, a thick waist and four wings of about the same length; ants have elbowed antennae, a pinched waist and front wings longer than the hind wings. Our guide to termites vs. flying ants has more side-by-side tips.

Sign 2: Shed Wings on Sills and Floors

After a flight, swarmers break off their wings. Piles of small, equal-sized, translucent wings on windowsills, in light fixtures, on floors near doors or in spider webs are often all that is left by morning. Wings in several rooms, or in a room with no open window, are a strong reason to call an inspector.

Sign 3: Mud Tubes and Foraging Tubes

Subterranean termites build shelter tubes of soil, chewed wood and saliva to travel between the soil and wood without drying out. Look for pencil-width tubes on:

• The foundation and slab edge, especially behind shrubs and planters
• Garage walls and expansion joints
• Plumbing penetrations under sinks and behind tubs
• Tree trunks and roots near the house

In the Keys, UF/IFAS has documented foraging tubes built with coral sand, so tubes may look pale rather than brown. If you break a small section and it is rebuilt within days, the colony is active. Better still, leave it alone and let a professional inspect it.

Sign 4: Hollow Wood, Bubbling Paint and Carton

Workers eat wood from the inside, so the surface often looks normal while the inside is lined with galleries. Signs inside the house include:

• Wood that sounds hollow or papery when tapped, or that a screwdriver sinks into
• Paint that bubbles, blisters or peels over door frames, baseboards and trim
• Galleries in damaged wood that contain soil
• Carton: a brown, spongy, layered material made of soil, wood and saliva packed into wall voids, door casings or hollowed beams

UF/IFAS lists carton in hollowed wood or structural voids as a mark of an advanced infestation. Bubbling paint and soft wood can also come from moisture, so read water damage vs. termite damage before assuming the worst, and have it checked either way.

Asian Subterranean Termite Signs at a Glance

That last row is a common mix-up. Asian subterranean termites do not push piles of hard pellets out of the wood. If you find small, sand-like pellets under furniture or trim, you are more likely dealing with drywood termites, which need a completely different treatment.

Asian or Formosan? Why the Species Matters

Broward and Miami-Dade were the first counties where UF/IFAS documented Asian and Formosan subterranean termites both established, so homeowners here can face either one. Both belong to the genus Coptotermes, both build carton nests and both form very large colonies.

The timing of your swarm is often the fastest clue. UF/IFAS scientists stress that each termite species is controlled differently, so identification comes before treatment. If you want to know how a colony grows from that first swarm into millions, see the life cycle of Asian subterranean termites.

What to Do If You Find These Signs

1. Do not spray or knock down tubes. Killing the termites you can see does nothing to a colony in the soil or a tree, and it removes the evidence an inspector needs.
2. Collect a sample. Put a few swarmers or wings in a sealed bag or a small jar of rubbing alcohol.
3. Write down what you saw: date, time of day, where the swarm came from, and where you found tubes or damage.
4. Check outside. Walk the foundation, garage and nearby trees for tubes.
5. Schedule a professional inspection. Termite companies must be licensed by the state, as the EPA points out, so ask to see the license.

FDACS notes that termites do their damage behind closed walls and can go unnoticed for years, so a clean visual check does not always mean a clean house. For a closer look at what this species does once it is inside, read how Asian subterranean termites damage homes.

How Toro Confirms and Treats an Infestation

A Toro termite control visit starts with a free inspection. A trained technician identifies the species, checks how far the damage goes and explains the options before any work begins. For Asian and other subterranean termites, Toro installs the Sentricon baiting system in the soil around the property, with no drilling into the slab and no trenches. Termites carry the bait back to the colony, which is designed to eliminate it, including the queen, and the stations stay in place for year-round protection.

Toro has protected homes across Miami-Dade, Broward, Palm Beach and the Keys since 1969, with technicians trained at the TORO Institute alongside on-staff entomologists, and the work is backed by the 110% Satisfaction Guarantee.

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Frequently Asked Questions

Educational content. This article is for general information about pests in South Florida and is not medical, legal or professional advice. If you have a bite, sting or allergic reaction, contact your doctor; in an emergency, call 911. Pest problems vary from home to home, so a licensed professional should inspect before treatment. When using any pesticide, always read and follow the product label.

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