How Do Asian Subterranean Termites Damage Homes?

Asian subterranean termites damage homes by eating structural wood from the inside out, filling the hollowed galleries and wall voids with carton nest, and doing it in colonies large enough to cause severe damage in a relatively short time. The surface of a door frame or beam can look normal while the wood behind it is reduced to thin layers.

The species is an invasive termite from Southeast Asia, first found in the continental US in Miami in 1996 and now very common from Key West to West Palm Beach, according to UF/IFAS. It attacks buildings, yard trees and even boats. This article explains how that damage happens, where in a house it concentrates, why South Florida trees are part of the story and how to limit the harm.

How Asian Subterranean Termites Feed on Wood

Like other termites, Asian subterranean termites feed on cellulose: wood, paper, cardboard and the paper facing on drywall. Only the workers eat and digest it; they then feed the soldiers, reproductives and young. In the closely related Formosan termite, UF/IFAS notes that workers feed on the softer spring wood in each growth ring, leaving the harder layers behind. That is why infested wood often looks like a stack of thin, papery sheets when it is opened.

Three habits make the damage worse than the numbers of termites alone would suggest:

• They stay hidden. Workers travel inside soil, mud tubes and the wood itself, and seal openings with soil. The finished surface, paint or drywall often stays intact.
• They bring soil and moisture in. Galleries in damaged wood often contain soil, which keeps the wood moist and makes it softer.
• They build carton. A mix of soil, chewed wood, saliva and feces packed into hollowed wood and wall voids. UF/IFAS lists carton in hollowed wood or structural voids as a mark of an advanced infestation.

How Big Colonies Turn Into Fast Damage

UF/IFAS scientists report that colonies of the invasive subterranean species can reach several million termites, and that Asian subterranean termites can forage underground up to 100 feet from their central nest. A colony that big has far more workers feeding at once than a small colony, so wood disappears faster.

The UF/IFAS profile of the species puts it plainly: damage can become severe in a relatively short time, especially when a large, mature colony invades a structure. Documented examples include fascia on Grand Turk Island, a church pew in Miami and carton packed into a door casing in Key West.

Colonies also grow quietly for years before they show themselves. In the closely related Formosan termite, UF/IFAS says an established colony takes about 5 to 8 years to mature and begin producing swarmers, so by the time a swarm reveals a Coptotermes colony, it has usually been feeding for a long time. To see how they build these colonies, read how Asian subterranean termites build massive hidden colonies.

Where in a House the Damage Shows Up

Termites go wherever wood meets moisture and a hidden path. In South Florida homes, damage most often concentrates in these areas:

As damage advances, the signs become structural: floors that feel soft or sag, doors and windows that stick, cracked drywall and ceilings that dip. A full checklist of early warning signs is in our guide on how to tell if you have an Asian subterranean termite infestation.

Why Damage Is Found So Late

The Florida Department of Agriculture and Consumer Services warns that termites do their damage behind closed walls, and that it can go unnoticed for years until a remodel or a swarm reveals it. Common moments of discovery in South Florida include:

• A swarm at dusk between February and April, often inside a bathroom or near a light
• Replacing baseboards, flooring or a door frame
• Repairing a roof or fascia after a storm
• A pre-sale inspection when the home goes on the market

By then, repairs can involve framing, trusses and finishes, not just a single board. The financial side is covered in the cost of Asian subterranean termite damage.

The Tree Problem: Damage You Do Not See in the House

UF/IFAS reports that Asian subterranean termites can infest live, healthy trees. Invasive termites eat trees from the inside, often with few visible signs, so a tree can look healthy while its core is hollow. UF/IFAS entomologist Thomas Chouvenc has warned that termite-weakened trees are more likely to fall during storms, and that many trees that ended up on roofs and cars after hurricanes would have withstood the storm had termites not compromised them.

The scale is significant. In a five-year project with the City of Fort Lauderdale, UF/IFAS researchers monitored park trees for the two invasive Coptotermes species:

Baiting eliminated the detectable colonies, but about 15% of previously treated trees were reinfested within three years, which is why the researchers call for ongoing monitoring. For a homeowner, an infested tree means two risks: a weakened tree that can fall on the house in a hurricane, and a large colony foraging within reach of the foundation. Our article on termites after the storm covers what to check once a storm has passed.

Boats and Marinas

UF/IFAS has recorded shipboard infestations on private boats docked in Fort Pierce, Hollywood and Fort Lauderdale, and on boats in the Keys. Swarms on board can reach land, which makes boats the most likely way people spread this species. If you live on the water, include your boat in termite inspections.

How to Limit Asian Subterranean Termite Damage

You cannot undo damage that is already done, but you can stop it from growing and make new infestations easier to catch:

1. Fix moisture first. Repair roof, plumbing and AC leaks, clean gutters and aim sprinklers away from walls.
2. Keep the foundation visible. Thin mulch near the house and a clear strip next to the slab let you see tubes.
3. Get wood off the ground. Remove stumps, stored lumber and cardboard from against the house and the garage floor.
4. Inspect trees. Look for mud tubes on trunks and have nearby trees included in your termite inspection.
5. Schedule yearly professional inspections. FDACS calls them a must for older homes.

Our full guide to preventing Asian subterranean termites goes through each step in detail.

How Professionals Stop the Damage

UF/IFAS recommends the same strategies used for Formosan termites: baits and soil treatments. Baits use a slow-acting ingredient that workers share with the colony; for Formosan termites, UF/IFAS puts colony elimination at about 3 months. Liquid termiticides protect the treated zone around the structure but may not eliminate colonies nearby. Tent fumigation, used for drywood termites, does not solve subterranean colonies living in the soil.

Toro’s termite control service starts with a free inspection to confirm the species and map how far the damage goes, including garages, attics and nearby trees. For Asian subterranean termites, Toro uses the Sentricon baiting system installed in the soil around the property, with no drilling into the slab and no trenches. The bait is carried back to the colony, which is designed to eliminate it, including the queen, and the stations stay in place for year-round protection. If the bugs come back, so will Toro, at no additional cost to you.

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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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