Drywood vs. Subterranean Termites — and When to Call a San Antonio Termite Exterminator

Subterranean termites rule Bexar County and most of Central Texas. They live in underground colonies that can number in the hundreds of thousands, and they have to stay in contact with soil to survive. So they build bridges. To reach the wood in your home, they construct the pencil-width mud tubes you may have spotted along your foundation or walls.

Their damage pattern follows the grain of the wood, eating the soft spring wood while leaving the harder grain intact. This produces a honeycomb or layered appearance inside affected wood. Because they approach from below, damage often starts in the foundation sill plates, floor joists, and structural wood closest to the soil.

Drywood termites are more common in South Texas, along the Gulf Coast, and in areas of sustained warmth. Unlike subterranean species, they live entirely within the wood they eat and need no soil contact. They infest dry, seasoned wood: framing, furniture, hardwood floors, and wood trim.

A drywood infestation is typically smaller and slower-moving than a subterranean one. But they're also harder to detect because there are no mud tubes and no sign of soil activity. The colony lives invisibly inside the wood, and the first external sign is often frass, which are small pellets or granules pushed out through tiny kick-out holes in the wood surface.

Mud tubes are the definitive indicator of subterranean termites. If you find them, you're dealing with a subterranean species. No mud tubes doesn't rule them out entirely, since tubes can be hidden inside wall voids, but visible tubes are a firm identification.

Frass pellets are the signature of drywood termites. They accumulate in small piles directly below kick-out holes, often on windowsills, floor surfaces, or furniture. The pellets are roughly hexagonal and vary in color from cream to dark brown, matching the wood the colony is eating.

Subterranean termites are treated at the soil level with liquid termiticides applied around the foundation perimeter or with bait stations that slow-kill the colony from within. Both methods are designed to intercept termites traveling between soil and structure.

Drywood termites require a fundamentally different approach because there's no soil to treat. For small, accessible infestations, localized wood injection targets the galleries directly. Widespread infestations, or ones deep in inaccessible framing, are the cases where whole-structure fumigation gets raised: it eliminates all life stages throughout the structure, but it is a specialty service we do not perform, so if an inspection points that way we would refer you to a licensed fumigation specialist. Localized treatments are less disruptive but may miss portions of the colony.

In a standard San Antonio home, bet on subterranean. South Texas subterranean pressure is high, and most homes that get termite damage here are dealing with this species. Drywood is the exception. It turns up in older homes, homes near the coast, or in wood that was already infested when it came to the property, like furniture, antiques, and reclaimed lumber.

Bob Jenkins Pest & Lawn Services has done termite work long enough to have seen both. An inspection confirms which species is present and where the activity is, which is the only way to select the right treatment and not waste money on the wrong one.