Drywood termites are one of the most common structural pests in Florida, infesting wood framing, furniture, and trim without ever touching soil. Unlike subterranean termites, which build mud tubes up from the ground, drywood termites live entirely inside the wood they eat. That makes them harder to detect and, in many cases, harder to eliminate. If you own a home in Florida, understanding what to look for and how to respond can save you thousands in repair costs.
How Drywood Termites Differ From Subterranean Species
Florida is home to both drywood and subterranean termites, and the distinction matters because they behave differently, cause different patterns of damage, and require different treatments. Subterranean termites need constant moisture from the soil and build visible mud tubes along foundations and walls to reach wood. Drywood termites skip all of that. A mating pair flies directly to a piece of exposed wood, burrows in, seals the entrance, and starts a colony inside the timber itself. They extract all the moisture they need from the wood they consume.
Physically, the two groups look different as well. Drywood termite soldiers have a broad plate behind the head (the pronotum) that is as wide as or wider than the head itself, while subterranean soldiers have a noticeably narrower plate. Drywood soldiers also have multiple teeth along the inner edge of their mandibles, compared to just one tooth or none in subterranean species. If you happen to catch a winged swarmer and can look at its wings under magnification, drywood swarmers have three or more hardened veins along the front edge of the wing, while subterranean swarmers have only two.
In practice, most homeowners never see a soldier up close. The more reliable way to tell which type you’re dealing with is the evidence they leave behind.
Signs of a Drywood Termite Infestation
The signature calling card of drywood termites is frass: tiny fecal pellets pushed out of the wood through small exit holes. Under magnification, each pellet has a distinct six-sided, oblong shape and is roughly uniform in size, though color varies from light tan to dark brown depending on the type of wood being consumed. To the naked eye, frass looks like fine sawdust or sand and often accumulates in small piles on windowsills, floors, or shelving below the infested wood.
The pellets exit through “kick-out holes,” which are only about 1/16 of an inch in diameter. Termites cut these tiny openings to the wood surface, carry pellets to the hole, and push them out, essentially solving their waste management problem without leaving the safety of the wood. Finding a fresh pile of pellets beneath a small round hole is one of the clearest indicators of an active colony. Older, inactive holes may be sealed with a thin plug of frass or wood particles.
Discarded wings are another common sign. After a swarm, mating pairs shed their wings near windows, doors, and light fixtures. If you find small translucent wings clustered on a windowsill during late summer or early fall, drywood termites are the likely source. Tapping suspected wood with a screwdriver or hammer can also reveal damage: infested timber sounds hollow, and in advanced cases, a thin paper-like shell of wood is all that remains on the surface.
When Drywood Termites Swarm in Florida
Drywood termites in Florida typically swarm during the warmer months, from late summer into early fall. Swarms tend to happen in the early evening, often near dusk, and the winged adults are attracted to light sources. That means you’re most likely to notice them around porch lights, windows, and interior fixtures if they’ve entered the house.
This timing sets them apart from subterranean termites, which swarm earlier in the year, often in spring. If you see winged termites around your home in September or October, drywood species are the most probable culprit. A single swarm doesn’t necessarily mean your home is infested, since swarmers can come from nearby trees or neighboring structures, but it does mean conditions favor drywood termites in your area and an inspection is worth scheduling.
How Drywood Termites Damage Wood
Drywood termite colonies grow slowly compared to subterranean species. A mature colony may contain only a few thousand individuals, far fewer than the hundreds of thousands common in subterranean colonies. But what they lack in numbers, they make up for in persistence and stealth. Because they live entirely within the wood, a colony can feed for years before anyone notices.
Their galleries run primarily along the grain of the wood, with occasional lateral branches connected by narrow cylindrical passages roughly 1 millimeter wide. They eat both the softer springwood and the harder summerwood, giving the internal galleries a smooth, sculpted appearance. In lightly infested boards, you might find just a few longitudinal tunnels near the center. In heavily infested wood, interconnected cavities can riddle virtually every board, leaving only a fragile outer shell.
A single piece of furniture or a single structural member can harbor multiple colonies. Research on infested lumber pallets has found anywhere from one to eight separate colonies within a single pallet, each maintaining its own gallery network. Some of those colonies were small and confined to one board, while others had interconnected tunnels running through nearly every piece of wood in the stack. In a home, this means one infested wall section could contain several independent colonies, each needing to be addressed.
Tent Fumigation: The Whole-Structure Option
Whole-structure fumigation is the most thorough treatment for drywood termites and the one most commonly used when infestations are widespread or difficult to pinpoint. The process involves covering your entire home with a sealed tent and introducing a fumigant gas, typically sulfuryl fluoride, which penetrates all wood in the structure and kills termites at every life stage.
During fumigation, gas concentrations inside single-family homes range from roughly 1,400 to 3,850 parts per million. Before the gas is released, a small amount of a tear-inducing warning agent is introduced to ensure no one accidentally enters the structure. Everyone, including pets and plants, must leave before fumigation begins. Waterproof covers and items wrapped in plastic also need to be removed, since plastic slows the aeration process afterward.
You won’t be allowed back inside until air monitoring confirms the gas has dropped below 1 part per million. The entire process, from sealing to aeration, typically takes two to three days, meaning you’ll need to arrange somewhere else to stay. Fumigation doesn’t leave a residual chemical in the wood, so it won’t prevent future infestations, only eliminate current ones.
The major advantage of fumigation is that it reaches every colony in the structure, including hidden ones behind drywall, inside wall cavities, and in attic framing where no inspector could visually confirm their presence.
Localized and Spot Treatments
When an infestation is limited to a single board or a small cluster of accessible wood, localized treatments can be effective and far less disruptive than tenting. Options include injecting chemical liquids, dusts, or foams directly into termite galleries; applying heat to raise the wood temperature to at least 120°F and holding it there for a minimum of 33 minutes; using microwave devices that heat wood from the outside; and in some cases, simply replacing the infested wood entirely.
Botanical-based products like orange oil (which contains the active compound d-limonene) and neem oil are also used as injection treatments. These kill termites on contact within the treated wood but, like all localized methods, only work where they’re applied.
The fundamental limitation of any spot treatment is uncertainty. Current detection methods can’t reliably map every colony hidden behind walls, and drywood termite colony boundaries are difficult to determine from the outside. You may treat the visible problem and miss a second colony two feet away inside the same wall. For homes with a confirmed but isolated infestation in accessible wood, localized treatment is a reasonable and cost-effective choice. For homes with multiple infestation sites or evidence of long-term activity, fumigation is generally the more reliable path.
Preventing Drywood Termites in Your Home
Prevention starts with limiting entry points. Drywood termites get inside by flying to exposed wood and chewing in, so any unsealed crack, gap, or vent opening is an invitation. Screen attic vents and soffit openings with fine mesh to block swarmers. Seal gaps around window frames, door frames, and where utility lines enter the structure. Pay particular attention to fascia boards and eaves, since these are common infestation sites and also where kick-out holes are most frequently found during inspections.
Wood treatments add another layer of protection. Borate-based products applied to bare wood before painting or finishing penetrate the surface and make the wood toxic to termites that try to feed on it. This is especially practical during construction or renovation when framing is exposed. For existing homes, borate treatments can be applied to accessible attic framing and crawlspace lumber.
Reducing wood-to-exterior contact also helps. Store firewood away from the house, avoid stacking lumber against exterior walls, and inspect secondhand furniture before bringing it inside. Drywood termites are frequently introduced to homes through infested furniture, picture frames, and other wooden items rather than through outdoor swarms alone. In Florida’s climate, where warm temperatures and humidity favor termites year-round, annual inspections by a licensed pest professional are one of the most practical investments a homeowner can make.