Florida’s warm, humid climate supports some of the highest termite activity in the United States, and the signs vary depending on which species is doing the damage. The three main types you’ll encounter are native subterranean termites (found statewide), Formosan subterranean termites (concentrated in coastal and urban areas), and West Indian drywood termites (which live entirely inside structures). Knowing which clues to look for can mean the difference between catching an infestation early and discovering extensive structural damage.
Mud Tubes on Foundations and Walls
The most recognizable sign of subterranean termites, both native and Formosan, is mud shelter tubes. These pencil-width tunnels made of soil and saliva run along foundation walls, support piers, plumbing, and other vertical surfaces. Termites build them as protected highways between their underground colonies and the wood they’re feeding on. You’ll most commonly spot them on the exterior foundation or inside a crawl space, but they can also appear higher up on interior walls, ceilings, soffits, and fascia boards.
Mud tubes traveling over or through foam insulation are another red flag, and one that’s easy to miss since the tubes can blend in with the insulation’s color and texture. If you find what looks like a dried mud line running up a surface, break it open. Active tubes will have small, pale worker termites inside. Even an empty tube doesn’t mean the problem is gone; termites often abandon one route and build another nearby.
Pinholes and Sunken Trails in Walls
Not every sign is as obvious as a mud tube. Subterranean termites sometimes accidentally break through drywall or paneling from behind, creating tiny openings about the size of a BB. They quickly patch these “pinholes” with a dot of dried mud because exposure to outside air threatens them. If you notice small brown or tan spots on an interior wall or ceiling that look like dried mud spatters, they may mark exactly where termites are feeding just behind the surface.
Another subtle indicator is narrow, sunken, winding lines underneath paint or wallpaper. Termites feed on the paper backing of drywall and can consume the material right up to the painted surface, leaving only a thin, rippled shell. You might notice the paint looking slightly buckled or wavy in an irregular, trail-like pattern. Pressing on these areas may reveal hollow or soft spots beneath.
Frass Pellets from Drywood Termites
Drywood termites don’t need contact with soil, which means they won’t leave mud tubes. Instead, the telltale sign is frass: tiny, dry, six-sided pellets about one millimeter long that get pushed out of the wood through small “kick-out” holes. These pellets accumulate in small piles that look like fine sand or sawdust, often found on windowsills, floors beneath wooden furniture, or along baseboards.
The kick-out holes themselves can be hard to spot. Drywood termites typically plug them with cemented-together frass, so the opening blends into the wood surface. If you sweep up a frass pile and it reappears days or weeks later in the same spot, that’s a strong indication of an active colony inside the wood above. The pellets are distinctive if you look closely. Unlike actual sand grains, each one has six concave sides, almost like a tiny barrel with dimpled faces.
Wood damaged by drywood termites has a characteristic look when exposed. Feeding tunnels are smooth inside, almost as if sanded, and the wood may be consumed nearly completely while the outer painted surface stays intact. Tapping on infested wood often produces a hollow sound.
Swarmers and Shed Wings
Termite swarms are one of the most alarming, and most useful, signs of an infestation. Swarmers are winged reproductive termites that leave an established colony to start new ones. In Florida, swarming activity varies by species and can happen across multiple months, with native subterranean species typically swarming in spring and Formosan subterranean termites swarming in late spring to early summer, usually in the evening around dusk and drawn to lights.
Finding swarmers emerging directly from your walls, ceiling, or floors is a clear sign your structure is infested. Even finding large numbers of swarmers or piles of shed wings indoors, near windows or light fixtures, should raise immediate concern. Formosan swarmers are about half an inch long including their wings and tend to appear in large numbers because their colonies can contain millions of individuals.
Swarmers vs. Flying Ants
Many people confuse termite swarmers with flying ants, but three physical differences make identification straightforward. Termite swarmers have straight, beadlike antennae, while flying ants have distinctly elbowed antennae. Termites have a thick, uniform waist, whereas ants have a pinched, narrow waist. And termite wings are two equal-length pairs that extend well past the body, while ant wings come in two pairs of clearly unequal length. If you’re finding insects you can’t identify, collecting a few in a plastic bag for a pest professional to examine is a practical first step.
Signs Specific to Formosan Termites
Formosan subterranean termites deserve special attention in Florida because of the sheer scale of damage they cause. A single colony can forage up to 300 feet from the nest and contains a far higher proportion of soldiers (10 to 15 percent) compared to native species (1 to 2 percent). This means damage accumulates faster.
One sign unique to Formosan termites is the “swarm castle,” an odd-shaped formation of dried mud that sprouts from walls or ceilings in late spring. These structures are built in preparation for swarming. If you break one open, you’ll likely see soldier termites rushing to defend the breach. Formosan soldiers are also distinctive because they release a white, glue-like defensive secretion from the top of their heads when disturbed, something native subterranean soldiers don’t do.
Formosan termites also build carton nests: large masses of chewed wood pulp, soil, saliva, and feces packed into wall voids, attics, or other enclosed spaces. These nests retain moisture, which allows the colony to survive without maintaining a direct connection to the ground. This is why Formosan infestations sometimes appear in upper stories of buildings or in locations where you wouldn’t expect subterranean termites to reach. They also commonly infest live trees, hollowing out the dead wood at the center. While this doesn’t kill the tree directly, it weakens the trunk and makes the tree far more likely to collapse in a hurricane or strong storm.
Damage Patterns in Wood
The way termites eat wood can itself be a diagnostic clue. Subterranean termites, including Formosan species, feed along the wood grain, consuming the softer spring wood and leaving the harder layers behind. This creates a layered, almost comb-like pattern. You’ll often find soil packed into the feeding galleries, especially with Formosan termites. Drywood termites, by contrast, eat across the grain and create smooth, clean tunnels that may be packed with frass or completely hollowed out.
In both cases, wood that looks intact from the outside may be severely compromised inside. Probing suspicious wood with a screwdriver or similar tool is a simple way to check. If the tool sinks easily into what should be solid wood, or if the surface crumbles to reveal hollow galleries beneath, you’re looking at termite damage.
Annual Inspections and Prevention
Because termite signs are often hidden behind walls, underground, or inside wood, UF/IFAS Extension recommends annual inspections by a licensed pest management professional trained in identifying termites and other wood-destroying organisms. These annual renewal inspections are especially important in Florida, where termite pressure is year-round and multiple species can infest the same property simultaneously.
For subterranean species, the two main preventive approaches are liquid soil treatments and bait systems. Liquid treatments create a chemical barrier in the soil around and beneath a structure. These come in two categories: non-repellent formulations that termites unknowingly travel through and pick up, and repellent formulations that deter termites from entering treated soil. Both types protect the structure, though soil treatments generally don’t eliminate entire colonies. Bait systems, on the other hand, use stations placed in the ground around the property that termites feed on and carry back to the colony, with the potential to kill the colony over time.
For drywood termites, prevention looks different because they enter through exposed wood above ground. Sealing cracks around eaves, window frames, and attic vents, and keeping exterior wood surfaces painted or sealed, reduces entry points. Localized or whole-structure fumigation is the standard treatment once drywood termites are established inside a home.