Two weeks ago, we walked through what happens during a drywood termite tent fumigation. That post gets the most attention because fumigation is dramatic — the tent, the gas, the whole neighborhood watching. But drywood termites are only half of Tampa Bay’s termite picture. The other half lives underground, and it’s the one most homeowners never think to look for.
Two Different Termites, Two Different Playbooks
Drywood termites live entirely inside dry wood — no soil contact required. Subterranean termites are the opposite: they nest in the soil and build distinctive mud tubes to travel from the ground into wood, because they need consistent moisture to survive. In Florida, subterranean termites typically swarm from late winter through spring, often during daylight hours following rainfall, while drywood swarms tend to happen at night, later in the year.
Because the biology is different, the treatment has to be different too. A drywood colony inside a wall stud isn’t reachable by anything applied to the soil around your foundation. A subterranean colony foraging up through the slab isn’t reliably addressed by a wood treatment applied at the surface. Confusing the two — or assuming one treatment covers both — is one of the more expensive mistakes a homeowner can make.
What Subterranean Termite Activity Looks Like
The clearest sign is mud tubes — pencil-width tunnels of soil and wood particles running along a foundation wall, a pipe, or up through a slab crack. Other signs include hollow-sounding wood when tapped, soft or spongy baseboards and window sills, and swarmers or discarded wings appearing near baseboards or ground-level entry points, typically after a rain event. Unlike drywood termite frass — which looks like small piles of pellets or coffee grounds — subterranean termites don’t leave visible droppings, since they stay inside their mud tubes and soil galleries.
Why Termidor Is the Standard Treatment
Termidor is a non-repellent liquid termiticide applied as a barrier in the soil around and beneath a structure. The key word is non-repellent — termites can’t detect it and avoid it the way they can with older repellent formulations. They tunnel through treated soil without knowing it, carry the product back to the colony on their bodies, and transfer it to other termites through normal colony contact. Over time, this reaches members of the colony that never directly touched the treated soil, including the queen.
This is a meaningfully different mechanism than a borate wood treatment. Termidor doesn’t rely on termites finding exposed wood — it’s positioned in the pathway they already use to reach a structure from the soil, which is why it’s the standard approach for subterranean species specifically.
What the Treatment Process Looks Like
An inspection comes first, confirming subterranean activity and mapping the extent of mud tubes, moisture conditions, and foundation type. From there, treatment typically involves trenching and rodding along the foundation perimeter to place the barrier in the soil, and in some cases drilling through slab areas where interior activity is present. Unlike fumigation, this doesn’t require vacating the home or tenting the structure — it’s a targeted, localized application rather than a whole-structure event.
What to Expect Afterward
A properly installed Termidor barrier is intended to remain effective in the soil for an extended period, providing ongoing protection against new subterranean activity rather than addressing only what’s active at the time of treatment. That said, no soil treatment is a substitute for periodic inspection — conditions like new landscaping, irrigation changes, or construction near the foundation can affect long-term protection, which is why we recommend keeping up with your inspection schedule even after treatment.
Which One Do You Actually Have?
If you’re seeing mud tubes, it’s subterranean. If you’re seeing small pellet-like frass and kick-out holes in wood trim, it’s drywood. If you’re not sure — and most homeowners aren’t, since both can produce swarmers around the same time of year — that uncertainty is exactly what a licensed inspection resolves. Treating the wrong species with the wrong method wastes time and money while the actual colony keeps working.
Pestex Services Inc. is a family-owned pest control company based in Tampa, serving Hillsborough, Pinellas, and Pasco Counties for over 40 years. Contact us at 813-960-PEST or visit pestexweb.com.