Local termite education
Drywood vs Subterranean Termites in San Diego
San Diego has both drywood and subterranean termites, and the treatment for each is completely different. Drywood termites live inside dry wood with no soil contact and are very common near the coast. Subterranean termites nest in the soil and build mud tubes, and they are more common inland. Identifying the species correctly is the first and most important step.
How do I identify drywood termites?
Drywood termites live entirely inside the wood they eat, so the classic sign is small piles of six-sided fecal pellets that look like coarse sand, salt, or coffee grounds, often below a tiny kick-out hole. You may also see discarded wings near windows after a swarm. In San Diego, drywood termites swarm most often in late summer and fall and are very common in coastal, wood-framed homes.
How do I identify subterranean termites?
Subterranean termites nest in the soil and build pencil-width mud tubes up foundations, piers, and walls to reach wood while staying protected from the air. You will see these tubes in the substructure, garage, or along the foundation. They swarm in spring, often after warm rain, and are more common in inland San Diego. They cause damage faster than drywood termites.
- Drywood: pellet piles, kick-out holes, fall swarms, coastal
- Subterranean: mud tubes, soil contact, spring swarms, inland
- Both leave discarded wings after a swarm
- San Diego also has confirmed Formosan subterranean termite sites
How are drywood termites treated?
A widespread drywood infestation is eliminated with whole-structure fumigation, because the gas reaches the colonies hidden inside walls and stucco where roughly 90 to 95 percent of the framing is concealed. California does not accept localized treatment as a whole-structure substitute when full eradication is required. For a small, accessible, isolated infestation, a local treatment can be appropriate, and we will tell you honestly which fits.
How are subterranean termites treated?
Subterranean termites are treated by addressing the soil, not by tenting. The standard is a liquid non-repellent barrier, such as a fipronil-based termiticide, applied around the foundation. Termites pass through it undetected and carry it back to the colony, collapsing the nest. Bait station systems are an alternative. Both require licensed application and are very different from fumigation.
What about Formosan termites?
The Formosan subterranean termite, an unusually aggressive and destructive species, has been detected in San Diego County, including in La Mesa and Rancho Santa Fe. It is not yet widespread here, but it is one more reason to have an unfamiliar infestation correctly identified by a professional rather than guessed at.
Why does correct identification matter so much?
Because the treatments do not overlap. Fumigating for drywood does nothing to a subterranean colony in the soil, and a soil barrier does nothing for drywood termites in the attic. Misidentifying the species wastes money and leaves the real problem active. This is exactly where an entomologist-led inspection pays off.
Common questions
Drywood termite droppings, called frass, are tiny six-sided pellets that look like coarse sand, sawdust, or coffee grounds, usually in small piles beneath the infested wood near a pinhole kick-out hole. Finding these pellets is the most common way San Diego homeowners discover a drywood infestation. If you see them, have it inspected before it spreads.
Pencil-width mud tubes running up a foundation, pier, or wall are the signature of subterranean termites. They build these tubes from soil and saliva to travel between their underground nest and your wood while staying protected. Active tubes mean an active colony, and subterranean termites damage wood faster than drywood, so prompt treatment matters.
Drywood termites swarm most often in late summer and fall, while subterranean termites swarm in spring, frequently after warm rain. A swarm of winged termites, or a pile of discarded wings near a window, is a strong sign of an established colony nearby. San Diego's mild climate means some activity is possible nearly year-round.
Subterranean termites generally cause damage faster because their large soil-based colonies forage aggressively and stay active year-round. Drywood termites work more slowly but are extremely common in coastal San Diego and can infest multiple separate areas of a home. Both warrant prompt treatment, and the right approach depends entirely on which one you have.
Yes. It is possible to have drywood termites in the attic or eaves and subterranean termites coming up from the soil at the same time, especially in older homes. That is why a thorough inspection identifies every species and condition present, so the treatment plan addresses all of them rather than just the obvious one.
Not always. Whole-structure fumigation is required when the infestation is widespread or hidden throughout the framing, which is common. If the infestation is small, isolated, and fully accessible, a local treatment can work. We inspect honestly and recommend the least invasive option that will actually solve the problem, not automatically the biggest one.
Subterranean termites live in the soil, so they are treated from the ground, not with a tent. We apply a liquid non-repellent termiticide barrier around the foundation that the termites carry back to the colony, or install a bait station system. Both are licensed professional treatments and are completely different from drywood fumigation.
Almost never. Termite damage is considered preventable through maintenance, so standard homeowners policies exclude it. That makes periodic inspection and prompt treatment the only real protection, especially in coastal San Diego where drywood termites are widespread. Catching them early is far cheaper than repairing structural damage later.
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