Scientific Name: Incisitermes minor | Reviewed by The PCC Research Team
If you live in Southern California or along the coast, the Western Drywood Termite is the single most common cause of structural fumigation (tenting).
Unlike Subterranean termites that live in the dirt and require constant moisture, Drywood termites are biologically engineered to survive deep inside bone-dry wood. They infest attics, roof eaves, fascia boards, and window frames, completely hollowing them out from the inside while leaving the exterior paint perfectly intact.
The “Cliff Notes”: Key Takeaways
- No Soil Contact Needed: They do not build mud tubes. They fly directly onto your roof or siding, bore a hole, and live entirely inside the wood.
- The “Frass” Warning: The defining sign of a Drywood colony is the presence of hard, 6-sided fecal pellets (frass) that look like a pile of coffee grounds or sawdust near baseboards.
- Slow but Destructive: Their colonies are smaller than Subterranean termites (usually a few thousand bugs), but they create smooth, clean galleries that chew directly across the grain of the wood.
- The Cure: For widespread infestations, Vikane gas (tenting) is required. For minor, localized spots, Orange Oil or Borate injections can work.
Biology: The “Water Extraction” Secret
Homeowners often wonder: If all living things need water to survive, how do Drywood termites live in a 130-degree, bone-dry attic?
The answer lies in their highly specialized anatomy. Western Drywood Termites have developed unique rectal glands that absorb virtually every microscopic drop of moisture from their own feces before they excrete it. They utilize the metabolic water generated from digesting the wood cellulose itself to survive.
Because they extract all the water from their waste, the feces they leave behind are incredibly dry, hard, and perfectly shaped. This is why their “frass” looks like rigid, 6-sided hexagonal pellets under a microscope, rather than the muddy, wet smears left by Subterranean termites.
Drywood termites are notoriously clean insects. Because they spend their entire lives sealed inside a piece of wood, their tunnels (galleries) eventually fill up with their hard fecal pellets. To make room, they bore a tiny, 1-millimeter “kick-out hole” through the surface of the wood or drywall. They use this hole like a garbage chute to push the frass out of the nest, which is why you suddenly find a mysterious pile of “sawdust” on your floor overnight.
The Late Summer Swarm
In California, Western Drywood Termites typically swarm in the late summer and fall (September through November), often correlating with hot, dry days or the Santa Ana winds.
The mature colony will produce winged reproductives (Alates) that feature dark brown bodies and reddish heads. They fly out of the kick-out holes in a massive swarm, attempting to find a mate and locate a new piece of exposed wood to bore into.
Eradication: How to Kill Drywood Termites
Because they are completely disconnected from the soil, liquid trenching and bait stations (like Sentricon) are 100% ineffective against Drywood termites. You must treat the wood directly.
1. Whole-House Fumigation (Tenting)
If the infestation is widespread (e.g., in the attic, the subfloor, and multiple window frames), structural fumigation using Vikane gas is the only scientifically guaranteed way to penetrate the wood and kill 100% of the hidden colonies. Learn about the 3-Day Tenting Process here.
2. Localized Spot Treatment (Orange Oil)
If an inspector catches the infestation early, and it is isolated to a single, accessible piece of wood (like a patio beam), they can drill holes into the wood and inject a contact killer like Orange Oil (d-limonene) or a non-repellent foam (Termidor). Read the pros and cons of No-Tent treatments here.
Stop the Damage Before It Spreads
Drywood termites hollow out load-bearing wood from the inside out. Do not wait for the beam to collapse. Find a licensed California structural pest control operator today to conduct a thorough acoustic tap-test of your home’s framing.
Call For Termite Inspection: (866) 204-1751Frequently Asked Questions
Q: Will my house eventually collapse if I ignore them?
A: Yes, but it takes time. Drywood colonies grow relatively slowly compared to Subterranean species. However, over a period of 5 to 10 years, they will completely hollow out structural studs and rafters, causing severe roof sagging or patio collapse.
Q: Does painting the wood prevent Drywood termites?
A: A thick, well-maintained coat of exterior paint is an excellent deterrent, as the swarmers cannot chew through the thick acrylic to reach the raw cellulose beneath. However, any cracks, peeling paint, or exposed joints will provide an immediate entry point.
Q: I cleaned up the sawdust, but it came back the next day. Why?
A: Because the workers are still actively excavating the tunnels inside the wood. If you sweep up a pile of frass and a new pile appears directly beneath the same kick-out hole 24 hours later, you have an active, living colony inside that wall.