Drywood vs. Subterranean Termites: Which Does Monterey County Have?

Why This County Carries All Three

Most inland California counties are subterranean country and little else. The Monterey County coast supports all three at once, and the reason is the combination of a fog belt that keeps wood and soil damp, a housing stock full of pre-1960 fir and redwood framing, and winters mild enough that nothing goes properly dormant. Where you are in the county tips the odds toward one species or another.

• Drywood — Heaviest along the coast: Monterey, Pacific Grove, Carmel, Carmel Valley, and the older streets of Salinas. Any wood-frame house in those areas should be treated as at risk regardless of how it looks.
• Subterranean — Present countywide, and concentrated where the soil stays wet. That means the Salinas Valley floor, irrigated yards, properties with poor drainage, and any house where wood meets dirt.
• Dampwood — Turns up wherever wood is already wet, which usually means a leak, a drainage failure, or persistent crawl space condensation. Redwood-framed structures on the coastal side see it most.

Western Drywood Termites: Pellets and Kick-Out Holes

Western drywood termites (Incisitermes minor) live their whole lives inside dry wood. No soil contact, no water source, no connection to the ground at all. A winged pair flies in, finds a crack in exposed framing or a window frame, and starts a colony directly in the member. That is why a second-floor eave can be infested while the crawl space is clean, and why one house can hold several unconnected colonies at the same time.

• Pellets — The colony pushes its waste out through small openings. The pellets are about a millimeter long, six-sided with flat faces, and the color of the wood they came from. They collect on whatever sits below: a sill, an attic floor, a shelf, the top of a picture frame.
• Kick-out holes — Round openings roughly a millimeter across in an otherwise sound wood surface, sometimes sealed with a thin plug the colony reopens.
• Damage pattern — Broad smooth galleries cut across the grain, with clean walls and no soil or mud inside them.
• Where to look — Attic framing, window and door frames, fascia, rafter tails, and exposed exterior trim. Rarely down in the crawl space, which is too damp for them.
• Swarm months — August through October here, on warm afternoons following a hot stretch. That is later than the spring date most national guides print, and it is the single most useful timing fact for a Monterey County homeowner.
• Treatment — Fumigation when activity is spread through the structure, or orange oil and direct injection when inspection shows it confined to a few reachable members.

Western Subterranean Termites: Mud Tubes

Western subterranean termites (Reticulitermes hesperus) are the most widespread structural termite in California. The colony lives in the soil, not in the house, and it cannot survive in open air, so every trip up into your framing happens inside a shelter tube the workers build out of soil and waste. Those tubes are the giveaway, and they are the reason a subterranean problem is a ground problem rather than a wood problem.

• Mud tubes — Pencil-width earthen tubes running up foundation walls, concrete piers, and sill plates. They can also cross bare concrete to reach wood above it. An active tube is the most reliable sign there is.
• Swarmers at ground level — Winged reproductives come out of the soil or from a tube near the ground, not out of a wall or a ceiling. Wings shed near a slab edge or a porch step fit this species.
• Damage pattern — Wood eaten along the grain, leaving a layered, laminated look with soil packed into the galleries. It crushes rather than snaps under a probe.
• Where to look — Sill plates, floor joists, girders, lower wall framing, and anywhere wood touches soil. Crawl spaces first.
• Swarm months — February through May, usually during or just after a warm rain, which is the opposite end of the year from the drywood flights.
• Treatment — A liquid termiticide applied to the soil around the foundation perimeter, sometimes with borate treatment of accessible framing.

Pacific Dampwood Termites: A Water Problem Wearing a Termite Costume

Pacific dampwood termites (Zootermopsis angusticollis) are the biggest termites in the state, with winged reproductives close to an inch long including the wings. They need wood with a high moisture content, so finding them is a finding about the building rather than about insects. Somewhere there is a leak, a drainage failure, or a crawl space that never dries out, and the termites arrived because of it.

• Pellets — Larger than drywood pellets, softer, and usually packed into the galleries or stuck together rather than falling clear. You often see nothing on the floor below.
• What is absent — No mud tubes, unlike subterranean, and no neat pellet piles on surfaces, unlike drywood. Activity often stays hidden until somebody opens the wood.
• Where to look — Wood in contact with soil, framing under a persistent roof or plumbing leak, crawl space members affected by condensation, and redwood structures on the coastal side.
• Swarm months — Late summer into fall, most often on warm evenings, and they are strongly drawn to lights.
• Treatment — Correct the moisture first. Direct treatment of infested members and replacement of damaged wood follow, and without the moisture fix the same wood gets colonized again.

What Misidentification Costs

Treat the soil for a drywood infestation and you have paid for a barrier around a colony that never touches the ground. Tent a house whose real problem is subterranean and you will kill whatever workers happened to be inside on the day, then watch new mud tubes appear on the foundation while the colony under the yard carries on. We have been called to re-treat houses where the previous contractor did competent work aimed at the wrong species. The step that prevents it costs nothing extra: an inspection by a licensed structural pest control technician who names the species before anyone writes a treatment plan.

What a WDO Inspection Covers

A Wood-Destroying Organism inspection on a Monterey County property works every accessible area in turn. The attic gets checked for drywood pellets and damaged framing. The crawl space gets checked for mud tubes, moisture readings, and dampwood activity in the joists and sills. The exterior perimeter gets checked for tubes, earth-to-wood contact, and damaged trim. The interior gets checked at windows, door frames, baseboards, and flooring. Findings are written into the standard California report format, which separates Section 1 conditions, meaning active infestation or existing damage, from Section 2 conditions, meaning situations likely to lead to it. The report also lists any area the inspector could not reach, so you know exactly what it does and does not cover.