Termites in Central Coast Homes: Signs and Treatment

1Which termites live on the Central Coast

California has at least 23 termite species, according to UC IPM, but three of them account for nearly everything we find in Monterey, Santa Cruz, and San Benito counties. Western drywood termites (Incisitermes minor) are common along the Pacific coastal region. Western subterranean termites (Reticulitermes hesperus) live statewide. UC IPM calls Reticulitermes the most destructive termites in California. Pacific dampwood termites (Zootermopsis angusticollis) are the third. UC IPM ties those to cool, humid areas along the coast.

Water is what separates them. Drywood termites need no contact with soil at all. They fly to a house, enter through a crack or an unsealed joint, and live their whole lives inside the wood they are eating. Subterranean termites need soil moisture, so they nest in the ground and travel up to the framing. Dampwood termites need wood that is already wet, which usually means a leak or long-term ground contact.

Colony size is the reason subterranean damage adds up quietly. UC IPM reports that a mature Reticulitermes colony holds hundreds of thousands of individuals. A queen can live a decade or more. One 2,400-square-foot home can host several colonies at once, with hundreds of thousands of foragers between them. Two other California species stay out of this region: Heterotermes aureus in the Sonoran Desert, and the Formosan termite Coptotermes formosanus around San Diego.

Termites are not the only insects that damage wood here. Carpenter ants cut galleries into damp framing, wood-boring beetles feed inside floors and rafters as larvae, and carpenter bees drill into bare exterior boards. Their frass and their damage look nothing like a termite's, and our wood-destroying insects guide covers all three.

2Why Central Coast homes get termites

In our experience across this service area, the species you get depends less on the town than on the ground the house sits on. Western drywood termites dominate in Monterey County's older coastal homes and in the farm buildings of the Salinas Valley, where dry, exposed redwood and Douglas fir give them everything they need without a drop of soil moisture. Subterranean termites are the bigger problem in the Santa Cruz mountains, on the coastal flats, and in the clay soils of San Benito County, where the ground holds water long after the rains stop. Two houses twenty minutes apart can have completely different termite problems, which is why a species call has to come before a treatment decision.

The coastal fog belt adds a third layer. UC IPM associates Pacific dampwood termites with cool, humid coastal areas, and that description fits Santa Cruz and the Monterey Bay shoreline closely. Older homes here often pair that marine moisture with a crawlspace that has poor ventilation and no working vapor barrier, and wet substructure wood is what dampwood termites are looking for.

UC IPM names the conditions that invite termites into a structure. Every one of them is something a homeowner can look at this weekend.

• Structural wood in direct contact with soil, including posts, siding, and stair stringers.
• Poorly ventilated crawlspaces and damp substructure areas.
• Stucco siding that runs all the way down to ground level.
• Cracks in the foundation, faulty grading, and plumbing leaks.
• Firewood, lumber, untreated fence posts, and buried wood debris stored against the house.

3How to tell termites from ants

Winged termites and winged ants swarm at the same times of year and get mistaken for each other constantly. You can separate them with your eyes alone, no magnifying glass needed. Catch one under a glass, or collect a few of the wings left behind, and check three things.

• Antennae: a termite's antennae are straight and look like a string of tiny beads. An ant's antennae bend in the middle, like an elbow.
• Waist: a termite's body is broad from front to back with no pinch. An ant has an obvious narrow waist between the middle and rear sections.
• Wings: a termite's four wings are all about the same length. An ant's front wings are noticeably longer than its rear pair.

4Where to look during a self-inspection

You can do a useful walkaround with a flashlight and a flathead screwdriver in about half an hour. The goal is not to treat anything. The goal is to find out whether you have evidence worth acting on, and where it is.

1. 1

   Walk the full foundation line

   Start outside and follow the perimeter, then repeat the loop inside the crawlspace if you can see into it safely. You are looking for mud tubes about the width of a pencil running up concrete, piers, or plumbing. UC IPM describes four kinds: working tubes from soil to wood, exploratory tubes, drop tubes hanging from framing, and swarm tubes. Break one open. Live workers or soldiers inside mean the infestation is active right now.

2. 2

   Sound the substructure wood

   Tap along sill plates, joists, and posts with the screwdriver handle and listen for a hollow tone. Then press the tip into any wood that sounds off. Termite-damaged wood gives way with little effort. Subterranean galleries are enclosed and run lengthwise with the grain, because the termites eat the soft springwood and leave the harder summerwood behind. Note the exact locations rather than opening up the wood.

3. 3

   Check windowsills, door frames, and light fixtures indoors

   This is where drywood evidence shows up first. Look for small piles of hard pellets on sills, floors, and shelves, and for the kick-out holes they came from, which UC IPM puts at less than 2 mm across. Drywood pellets have six flattened sides. Dampwood droppings are rounded at both ends instead. Shed wings in the same spots point to a recent swarm.

4. 4

   Inspect attached structures and stored wood

   Garages, decks, porch columns, fences, and trellises are usually where an infestation starts, because they are built with less protection than the house. Move the firewood pile away from the wall and look underneath it. Anything that touches both soil and the house is a bridge.

5What does not work

UC IPM states plainly that do-it-yourself termite pesticides are generally not effective. What it calls for instead is a professional inspection and an integrated control approach. The reason is that one structure often holds several colonies, of the same species or of different ones. That is the core problem with home remedies. They act on the termites in front of you and leave the colony intact.

• Cutting out and replacing the damaged board. The wood was the symptom. If the colony still has a route in, it comes back to the next board.
• Spraying a swarm as it emerges. Swarmers are the reproductives leaving an established colony. Killing them changes nothing about the colony that produced them.
• Assuming fumigation is the only option. UC IPM lists localized treatments, including liquids, dusts, microwaves, electrocution, and wood replacement, as appropriate for limited, well-defined drywood infestations.
• Waiting for another swarm to confirm the problem. Subterranean termites swarm in spring or fall and drywood termites swarm in summer and fall, so waiting for confirmation can cost you months of feeding.
• Treating the termites and leaving the leak. A colony that came in through wet wood finds wet wood again.

6What a California termite report actually says

A wood-destroying pest and organism inspection report, usually called a WDO report or a termite report, is a written record of what a licensed inspector could see in the areas they could reach. The California Structural Pest Control Board notes that most lending institutions require a California home to be inspected for wood-destroying pests and organisms before they finance a loan. State law does not require that inspection before a sale. Any company doing this work in California holds a Board license. Ours is SPCB Lic. #9119.

The report separates two different things, and escrow timelines usually hinge on which one a finding falls under.

• Evidence of infestation or damage: live termites, mud tubes, frass, damaged framing, and fungus or dry rot found in accessible areas.
• Conditions likely to lead to infestation: earth-to-wood contact, poor ventilation, leaks, faulty grade, and similar defects. Areas the inspector could not reach are recorded separately as needing further inspection.