Drywood Termite Swarming Season: What to Watch For This Fall

Most people in the Temecula Valley think of termites as a spring problem. That's the subterranean termite calendar, where swarms follow the rains. The western drywood termite, which UC IPM lists as California's most common drywood species, runs on a different clock. Its winged reproductives fly in daytime in summer and fall, which is why wings on a window sill in Murrieta, Menifee or Wildomar on a dry fall day point to drywood termites first, though a fall rain can bring out subterranean swarmers too.

This post is about that fall flight: when it happens, what it looks like, what it tells you about the wood in your house, and what to do in the hour after you spot it. If you want the rain-driven swarm instead, read our post on subterranean termite swarming season. For the full list of termite clues to check in any month, the signs of termites guide covers them room by room.

When do drywood termites swarm in Southern California?

During daytime hours in summer and fall. UC IPM's Pest Note on drywood termites describes the western drywood termite flying during daytime hours in those two seasons, without the rain cue the subterranean species waits for. The trigger is a mature colony plus a warm, bright day. You'll see the same timing in Temecula, Murrieta, Hemet and Riverside, and in Oceanside and Carlsbad on the warmer days near the coast. One colony doesn't send everyone out at once, either. A home can have a small flight on a Tuesday, nothing for a week, and another on the next warm day. If you saw a few winged insects at a window this week and then nothing, the colony hasn't gone anywhere. It's waiting for the right conditions. People ask us whether there's a termite season in California, and the plain answer is that both species are active all year here. The swarm is just the part you get to see.

What does a drywood termite swarm look like?

A drywood swarm is smaller and quieter than people expect. You won't see a cloud. You'll see a few dozen dark, winged insects, each about the size of a grain of rice with wings that stretch well past the body, crawling on a sunny window, bumping against a sliding door or gathered on a patio light that's still on in the afternoon. Within an hour or two they shed their wings, which is why the most common thing homeowners in Menifee or Lake Elsinore find is a small litter of look-alike veined wings along a sill, in the tub, caught in a web by the patio light, or just inside the garage door. The insects themselves are often gone by then, eaten by lizards and birds or hidden in a crack to start pairing off. Wings without bodies still count. They prove there was a flight, and a flight means a colony old enough to produce reproductives is in or very near the structure.

Why a swarm means the colony is already years old

Because drywood colonies grow slowly. UC IPM notes that drywood termite colonies are small compared with subterranean colonies and take years to mature before they produce winged reproductives, the swarmers you see. A colony starts when a single pair finds a crack in a fascia board or a check in a patio post, seals itself in and begins laying eggs. For the first years there are only a handful of workers, feeding quietly on the inside of that board. By the time the colony has enough members to send out a flight, it has been eating the wood above your window or along your eave for a long time. That's the part that matters for a Temecula homeowner. A fall swarm isn't the start of a problem. It's the first visible announcement of one that's been underway for years. Inspect it early and the treatment has a better chance of staying local to one board or one section of framing instead of growing into a whole-house job.

Where drywood termites live in a Temecula or Murrieta home

Inside the wood, never touching the ground. That's the defining difference from subterranean termites, and UC IPM describes drywood termites as living entirely inside sound, dry wood and taking the moisture they need from it. So the spots to think about are the ones that are wood, exposed and warm: fascia boards and eaves, the trim around windows and sliding doors, garage door jambs, patio covers and pergolas, attic rafters and the framing around attic vents, wood fences where they tie into the house, and furniture or picture frames that came from somewhere else. Stucco tract homes in French Valley and Winchester have less exposed wood than the older houses in Old Town Temecula or Fallbrook, but every stucco home still has wood fascia, wood trim and a wood-framed attic. The fall swarmers that land on your house look for a crack, a joint or an unpainted end grain to start the next colony, which is why keeping exterior wood painted and sealed is more than cosmetic.

Is it a termite swarmer or a flying ant?

Fall also brings winged ants, and the two get mixed up every week. Three things settle it, and all three come straight from UC IPM. Wings: a termite has two pairs of equal length that extend well past the end of the body, while an ant's front wings are clearly longer than its back wings. Waist: a termite is thick and straight from thorax to abdomen, while an ant has a pinched waist you can see without a lens. Antennae: a termite's are straight, like a string of beads, while an ant's are bent at an elbow. If you only have wings and no bodies, look at the wings themselves. Termite wings in a pile are all the same size and shape. Ant wings come in two sizes. Still unsure? Put a few insects or a pinch of wings in a sealed bag, take a photo of where they were, and mention both when you call (951) 535-4220. A sample makes the identification far easier than a description over the phone.

What should I do if I find swarmers or wings this fall?

Four things, in order. First, don't spray them. A can of aerosol kills the handful you can see and does nothing to the colony inside the wood, and it scatters the evidence that tells an inspector where the flight came from. Second, collect a sample: a few insects or a pinch of wings in a zip bag or a jar, and a photo of where they were. Third, look around that spot. Check the window frame, the fascia above it and the trim below for tiny round holes and small piles of pellets, and if you can get into the attic, look at the rafters near the nearest vent. Fourth, book an inspection with a licensed termite inspector, who looks at the accessible wood of the whole house rather than just the window where the wings landed, because that window isn't always the only spot. Ours is Tyler Williams. Call (951) 535-4220 and ask Jenni for him. A fall swarm is a good reason to ask whether the schedule has room for us today.

Why spraying the swarmers fixes nothing

Because the swarmers aren't the problem. They're the colony's attempt to start new colonies, and most of them die within a day whether you spray or not. The colony that produced them is sealed inside a board, feeding on the inside where no surface spray reaches. Drywood termites don't travel outside the wood to forage the way subterranean termites do, so there's no trail to treat and no soil to barrier. The only ways to reach them are the ones licensed termite companies use: treating the infested wood directly when the colony sits in a few boards you can point to, or fumigating the whole structure when it has spread into framing nobody can get at. Which one fits depends on what the inspection finds, which is the honest reason to say inspection first and treatment second. Spending a weekend with hardware-store products delays the real answer and, in the meantime, the colony keeps eating. UC IPM's drywood Pest Note makes the same point: control depends on finding and treating the infested wood rather than on killing the insects you can see.

What happens after a fall swarm is inspected

The inspection answers two questions: which termite, and how far. Drywood pellets and kick-out holes point one way, subterranean mud tubes point the other, and the two need different work, which is why identification comes first. For drywood termites, UC IPM describes two broad approaches. When the colony is confined to a spot or two, say one fascia board or a window header, that wood gets treated directly. When colonies have spread through framing nobody can get at, whole-structure fumigation is the method that reaches all of it. Which case your home is in is exactly what the inspection tells you. Tyler Williams does our inspections and Dylan Reed does the treatment. We treat drywood termites ourselves, and when a house needs tenting we arrange the fumigation through a subcontractor. If the house is going on the market, the WDO inspection and report Tyler prepares for a sale or refinance is $99, and our termite inspection page explains what the report covers. Either way the first call is (951) 535-4220.