Termite swarmers are winged reproductives that leave a mature colony to start new ones. The University of Maryland Extension says they signal a colony nearby, not a finished indoor infestation. The eastern subterranean termite is the species reported for Maryland, and swarms are seen in spring.
Key takeaways
- A swarm is a sign that a mature colony is nearby. It is a reason to inspect, not proof of how much damage exists.
- Indoors, swarmers die of dehydration and are not a threat in themselves. The concern is the colony that produced them.
- The eastern subterranean termite is the species reported for Maryland in an older state-officials report, so the page does not name any other species.
- Swarm sightings in this county fall in spring, and the 2004 report gives roughly March through June after warm, rainy weather.
- Collect a sample, note where it was found and call for an inspection. Spraying the wings does not reach the colony.
What is a termite swarm, and what does it mean?
A termite swarm is a group of winged reproductives leaving a mature colony to found new ones. A swarm tells you the colony exists nearby, while the damage, if any, is found by inspecting the wood and soil.
The insects in a swarm are called swarmers, or alates. They have left the colony to mate and start a new one, and most will not survive long. The University of Maryland Extension describes them as the sign of a nearby mature colony, which is why a swarm is taken seriously even though the insects themselves are harmless once they are indoors.
A swarm is not a measure of damage. A colony can be active in a structure for a long time without producing a visible swarm, and a single swarm does not say how much wood has been affected or how far the colony reaches. The only way to learn that is an inspection of the structure, including the foundation, the sill plates, the crawl space and any wood in contact with soil.
The useful question after a swarm is where the colony might be. Swarmers often come out near a window, a door frame or a light, which means the insects found their way in from somewhere close. The location of the swarm is a clue for the inspector, and a note of where it happened is worth more than the insects themselves.
Which termite is reported in Maryland?
The eastern subterranean termite is the species reported for Maryland. That information comes from a 2004 newspaper report quoting state agriculture officials, so it is older than the rest of this page and should be read with that in mind.
A 2004 newspaper report quoted state agriculture officials as saying the eastern subterranean termite is the only species found in Maryland. Because the report is more than twenty years old, this page states it as the species reported rather than as a current count. No newer state survey was sourced for this guide, and none is implied.
The species matters for the work because treatment and monitoring depend on how the colony lives. Subterranean termites nest in the soil and move into structures through the ground, which is why soil contact and the foundation are central to an inspection. The technician records the conditions that make a structure attractive to them, not just the insects that were seen.
A swarm seen on a Maryland property should still be checked by a technician, because the species report is a regional pattern and a single house can differ. The inspection, not the species name, is what determines the next step.
When does swarm season happen here?
Swarms in Maryland are reported in spring, after warm weather and rain. A 2004 state-officials report gives roughly March through June, but the detailed month range was not confirmed from a current source, so the safe frame is spring.
The 2004 report that names the eastern subterranean termite also describes swarming in the period from about March through June, following warm weather and rainfall. That is the best documented window for this county, though it is an older source. Warm, wet spells are the trigger that matters most, which means a mild, damp April can bring swarms that a dry one does not.
A swarm is usually a short event. Swarmers emerge over a few hours or days, and then the colony keeps working underground or inside the structure. A property owner who saw one swarm may see none the next year, while the colony continues to feed on wood. The absence of swarmers is not proof that the colony has gone.
Because this calendar is spring-based, the most useful planning is to schedule an inspection in late winter or early spring, before the warm, wet period arrives. A technician can look at the structure while it is accessible and plan any follow-up around the swarm window, rather than reacting after the insects are already in the living space.
How do you tell swarmers from flying ants?
Swarmers and flying ants are easy to confuse. Swarmers have straight antennae, two pairs of wings of nearly equal length and a broad, uniform waist, while flying ants have elbowed antennae and a pinched waist.
The most common mistake is treating every winged insect on a window sill as the same thing. Flying ants also leave their nests in warm weather, and they are a different problem with a different cause. The difference matters because the response to a flying ant nest and the response to a termite colony are not the same job.
Look at the body and the wings before deciding. Swarmers tend to have wings of nearly equal length that extend well past the body, and they shed the wings easily, leaving them on window sills or floors. Flying ants keep their wings and have a visibly narrow waist. Those features are general identification points rather than a verdict, so a photo or a sample is the most reliable way to settle the question.
When in doubt, keep a sample in a sealed container or a folded paper, label the date and location, and show it to the technician. Identification is quick once the specimen is in hand, and it prevents a homeowner from treating a harmless insect while missing a colony nearby.
What should you do after you find swarmers indoors?
Do not spray the swarmers and hope the problem ends there. Collect a sample, note where the insects were found, check the wood and soil near that spot and call for an inspection of the structure.
Vacuuming or collecting the insects and any shed wings gives the technician something to identify and tells the inspector where to look. Spraying the insects does not reach the colony, and it can leave residue on surfaces that a technician would prefer to examine clean. The spot where the swarmers were found is the first place to inspect.
Look at the wood and soil close to that spot. Mud tubes on a foundation wall, soft or hollow-sounding wood, and damp areas in a crawl space are the signs an inspector will check first. A moisture source does not cause termites on its own, but it makes a structure easier for them to use, so the inspector will note it.
Keep the windows and doors near the swarm closed while the insects are active, if that is practical, and note whether the swarmers appear again on another day. A second swarm in a different room would suggest a colony with more than one route into the structure, and that detail should be given to the technician.
What does a swarm not prove?
A swarm does not prove the structure is being eaten, and it does not prove the structure is clean. It is a signal that tells you to inspect, and only the inspection can say how much of the building is affected.
A swarm can be a single event with a colony that is small, far away or no longer active. It can also be the first visible sign of a colony that has been working for years. The insects do not measure either possibility, which is why the inspection is the only reliable next step.
An inspection covers the structural wood, the sill plates, the soil contact, the crawl space and any hidden areas that can be reached. The inspector records what is found and what is not, and any treatment is quoted separately on the findings. The termite inspection service is built around that record, and the termite control service is quoted only after the inspection shows what is needed.
The practical result is a plan. If the inspection finds no activity, the record says so and the homeowner has a baseline. If it finds activity, the written findings show where the colony is and what the options are. Either way, the swarm has done its job of prompting a look at the structure.
What should you tell the technician about a swarm?
Record the date, the time of day, the weather that week, where the swarmers were seen and how many there were. Those details help the technician decide where to look first and whether the swarm points to a colony close to the structure.
Note whether the swarm was seen indoors or outdoors, and whether the insects were around a window, a door frame, a light or the base of a wall. A swarm near a foundation wall or a window at ground level points the inspection toward the soil line. A swarm on an upper floor may point to a route through the structure, and the technician will want to check the framing and any wood in contact with masonry.
Count the wings. A small pile of shed wings on a sill suggests the swarm happened in that spot, while a single insect could have been carried in on clothing or a pet. Photograph the pile and the spot before cleaning it up, because the photograph is the record the technician will compare with the inspection.
Mention whether there was rain or a warm spell in the days before the swarm. The 2004 state-officials report ties swarming to warm weather and rainfall, so a note of recent weather helps place the swarm in the season. Include any signs already noticed, such as soft or hollow-sounding wood, mud tubes or moisture in a crawl space.
Frequently asked questions
Are termite swarmers dangerous to people?
Swarmers are not a threat to people in themselves. Indoors they die of dehydration. The concern is the colony that produced them, which can damage wood in the structure.
Does one swarm mean my house is being eaten?
Not necessarily. A swarm shows that a mature colony is nearby. Whether the structure has been damaged is found by inspecting the wood and soil, which a single swarm cannot answer.
Can I treat the swarmers myself?
Killing the insects you can see does not reach the colony, and it can leave the nearby wood unexamined. Collect a sample, note the location and have a technician inspect the spot where the swarmers were found.
What should I keep for the technician?
Keep a few insects or shed wings in a sealed container or folded paper, with the date and the exact place they were found. A photo of the spot and of the insects helps, too, and a technician can use it to plan the inspection.
Sources
This guide is general information for Prince George's County homeowners, not a substitute for an on-site inspection. Prices are estimates. See our disclaimer.