Louisiana termite swarms typically begin in April, peak in mid-May, and remain active through June. These swarms are a mating flight: thousands of winged termites leave an established colony all at once, looking to pair off and start new colonies. For homeowners, a swarm is both a spectacle and a warning sign, especially in a state where Formosan subterranean termites cause billions of dollars in structural damage each year.
When Swarms Happen and What Triggers Them
Swarm season follows a predictable pattern tied to temperature and moisture. Native subterranean termites tend to swarm earlier in spring, often in daylight hours. Formosan subterranean termites, the species that causes the most damage in Louisiana, swarm at night, usually between dusk and about 10 p.m. on warm, humid evenings from mid-May into June. Long stretches of rain keep soil damp and help subterranean termite colonies thrive, which means wet springs often produce heavier swarm years.
You’ll notice swarmers congregating around streetlights, porch lights, and illuminated windows. A single Formosan colony can contain several million individuals, and when conditions are right, it releases tens of thousands of winged reproductive termites in one evening. The swarm itself is brief, often lasting less than an hour, but in neighborhoods with heavy infestations it can look like a blizzard under every light source on the block.
Termite Swarmers vs. Flying Ants
Not every winged insect around your porch light is a termite. Flying ants swarm around the same time of year, and the two are easy to confuse at a glance. Three physical differences will tell them apart quickly:
- Wings: Termite swarmers have two pairs of wings that are equal in length. Flying ants have two pairs of unequal length, with the front wings noticeably longer.
- Waist: Termites have a thick, straight waist with no pinch between the thorax and abdomen. Ants have a distinctly narrow, pinched waist.
- Antennae: Termite antennae are straight or gently curved. Ant antennae are sharply elbowed.
If you’ve swept up a pile of dead insects from your windowsill, pick one up and look at the waist. That’s the fastest way to know what you’re dealing with.
What a Swarm Inside Your Home Means
Seeing a few swarmers drift through an open door isn’t necessarily alarming. They’re attracted to light and will fly toward any opening. What matters is where they’re coming from. If swarmers are emerging from your walls, ceiling, floor, or from cracks in the foundation, that points to an active colony already feeding on the structure. Large numbers of Formosan swarmers indoors, or even a modest number of native subterranean swarmers emerging from the building itself, should be treated as a serious red flag.
After a swarm passes, the most common evidence is piles of shed wings near windowsills, doors, and light fixtures. Swarmers drop their wings within minutes of landing, so a scattering of tiny, translucent wings is a reliable indicator that termites were present, even if you didn’t see them flying.
Other Signs of an Active Infestation
Swarms get your attention, but termites leave other clues year-round. Mud shelter tubes are the most recognizable. These pencil-width tunnels of dried soil run up foundation walls, support piers, and plumbing under the house, giving termites a protected highway between their underground colony and the wood they’re eating. If you see tubes on your foundation, the colony is actively foraging on or near your home.
BB-sized spots of dried mud on interior walls or ceilings are another telltale sign. These “pinholes” form when termites accidentally break through drywall or paneling and then seal the opening with mud to block outside airflow. If you scrape away one of these spots and find a small hole underneath, watch it. A termite will often appear within seconds to investigate the breach, and the hole will be patched within a few days.
In late spring, you may also notice odd, lumpy mud formations sprouting from walls or ceilings. These are “swarm castles,” built by Formosan termites as launching pads for their winged reproductives. Breaking one open typically reveals soldier termites rushing to defend the opening. Finding a swarm castle means a mature Formosan colony is established inside the structure.
What To Do During a Swarm
The single most effective thing you can do on a swarm night is turn off your lights. Formosan termites are intensely attracted to light, and leaving your porch light, yard lights, or bright indoor lights on is essentially a beacon. Turn off all non-essential outdoor lighting between about 7:30 and 10:00 p.m. during peak season. Close curtains and blinds so interior light doesn’t draw swarmers to your windows.
For the swarmers that do get inside, a vacuum cleaner is the best tool. They’re harmless, can’t bite, and will die quickly without soil contact. Resist the urge to spray store-bought insecticide around your doors and trim. Repellent sprays can actually drive termites away from professional bait stations installed around your home, making your existing termite protection less effective.
Why Formosan Termites Are a Bigger Problem
Louisiana is home to both native subterranean termites and Formosan subterranean termites, but Formosans are in a different category of destructive. A native subterranean colony might contain a few hundred thousand individuals. A mature Formosan colony can reach several million. Formosan colonies forage up to 300 feet from the nest, meaning a single colony under your neighbor’s yard can reach your house with ease.
The economic toll reflects this. Subterranean termites collectively cause over $30 billion in damage annually across the United States, and Formosan termites alone account for more than $4 billion of that. Louisiana, with its warm climate, high humidity, and heavy Formosan populations concentrated in the New Orleans metro area and across the southern part of the state, bears a disproportionate share of those costs.
Professional Treatment Options
Termite control in Louisiana generally falls into two categories: liquid soil barriers and baiting systems. The right choice depends on the situation, and many pest control companies use both together.
Liquid treatments involve applying a long-lasting termiticide into the soil around and under the foundation. The goal is to create an unbroken chemical barrier that termites can’t cross without picking up a lethal dose. Modern products are non-repellent, meaning termites don’t detect the chemical and walk right through it, carrying it back to the colony. This approach provides immediate protection and works well for active infestations that need to be stopped quickly.
Baiting systems take a different approach. Plastic stations containing cellulose (a wood-based material termites eat) combined with a slow-acting growth disruptor are installed in the ground every 10 to 15 feet around your home’s perimeter, with extra stations near known problem areas like woodpiles, stumps, or previous damage. Termites find the bait, feed on it, and share it with nest mates. The colony declines gradually over weeks to months. Bait stations require ongoing monitoring, with inspections ranging from monthly to annually depending on the system and the pest control company’s protocol.
Some homes rely on baits alone. Others combine a partial liquid barrier around high-risk areas with a full bait station perimeter. Given the severity of Formosan pressure in Louisiana, many pest control professionals recommend maintaining some form of active protection year-round rather than treating only after damage appears.