Hawaii has one of the worst termite problems in the United States, thanks to a tropical climate that gives termites warm, humid conditions year-round. Two species cause the vast majority of damage: the Formosan subterranean termite and the West Indian drywood termite. Together, they cost Hawaiian homeowners and businesses hundreds of millions of dollars annually, and nearly every structure on the islands is at risk. Understanding which species you’re dealing with, what signs to look for, and how to protect your property makes a real difference in how much damage they can do.
Formosan Subterranean Termites
The Formosan subterranean termite is the more destructive of the two major species. A typical colony can exceed one million insects, and that sheer number means they consume wood far faster than mainland subterranean species. They live primarily in the soil but build mud tunnels up foundations to reach the wood in your home. Once inside, they feed on both the softer spring growth and the harder summer growth layers of wood, leaving almost nothing behind.
What makes Formosans especially aggressive is their willingness to build aerial nests directly inside structures. These nests are made from chewed wood, soil, saliva, and fecal material, and they can grow to several cubic feet. An aerial nest means the colony no longer depends on its ground connection for moisture, making it harder to detect and harder to eliminate. Formosans have also been documented chewing through non-wood materials like thin sheets of copper and lead, asphalt, plaster, rubber, and plastic when those materials stand between them and a food or moisture source.
West Indian Drywood Termites
Drywood termites take a completely different approach. Instead of nesting in soil and tunneling up, they live entirely inside the wood they’re eating. They don’t need contact with the ground at all. They pull moisture from the wood itself and from their own metabolic processes, which means any exposed wood in your home, including furniture, is a potential colony site. They tend to prefer sapwood and typically infest lumber that’s shielded from direct rainfall.
A drywood infestation starts when a mated pair of winged termites (called alates) finds a crack, hole, or knot in a wooden surface. They excavate a small chamber inside, seal it off, and begin laying eggs. Colonies grow slowly compared to Formosans, but they’re also much harder to spot early. The most reliable external sign is fecal pellets: tiny, hexagonal granules that workers push out through “kick-out holes” roughly 1 to 2 millimeters wide. These pellets accumulate in small piles on windowsills, floors, or shelves below the infested wood, and they can range in color from cream to red to black. You might also notice blistering or peeling paint on wood surfaces where galleries have been carved just beneath.
When Termites Swarm in Hawaii
Swarming is the event that makes most homeowners realize they have a termite problem. In Hawaii, the primary swarm season for Formosan subterranean termites runs through May and June, though smaller swarms can happen at other times of year. Swarms occur only on warm, humid, nearly windless nights and typically last about 30 minutes. Thousands of winged termites pour out of colonies and fly toward light sources, so you’ll often see them clustering around porch lights, streetlights, and illuminated windows.
Drywood termite alates also swarm during summer months but are less dramatic in number. If you find piles of shed wings near windowsills or doorways, that’s a strong sign that alates have entered your home and may be starting new colonies in your woodwork.
Signs of an Infestation
For subterranean termites, the most obvious evidence is mud tubes running along your foundation, walls, or support posts. These pencil-width tunnels connect the soil colony to the wood above. Damaged wood will contain soil deposits inside the galleries. You may also find the large aerial nests mentioned earlier inside wall cavities or in attic spaces.
Drywood termites leave different clues. Look for the hexagonal fecal pellets beneath furniture, along baseboards, and on shelves. Tap suspect wood with a screwdriver handle: hollow-sounding wood or wood that crumbles easily under light pressure is likely compromised. The University of Hawaii Termite Project recommends visually inspecting your home once a month. Removable baseboards can give you a non-destructive way to check inside wall cavities where damage often hides.
Treatment Options
The right treatment depends on which species you’re dealing with and how far the infestation has spread.
For widespread drywood termite infestations, the standard approach in Hawaii is structural fumigation, commonly called “tenting.” Your home is enclosed in a sealed tent, and a fumigant gas is introduced that penetrates deep into the wood, killing termites at every life stage. The gas doesn’t leave residue on surfaces, but you’ll need to vacate the home during treatment and go through a preparation process for food, plants, and pets. Tenting is recommended when drywood termites have spread throughout the building and localized treatments won’t reach every colony.
For localized drywood infestations caught early, spot treatments can sometimes handle the problem without full fumigation. These target individual colonies within a specific section of wood.
Formosan subterranean termites require a different strategy because the colony’s base is in the soil. Soil-applied chemical barriers around the foundation are a primary defense, creating a treated zone that kills termites as they try to tunnel through. Baiting systems are another option: stations placed in the ground around the structure contain materials that workers carry back to the colony, gradually eliminating it. Because Formosans can build aerial nests that bypass soil treatments, a thorough inspection matters before choosing a treatment plan.
How Hawaii’s Building Code Addresses Termites
Hawaii’s building code is among the most termite-conscious in the country, reflecting just how serious the threat is. All structural lumber installed above ground must be preservative-treated wood. Any wood in direct soil contact or embedded in concrete that touches the earth must be treated to federal preservation standards for ground-contact use.
For wood-frame buildings sitting on concrete slabs or masonry foundations, the code requires Formosan subterranean termite protection through one of three routes: chemical soil treatment applied at maximum label rates by a licensed pest control operator, a stainless steel termite barrier, or another protection method approved by the building official. Openings around pipes or other penetrations through concrete slabs must be sealed with non-shrink grout or an approved physical barrier to eliminate entry points.
The code also sets specific clearances. Floor joists need at least 24 inches of clearance above the ground beneath them, girders need 18 inches, and open-slat wood decks require a minimum 6-inch ground clearance. Any wood within 6 inches of finished grade must be treated for ground-contact use. Planter boxes against wood-frame walls must have a 2-inch air space between the planter and the wall, with flashing installed when that gap is under 6 inches.
Prevention for Homeowners
Moisture is the single biggest factor you can control. Fix leaky faucets and sprinklers that keep soil near your foundation consistently damp. Design storm drains to empty a few feet away from exterior walls, not right against them. Standing water near your home creates ideal conditions for subterranean termite colonies.
Keep plants and planters away from house walls. Plants growing against your home provide both food and moisture for termites (especially when you’re watering them regularly), and they block your view of the foundation during inspections, hiding mud tunnels and early damage. Watch for cracks in cement walkways and your foundation. Even small cracks, nail holes, and wood crevices can serve as entry points for a new colony.
Eliminate wood-to-soil contact wherever possible. Don’t stack lumber, firewood, cardboard, or plant debris against your home or on bare ground near the structure. Every piece of wood touching soil is an open invitation.
Lighting management matters during swarm season. Formosan alates are strongly attracted to light on warm, humid evenings. Use motion-sensor lights that shut off automatically rather than leaving porch lights on all night. Place fixtures in recessed areas so the glow is less visible from a distance. Keep lights away from windows and doorways where alates could enter, and turn off exterior lights entirely when you notice a swarm in progress. Even 30 minutes of darkness during a swarm event can significantly reduce the number of reproductive termites that land on your home.