Drywood Termites

Unlike Subterranean Termites who build their colonies in the ground soil, Drywood termites do not need contact with soil moisture or any other water source. The moisture needed to survive is obtained from the wood they consume. Drywood termites build colonies in sound wood such as structural framing, roof shingles, fence and utility posts, hardwood floors, furniture, moldings, and door and window frames. New colonies are initiated when the swarmers enter cracks, knotholes or joints and bore into the wood. These swarmers often enter homes through unscreened attic or foundation vents or cracks in the exterior, around window and door frames, soffits, fascia boards and roof sheathing.

Colonies are usually constructed inside wood and finding these termites can be difficult during routine inspections.

Drywood termite colonies are small compared to Subterranean termite colonies and number a few thousand termites. Infestations are often localized in areas such as attic framing, door and window trim, cabinets, a piece of furniture or even a picture frame. Multiple colonies may be present in a structure, increasing the potential for serious damage.

Drywood termites are about a quarter of an inch long, and translucent red or dark brown in color. They have darkened ridges across their backs, six legs and a set of antenna on the forefront of the heads.

Eggs hatch into larvae and molt, shed their exoskeletons, to develop into workers, soldiers, primary reproductives and secondary reproductives.

Once the eggs hatch, they go through several instar phases in which regular feeding and shedding accommodate their rapid growth to maturity. They will also grow wings during this time and will become fully mature within six months. A female may lay several dozen eggs establishing her own colony very quickly and become a queen. Her mate will become a king and continue to breed with her and any subsequent young will become workers or protectors of the colony.

Nymphs excavate feeding galleries in the wood, tend to the eggs and young and feeds the king and queen. They make emergence holes during swarming season. These holes are guarded by the soldiers with their long mandibles. Soldiers plug up cracks or holes with their enlarged head until it is safe for the alates to emerge.

The responsibilities of worker termites includes caring for eggs, feeding soldiers and reproductives, and maintaining the nest.

The termite life cycle also includes swarming. Once reproductives become fully mature termites capable of reproducing, they develop wings. The bodies of these termites, now called alates, also become harder and darker to help the swarming termites withstand exposure to light and less humid air.

Drywood termite swarmers are most likely to be seen when mating. The Drywood termite swarmer is a winged breeder expanding the population by creating a new colony in another location. Once a colony has grown large enough in numbers, they will swarm before finding their mate in midair.  Also known as alates, these termites mate and then lose their wings.  Mated queens will then find gaps, holes or other openings in wood to enter.  These openings become nests and they are where mated queens will lay their eggs and brand new colonies will be formed.

The roof is a common entry point for newly mated termites. Swarmers crawl under the eaves and enter the wood through joists between rafters and sheathing, fascia boards, cracks around door and window frames, soffits and structure siding.

Swarming is usually most common during midday when temperatures are warm.  Termites swarming at night are often attracted to bright lights and frequently found near porch and patio lights or near other, picture windows, or nighttime landscape lighting features. Drywood termites are not adept fliers.

The most common signs of termite swarmers are the discarded wings that they leave behind once they have mated.  These wings are thin and silvery and look a lot like fish scales.  

Drywood termite damage tends to progress more slowly than damage from subterranean termites but because it is so difficult to detect, considerable damage, extending over a wide area, may be present by the time it is discovered.

The best ways to identify an active infestation is the presence of fecal pellets.

The damage caused by Drywood termites is different than the damage caused by Subterranean termites. There are no mud tunnels. Drywood termites build large galleries both across and with the wood grain. The cavities are clean and smooth as though they had been treated with sandpaper. As the feeding galleries enlarge, a thin layer of wood is left intact. The most obvious sign of an infestation is the tiny fecal pellets the termites eject from the galleries. The pellets are ejected thought kick out holes and often accumulate in small piles below the infested area. The color of the pellets will vary with the color of the wood eaten.

Wood is damaged as the Drywood worker termites tunnel to enlarge their colony. Drywood termite galleries cut across the wood’s grain weakening the wood’s internal structure.

Drywood termites can chew through support beams, floors and walls, causing expensive home repairs. In fact, Drywood termites and other termite species cause a collective $5 billion in property damage each year.

Baiting for Drywood termites is not an option because Drywood termites never leave the protection of their galleries. Perimeter sprays, that are effective for carpenter ants, won’t work either. Treating the soil under and around the structure with a termiticide, which is used for subterranean termites, does not work because Drywood termites may never contact the soil.

Control can be achieved by treating individual colonies as they are found during reconstruction or remodeling. These found colonies can be treated by drilling into the wood and injecting products such as Bora Care, Termidor or Premise.