Expert Contributor - Scott Dideon

Winged Termites in Washington StateIt always happens in the late summer and early fall around August and September.  As people are spending their last hours of the summer outside on their back deck, they see a few flying ants landing near them.  On further examination, they realize that they don’t look like the average winged ants, but more like termites.

Using their cell phone, they do a quick check on termite images and their fears are confirmed.   Now they realize that their home might be under attack from termites coming in from the woods.  Visions of termites chewing away at their structure haunts them through the night until the next morning when they give Green City Pest Control a call to confirm what they think is the bad news.  But it is often not the “bad news” that people might be thinking.

Pacific Damp wood Termites

Termites do exist in Washington State, but the predominant termite is a native species the Pacific Dampwood Termite (Zootermopsis angusticollis).  Reproductive (swarming) termites can be identified from reproductive ants by having two pairs of wings of equal length (ant wings are different lengths), straight antennae (ants have elbowed antennae), and their thorax and abdomen look fused together (ants have 3 distinct body parts).  While the Pacific Dampwood Termite is the largest termite in the United States, usually about ½ to 1 inch long, and is often a light brown or milky color, it does not aggressively attack homes.

Water is key for dampwood termites.  In fact, they don’t infest wood unless the wood is almost completely saturated in water.  The whole termite colony is commonly found in tree stumps and logs that are consistently wet.  The dampwood termites are a vital part of the natural decomposition of old trees in our rainy forests.  Because they need wood saturated by water it is extremely rare for dampwood termites to infest wood inside a home.  In the few cases where we have seen them in a home, it often is where the roof or siding is damaged, and rain is coming into the wall voids saturating the structural wood.  The treatment plan is almost always to remove the damaged wood and prevent the water from coming back.  Once the wood is removed, the termites will normally die, and it shouldn’t require the use of any pesticides.

Western Subterranean Termites 

Western-Subterranean-TermitesIn our area of the country we do have termites that could damage homes, and these are the Western Subterranean Termites (Reticulitermes hesperus).  Over the past 100 years the Western Subterranean Termites have been slowly expanding from California up into the Pacific Northwest.   There are areas around Seattle where subterranean termites are more likely to appear (such as West Seattle and Maple Valley).  As the name implies, the termite’s nest is inside the ground and they develop tunnels in the soil to potential food sources.  While most of the time they are attacking tree stumps and logs, they are also interested in the wood inside your home.  The Western Subterranean Termites reproductives are black and about 1/4th inches in length, while the workers are white.  They frequently develop mud tubes in order to access wood that is not touching the soil.  Termite Mud TubeThe wood being destroyed also will have mud incorporated into the galleries that they are making.  The Western Subterranean Termites are often discovered when the small black reproductives swarm inside the home in the fall or when a homeowner sees a mud tube.

Western Subterranean termites can do over time significant damage to the structural wood in your home.  But this is often over months or even years if they are left unattended.  If your termites are confirmed to be Western Subterranean, then the traditional approach would be to try to create a pesticide barrier in the soil around the home to push the insects away from the structure.  At Green City Pest Control, we prefer to take a different approach using products with Fipronil as the active ingredient.  This material has the track record of causing the populations of termite colonies to collapse without having to use excessive amounts of pesticides.  We do not recommend termite baiting programs in Seattle because we do not have the excessive pressure of termites like in other states.  We also don’t recommend termite pre-treatments in the soil for new construction unless you are required to do so by your lending association.

Dry Wood or Formosan Termites

Other termites can appear in the Seattle area, but they are extraordinarily rare.  They tend to only occur if they are accidentally brought here through imported furniture or wood material that is already infested.  The most common Dry Wood Termites (Incisitermes minor) could potentially come from wooden furniture that was moved to Seattle from California.  The other feared termite, but it is extremely rare, is the Formosan Termite (Coptotermes formosanus).  This termite is known for being the most aggressive at damaging wood in our industry, and they also would only appear if it was accidentally shipped in.  In both these cases, when these termites have appeared, they do not seem to be able to become established in the Pacific Northwest.

What to Do if you Suspect Termite Activity?

Ultimately, if you suspect that you might have termites, it is likely they will be the Pacific Dampwood Termites.  But to make sure, keep a sample and submit a picture of it to the Green City Pest Control office.  If we can’t confirm the species through a photo, we can then set up a Wood Destroying Insect (WDI) Inspection to determine what pest issues you are experiencing.  By taking the time to properly verify the insects we can then determine the best treatment options for your situation, if any are ultimately needed.Pacific Dampwood Termite

Until then, enjoy living in the Pacific Northwest with our vast evergreen forests.  Even if that means our peaceful evenings are occasionally interrupted by swarms of dampwood termites looking for old wet wood that they could naturally break down.


Green City Pest Control is owned and managed by one of the few Urban Entomologists in the Greater Seattle area and beyond, who has been designing pest management programs for challenging situations over the past 32+ years.

Green City Pest Control Ad