Seasonal Pests: Dampwood Termites
and Moisture Ants

Last Updated: September 23, 2021

Seasonal Pests: Dampwood Termites
and Moisture Ants

Last Updated: September 23, 2021

If you have lived in the Pacific Northwest long enough to experience the rainy season, then you know that we’re getting close to another six or seven months of regular drizzling. This often results in water-damage to susceptible wood, such as roofs or porches. 

Because of this, Washington has more than a few pests that feed on or nest in water-damaged wood. They’re known as Secondary Wood Destroying Organisms. These insects are not exactly interested in any type of wood, just the stuff that has rotted or has other potential food sources growing on it, like fungus. An example of a Primary Wood Destroying Organism would be a Carpenter Ant, which nests in sound wood.

In this article, we’ll be talking about two common pests to monitor: Dampwood Termites and Moisture Ants. Their behavior is similar, but there are some key differences. The more you know about how to handle these infestations and what to expect, the better you can protect your home.

Table of Contents

Identification, Behaviors, and Habits

Pacific Dampwood Termites

These are the largest Termites species in Washington. Winged Termites may exceed 1” (with wings included) in length. They are cream colored to dark brown, but soldiers have a large red-brown or black head and cream-colored body. They are about ¾” long. You can identify them by their large head and long mandibles, which make up ⅓ of their overall body length.

Dampwoods have a caste system that comprises Queens, Kings, and Soldiers. There is no Worker caste (like many species of Ant, for example). Instead, Nymphs and Soldiers perform any necessary Worker functions.

As previously mentioned, these Termites aren’t after the sound (dry, undamaged) wood of your home. They’re looking for damp wood. Leaky plumbing, clogged gutters, or faulty grades on porches and patios can all cause wood damage if left alone for too long. If you have decaying stumps or fallen trees around your home, you might find colonies of Dampwood Termites in those areas. Condensation and rain-soaked firewood are also potential sites of an infestation.

The major difference between Dampwoods and Moisture Ants is that Dampwood Termites eat the wood that they infest. They also live in the wood and will expand the colony at the site of infestation, unlike their cousin, the Subterranean Termite. These Termites can be readily identified by their galleries, or the areas of chewed wood they leave behind. Galleries will contain their hexagonally shaped fecal pellets, which can appear adhered to soaked wood or on the gallery floor. Colonies produce winged reproductives upon maturation. Swarming of winged reproductives occurs on warm evenings in late Summer or early Autumn. Swarming is more likely to occur after a big rain.

Moisture Ants

Moisture Ants are yellow or reddish to dark brown. This species is monomorphic, meaning that they’re all the same size. You may find them in naturally decayed wood, such as logs or stumps, but they also appear in soil.

Infestations occur on/in water-damaged wood, just like Dampwood Termites. However, Moisture Ants do not consume the wood that they infest. As they dig out galleries, they may leave behind a wet-sawdust-like substance called frass. Their frass is like coffee-grounds in texture and color.

Moisture Ants will bring some additional moisture into the wood that they are infesting, which will speed up wood deterioration, but not significantly. These Ants tend aphids for honeydew and feed on other sweet materials, so you may find them inside your home searching for food sources. They’re often confused with Odorous House Ants (i.e. the sugar ant).

Reproductive swarming occurs in late Summer or early Autumn. Winged reproductives may appear to be slightly larger than workers.


Earlier, we mentioned in an above section that these Ants are sensitive to chemicals. This point is important to remember: do not treat the Ants yourself. Using substances like those listed below may cause the Ants to react instinctively by splitting their colony up and moving to new locations. 

By spraying your counters or using store-bought gel bait, you may see a decrease in activity. However, be aware that just because you don’t see Ants in that spot doesn’t mean they’re gone for good. More often than not, you’ll see them leave the kitchen and pop up a week later in the bathrooms, crawlspace, and living room!


Make sure that you take care of leaks as soon as you notice them. Regularly inspect around your home to see if you have any faulty grades, clogged gutters, leaks, or areas where water may pool underneath or beside your home. Alleviate the problems as soon as you can to prevent any damage from occurring.

Stopping an infestation before it starts is tricky, but we know better than anyone what methods to use. We offer a maintenance service to help with all kinds of pests. All Pest Protection is a quarterly maintenance service aimed to prevent infestations of general pests such as Ants, Rodents, Wasps, Spiders, and other insects. We come out on a 3-month rotation to provide an exterior perimeter spray where the home and foundation meet, spot treat around doors and windows for activity, sweep reachable webs and Spider egg sacs, and maintain Rodent Bait Stations (secured, locked, black plastic boxes) on the exterior of the home to mitigate outside Rodent populations.

All Pest Protection (APP) also can include various warranties for general pests, which are established after the Initial Inspection and Treatment. Once you get started, each quarterly service is only $109 before tax. Should Fleas, Bees, or Spiders overrun your house, or any of the pests eligible under your warranty, all you would have to do is call us. We’ll dispatch a Technician to complete a pest-specific treatment at no cost to you under your APP Warranty.


Antonelli, Arthur L. Pest Management Study Manual for Pest Control Professionals. Washington State University Extension, 2016.

About the Authors

This article was created and edited in collaboration with multiple licensed pest control technicians, experts, researchers, and authors.

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