No Hundred Year Floods, Please!

No Hundred Year Floods, Please! (Damp Wood Termites and Carpenter Ants)


I have an account that has dampwood termites and carpenter ants, neither of which is unusual. It’s the location of the house, which is built on stilts and straddles a stream that feeds into the Puget Sound. What are my options on treating this situation? Many pest control companies have looked at this property and just walked away, I would like to think that we could give the homeowner a solution, instead of being one of the many to walk away. Looking forward to your answer. – Eric, WA


Wow, when some people build their dream home, they just don’t plan on anything out of the ordinary happening in the future. This must be an old house, because I have difficulty imagining someone now being allowed to place a home over the top of a natural stream, so maybe they planned for those high water levels. Carpenter ants and the state of Washington are never going to part ways, so obviously there is always going to be a pressure from the surrounding areas to feed carpenter ants toward this structure. One reason they move into homes is a need to find a drier habitat for late stages of their larvae and pupae, and form the satellite colonies. In the Pacific Northwest, carpenter ants also just live in many homes, causing tremendous destruction. Although, according to Dr. Laurel Hansen, still most are often connected to a primary colony somewhere outside in the soil, probably in buried wood.

Since carpenter ants do not eat wood, it insinuates that those ants in the structure are still leaving on a regular basis to forage for food outdoors (although not this time of year, and not this year in particular), or to return to their parent colony to socialize. During the season when the ants are active outdoors, you have two pretty good options for nailing them. One is the use of the non-repellent insecticides. Termidor is a good choice, since its “transfer effect” ability has been shown to be excellent. A treatment around the perimeter of the structure – or those places where the stilts reach the soil and the ants may be traveling down – should get the active ingredient onto the ants, and then onto other ants they contact in the colonies. You can also treat up onto the structure with this product, adding a bit more opportunity for the ants to contact the material.

Carpenter ants, in northern California at least, are exceptionally fond of granular insect baits. Products like Maxforce, Advance, or Niban granular may give you another great way to get a toxic material into the colony. As the workers are becoming active again in the spring would be the ideal time to use baits, as the colony has been surviving on stored fat for months now, and is going to be desperate to find new food sources. If the ants are foraging within the structure this time of year; you could consider the use of granular baits inside wall voids, as this is a high traffic area. An effort also should be made, or communicated to the owners, to remove as much access as possible for the ants. If trees and shrubs are growing adjacent to and touching the structure, these become ant highways, and need to be trimmed well back.

Wood debris on the property that serves no aesthetic purpose should be removed, taking away some of the nesting opportunities for the ants that bring them closer to the structure. If you can identify specific voids that the ants are nesting in you can treat them. I have gotten some reports of excellent control using Premise Foam for these kinds of void injections for ants, and it is labeled for that use.

Dampwood termites usually can survive in wood only if the moisture content is very high, and it must be high enough to also support the growth of decay fungi. I have always been taught that the control of dampwoods is done by eliminating that moisture source and the wet wood, which should not be in the structure anyhow. There are plenty of insecticides labeled for Zootermopsis. It is the genus of western dampwood termites, so local treating for them can be done, including with that Premise Foam mentioned above. You could identify the wood members infested, drill a small opening to access the galleries, and inject this or one of many other termiticides as a foam application that will fill the voids effectively. However, if there is an excessive moisture condition in the wood of the structure that is supporting the existence of these termites it must be corrected.

If the termites are somewhat sporadic, such as those seen around porch lights, they may not be a problem. These termites are common residents of the wooded forests of the western states, and swarmers are drawn to lights at night. They swarm at dusk (sometimes in absolute clouds), and may head to structures only because the lights draw them. As long as they cannot find wood wet enough to establish their colonies, they should not be able to become pest problems in the structure itself. I would love to see you tackle the job, explaining to the customer their role in reducing habitat and access for the carpenter ants, and eliminating moist wood that might encourage dampwood termites. While you may not be able to completely resolve the carpenter ant problem, you sure could put a serious dent in their populations and ability to survive in the structure.

Date: Friday, 15. January 2010 17:29
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