Sep 29, 2011 – Carpenter Ants Are Everywhere

QUESTION:

Can you give me a proposal or protocol to get rid of carpenter ants?

ANSWER:

Yes, even in the hot, dry environments of our Southwest states there are carpenter ants. Wherever there is wood there will exist the insects needed to recycle that wood when it is dead. In the Pacific Northwest the carpenter ants are the principal wood infesting pest in structures, and much of what I have learned over the years has come from fantastic seminars presented by Dr. Laurel Hansen, who has spent many years studying these insects in Washington state.

One of the important things to keep in mind about their biology is that the carpenter ants that may be seen within a structure, even if there is an actual nest in the structure, are almost always still part of a primary nest that is outside somewhere, often underground and within some buried wood such as an old root system. This is where the primary queen will reside along with the majority of the workers, but later stage larvae and pupae may need a drier location, so when the time is right some of the workers will relocate these nest mates to a nearby structure and either hole up in an existing void or create their own by hollowing out structural wood. But, these workers still may make a daily trek back to the primary colony. Since these ants are primarily nocturnal you may not see this activity unless you visit the account at night, at which time their movements along well defined trails could be much easier.

Fortunately, a lot of PMP's have found that carpenter ants readily accept granular insect baits, so this can be one great tool in your arsenal. The bait should be placed as close to the active ants as possible to ensure they find it, meaning directly in their path on those well used trails outside, and therefore you need to know where the trails are by visiting when the ants are active. You also need to know where the ants may be creating their nests indoors, and once you do you can treat directly into the nest using pressurized dusts or aerosols or fogging with a void injector that pushes the mist deeply into voids. As you likely know, the evidence of carpenter ants working indoors will be the debris they push out of their nests, composed most often of tiny bits of wood and sawdust but also dead ants, body parts of other insects they eat, and the white silk pupa cases left over after the pupae have hatched. Under magnification you can tell what that dust on the kitchen counter or the hardwood floor is composed of.

Baiting can also be done indoors using granules within wall voids or gel baits placed where the homeowners are not going to have to watch a lot of ants feeding. Carpenter ants love to travel along trails already provided for them, so within the wall they move along wires or pipes that move from void to void. A dust insecticide used within interior walls should coat all of these surfaces and contact the ants as they pass along, and inorganic dusts such as diatomaecous earth or silica gel work well and last forever. One like Drione incorporates the pyrethrum as well to achieve some knockdown.

The keys to control will be to FIND that primary nest outdoors and treat it in some manner so that the source of the problem is eliminated, to find the secondary nest indoors and treat it as well to eliminate the entity that is damaging the structure, and to find the pathways outdoors that the ants are using. Once these paths are determined you can treat more directly where you know the ants will encounter what you place. A non-repellent spray insecticide with a good transfer effect also can be very helpful, as using this where you know the traveling ants will contact it will improve the chances for the foraging workers themselves to carry the material directly into the colonies.

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