Carpenter Ants…They Do Not Eat Wood
Background
Carpenter ants extend in the U.S. from southern Florida to the Pacific Northwest. The most common is the black carpenter ant (Camponotus pennsylvanicus), with a range covering the eastern half of the U.S. Carpenter ants nest in and around logs, stumps, trees, leaf litter and in any other natural wooded habitat. These ants are predators that feed on a large variety of food sources. In the initiation of a new colony, the winged reproductives emerge from the nest for their mating flights during the first warm days of spring. Winged reproductives are produced in colonies 6-10 years old when the colony population numbers over 2,000 workers. These mature (parent) colonies will establish satellite colonies whenever the ants require a drier or warmer environment for their larvae and pupae to thrive.
Several species invade dwellings, establishing satellite nests to temporary house brood (young) and reproductives. Carpenter ants do not eat wood but excavate galleries (passageways to allow for movement between different sections of the nest) within wood to use as nesting sites when forming satellite colonies. They will also use voids in walls, soffits, and other spaces conducive for satellite nest formation. Carpenter ants often enter homes through openings such as attic vents. Foraging activity usually occurs during nighttime. When foraging inside dwellings, carpenter ants are attracted to many carbohydrates, proteins, and fats.
Inspection
If the purpose of the visit by Millette Pest Control is to perform a wood destroying insect inspection; any carpenter ants in, on or under the structure will be reported. The first sign of a carpenter ant infestation is usually the sighting of live ants in or near the structure. If the ant is winged, the difference between a carpenter ant winged reproductive and a termite winged reproductive (note the constrictions in the thorax and body of a winged carpenter ant versus a straight contoured body for a winged termite) is notable.
Also, look at any stacked firewood which is a common source of carpenter ants. In winter, you may observe carpenter ants emerging from firewood brought into the structure. Carpenter ants can survive lower temperatures and will become active when the infested logs warm inside.
Carpenter ants can be found near hardwood trees or the structure, and you might observe ants on decks, siding or even inside the structure. Frequently a homeowner has tried to eliminate the ants by broadcast spraying of the surfaces where ants are seen. Unfortunately, these sites are not where the ants are most concerning and eliminating the ants on surfaces only makes Millette Pest Control’s job harder. As with any pest management, the inspection phase is the cornerstone of integrated pest management. The presence of workers is usually a positive indication that an active, mature infestation is either in or near the structure or nearby. When inspecting, look for tree branches that may be just above or in contact with the roof.
Workers usually are active in the evening and into the night, resulting in heightened activity and even the presence of dead workers. Physical signs of intrusion can be absent, but the presence of wood sawdust beneath slit-like openings in wood members is a good indication that a sub-colony has been established. When viewed under a hand lens, note that the frass (sawdust) shows that it was excavated from the wood; in contrast, carpentry sawdust from a saw has a distinctive different appearance and is more regular in size. Millette Pest Control will easily distinguish carpenter ant frass from sawdust.
Galleries
When tracing to a source, note that carpenter ant galleries in wood have smooth surfaces as compared to termite galleries, which are coarse and often contain remnants of dirt. Carpenter ants usually excavate wood that is continually moist and has been softened by decay. Carpenter ant galleries will normally be clean and smooth, and excavated frass will be discarded via “kick out holes”, frequently leaving scattered frass visible we will likely ask if you’ve observed sawdust that they removed. This could point to the source of infestation.
Control
There are several control methods that should be used concurrently. Ultimately, we will focus on developing a full Integrated Pest Management (IPM) system; however, the most expedient method of control is by directly treating the main colony, if possible. Track foraging workers to the central nest. One can follow workers by placing cookie crumbs where workers are foraging. Foragers will take the crumbs to the main colony’s nest. Once it is located, they can treat the main colony directly.
Mechanical Modifications:
1. Remove wood piles from foundation walls
2. Cut tree limbs back roof lines or from touching the exterior
3. Seal cracks along foundations, siding, windows, and doors with caulk
4. Install fine mesh screens over crawl space and attic vents
5. Clean gutters
6. Eliminate over-abundant water sources
Insecticide Method(s): Overall, there are five common methods of pesticide application we may use to control carpenter ant infestations, including exterior perimeter treatments, interior void treatments, treating infested wood, preventative wood treatments and baiting.
1. Exterior Perimeter: Perimeter treatments will not prevent ant access from roof lines and other high access points. They will treat access points on exterior, including using select products to knock down workers. Baits for carpenter ants on the exterior near the foundation have been proven to be effective against carpenter ants. If fortunate to find, we will treat the main colony. They will also apply bait around the base of all trees, stumps, firewood piles and other locations where carpenter ant workers are seen foraging.
2. Interior Insecticide Void Treatments: Interior treatments should work in conjunction with exterior treatments through liberally applying a specifically labeled insecticide into voids to guarantee ant contact. This includes plumbing lines as well as in other cracks and crevices. For interior applications, we will likely choose to use small bait containers and place them in specific locations and/or place in cracks and crevices.
3. Spot Treatments of Infested Wood and Foam Panels: Sometimes just a small spot treatment is needed. There are specific insecticidal products we can use to inject directly into the carpenter ant galleries.
4. Preventative Wood Treatments: There are products available that will prevent carpenter ants from excavating the wood. We may suggest this as an additional option to consider for long-term preventive maintenance only in certain areas with exposed and unstained wood.
5. Baiting: We may choose a common option by using a granular bait. They will treat the main colony directly, if found, as well as broadcasting around the periphery of the structure, whereby both the main colony and sub-colonies have access and can forage for the bait. In addition, they will likely apply the bait around the base of all trees, stumps, firewood piles and other locations where carpenter ant workers are seen foraging. For interior applications, they place a gel in cracks and crevices.
Using this (or similar) integrated pest management approach will demonstrate excellent results in both control and prevention.