Carpenter Ant Control Methods
The first step in carpenter ant control should always include mechanical modifications to the structure and environment. The object is to reduce the avenues available for carpenter ants to enter a home or structure, as well as removing possible food and water sources.
There are basically four methods of pesticide application used for controlling active infestations of carpenter ants: exterior perimeter treatments, interior void treatments, treating the infested wood and baiting.
The most commonly used method for controlling carpenter ants is treating the perimeter of a home with a dust or spray. There are several products available for this type of application, but Suspend SC and Cynoff WP are the best. When used in accordance with their labels they work well. However, these treatments do not keep ants from entering a home from overhead trees and power lines. Also, as a stand alone treatment, they rarely eliminate ants inside voids and walls.
The treatment of interior wall voids has become more popular with the availability of borate dusts. The efficacy of these dusts depend on ants ignoring their presence and walking through them, contaminating the ants' bodies in the process. Ants then ingest the borate while grooming. If dusts are not applied properly, ants and other insects simply detour around the insecticide. To apply dusts properly, an electric duster or bellows duster (such as the Crusader Duster) must be used. You need to use either Drione Dust or Delta Dust for carpenter ant infestations of interior wall voids. Drione Dust works well in a dry environment, but Delta Dust is the best where there is any sign of moisture. Delta Dust is a synthetic pyrethroid insecticide dust that is water proof.
One limitation of this control method is that the dust must be placed directly onto the pathway used by the ants. If, for example, the dust is placed on the floor plate and the ants are using an electrical conduit located three inches above the plate as their pathway, control will not be attained. This means simply that dust is an excellent tool, but should be used along with other control methods, not as a "stand alone" carpenter ant eliminator.
Another problem with using dusts is their sensitivity to high moisture conditions. Dusts have a tendency to cake or crust when they get damp. This makes them ineffective since ants can then walk across them without picking any up on their bodies. Only Delta Dust is water proof.
Spot treating infested wood with Bora-Care will quickly eliminate a localized carpenter ant infestation. Whenever practical, inject Bora-Care directly into the carpenter ant galleries. However, it is important to treat an entire infested area in order to reduce the possibility of colony relocation. A frequent problem encountered with carpenter ants is the fragmentation of a colony when subjected to a pesticide. Bora-Care, like many other pesticides, is repellent to carpenter ants and may cause them to avoid treated areas and seek out untreated wood. The best treatment method consists of not only treating the infested area, but also treating all wood susceptible to attack. This would include an entire crawl space, wall or attic showing any signs of damage. All bare wood should be sprayed to the point of wetness. Confined areas can be treated using a foaming or fogging device but heavily infested wood should be directly sprayed either before or after fogging.
Treating Infested Foam Panels
Carpenter ants will occasionally infest foam insulation panels around foundations and under stucco and other types of siding. Carpenter ant infestations in foam may be treated by spraying the infested area, if accessible, or by drilling and injecting diluted Bora-Care directly into ant galleries.
The newest and most efficient method of controlling carpenter ants is by using baits. Baits work by decreasing the population of carpenter ants in an area, thus reducing their potential for entering a structure. Advance Carpenter Ant Bait, Niban Granular Bait and Niban-FG Fine Granular Bait are carpenter ant baits which can be used for both interior and exterior applications. The newest bait in the fight against carpenter ants is Maxforce Gel Carpenter Ant Bait. This material is one of the fastest acting baits on the market.
Note: One of the quickest ways to destroy the effectiveness of any bait is to contaminate it with another pesticide. Never treat the same area with both a spray and a bait at the same time. If you must use a pesticide spray, wait at least the weeks after application before beginning your baiting program. And never use the same containers, measuring cups or dusters for both baits and contact pesticides. A little bit of pesticide residue can contaminate a lot of bait!
A primary objective in an exterior baiting program is to place a band of bait between the satellite colonies in the structure and the main nest. Since there is a continual exchange of workers between satellite colonies and the main nest, you want to give worker ants an opportunity to pick up the bait on their way to and from nesting sites. Since the main nest is frequently in an old log stump within a 300 foot radius of the home, it is important to locate and treat it with the bait. Although following ants and their trails to the main nest can be a tedious task, especially at night, it is well worth the effort. Elimination of the main nest will substantially reduce the risk of re-infestation.
A two to four foot band of Niban Granular Bait or Advance Carpenter Ant Bait, should be applied around the perimeter of the structure as well as around the base of all trees, stumps, firewood piles and other locations where carpenter ants may nest. Advance Carpenter Ant Bait or Niban Granular Bait should also be applied along ant trails and other areas where ant activity has been noted.
Unlike other carpenter ant baits, Niban Granular Bait will not degrade from exposure to heat or sunlight and studies have shown that Niban will remain effective through about two inches of rainfall. Re-application of Niban Granular Bait should be made periodically during intervals of very wet weather.
Whenever possible, exterior baiting should be combined with an interior baiting program. This will speed the eradication process and provide residual bait in order to prevent a re-infestation. However, you must use a long-lasting bait like Advance Carpenter Ant Bait or Niban-FG Fine Granular Bait which remains effective for months rather than days or weeks.
As previously stated, new construction is particularly susceptible to carpenter ant attack. Un-infested wood properly treated with Bora-Care will be protected from carpenter ant attack. Exterior wood surfaces exposed to rain or snow which have been treated with Bora-Care should also be coated with a water resistant finish such as paint or stain. Interior Bora-Care treated wood surfaces do not need to be coated.
During construction, the application of Niban-FG Fine Granular Bait in wall voids and other confined spaces will help prevent carpenter ant infestations. Re-application of these baits on a periodic basis will significantly reduce the likelihood of carpenter ants establishing a satellite colony within a structure.