Product Education   |   June 7, 2023

Tackling Carpenter Ants

carpenter ant behavior

It’s the call you’ve come to dread: “I need you to come back out, there are still ants everywhere.” Ants have earned a reputation for being difficult to control and for constantly returning, leading to costly callbacks and eating up your valuable time. It doesn’t help that they often seem like they’re trying to attract customers’ attention, marching in their lines in plain sight on the kitchen counter. Carpenter ants especially are a nuisance, with their large colony sizes and destructive tendencies. While carpenter ants are certainly a challenge, it is possible to get them under control if you focus on their behaviors and leverage the right tools, using both to your advantage.

Understanding Carpenter Ant Behaviorcarpenter ant habits

To begin, it is helpful to know a general timeline of behaviors for carpenter ants. Many insect activities, including those of carpenter ants, are suspended during the winter months. As it gets warmer, insects shrug off their overwintering states to become more active. Ants start to grow their colony sizes, resulting in increased foraging. This moment—when insects are just beginning to emerge, but natural food sources are not yet widely available—is an ideal time to perform a preliminary insect bait treatment around the perimeter of a structure. The bait will be the most attractive food source available to pests during this period, which can increase their efficacy as the baits are more likely to be consumed and for foragers to bring it back to nests or harborages.

Carpenter ants establish parent colonies that are home, on average, to roughly 3,000 ants, as well as satellite colonies that are home to even more worker ants. Parent colonies are often found near hardwood trees, lumber or firewood piles, tree stumps, or other wooden structures. Finding and treating the parent colony where the queen resides and eliminating satellite colonies are two main components of establishing control. Developing satellite colony nesting sites are often located inside residences and other structures where their destructive wood excavation can lead to structural damage. Many satellite colonies are founded in wall voids, soffits, under bathtubs and sinks, and other similar spaces where leaks and excessive moisture build and go undetected.

Selecting the Right Toolscarpenter ant bait

When baiting in the early spring, it is typically best to select a granular bait. The characteristics of the bait, such as its particle size and attractants, promote its effectiveness against a particular pest insect species. For example, there are some larger granular baits that attract carpenter ants more effectively than others, while some smaller ant species, such as the little black ant, might not find a larger granular size attractive at all. Carpenter ants are general feeders and forage for a large swath of food items. Selecting an attractive bait and spreading it early in the season will help control ant populations before they get out of control.

By applying a granular, food-based bait such as Niban® Granular Bait around the perimeter of the structure, ants will begin to pick up and take the bait back to the parent colony, leading you right to the source of the problem. Once the population source is found, apply Niban around the base of the structure. A non-repellent, slow-acting dust such as Nibor-D® can be dusted or foamed into areas where satellite colonies are found. Ants will spread the dust among the satellite nests and transport the dust back to the parent colony.

It is imperative to have a slow-acting active to allow transfer for a period of time before the ants start to die. Nibor-D is not only an insecticide, but it is also a wood treatment. Carpenter ants prefer areas with high moisture. Applying Nibor-D not only eliminates the ants, but also kills and prevents wood decay fungi from developing. Active ingredients that have a delayed action, like borates, can be beneficial because the baits are consumed and spread throughout the colony before they take effect, allowing for a wider impact on the pest population. The goal is to ensure that the bait makes it way into both the parent colony and its satellites, and that the queen consumes the bait along with her workers.

There are even more benefits to using borates as part of your baiting program. Borates do not result in any known physical resistance in insect populations, can be used in conjunction with other active ingredients, and can remain a vital component of a bait rotation schedule during the months when pests are active. In fact, a granular, borate-based bait like Niban will not degrade in sunlight and can withstand up to 6” of water, meaning that it will remain active long after you apply it and will still be effective if/when it is brought into the colony by a foraging ant.

In addition to prebaiting with granular baits, liquid baits are also useful in a baiting program. Using liquid baits alongside granular ones can help lower initial colony sizes, leading to a reduction in overall colony numbers. It is also advisable to move the liquid bait stations according to changes in foraging patterns and colony movement to get the best results, monitoring them over the course of the season so they can be refilled or relocated as necessary.

It's important to remember that baits are not equally attractive at all times. In early spring, a liquid bait like DominAnt® is best as a secondary line of defense because ants are looking for carb-based food sources first, likely gravitating more readily to granular baits. During this period, a liquid bait can be placed outside around the structure or inside the structure near openings (such as near doors or between windows and their screens) to reinforce the success of your perimeter granular baiting program. As the weather cools in the fall, ants are more likely to choose a bait that’s higher in sugar as they prepare for winter. At that point, a liquid, sugary bait like DominAnt will be the most attractive and thus at its most effective.

At the end of the day, attention to detail is what maximizes results. Spreading granular baits and placing liquid stations strategically will help efficacy and reduce callbacks. Your field experience and know-how are key to making products as effective as they can be and for providing your customers the best experience possible.