Persistence and vigilance are required. Frequent return trips may be necessary following initial treatment. Management of TCA requires numerous tactics, both nonchemical and chemical. Refer to Insecticide Basics for the Pest Management Professional for guidance.

Before control measures are undertaken, a thorough inspection of the outdoor premises should be conducted to determine the extent, and especially origin, of TCA infestation. The inspection should help the PMP to determine where to treat and which products and formulations to use.

Although there are a number of chemical approaches that may be utilized for the treatment of existing TCA infestations, no single insecticide-based approach is completely effective. An integrated approach that incorporates both chemical and nonchemical techniques is best suited for the management of this highly invasive ant. When chemical controls are used, especially liquid sprays and granular products, it is important that PMPs read and strictly follow all product label instructions. Some insecticides are highly toxic to fish and other aquatic life. It is therefore important to avoid the application of pest control products in a manner that might inadvertently contaminate a local body of water.

Figure 5. Ants exchange food in a process known as trophallaxis.

Baits, toxicants incorporated into a palatable food source, are effective against ants because workers share food (bait) in a behavior known as trophallaxis (figure 5). Baits should be placed in areas where ants are found foraging around the outside of structures, especially in the landscape. Interior baiting should be avoided as it may attract foragers into structures. Because colonies can be large and forage over large areas (often multiple properties), baiting for TCA may require multiple placements of large quantities of bait.

Baiting for ants as ubiquitous as TCA can be labor intensive. If a newly established TCA infestation is discovered prior to its period of rapid growth, bait treatments can be very helpful in providing control.

The success of chemical control tactics against ants is often based on the target’s colony structure and foraging biology (colony size, food preferences, and nesting habits). Control of some ant species, for instance, is best achieved with bait, because worker populations are relatively small (several thousand ants) and food preferences are met by available baits.

Control of large colonies of ants covering large swaths of property may be best achieved by actively searching for and treating central nest sites (characterized by an accumulation of eggs, larvae, pupae, and queens) with a liquid spray product. This active approach is dependent upon thorough inspection. Liquid sprays also should be applied to the structure’s perimeter as band treatments to protect the immediate area surrounding the structure and to keep ants from entering.

Perimeter treatments are typically made with liquid spray products. All will kill ants upon direct, topical treatment, and some products provide longer contact residual activity than others. When using liquid insecticides, never apply the product to flat, hard surfaces, especially if the surfaces are routinely exposed to irrigation or rain.

Contact insecticides also may be delivered as a granular formulation. Granulars are applied to thatch, high grass, mulch, leaf litter, and other areas where ants are known to nest. Never allow stray granules to remain on flat, hard surfaces where they might accidentally be washed into a local body of water.

The weight of the granule allows the insecticide to reach deeper into treated areas than would occur with a liquid spray applied to the surface of the same substrate. After application, the insecticide must be released from the granule by allowing water to wash over it in a process referred to as activation.

Granular products often are not effective during periods of drought or when artificial irrigation is not available. Granular products do, however, result in pulse activations of insecticide after every irrigation event until the granule has completely dissolved. Like liquid sprays, granular products kill ants by contact. Some granular products, such as those containing rosemary, spearmint, and cedar essential oils, may help to keep foraging ants out of treated areas. Essential oils are highly repellent to many ants.