A PCO's Guide To The Latest Ant Control Techniques

As the 1990s draw to a close, few would dispute the fact that ants have replaced cockroaches as the primary pest infesting structures. True, in commercial food operations, cockroaches are still "king," but talk to pest management professionals around the country and they’ll tell you more customers call complaining about ants than any other structural pest.

When I entered the pest control industry as a service technician 20 years ago, I used four primary insecticides: Dursban, DDVP, Ficam and diatomaceous earth dust. Like most of my fellow technicians, I’d come to work in the morning, fill a B&G sprayer with pesticide and begin servicing my accounts, frequently using the same pesticide all day long, no matter what the pest. But times have changed.

The past two decades have unleashed a period of innovation and product variety far beyond anything experienced by PCOs in the previous 60 years. Today, for ant control alone, service professionals have more than 20 water-based formulations from which to choose. A variety of dusts, aerosols and granular insecticides are also available to PCOs to combat ants. In fact, nearly all insecticides list ants on their label. Yet even with the wide range of products that are currently available, manufacturers continue to invest thousands of dollars in research and development. Nowhere is that research and development effort more apparent than in the area of ant baits, where several manufacturers have introduced new products in the past year and other products are in various stages of development.

But before this new bait technology is discussed further, it’s important to review the basic elements of a successful ant control program. I recommend a program that includes the following seven steps:

1. Identify the ant(s) involved. This first rule cannot be emphasized enough. Too many ant control failures can be traced to the perception among many PCOs that "an ant is an ant is an ant." In the recently published second edition of the PCT Field Guide for the Management of Structure-Infesting Ants, 41 ant species are described. Each has unique habits and biology that could impact the PCO’s ability to control a particular species. Therefore, it’s essential that business owners provide service personnel with sufficient training in the proper identification of the most common ant species and provide a magnifying device and reference materials on all service vehicles.

2. Find the colony, solve the infestation. The source of an infestation is the colony or colonies involved in invading the structure. With the exception of Pharaoh ants, it is crucial that an effort be made to find the colony involved. Unfortunately, when dealing with Pharaoh ants (and, in some cases, ghost ants and thief ants) finding the colony is often an exercise in futility due to the location of nest sites within walls and voids throughout the structure.

3. Treat the colony directly. Obviously, once discovered, an ant colony is easily dispatched by treatment with the appropriate insecticide formulation, depending on the site involved. Too many service professionals, however, treat foraging trails or throw bait around a structure indiscriminately, expecting quick, long-term results. In such cases, too much is left to chance and control is seldom achieved.

4. Target exterior treatments. Broadcast treatments with residual liquids are a recipe for frustration when dealing with most ant species, especially Argentine ants and crazy ants. Identification and direct treatment of as many colony sites on the property as possible achieves far better results.

5. Expose the colony to treatment. Ant colonies in soil or mulch require thorough penetration for total elimination. Raking the mulch or soil permits even, complete coverage of the toxicant.

6. Baits must be placed along active trails. Ants must find the bait in order to carry it back to the colony. Too often, one trail is baited with a little bait or bait is spread where the PCO hopes ants might be foraging. For bait to work, the ants must pick up and carry enough back to the colony to affect every member of the colony. The challenge in properly applying bait lies in accomplishing this goal. Placing too little bait or placing bait in areas where ants will not find it are the two primary reasons bait fail.

7. Follow-up all bait applications. Ants are finicky. Just because they start feeding on bait in your presence doesn’t mean they will be picking up the bait an hour or even a few minutes later. Ideally, checking the next day is best because waiting a week or more — if the ants are not feeding on the bait — allows your customer more time to become dissatisfied with your service. The number one reason for ant baiting failures is the lack or absence of follow-up on the part of the service professional.

WHAT’S NEW? Given the challenging nature of modern-day ant control, what are the latest tools PCOs should consider adding to their product arsenal? The truly exciting innovation for ant control this year is the introduction of liquid ant baits. Liquid baits are advantageous over solid ant baits because adult worker ants cannot consume solid food. They must carry it back to the colony for the larvae to chew up and partially digest.

Adult ants derive much of their energy from the honeydew produced by homopterous insects, such as aphids, mealybugs and scales. Therefore, it makes perfect sense to offer pest ants a sweet liquid they will ingest on the spot and feed to the various castes within the colony. In ongoing research by Dr. John Klotz and his associates at the University of California-Riverside, Argentine ants have demonstrated an interest in liquid ant stations throughout most of the year in southern California. In other informal field tests, crazy ants and white-footed ants both show a continual interest in liquid bait over an extended period of time.

Currently, two liquid ant baits are being introduced this spring. J.T. Eaton & Co. is offering Dr. Moss’s Liquid Ant & Roach Bait and Waterbury Companies is introducing the Drax Liquidator System. Both baits contain boric acid as the toxicant dissolved into a sweet liquid base.

The primary problem with liquid ant bait is in the delivery system. Ants must be able to enter the station and feed on the bait, but at the same time the station must be child- and pet-resistant and minimize evaporation. Should the bait evaporate too quickly, it will need to be replaced frequently, thus requiring regular (weekly) visits. More important, however, as the liquid evaporates, the boric acid becomes more concentrated which possibly — and probably — results in feeding deterrence or too rapid kill.

The Drax Liquidator comes complete with a delivery system (Figure 1). The bait is contained within an easily replaced cartridge and the ants access the bait by crawling up the sides of the station through grooves on the sides of the cap. They then wander on top of the cartridge’s membrane cover, feeding at their leisure.

Eaton’s liquid bait currently does not have its own delivery station, but the manufacturer hopes to have one soon. In the meantime, Kness’ new ant bait station could be used to hold the Eaton bait. This station (Figure 2) has two chambers. Both can be filled with liquid bait, one with liquid and the other with solid bait, or both with solid bait.

Other manufacturers are working on developing liquid ant baits. The establishment of liquid bait stations around the perimeter of a property and the building itself will aid in long-term suppression of such noxious ant species as the Argentine, crazy and white-footed ant. Dr. Klotz’s tests in California have shown that even though Argentine ant activity continues at liquid stations throughout the summer, ants are often drawn out of the building itself. Therefore, the ants are not totally eliminated, but because ants are no longer seen inside, successful control is achieved. Of course, a liquid baiting system should not replace looking for and treating colonies directly; it should simply be an adjunct to your overall ant control program.

Another exciting innovation is Clorox’s introduction of Maxforce Carpenter Ant Gel Bait this spring (see related story on page 42). In various studies the past few years carpenter ants have shown a real interest in consuming gel- or paste-type baits, so this new bait should prove to be a useful tool for PCOs. The gel stays pliable for several weeks and can be rehydrated with a drop of water. It is labeled for both indoor and exterior use and can be applied along trails, in voids and in stations, such as the B&G Perimeter Patrol System (Figure 3) and the Kness Ant Bait Station mentioned earlier.

Maxforce Carpenter Ant Gel Bait contains fipronil and a sweet "honeydew" formula. This insecticide is unique in that it seems to be virtually non-detectable to ants, even at higher concentrations. This fact may enable the bait to reach the queen more quickly than might otherwise occur with traditional baits. Although the bait is currently labeled only for carpenter ants, Clorox is testing it against other species and anticipates adding more species of ants to the label.

Whitmire Micro-Gen introduced its Advance Granular Carpenter Ant Bait (Figure 4) last year and the results have been very good in many situations. The problem with carpenter ants is their food needs vary throughout the year. One colony may prefer Advance over Maxforce Granular Insect Bait or a sweet bait (such as the new Maxforce gel bait), while across town another colony may prefer one of the other baits. The next month, taste preferences may switch. This factor is the reason follow-up and thorough inspections are so important. If ants feed on the bait long enough, control will be achieved.

Also, be aware that carpenter ants have been observed readily collecting granular baits and then carrying them several yards before depositing them or burying them along the sides of their trail. This behavior doesn’t mean these granular baits are ineffective, it just means some carpenter ant foragers change their minds.

CONCLUSION. Manufacturers and researchers will continue to research the biology of pest ants and develop new ant control products. One thing is clear, however. Liquid baits and exterior bait stations will play an increasingly important role in managing ant infestations in the years to come.

Identifying the most effective ways to generate the desired results using these new technologies, as well as those developed in the future, is the responsibility of the pest management professional. Are you up to the challenge? Only time will tell.