The following research project was embarked upon by University of Florida researchers in hopes of developing better detection tools for termite infestations in structures. The authors knew that hidden access points in structures continue to make detecting termites a difficult task when only visual methods are used. Visual inspection methods typically include a walk around and through the structure with a flashlight, a probe, and maybe a moisture meter, with a clipboard to record findings. Dogs use smell, not vision, as their primary method of detection. Thus, visually inaccessible areas could be inspected as long as the dogs could sniff the area.

In part I, we documented that using pure training materials and the U.S. Customs Method of training combined with the food reward method of training, dogs were able to reliably detect termites with positive indication rates greater than or equal to 95% and false positive rates less than or equal to 6%. We defined "positive indications" as correctly identifying the presence of termites. "False positives" in this study meant that the dogs incorrectly indicated there were termites when there were no termites. Other questions surfaced during the course of our research. For example, if dogs were trained on eastern subterranean termites (EST), would they be able to detect other types of termites? Would dogs trained on eastern subterranean termites respond to damaged wood? Would they respond to other structural pests that live in a similar habitat? In part II, we answer these questions and discuss other studies where dogs successfully have been used.

MATERIALS AND METHODS. We again used six dogs, one German shepherd (Dog A) and five beagles (Dogs B through F) for our study. All were trained, maintained and handled by Pepe and Maggie Peruyero, owners of J&K Canine Academy, Alachua County, Fla. The dogs were trained using the method outlined by the U.S. Customs Service. Dogs B through F were trained with a combination of USCS method and food reward method to reinforce correct behavior. All dogs, except Dog B, were trained with pure termite samples. Dog B was trained with a mixture of EST and termite damaged material and debris (1 gram EST to 85 grams of termite-damaged material and debris). Daily training lasted from three weeks to three months depending on the dog. Each dog began testing after consistently reaching 100% accuracy in locating about 100 termite workers buried under gravel. Training methods are detailed in Brooks (2002).

The same experimental design as in part I was used to test the dogs’ ability to differentiate between ESTs, dark southeastern subterranean, Formosan, drywood and powderpost termites except tests were conducted with 80 workers of each species. Briefly, termites were placed in plastic cups (1 fluid oz.) with a moistened piece of paper towel (1 square inch). The plastic cup lids were perforated with 30 holes to allow scent to permeate out. The plastic cups were placed inside 2-inch PVC tubes that were fitted with caps and secured onto a pine board surface. A 1¼ -inch hole was drilled in the center of the PVC cap to allow any termite scent to escape. The PVC tubes were placed onto the boards and allowed to sit for 12 to 14 hours before being inspected by the dogs.

Five PVC containers were placed on the ground linearly, about 1 yard apart. The handler led the dogs to each of the five PVC containers for inspection. The dogs responded to the presence of termites in individual containers by digging. Responses were categorized as "positive indications," which is defined as a dog responding correctly to containers with termites and "false positives," which is defined as the dog incorrectly responding to containers without termites.

In order to eliminate a testing pattern, we "mixed up" how many PVC containers held termites. We tested the dogs where more than one, one or none of the PVC containers held termites. We also rearranged the order of the PVC containers with termites for each replicate. However, data presented here are for the situation where one PVC container held termites. Testing was conducted during a period of several months. The dogs’ level of proficiency was maintained by daily training sessions.

In summary, to evaluate the dogs’ ability to detect various species of termites, six dogs were tested using three densities of termites with 15 repetitions.

RESULTS OF DETECTION. The dogs reliably located termites in 96.67% of the containers (positive indications), regardless of species. The dogs responded to 1.73% of the empty containers (false indications). Individual dogs were equally effective in locating EST, dark southeastern (R. virginicus), Formosan (C. formosanus) or powderpost (C. cavifrons) termites (see table on page 70). However, the dogs’ ability to reliably locate drywood termites (I. snyderi) was significantly lower than for dark southeastern subterranean (R. virginicus), Formosan (C. formosanus), and powderpost (C. cavifrons) termites (see table on page 70).

NON-TERMITE MATERIAL RESPONSES. Since we do not know the identity of the chemical(s) that the dogs use to detect termites, we needed to make sure that the dogs would not indicate on "non-termite material" common to structures. The non-termite material we tested included termite-damaged wood and two pests commonly located within structures: cockroaches and ants. We used American cockroaches and Florida carpenter ants. For this experiment, either one piece of termite-damaged wood, American cockroach adults of mixed age and sex, or Florida carpenter ant workers were placed in PVC containers. Responses to termite-damaged wood, cockroaches and carpenter ants from dogs trained with EST were tested by all dogs except Dog A.

RESULTS. The rate of false positives for dogs trained with EST was 25.33% when termite-damaged wood was tested, 6.67% for American cockroaches, and 2.67% for carpenter ants (see table 2 on page 72). The dogs’ rate of false positive responses to termite-damaged wood was significantly higher than their rate of false positive responses to American cockroaches and Florida carpenter ants. The significantly higher rate of false positives to termite-damaged wood was attributed to Dog B, who was trained with a mixture of EST, termite-damaged material and debris. Dog B had a significantly higher rate of indications to termite-damaged wood than the other four dogs (see table 3 on page 74).

SUMMARY. Our study has demonstrated that dogs can not only detect the species of termites they were trained on with greater than or equal to 95% accuracy, but we also demonstrated that the dogs were able to locate four additional species of termites, after being trained with EST, resulting in positive indication rates of more than 96%. As importantly, we determined that the dogs trained with pure termite material correctly did not indicate when presented with termite-damaged wood (76.6%; 91.6% without Dog B), American cockroaches (93.3%) and Florida carpenter ants (97.3%).

The ability to detect different species suggests the dogs detect a common odor among the species of termites used here. The odor could be cuticular components, which are common among closely related species of termites or some pheromonal component used in communication.

High false positive rates may result from using cross-contaminated training materials containing both target odor and non-target or extraneous odor. With the exception of Dog B, our study prevented contamination with extraneous odors by aspirating the termites from the damaged material, possibly reducing the number of false positives. Dog B was an older dog that was initially trained on termites and wood debris before the study began, but maintenance training during the study utilized only termites.

Other studies have documented positive indication rates less than 90%. Jack Russell Terriers trained and employed to locate brown tree snakes in shipping cargo had a positive indication rate of only 70 to 80%. The lower rates of positive indications observed by other researchers (see sources online) could have resulted from several factors not defined in the material and methods, including the amount of maintenance training, length of search time and environmental influences.

Environmental influences, such as handler error, temperature extremes and wind speed, can also decrease the accuracy of the dog. Welch (1990) ensured search proficiency at more than 99% by daily maintenance training. SNL (1998) notes scent detection dogs can search for 40 to 60 minutes before search proficiency decreases significantly but providing a rest period maintains search proficiency.

The positive indication rate in our study was possible because each dog received two training sessions daily to maintain accuracy and the length of time each dog was tested was kept under 40 minutes to eliminate fatigue from affecting their ability to detect termites. To eliminate environmental influences, a single blind study was used to eliminate handler error, and testing was not conducted during extremes of temperature or wind speed.

CONCLUSION. The value of detector dogs is defined by their ability to locate hidden objects when the target odor is present and to not respond when the target odor is not. Several studies have documented the accuracy of scent detection dogs trained to locate narcotic constituents and insects. Dogs tested with methyl benzoate, a degradation product of cocaine hydrochloride, at concentrations greater than or equal to 50 parts per billion had a 90% positive indication rate and 9.6% false positive rate. Three German shepherd dogs were successfully trained to locate gypsy moth, Lymantria dispar (Linnaeus) egg masses with a 95% positive indication rate. German wirehaired pointer dogs were trained to locate screwworm, Cochliomyia hominivorax (Coque-rel), with a 99.7% positive indication rate. The positive indication rate for dogs trained to detect termites was 96%, which is similar to previous studies. Therefore, we believe that it is not unreasonable to expect a properly trained termite dog to meet a minimum acceptable standard with a positive indication rate of greater than or equal to 90% and a false positive rate of less than or equal to 10%.

The authors are a research entomologist, a graduate research assistant and the Margie and Dempsey Sapp Endowed Professor of Entomology at the University of Florida, respectively.

Most of the public have a definite opinion about snakes and it seems that the majority don’t like them. In actuality snakes are generally beneficial and many species aid in the reduction of rodents in the areas where they live. Whether a lot of this dislike is reflective of biblical events of Adam and Eve or the fear of the unknown, the sight of a snake in or around a homeowner’s property often generates a telephone call for help. In this article we’ll take a look at some basic principles of snake biology and tips in dealing with "snake management" in and around homes.

GENERAL BIOLOGY. All snakes are reptiles and cold blooded. The temperature of the environment where they are living directly affects most of their activity. In North Carolina we definitely see seasonal periods of movement that we can track by the calls coming into our offices. The largest number of calls occur in late spring and early summer. We also see a lesser period of increased activity in the early fall as snakes are beginning to seek shelter from cooler weather. Snakes also have an efficient metabolism. Depending on the size of their last meal, a snake may remain inactive for a week or more following feeding. If you are inspecting for a snake in a structure it is uncommon to see them "on the move" unless they are looking for food or have been disturbed from resting.

In the United States the vast majority of our snakes are non-poisonous. The most venomous species include rattlesnakes, copperheads (see photo above right), water moccasins and coral snakes. In which part of the country you are located will determine the most common species of snake you are likely to encounter. It is important for you and your staff to have a thorough knowledge of the various snake species that are present in your area if you are going to be involved with snake removal and exclusion services.

At our firm we look at five general areas of service needs and potential revenue sources in dealing with snake calls. These include, on-site animal removal, trapping services, exclusion services, habitat modification and reduction of food sources.

ON-SITE REMOVAL. One of the easiest snake calls to deal with occurs when a homeowner encounters a snake that is undisturbed. The snake may be sunning in a bush, lying out in a warm attic or coiled on top of the hot water heater. In these cases removal of a non-venomous snake can often be as simple as inverting a cloth "snake bag" over your hand and picking up the snake and pulling the bag back over the snake. Equipment to have on hand should also include a good flashlight, snake tongs, a snake hook, snake bags, a sturdy lockable snake cage or bucket and heavy gloves. You should always be prepared to deal with the unexpected.

In certain parts of the country there is always a possibility of encountering a non-native escaped venomous snake or venomous snakes that require more caution and expertise in capturing. If the snake is resting you should take your time to evaluate the situation and the best manner in which to capture the snake. At times you may only have one opportunity to capture the animal and a snake in a wall void or under a slab foundation can be difficult to remove. You should also keep in mind that snakes can be easily injured with the improper use of snake tongs. The snake can often be grasped with a set of tongs and the remaining weight of the snake supported with a snake hook. Many years ago I spent a fair amount of time capturing venomous snakes and always enjoyed "pinning" and picking up captured snakes by hand. Being a little wiser today, plus a little slower than in my younger days, I opt to always avoid handling venomous snakes. Remember, the more you handle venomous snakes then the greater your chances are of being bitten.

Last year we had an electrician step through the ceiling of a home and fall about 20 feet after seeing a snake in the attic of a home. A month ago we had a heating and air conditioning crew refuse to enter a crawl space after seeing a black rat snake in the crawl space of a home where they were working. Several years ago I even had one individual shoot holes through the roof of his own house trying to kill a snake that was crawling on top of a suspended ceiling. Many folks are truly terrified of snakes and you should always keep this in mind when responding to service calls, answering questions and removing snakes from a property.

TRAPPING SERVICES. It is common to receive calls for snake removal where a snake was seen and the homeowners want the snake removed. Depending on the specific situation you may or may not have success in locating the animal and removing it from the property.

When talking with the customer I always try to obtain as much information as possible concerning the sighting(s). I try to determine why the animal was there (i.e., food, shelter or just "passing through the area"). I also try to get a description of the snake, which may provide enough information for tentative identification. Keep in mind that different snake species have different types of behaviors, which will dictate where you may look for or attempt to trap the animal. For example, rat snakes are excellent climbers. If I am going into a basement in search of a rat snake I always try to think "3D," which means looking down as well as up along the sill lines and overhead ductwork. On the other hand, if I were going after a copperhead I would concentrate my inspection efforts closer to the ground level since these snakes are not efficient climbers.

Once on site at a home I always like to inspect for evidence of prey animals, such as mice, rats, voles, chipmunks, birds, etc. I also inspect for potential points of entry into the structure and the highest potential travel routes. I also look for evidence of snakes though shed skins, droppings and movement in dust and loose soil.

If a snake cannot be located during the inspection process I often install large rodent glueboards in locations of potential movement. You may want to secure these glueboards to a plyboard if you are dealing with a larger snake to avoid it from pulling the board away once it is captured.

We recently had a situation where one of our technicians placed a large rodent glueboard next to a hot water heater in a home where the owner had seen a rat snake go into a hole behind the hot water heater. That afternoon we received a call from the homeowner that the snake was caught on the glue board and had pulled the board up under the hot water heater and was halfway back into the hole. Once back on site our technician was not able to reach the snake and we ended up having to call in a plumber to move the hot water heater. Of course the snake got off the board during this ordeal and crawled back in the wall. We then had to cut a hole in the wall to reach the snake and remove it in order to calm the highly alarmed homeowner. Needless to say that was not a profitable snake-trapping experience!

According to some literature, loose burlap can be laid over a moist towel and snakes will crawl beneath it to rest and hide. I personally have limited experience trying this method of snake capture. I have had repeated success in capturing snakes outdoors by placing sections of plyboard or roofing tin on the ground with one end slightly elevated in areas where snakes are present. These created "harborage sites" require repeated inspection and care should always be taken during the inspection process to avoid close contact with potentially venomous snakes.

There are also several commercial snake traps available for purchase. One type involves the use of an easily assembled box that uses a glue-covered trapping surface. This particular trapping device appears to be relatively effective in capturing snakes. Always keep in mind that if large rodent glueboards are being used it is often wise to have these covered to prevent contact with non-target wildlife, children or pets. One of the keys to success in capturing snakes inside homes is to have trapping devices placed along potential travel routes. I will often use boxes or boards to restrict or "narrow down" potential snake travel paths onto trapping devices. If a non-venomous snake or a lizard is captured on a glue trap I will normally apply a liberal amount of cooking oil directly on the animal. The oil will allow the snake or lizard to be removed from the board and be relocated elsewhere.

EXCLUSION SERVICES. I feel that offering snake exclusion services is of true value in preventing the recurrence of snakes in a home. This service should be approached similarly to rodent proofing and can provide a viable "add-on" revenue source. Keep in mind that in areas with snake species that are excellent climbers, such as rat snakes, it is often important to extend your exclusion efforts above ground level to the roofline.

HABITAT MODIFICATION. I always look for potential snake harborage sites around the home’s exterior. This may include such things as a woodpile stacked on the ground, high weed growth, ivy beds, dense shrubbery, rocks used in landscaping and even tree limbs touching the home. By eliminating conditions that are conducive or attractive to snakes for harborage or their food sources then the likelihood of snakes living immediately next to the home will be reduced.

I will often tell folks that they can’t effectively keep a snake from crawling through their yard, however; they can keep them from living next to their home by modifying the habitat.

REDUCTION OF FOOD SOURCES. As discussed earlier, many snake species feed on rodents and should be considered beneficial because of this behavior. Many farmers will often welcome the presence of a snake around their barn to help in keeping down the resident rodent population.

When a customer is concerned about the presence of snakes on their property you should also evaluate the need for corrective and/or preventive rodent control services at that location. This situation also creates an opportunity for providing a valuable service and increasing revenue for your company.

THE USE OF CHEMICALS. Over the years there have been many home remedies used by the public to repel snakes from their property. I personally have a limited amount of experience in the use of repellents in snake control and prevention. There is at least one product currently available to our industry for the specific use in repelling snakes. It is my personal opinion that exclusion, habitat modification and food source reduction are the best long-term methods of preventing snake encounters in and around a home. The use of snake repellents may be considered and be of value in certain situations in or around a home.

CONCLUSION. Whether it’s an instinctive or learned behavior I think there always will be folks who dislike and are afraid of snakes. If your company is (or is considering) dealing with calls concerning snakes then you and your staff should be properly trained and equipped to deal with the various situations that you/they may encounter. By responding to service calls concerning snakes we are often placed in situations where it is appropriate to offer more traditional pest management services, extend our customer base and expand our revenue opportunities.

All photos are courtesy of the author.

The author is owner of McNeely Pest Control, Winston-Salem, N.C. He can be reached at smcneely@pctonline.com.

Urban wildlife is not a problem until those animals decide to take up residence in YOUR house. Then it becomes, "Do whatever you have to do to solve this problem as fast as possible!" Mild mannered and sweet women want the offending party torn limb from limb. The noise above their bed at night might be causing them to lose sleep. The disturbances may change how they do everyday things.

The daughter of one of my customers got the scare of her life when she sat on the toilet and heard a noise underneath her. I’m sure her scream could be heard throughout the neighborhood. The hysterical teenager called her father’s cell phone to tell him about the rat in the toilet. She will never go to the bathroom again without looking first.

So, here are my choices for the "Top five" urban pests for my area of the country (St. Louis):

1. Squirrels

2. Raccoons

3. Mice/Rats

4. Birds

5. Moles

GRAY SQUIRRELS. These are the cute, spirited animals that claim the homes of people who unknowingly provide them a special place. What kind of damage will they do? Many times they find their way into a structure and once in the home, they may chew on wiring, creating a possible fire hazard; they may disturb the insulation, making trails through it; they may chew rafters or window trim or scratch through drywall. But by far the biggest complaint is the noise. They are active primarily from 5 a.m. to 7 a.m., meaning they can loudly wake up anyone that might be sleeping under them.

They might move into a structure in October or November and sometimes stay through March or April. They may give birth inside of a structure in February or March and again in August. As the heat of summer comes, they may move out. In my opinion, the only good way to deal with gray squirrels is to trap them. What separates the novice from the professional in catching squirrels is that the novice has only one plan to trap the animal — the professional will have plan A, B and C if necessary. Use different baits, move the traps or change the type of trap you use if you are not having success. I trap them until I have no activity at the traps for a week or so, then I make a temporary cardboard repair over the hole. If the temporary repair is not disturbed in a week, then I permanently repair the hole. For a permanent repair, I use either a double layer of ½- by ½-inch hardware cloth or sheet metal (whichever one works best for the situation).

RACCOONS. This masked bandit is one of the strongest animals, pound for pound. I have had a raccoon on the end of a catchpole move my 230-pound frame. Raccoons also are one of the most intelligent animals I deal with. Some of the creative ways they enter a structure are amazing. I serviced a three-story house where they hung over the roof, ripped off the soffit and got in. They may tear apart a gable vent, open a hole in the roof or climb in a chimney to have their young.

If you want to be embarrassed, raccoons will do it to you. Catching a trap-shy raccoon can be quite a feat. Trap shyness comes primarily from relocation. They have learned that a trap is not a place they want to be. No matter how good the bait is, they may go somewhere else. Once they have been imprinted with the idea that "traps are not fun," the bait is not worth the risk. To catch a trap-shy animal, I may tie open a trap, fill it with bait to get them comfortable eating in the trap, then untie the door. This also works well for the job that’s open and you’re taking a few days off. Bait the traps heavily and tie them open. You waste a trip but you may make up for it in the increased speed of trapping the animals.

I believe relocation is unkind and ineffective. I have found that most relocated animals don’t stay on the property they are taken. They leave in search of their previous home. Many times they become a "victim" killed on the road. Left to nature, animals don’t welcome newcomers to their area or invite them over for dinner. Animals are territorial about food stores and about boundaries. The relocated animals frequently die of starvation or are killed by the animals in their new territory.

It is my opinion that all animals trapped within a structure should be euthanized. But, be aware that you also need to look at your state’s laws. The state or county in which you operate may tell you what has to be done with the animals you trap. You need to find out about laws regarding disposal of the carcasses in your state. This varies from state to state and/or county, township, etc.

MICE AND RATS. Mice and rats are a huge part of my business. I frequently find evidence of rodents while inspecting for squirrels or raccoons. This is why I have included them in the top five wildlife problems. The complaints I usually receive are of a noise in the attic or maybe droppings under the sink.

I use traps inside the house and rodent stations outside the house. Inside I want to know where the rodent is going to die. I used to tell prospective customers to buy snap traps and do it themselves, but I discovered something: they wouldn’t have called if they didn’t want me to come and help them. Even if it’s as simple as instructing them on how to set a mouse trap I’m helping them. Place packs indoors or in stations inside may create a smell for you to find later. After a rodent has eaten a rodenticide it’s a "dead mouse walking" for up to five days. Where it stops is where it smells: in or out of the wall. I don’t use glueboards for mice except inside a mechanical trap. In the mechanical trap, they will die anyway and the boards prevent escape. I also use live traps for rats indoors. I’ve found that rats and mice like vanilla extract, so I put that under the triggers of all the traps I set.

BIRDS. A residential pest bird job usually involves fixing or repairing something. This can be an excellent revenue source. The problem may be simple to solve, although a ladder is going to be needed. You must identify the bird species before you attempt any type of control.

Most pest birds are starlings, sparrows or pigeons. These are not protected by the Migratory Bird Act; just about every other species is protected.

Woodpeckers can be trapped with the right permit. Woodpeckers may peck out the knotholes in wood siding and starlings may move into the holes to build their nests. I make a trap in the shape of a birdhouse, with a hole in the front and a back hole that I place over the hole in the siding. Inside the birdhouse trap, I place a rat trap. This has been relatively effective for problem birds.

Most pigeon work involves exclusion techniques, such as spikes or netting. It may involve only repair of a structure to close the opportunistic holes or cracks. Once again, the repairs are generally made with hardware cloth, sheet metal, caulk or any combination of these materials.

MOLES. This pest is enemy No. 1 in many people’s minds. They spend time and money on their lawns and are furious at the damages wrought by such small creatures. In my opinion, the only effective way to eliminate moles is to trap them. I have traveled the country as "The Mole Hunter," speaking at home shows teaching people how to rid their yards of moles and keep them that way. Education combined with the right tools can make you a champion mole catcher. If you take care of someone’s mole problem, you will have a customer for life.

The author is president of Holper Pest & Animal Solutions, St. Louis, Mo. He can be reached at jholper@pctonline.com.

The odorous house ant, Tapinoma sessile (Say), is found throughout much of the United States and is often the topic of discussion among pest management professionals from Tennessee, Kentucky, Ohio, New Jersey, Virginia, North Carolina, northern California, Washington state and elsewhere. In fact, the odorous house ant is the most common ant invading structures in the Midsouth region and is ranked as the No. 2 "bad girl" in the United States.

This ant is easily identified by the following characteristics:

1. When crushed between fingers and held under the nose, an odor of rotten coconut (not as fruity as a rotten banana) and pine is detected;

2. 1/8-inch long, dark brown/black;

3. Node (bump) on one-segmented waist is barely visible and is hidden below the gaster;

4. A slit-like opening on the underside of the gaster; and

5. Workers are one size.

WHY A PEST? Both foragers and alates cause a nuisance, especially when they are found indoors. In fact, in Tennessee, odorous house ants (OHAs) can usually be seen actively foraging outdoors from March through November, although foraging has occurred on warm days in the winter months. Male OHAs also have been found attracted to lights in homes from late May through the end of June.

However, the reputation of the odorous house ant is a bit of a paradox. It is the most common structure-invading ant in the Mid-south, yet it has been termed submissive and subordinate. OHAs have been described as submissive because it defends only its nest and not its food source or foraging territory. It has been called subordinate because other ants displace it from a food source even if it arrives first (which rarely happens). However, it is more dominant when it outnumbers other ants. We believe most of our clients contact us when OHAs are very numerous and thus more dominant.

BIOLOGY AND BEHAVIOR. These ants are opportunistic nesters and occupy any object that will provide shelter. Because OHAs are a multiple queen species and some nests are formed by budding, many nests may be located throughout the structure and landscape. For example, we have found OHA nests in or under landscape timbers and rocks, logs, debris, siding, leaves, pine straw, mulch, loose bark and bee hives. Indoors, they are usually associated with moisture, such as wall voids near pipes and heaters, bathtraps, termite-damaged wood and beneath toilets. We’ve even found them clustered in the back corner of a kitchen cabinet that held the garbage can and sink pipes. They did not even bother to hide under anything.

Odorous house ants forage day and night, using guidelines, such as vines, limbs and trunks of trees and shrubs or edges of buildings, baseboards and counters, to move from place to place. Foraging occurs at temperatures from about 43° to 95°F, although some researchers report higher foraging temperatures. In some of our studies, foraging decreased as temperatures approached 90°F because Forelius ants out-competed OHA when temperatures exceeded 90°F.

Outdoors, odorous house ants feed on dead animals (skunks, birds, moles, voles, etc.); living and dead insects; excrement (honeydew) from aphids, scales and mealybugs; and nectar from plants such as rhododendron. Indoors, they can be found feeding on sweets and other household foods and are often found trailing to water. In general, oils are not preferred.

OHA often occur in large numbers along the outdoor base of the structure; however, client calls are related to ants seen indoors. To determine if ants indoors were, at the very least, sharing food with ants outdoors, we placed sugar-water containing dye near indoor OHA activity. At hourly intervals, white paper was placed over outdoor foraging trails and ants crushed on the paper. Dye was noted on the white paper two hours after placing the dyed solution indoors.

In 2002, before including a structure in our research study, we conducted the above procedure and determined that OHAs found inside 17 of 18 houses foraged outdoors or exchanged food with outdoor ants. In the one house where we failed to establish an association between indoor and outdoor ants, only a few foragers were seen inside and recruitment to the sugar-water failed. After establishing food flow between the indoor and outdoor ants, we knew we could treat outdoors and affect the indoor ant populations without disturbing the dweller.

PREVENTIVE MANAGEMENT OPTIONS. Ants occur in structures because food or water and/or nesting sites are present. Management efforts, especially bait treatments, are more effective if other food sources for ants are removed. Inform clients that reducing these resources, such as water from leaky faucets, dropped food and dead insects on window sills, can reduce indoor foraging. For example, ants were found in one home from the spring through the first week in December. The only day ants were not seen was the day the family returned from vacation in July. We believe this occurred because prior to leaving on vacation, the family had emptied the indoor garbage that had served as a food source. Clients need to remove garbage from the structure regularly and place outside garbage cans away from the structure.

There are other ways to remove access to these needed resources. Pet food serves as a reliable food source for these ants, so it is important to train pets to eat food within 10 minutes of placement. Trail pheromones to alternate food sources, not bait stations, can be removed by wiping the surface with a mild detergent.

While indoor food sources are more easily removed, it is almost impossible to remove all outdoor food sources. In addition, removing outdoor food sources may also cause ants to enter indoors in search of food. Some feel spring rains wash the sucking insects from plants and thus cause the ants to enter indoors in search of food.

Homes also provide nest sites for ants. Locate the entry point into the structure, such as a hole in the foundation around conduit, plumbing or poorly sealed windows and doors and seal these areas to prevent future invasions. Remind clients to check potted plants and firewood for ants before bringing them indoors. Keep branches, vines and other vegetation from coming in contact with the structure because ants follow these guidelines to gain access. Vines can also serve as nest sites. On one occasion, OHA workers, queens and immatures were found nesting between the stem of English ivy and a brick wall to which the ivy was attached. Pull mulch, pine needles, leaves and other cover away from the foundation of the structure.

Many of the previous recommendations may be more effective if performed prior to OHA infestations, that is, while the ants are next door just eying your client’s property, but haven’t made their move yet.

OTHER MANAGEMENT OPTIONS. Locating and treating nests is most effective when colonies are small and less numerous. In our research studies, when OHAs are present in low numbers and other ant species are present, we have seen other ants displace it from food. In fact, we have set our monitoring times to about 45 minutes because after this amount of time other ants displaced OHAs from our honey-smeared sampling cards. If we left them out for less time, OHAs didn’t find the cards. Thus, when OHA colonies are small, competition with other ants could be a reason for bait failure. If OHAs are just starting to move into the landscape, locating and treating nests may be effective; however, if the colony is well established and many nests are present around the structure, this type of treatment would be less effective. Large volumes of diluted insecticide sprayed through mulch as it is raked to expose nests will probably lower populations for a while, but it is unlikely to provide long-term control.

Baits, on the other hand, are collected by foraging ants and brought back to the nest where the pesticide is potentially circulated to all members of the colony that feed (workers, queen[s] and immatures or brood). Baits exploit the forager caste, causing them to introduce the toxicant into a previously inaccessible nest or nest of unknown location. Still, OHAs have been reported to move their nests about once every three weeks, often in response to rain. Prior to a rain, workers can be seen carrying brood to another location and when involved with this moving task, they are not interested in feeding on baits.

GELS, GRANULES or LIQUIDS? Gel, granular and liquid baits have different advantages. Gel baits are popular with pest management professionals because they are easy to use — gels are easily transported (the syringes can be carried in a holster) and gel baits can be placed into any crack or crevice. However, ease of use does not necessarily relate to efficacy. Bait attractiveness, as indicated by large numbers of ants feeding on a gel bait, may certainly impress a client, but will not guarantee distribution through a colony. A study by Silverman and Roulston indicated that Argentine ants fed eight times longer on a gel, but removed five times less sugar than ants feeding on a liquid. Also, when fipronil was added to these baits, more of the colony died due to the liquid formulation than the gel. They concluded that the liquid bait was more effective than the gel.

At the University of Tennessee we have evaluated several baits for effectiveness against small laboratory OHA colonies, but we haven’t evaluated all baits on the market, so failure to mention a bait in this article may not mean they are ineffective or effective, it just may mean they were not evaluated yet. In addition, one should be cautioned about making the assumption that the results of a small laboratory colony will reflect the results of a bait applied to a structural infestation or even to a large laboratory colony. Test colonies are usually started with about four queens, 400 workers and 1 cm2 brood. Food is removed for two to three days, then about two grams of bait are introduced. Three days later, the regular feeding schedule starts. Baits typically remain in the colony for the duration of the test. In a field situation, however, there will always be competing food sources. Second, in this protocol, each individual worker could have fed on the bait. When a large colony, such as that found around structures, is baited, only a small percentage of the colony actually forages. We don’t know how well any of these baits would be transferred around a large odorous house ant colony.

Thus far, the only gel-type baits tested that have killed all colony members (workers, queens and immatures) by eight weeks are Terro Ant Killer II (5.4 percent borax), Gourmet Ant Bait Gel (6 percent disodium octaborate tetrahydrate), Whitmire Micro-Gen experimental gel bait (now registered as PT388B Advance Ant Gel Bait, 5.4 percent borax), Outsmart (6.25 percent boric acid), AntX (7.5 percent orthoboric acid) and Pro-Joe-S Ant Bait/Gel Formula 4.5 (4.5 percent boric acid).

Granular baits can be scattered around the perimeter, placed in small piles, in cracks and crevices or in bait stations. Of the granules that we have tested as described in the previous laboratory protocol, Maxforce Fine Granule Insect Bait (1 percent hydra-methylnon), the New Niban baits (5 percent orthoboric acid) and Bayer experimental granular baits (0.05 percent, 0.1 percent imidacloprid) have killed all colony members by eight weeks. Regardless of the ease of use of gel or granular baits, however, our best strategy for managing odorous house ants includes a combination of a nonrepellent perimeter spray and a liquid bait in the landscape (see field results on page 100).

Liquid baits, although readily fed upon and quickly distributed through colonies, do have some disadvantages. The difficulty encountered with liquid baits is with the delivery system. Several bait stations have been developed to deliver liquids, most with a filter-type material with a plastic housing. Results from other ant researchers indicated that some stations gained weight (moisture), while other stations lost weight due to evaporation.

Also, some pest management professionals are reluctant to use them because some consider baits bulky, baits may be expensive and could be difficult to anchor and they must be refilled. Rust and colleagues warned that the excellent results obtained with liquid baiting systems developed by researchers for sweet-loving ants, such as Argentine ants, may not be duplicated with commercially available liquid baits because of modifications made during the commercialization process. Thus far, Terro Ant Killer II (diluted to 2 percent borax), Whitmire Micro-Gen experimental liquid bait (now registered as PT381B Advance Liquid Ant Bait, 1.3 percent borax) and Bayer experimental liquid bait (0.025 percent imidacloprid) have eliminated all OHA colony members by eight weeks using the previously described laboratory protocol. However, better liquid delivery systems need to be designed so pest management professionals can use liquid baits with less maintenance.

Repellent perimeter sprays can be used to keep ants out of a structure; however, you must be careful to prevent sealing foragers indoors. While baiting has been the main strategy for managing ants and use of sprays has been downplayed, we may need to rethink this logic as nonrepellent sprays make their way onto the market. Nonrepellent sprays will not deter ants from entering a structure, but, like baits, may allow ants to spread the insecticide to other colony members.

FIELD RESULTS. Because many clientele are not home during the day, perimeter treatments are used by pest management professionals because they do not require access to the structure’s interior and, thus, are easily and quickly applied. Outdoor perimeter applications also reduce the risk of pesticide exposure to indoor occupants.

The objective of this study was to determine which treatment, a perimeter bait, spray or a combination of bait and spray, would reduce outdoor and indoor OHA populations. To evaluate the effects of these applications, outdoor OHA populations were sampled twice before treatments were applied and at 1, 2, 4, 6, 8, 10, 12, 14 and 17 weeks after treatment. Residents were phoned at each sampling period to determine indoor ant presence. The perimeter spray of 0.06 percent fipronil (Termidor SC) was applied at 244 ml/m2 (6 gallons per 1,000 sq. ft.) to 1 foot up and out from the foundation base. The bait treatment applied consisted of a 1.3 percent borax experimental liquid bait (PT381B Advance Liquid Ant Bait, Whitmire Micro-Gen) placed in an Advance A.C.E. station and located on the ground against the structure. Baits were placed where more than 10 ants were found on a sampling card. A combination of the 0.06 percent fipronil nonrepellent perimeter spray and the 1.3 percent borax experimental liquid bait was applied as described above, except the bait was placed outside the spray zone to intercept ants coming from the landscape. Control structures received no treatment.

By week one, cards spaced 15 to 20 feet apart and placed two feet up and at the base of the structures indicated that the bait and spray combination treatment reduced populations by greater than 94 percent. This level of control remained throughout the 17-week monitoring period. The spray alone reduced populations by 93 percent or greater at four weeks after treatment and throughout the remainder of the study. The bait and spray combination reduction percentage was never significantly different from the spray alone on outdoor populations. The liquid bait reduced outdoor populations by 82 percent by week four and reductions were greater than 94 percent from weeks 10 through 17.

The liquid bait and spray combination treatment was the most effective in eliminating OHA indoors. Although ants had been seen in all four homes before treatment, no ants were seen inside any of the structures treated with a combination of a perimeter liquid bait and spray any time after treatment. The lack of rain following the initial placement of the bait and the drought-like summer conditions in general may have made the liquid bait more attractive. This system may not provide as quick a reduction in indoor ant populations when moisture is more easily accessible.

CONCLUSION. Our best results for reducing indoor and outdoor odorous house ant populations around homes were obtained with a treatment combination of 0.06 percent fipronil spray applied to the outdoor foundation 1 foot up and out combined with a 1.3 percent borax experimental liquid bait (PT381B Advance Liquid Ant Bait) applied in stations in the landscape near the structure. As efforts continue to reduce potential pesticide exposure to people, property and pets, we feel this perimeter bait and spray system, in which we have reduced the spray zone to one-eighth the area of a traditional barrier treatment, fits this philosophy well.

Author’s note: An example of a non-repellent perimeter spray for odorous house ant management was provided previously. In theory, other nonrepellent pesticides could act in a similar manner and we hope to evaluate some of these products this summer. We’ll keep you posted as new data is generated.

The authors are an associate professor in Entomology and Plant Pathology; Entomology and Plant Pathology Department graduate student and J. M. Waller Associates’ Pest Management Consultant; and English Department graduate student at the University of Tennessee.

References

Drees, B.M. and B. Summerlin. 1997. House-infesting ants and their management. L-2061. Texas Agricultural Extension Service.

Feller, J.H. 1987. Interference and exploitations in a guild of woodland ants. Ecology. 68: 1466-78.

Hedges, S.A. 1998. Field Guide for the Management of Structure-Infesting Ants. 2nd edition. G.I.E. Publishing, Cleveland, Ohio.

Hedges, S. 2002. 2002 Pest wrap-up. Pest Control Technology. December: 56-60, 86.

Oi, F. and D. Oi. 1997. IPM tactics for Argentine ant control. Circular ANR-999. Alabama Cooperative Extension System.

Paulsen, G.S. and R.D. Akre. 1991. Behavioral interactions among the formicid species in the ant mosaic of an organic pear orchard. Pan-Pacific Entomologist 67: 288-297.

Silverman, J. and T. H. Roulston 2001. Acceptance and intake of gel and liquid sucrose compositions by the Argentine ant (Hymenoptera: Formicidae). J. Econ. Entomol. 94: 511-15.

Vail, K.M. 2002. Structure-invading ants. PB1629. The University of Tennessee Agricultural Extension Service.