Pests of the home & landscape

March 19, 2001
Termites vs. the Homeowner

Introduction

Termites are ancient insects. Fossilized termite bodies indicate that this group of insects have been around for millions of years. Roman citizens knew of termites and referred to them as "Termes", meaning wormwood. Termites have caused problems in the United States at least since the early 1800's and were probably encountered much earlier than this date. These insects are actually beneficial!! This may be hard to accept, but as long as they remain in natural settings, they are responsible for the breakdown of large volumes of woody plant material. Building owners, however, take a dim view when it is their property that is being recycled.

Termites are social insects and live in colonies that are made up of several caste members. These members are the workers, soldiers and reproductives, (queen and king). At some point in the life of the colony, large numbers of virgin males and females are produced and the colony will swarm. The process is similar to that which occurs in honeybees. The swarmers or alates (winged forms) fly about, settle to the ground and mate. The mated pair will then seek out some protected site and start a new colony. Thousands of these termites do not survive because of predation by birds, ants, lizards, ground beetles, spiders and other predators.

Caste Descriptions

Workers: The worker termite is a small blind or nearly blind insect that is white in color. As the name implies, this is the caste member that accomplishes the many tasks of the colony. They collect food, feed and groom the queen, build and maintain the nest area, feed the soldiers, build shelter tubes, feed immature termites, etc. This is also the caste member most often seen if a limb or log is kicked open, or if, during repairs, a wall is opened and the studs are infested with termites. Workers are the termites that cause the damage associated with termite feeding.

Soldier: The body of this termite is white and the head is tan to a yellow tannish color. Due to their large mandibles, the soldier termite cannot collect food nor feed itself; however, they can defend the colony against insects such as ants. The head has more armor than the worker termite and the mandibles are capable of cutting an invading insect in half. If a feeding site or the colony area is disturbed, soldiers will bang their heads against a tunnel surface creating a noise which serves to warn other termites of danger.

Alates or Swarmers: In the spring thousands of this termite caste can emerge from an infested structure. They are virgin males and females, and they have equal sized front and back wings. Emergence may occur at any point in the structure; however, they will tend to congregate at the nearest window. A home owner may leave for work in the morning and return in the afternoon to find these insects on window ledges or on the floor beneath the window. They more than likely will have lost their wings and will be running around on the floor or will be dead due to the dry air in the building. A swarm which occurs in the home is a good indication that there is possible feeding within the walls. A termite colony that swarms some distance from the structure, and the termites are found on the patio, sidewalk or other area does not mean that the structure is infested with termites.

Termites or Ants

Ants are social insects and have a colony system similar to the termites and, like termites, the ant colony will also swarm. It is important to be able to distinguish between the two types of insects. Figure 4 in this section highlights major differences between the two insects. The wings, antenna and the area between the abdomen and thorax are important characters to consider.

Types of Termites

There are hundreds of termite species around the world with most of them located in the tropics; however, a number of species or types can be found within the United States. Broadly, termites can be divided into subterranean or drywood termites. Drywood termites will occur in Mississippi but are usually found only along the Gulf Coast. This termite type does not have to maintain contact with the soil. Subterranean termites must maintain contact with the soil, and they occur in all parts of Mississippi, with some exceptions that will be noted below.

Subterranean Termites. Termites in this group are very sensitive to drying, and the environment below ground provides the moist conditions necessary for survival. They will feed on dying roots below ground; however, to maintain a good food supply, they will forage above ground. Movement is not done "in the open"; they will build tunnels from one point to the next. This system of tunnels protect the termites as they move about looking for food. Soil is also carried into the feeding area. The presence or absence of soil in a damaged area can be used to distinguish between termite or carpenter ant damage. Termite feeding galleries will contain soil, while the egg laying galleries of carpenter ants will be clean. Carpenter ants do not use wood as food - the galleries are used only as harborage and for the rearing of young.

Mississippi has two categories, genera, of subterranean termites. The genera are Reticulitermes and Coptotermes. The names for the most common termite in each genera is the "eastern subterranean termite (EST)" (Reticulitermes flavipes) (EST soldier) and the "Formosan subterranean termite (FST)" (Coptotermes formosanus). The EST is a native species of termite found statewide, while the FST was introduced into the U.S., probably at the end of World War II. Its area of origin is the far east.

Based on sample identification, the following counties are known to have FST infestations. The coast counties, Jackson, Harrison, and Hancock, all have pockets of FST infestations. Forrest and Lamar have infestations of this termite, and these seem to be largely associated with the Hattiesburg area. The termite has been recorded from Pearl River County, and the infestations seem to be associated with the Popularville and Picayune areas. One structural infestation each has been recorded in Jones, Rankin, and Madison counties. The first confirmed identification of the FST in Mississippi came from Lauderdale County in 1984. The termites in this particular case were not found within a structure but were found in crossties in the front of a house. The infestations in Rankin and Jones Counties were also associated with crossties. One additional infestation has been reported in Lauderdale County, and this one was found in one of the older buildings downtown.

Although the Formosan (FST soldier) is subterranean in habit, it has some behavioral characteristics, as well as body differences, that separate it from the native species that exist in Mississippi. Probably the most unique thing about the Formosan is its habit of building a material called "carton" in the wall voids of infested structures. This material is a combination of soil, chewed wood, and secretions from the termite. Formosans can literally pack wall voids from top to bottom with this material. Once in place, the "carton" will trap and hold moisture and the termites do not have to return to the soil as frequently as they would if they did not have the "carton" in place. Overall, the populations of the FST tend to be higher, and the number of soldiers is much higher than in the native subterraneans.

Other differences include color of alates or swarmers, time of swarming, attractiveness to lights, shape of the head of the soldier, etc. These differences are listed in Table One.

Termite Descriptor:

Eastern Subterranean

Formosan Subterranean

Color of Swarmer or Alate

Black EST Alate

Honey or Tannish Yellow

Time of Year of Swarming

Late Feb. to Mid-May

Late May to End of June

Time of Day of Swarming

Morning

Late Evening to Night

Attracted to Lights

No

Yes

Wings

Without Small Hairs

With Small Hairs

Shape of Soldier Head

Rectangular (Fig. 2)

Tear-Dropped Shape (Fig. 7)

Table 1. Comparisons between the eastern subterranean and the Formosan subterranean termite.


A lot of the publicity about this termite has come from the New Orleans area. However, this area has some confounding factors that may have contributed to the develop of the Formosan problem. For example, the buildings are very close to the street; there may be whole blocks with nothing but buildings (very little available soil); building walls may be several feet thick; floor foundations may be several feet thick; the old construction holds moisture, etc. For whatever reasons, this does not lessen the extent of the damage that some in the New Orleans have suffered. By the same token, do not use this area as the only gauge when making judgments about the FST.

FST Facts from China. Information from China shows that the northern limit for the FST is about 33.5 degrees north latitude. In Mississippi, this latitude corresponds to a line just south of West Point on the East to just south of Cleveland on the west-- New Orleans is at approximately 30 degrees N latitude. The greatest area for FST damage in China is the area that is at and south of 25 degrees N latitude. Miami is located just south of 26 degrees N latitude. This data shows that the southern fourth of Mississippi is in an area that can support populations of this termite. Time will tell how far north it may move and be able to compete with the native species of subterranean termites. If one lives in the southern portions of the state and is having problems with termites, they should make sure of the species involved in the problem.

Termite Treatments

Building owners and managers are concerned about termite control and there are several factors to considered when planning a termite management plan. The first thing to know is the type of foundation your building is resting on or will be resting on--some of these foundation types have more potential for termite problems than others. Other factors to consider are timing of treatment (pre-construction or post-construction), type of treatment (liquid or feeding stations) and "good building management practices".

Foundation Types

Probably the most common foundation in the state is the monolithic slab, followed by (in no particular order) supported slabs (two different modifications), floating slab and the conventional or crawl space foundation. These foundation types are shown below along with a brief description.

Monolithic Slabs. The concrete for this foundation type is poured in one continuous pour. There are not any joints around the inside of the foundation and this foundation offers the least points of entry for termites, that is, as long as the slab does not crack. The weak points in this foundation are the bath trap located under tubs, or showers and the points where pipes or other service line pass through the slab.

Supported Slab. Supported slabs are constructed in two steps. The first step is the building of the foundation wall. The foundation wall can be poured concrete or blocks built on a concrete footing. The latter step is the most common. The joint between the foundation wall and the slab is a possible entry point; however, the joint is visible on the outside.

"L" - Block Supported Slab. The "L" block is fairly common and the foundation wall may be three or so concrete blocks high and the top block will be "L" shaped. The slab will set within this "L" shaped area. This creates a hidden joint around the entire inner perimeter of the structure.

Floating Slab. In this foundation type, the slab is not resting on or attached, in any way to the foundation wall. As with the supported slabs, it is built in two different steps. The joint is hidden by whatever the floor covering will be within each room.

Joint. The hidden nature of the joint in the floating and "L" block type of construction can be visualized by looking at a floor plan from the top. This joint may be hidden by floor coverings or the outside perimeter wall. If termite infestations occur after the structure is completed, ensuing treatments can be very invasive, depending on the type of treatment used.

Conventional Foundation. There are a number of variations with this foundation type and it is doubtful that any in Mississippi have a four inch reinforced concrete cap at the top of the foundation wall. It would be good if they did; however, it does add to the expense. This foundation type is very easy to inspect as long as a minimum 18 inches is allowed between the soil and the floor joists. In some situations, one end of the structure will have adequate to good clearance while the other end provides very little, if any clearance. If this situation exists, the structure cannot be inspected with any degree of reliability.

In review. The foundation type will influence the number of possible entry points for termites. The monolithic slab gives the least while the "L" block supported slab and the floating slab provide the most. The conventional foundation is easy to inspect as long as good clearance is provided in the crawl space.

Types of Termite Treatments

There are two times that a structure can be treated, before it is built (preconstruction treatment, often referred to as a "pretreat") or if termites are found in a building, a post-construction treatment can be applied. Or, a preventive treatment may be applied at certain points in time, post-construction. Types of treatments fall into two categories, liquid treatments and treatments applied as feeding stations.

Liquid Treatments. Several compounds are available as liquids, and they include permethrin (Dragnet, Prelude), cypermethrin (Demon TC), imidachoprid (Premise), fipronil (Termidor), and bifenthrin (Talstar, Biflex). The first name is the common name (active ingredient) of the chemical, and the one in parenthesis is the trade name of the product. There may be other trade names containing one of the above active ingredients. These products may be mixed at concentrations ranging from a low of 0.06% (the low end for products such as Biflex or Termidor) up to 0.5% (high end for Demon TC).

Compounds such as permethrin, cypermethrin, and bifenthrin will kill termites; however, they work primarily by repelling termites from the treated soil around and under the foundation. The compounds, fipronil and imidachoprid, do not repel termites, hence the insects will enter the treated zone and are eventually killed. In general, one does not care if the termites are repelled or killed, as long as the structure is protected. Some data however, suggests that as the termites move in and out of the treated zone (non-repellent materials), small amounts of the active ingredient are transported back to the colony. As the concentration builds-up within the colony, the colony itself is controlled. This could be very important especially, if one is dealing with FST. More work of this type has been done with fipronil than with other non-repellent compounds. None of these products are available to the homeowner for do-it-yourself treatments. They are only available to professional pest control companies.

"The PreTreat." This treatment is usually applied with one of the liquid materials, although some are advocating the use of feeding stations as a pretreat type of treatment (see below). If the liquids are used, the volume (of water) in which it is applied is very important. The water carries the active ingredient into the soil thereby coating the soil particles with the insecticide. The following case study is given as an example:

A pretreat calls for two applications, one applied to the soil before the foundation is poured, and the second one is applied after the structure is completed and the initial landscaping is finished. The volume for the first pretreat application calls for it to be applied at the rate of one gallon per 10 square feet of foundation surface. The house will be built on a monolithic foundation and the foundation measures 40 feet by 52 feet - this equates to 2,080 square feet or at one gallon of insecticide solution per 10 square foot 208 gallons. Most termiticide labels call for three to five gallons of solution per critical area. The above structure will have four critical areas (bath traps, kitchen pipes, etc.) and at four gallons per critical area, an additional 16 gallons will be required. Total gallons for the first application equals 208 plus 16 for a total of 224 gallons.

The second application is applied to the perimeter of the foundation at the rate of four gallons per 10 linear feet. The linear feet around the case study is 40 + 40 + 52 + 52 = 184 linear feet. Based on four gallons per 10 linear feet, a total of 73.6 gallons would be needed to treat the outside perimeter of the structure. A grand total is 73.6 gallons plus 224 gallons equal 297.6 or 298 total gallons. A question often asked is how much should this cost? The following cost estimate is based only on chemical cost, and calculations are on the cost per mixed gallon of insecticide solution.

Cost per
Mixed Gallon

Total Gallons
Needed

Chemical Cost
Col 1 x Col 2

Cost per Sq. Ft.
Col 3 ˜ 2080

 1.40

298

417.20

204

1.00

298

298.00

144

0.60

298

178.80

94

Many factors other than chemical cost should be factored into the above study; however, this should provide a baseline for the cost of a pretreat. Cost for postconstruction treatments are somewhat more involved because of the presence of the structure.

Post-Construction Liquid Treatments. These treatments are more involved due to the presence of the structure and may include a perimeter treatment plus drilling of the foundation. The drilling will be based on cracks in the foundation, presence of dirt filled porches, chimney bases, presence of joints in the foundation (see foundation types), etc. If only the perimeter of the structure is treated, figuring linear feet around the structure would be a good starting point, as far as cost estimates.

Feeding Station Treatments. Three products are currently registered as "feeding control materials." These are hexaflumeron (Sentricon), diflubenzuron (Labyrinth), and sulfluramid (First Line). The first two products are growth regulators, and the latter compound is a slow acting insecticide. All three are used as in-ground materials and at least two, hexaflumeron and sulfluramid, have feeding stations that can be placed within structures at locations of known termite activity. These three compounds are available only to pest control professionals.

Use of these three systems varies and a brief description follows:

  • Hexaflumeron. This system utilizes a two step approach Bmonitoring and baiting. The in-ground stations (green PVC cylinders with perforated sides--10 inches long) are placed at approximately 10 foot intervals around the structure. Initially, the in-ground stations contain two wooden strips (the monitoring phase) and the stations are inspected periodically. Inspection involves removing the cap and checking the wood for the presence of termites. If termites are found, the technician slowly removes the wooden strips and places them in a collecting container. As many termites as possible are collected, placed in a perforated tube containing rolled paper (the paper contains the active ingredient hexaflumeron) and this tube is returned to the in-ground station. The termites should begin feeding on the matrix containing the hexaflumeron (the treatment phase) and return to the colony. As food is shared, the hexaflumeron is spread among other termites as well as the queen. The growth regulator eventually kills the termites as they try to molt. This concept works; however, it works slowly, since the hexaflumeron is a growth regulator - control is not immediate. In some cases, the termites may not feed on the rolled paper and they leave the tube. In this case, continual monitoring is the only option. It may take several months before the termites return to the in-ground station or other stations are hit around the building. Above ground "in-building" stations are available. These stations are attached to walls in areas of known termite activity. They are monitored for activity just like the in-ground stations.
  • Diflubenzuron. As with hexaflumeron, this is a two step process; however, the process is different. The in-ground stations for this system are rectangular with interior dimensions of 2.625 inches wide by 6.875 inches deep. Once the station is placed in the ground, four thin boards are placed in slots on each surface leaving a cavity (size of cavity is approx. 2"x2"x7") within the center of the station. This is the monitoring phase. Once termites are discovered feeding on the boards, paper containing the a.i. (treatment phase) is placed within the central cavity. With this system, the technician does not have to collect the termites and transfer them to a separate container. Above ground stations are not available with this system.
  • Sulfluramid. This is a one step system, or at least that is an option. The in ground stations are 4.5 inch long cylindrically shaped plastic tubes filled with treated cardboard. As you can see, this eliminates monitoring. The treated cardboard is present so when the termites find the station, they immediately begin feeding on the active ingredient. On the surface, this sounds good because there is no disturbance associated with the system; however, the cardboard can become soaked fairly quickly.

These systems are usually applied to existing structures; however, there are some using this method as a "pretreat." If this is the case, it is important to remember that this is the only termite treatment that the structure has and the monitoring will have to be in place for the life of the structure. If houses are built for the spec market, prospective buyers should be told up front that this is the case. The owners of custom built homes may select this type of treatment but if the house is sold, the buyer should be aware that if they should choose to discontinue the system, the property will be without termite protection.

Good Owner Management Practices

Finally, are there things that can be done as the owner of a building to prevent termites or at least lessen the possibility of getting termites? Following are some things that should be done as preventative steps:

  • Do not alter the grade around a building so as to cause the accumulation of water against the foundation.
  • Do not stack material such as firewood next to the foundation.
  • Do not buy crossties without inspecting them for termites. Ask where the crossties came from, if it is south Louisiana or south east Texas it might be better, to do without.
  • Do not stack mulch over the treated zone adjacent to the foundation.
  • Do not till the area immediately adjacent to the foundation when planting ornamentals.
  • Do not plant ornamentals so close to the foundation that one cannot inspect the outer perimeter of the home or to reduce air flow around the structure. Plan on a zone of 18 to 20 inches between the mature width of the selected ornamental and the wall of the structure.
  • Do not block crawl space ventilation vents if the structure is built on a conventional foundation.
  • Do not place insulation or false stucco below grade if planning new construction. This invites termites and moisture problems.
  • Do not make contiguous additions to the existing structure without having the soil treated prior to pouring the new foundation.
  • Do not make additions to the existing structure that will cause wood to soil contact.
  • Do inspect the outside perimeter once a year looking for signs of termites, termite tubes or decay. Inspect the lower portion of the foundation for tubes and "sound" wood around window, doors or other exposed wood.

All pictures were scanned from the U.S.D.A, U.S. Forest Service Farm and Home Bulletin 64, except for Fig. 5 (U.S.D.A., U.S. Forest Service "You can protect your home from termites") and Fig. 7 (U.S.D.A., New Orleans Formosan Termite Web Site).

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