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Agricultural Extension Service The University of Tennessee PB1344

Subterranean Termite Control

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Page 1: Subterranean Termite Control

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Agricultural Extension ServiceThe University of Tennessee

PB1344

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Table of Contents

Introduction ________________________________________________________________ 3Termite Biology and Identification ______________________________________________ 3Prevention _________________________________________________________________ 6

1. Sanitation ______________________________________________________________ 62. Landscape practices ______________________________________________________ 63. Structural and construction defects __________________________________________ 74. Barriers ________________________________________________________________ 8

Mechanical barriers ____________________________________________________ 8Foundations_________________________________________________________ 8Metal termite shields__________________________________________________ 8Particle-sized barriers _________________________________________________ 8Stainless steel mesh __________________________________________________ 8

Chemical barriers ______________________________________________________ 8Treated lumber ______________________________________________________ 8

Soil termiticides _____________________________________________________ 8Insecticides _________________________________________________________ 9

Application Methods — Preconstruction _________________________________________ 9Monolithic slab____________________________________________________________ 9

Treating the soil outside the foundation _____________________________________ 9Suspended (supported) and floating slabs ______________________________________ 10

Crawl space _________________________________________________________ 10Control in Existing Structures _________________________________________________ 10

Inspection _______________________________________________________________ 10Termite control — post-construction __________________________________________ 10

Conventional soil treatment _____________________________________________ 10Slab-on-ground houses _______________________________________________ 10Crawl space houses __________________________________________________ 12Basement houses____________________________________________________ 12

Wood treatments______________________________________________________ 12Termite baits_________________________________________________________ 12

The Sentricontm System. ______________________________________________ 13Firstlinetm

_____________________________________________________________________________________________________ 13Terminatetm

__________________________________________________________________________________________________ 14Exterratm Termite Interception and Baiting Systemtm

___________________________________________ 14Professionally-installed baits or barriers — which is better? __________________ 14

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IntroductionSubterranean termites, the most destructive

wood-feeding insects in Tennessee, feed on cellulosethat is usually obtained from wood. Termites are veryimportant because they help recycle dead, fallen treesback into the soil. They do not easily distinguishbetween a dead pine tree and pine lumber; therefore,their food may be in the form of a dead tree or thewood in a house. They will also feed upon fenceposts, paper, books and fabrics of plant origin, as wellas living plants such as trees, shrubs, flowers andsome crops.

Colonies of subterranean termites live in the soiland enter structures through wood or foundation wallsadjacent to the soil. In cases of structures built partlyor completely on concrete slabs, infestation occursthrough expansion joints, cracks, and utility and seweropenings. The damage to buildings is reduced struc-tural strength of the wood caused by the removal ofpart of the tissues.

Information contained in this publication isprovided to inform the consumer, as well as the pestcontrol professional, of termite biology and thetechniques and materials available for termite control.In the past, the main method of termite control was toform an insecticidal barrier between the wood andsoil. Specialized equipment (sprayers with large tanks,rodding tools, large drills, safety equipment andothers) and special knowledge were and still arerequired for the proper application of termite insecti-cides. Currently, conventional soil treatments, as wellas baiting systems, are available for termite control.Knowledge of termites’ biology and behavior is evenmore crucial with the use of termite baits that suppress

or “eliminate” termite colonies. Experience usingbaits is a key component to achieving control withthis method. Therefore, securing the services of areliable pest control professional is advisable inalmost all cases.

Termite Biologyand Identification

Termites and termite damage are not difficult toidentify; however, people often mistake winged antsfor termites and become unnecessarily alarmed.Actually, the difference is quite pronounced (Figure1). An alate or “swarmer” of the most commontermites is generally black. It has a rather straightbody, straight antennae and four cloudy-white wings

SubterraneanTermite Control

Karen M. Vail, Assistant Professor,Harry Williams, Professor Emeritus, andJamie Yanes, former Assistant Professor

Entomology and Plant Pathology

Figure 1. Comparison of a winged (alate or swarmer)termite and a winged ant.

2nd pairwings equalin size

StraightAntennae

BroadWaist

ElbowedAntennae 2nd pair wings smaller

SlenderWaist

Termite

Ant

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of equal length that are twice as long as the body. Thewinged ant, on the other hand, may be similar in colorbut has a wasp-like constricted waist, elbowed or bentantennae and four clear wings. The ant’s hind wingsare shorter than the front pair and are not quite as longas the body.

The white, soft-bodied, wingless, workertermites, although seldom seen, are the ones that dothe damage. They eat the soft grain of wood, leaving athin shell outside and a layered effect inside. Oftenmud is present in the eaten layers of the wood, whichhelps distinguish termite damage from other wood-destroying insects.

Termites live in true social colonies with adivision of labor among the different types of indi-viduals. These different types, called castes, usuallyconsist of reproductives, soldiers and workers(Figure 2).

The primary reproductives of the most commonspecies in Tennessee are shiny black and are winged.They are produced in mature colonies and typicallyfly to find mates on a warm day after a rain. The threemost common termite species in Tennessee are theeastern subterranean termite, Reticulitermes flavipes;the southeastern subterranean termite, R. virginicus;and the light southeastern subterranean termite, R.hageni. R. flavipes often flies between March andMay, while R. virginicus flies April through June or inthe fall. R. hageni, a pale-brown species, may flyfrom August to October.

Mating flights can occur during other times ofthe year, especially in heated structures. After the

flight, they shed their wings and pair up. Each pairattempts to start a new colony by constructing a celladjacent to wood or other food source. Mating takesplace in the cell and eggs are laid that will produce thefirst small group of nymphs. These nymphs are fed bythe reproductive pair until the nymphs are largeenough to “go to work” themselves. As the colonyincreases in size, soldiers and reproductives areproduced. New winged swarmers (Figure 3) areseldom produced until the colony is more than 3 yearsold. Mating flights occurring indoors (Figure 4) arealmost never successful and fallen winged individualscan be vacuumed and discarded.

The workers are creamy white (Figure 5), verysoft-bodied and subject to drying out (desiccation).Thus, they need soil contact for a source of moisture.Workers build shelter or mud tubes from bits of soiland excretions as passageways from the nest to thefood source. Shelter tubes are usually the width of a

Figure 3. Winged native subterranean termiteswarmer.

Figure 4. Swarmers are often found at windows.

Figure 2. Termite life cycle.

winged

primary

eggs

nymphAdults

secondary

soldierworker

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pencil (Figure 6), but may be wider. The soil/excre-tion material is also used to close any breaks in thesurface of the wood the termites are infesting. Ter-mites need this closed system to preserve the neces-sary high level of humidity. Shelter tubes also serve asa protective barrier against their natural enemies,particularly ants.

The soldiers are also creamy white with large,dark, reddish-brown, rectangular heads (Figure 7).The strong mandibles or jaws are also hardened anddarkened. Soldiers use these strong jaws to protect thecolony from invaders such as ants.

Supplemental reproductives are usually white,larger than nymphs or workers and have short wingpads. Because they may be numerous, supplementalreproductives can become an important egg sourceand collectively can produce more eggs than the

primary female. Supplemental reproductives areformed if the queen or king dies, or if individualsbecome isolated from the main colony due to applica-tion of termiticide (which separates above-groundindividuals from those below ground), flooding,drought, physical disruption of the soil, such asduring construction, and other causes.

The Formosan subterranean termite,Coptotermes formosanus, (Figure 8) is a more aggres-sive feeder than the native subterranean termites. Ithas been introduced to the Memphis area in the past,but is not established. Unlike the other subterraneantermites that eat along the grain of the wood, theFormosan termite is less discriminating and will oftenhollow out a tree trunk or wooden beam. See Table 1for a comparison of Formosan versus other subterra-nean termites. Formosan termites found in Tennessee

Figure 5. Native subterranean termite worker.

Figure 6. Shelter or mud tubes are usually the widthof a pencil.

Figure 7. Native subterranean termite soldier.

Figure 8. Formosan termite soldier.

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should be reported to the Tennessee Department ofAgriculture, Division of Regulatory Services.

Drywood or powderpost termites are occasion-ally introduced into Tennessee through infestedfurniture or other wooden pieces. Drywood termitesare easily distinguished from subterranean by thepresence of their six-sided fecal pellets. These pelletsare concave on the sides and often appear in piles asthey are kicked out of the nest. No soil contact is

venting termites from invading a new building: 1)sanitation of the building site, (2) landscape prac-tices, (3) structural and construction defects and (4)barriers.

1. Sanitation — Do not bury wood in thebackfill or under porches or steps, as this will attractand provide food for termites (Figure 9). Removeform boards and wood scraps from soil before fillingor backfilling. Remove all tree roots and stumps fromthe building site before beginning construction.Remove spreader boards and grade stakes before theconcrete sets.

2. Landscape Practices — Landscapepractices can also determine the structure’s suscep-tibility to termites. Cellulose mulches (wood orbark chips and others of plant origin) placedagainst the foundation (Figure 10) give termitesaccess to the home without having to contact thetermiticide barrier that has been applied next to thefoundation. Leave a 12-18-inch plant/mulch freezone next to the foundation.

Landscape timbers or wooden decks can providefood for termites and can also become an access routeinto the structure if they are placed against the founda-tion or wood siding (Figure 11). Other landscapingmaterials for borders, such as concrete and vinyl, areavailable that will not degrade as quickly as wood andwill not provide food or structural access to termites.

Irrigation systems that wet the structure’sfoundation can also attract termites to the structure.

Table 1. Comparison of Formosan and nativesubterranean termites.

CharacteristicFormosan

subterraneanNative

Subterranean

shape of soldier head oval rectangular

wings hairy nearly bare

% soldiers in colony 20-30 1-3

swarm time dusk to midnight day

length of alatesincluding wings 12 - 15 mm 7 - 10.5 mm

needed, so mud is not present in the damaged wood.Also, these termites feed within and against the grain.Damage occurs slowly as compared to subterraneantermites. A pest control professional is needed forcontrol, especially if the infestation has spread tostructural timbers and fumigation is required.

Collecting specimens for identification Alates (swarmers) with wings and/or soldiers

should be preserved in rubbing alcohol when submit-ted for identification. Submit at least 10 — 15 speci-mens. Swarmers without wings and workers are notuseful in identification.

PreventionMost structures are pretreated during construc-

tion with a soil termiticide (termite poison) to protectthem from termite attack. The objective of the pre-treatment is to create a continuous barrier oftermiticide that repels or kills termites as they attemptto cross this barrier. Few people would considerbuilding a new house and then not insuring it againstdamage caused by fire or other calamities, yet manymore houses are damaged each year by termites thanby fire. Pre-treatment is relatively inexpensive andhighly recommended.

There are four major considerations in pre-

Figure 9. Wood buried in the backfill or underporches can attract and provide food for termites.

Floor framing infestedby termites

Termite tubesover surface andthrough voids infoundation wall

Wood debrisin soil

Wood debisin dirt fill

Concreteentranceslab

Direct access fromporch fill to wood

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Inspect irrigation systems regularly to ensure thewater is being applied to the proper location in theappropriate quantities. Hard water stains on thestructure’s foundation could indicate an irrigationproblem. Repair leaks in faucets (Figure 12) andhoses as soon as possible.

3. Structural and constructiondefects — Allow sufficient space (30-inch clear-ance) and ventilation outlets for air movement to aidin keeping soil dry beneath houses with crawlspaces,which will make the area less suitable to termites.Ventilation openings, in foundation walls and beneathbuildings with crawl spaces, should be large enoughand equally distributed to prevent dead air pocketsfrom forming. Such pockets would give rise to humidconditions conducive not only to termite activity, butalso to powderpost beetles, carpenter ants and wooddecay. Installing fans at the vents will keep aircirculating. Cover 80 percent of the soil surface in thecrawl space area with a 4-6 mm polyethylene (plastic)

layer. One way to do this is to cover all of the centerof the crawl space area, leaving a 1-foot-wide strip ofbare soil around the foundation. (A 100 percent crawlspace cover could dry hardwood flooring too muchand lead to warping.) Moisture rising from the soilaround the perimeter will be exhausted through thefoundation vents. The plastic cover will preventmoisture rising from the soil from being absorbed bythe floor joists, insulation and subfloor.

Figure 10. Plant-based mulches placed over termiticide-treated soil can give termites access to the home.

Figure 11. Wood products, including landscape timbersand wooden decks, should not be placed in directcontact with the foundation or wood siding.

Other construction practices can reduce termiteinvasion. The finished grade outside the buildingshould slope away from the foundation so water willnot collect under the house. Porch supports should beseparated from the building by at least 2 inches.Wooden steps should rest upon a concrete base thatextends 6 inches above grade. Do not place basementpartitions, posts and stair stringers until the concretefloor has been poured. They should never extend intoor through the concrete.

In the final grading, allow at least 6 inchesclearance between the top of the soil and the top ofthe foundation. Rigid board insulation, exteriorinsulation and finishing systems (EIFS) or syntheticstucco, stucco or other decorative materials thatextend below grade (below the soil) are especiallytroublesome. These materials installed below gradecan wick moisture into the walls of the house,creating conditions favorable to termites and woodrot. When stucco separates from the foundation

Figure 12. Faucets should be repaired before they causethis amount of damage. Moisture next to the foundationwill attract termites.

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wall, termites can build a tube between the wall andstucco and enter the home undetected. Termites canchew through the insulation if it is present belowgrade. Although the foam board does not providenutrition, it does provide optimal nesting and tunnel-ing conditions. Even if the termites are detected,liquid termiticides are difficult to apply in thissituation because the foam insulation resists wetting.

4. Barriers — Barriers can be classified intotwo major categories: mechanical and chemical.

Foundations — A poured, reinforced, crack-free, concrete foundation hinders the movement oftermites. Termites can go through a crack as small as1/32nd of an inch. Hollow-block or brick foundationsshould be capped with a minimum of 4 inches ofreinforced concrete. Of all foundation types, slab-on-ground construction is most susceptible to termiteattack. Termites can enter the wood by going over theedge of the slab, as well as through expansion joints,openings around plumbing and cracks. The mono-lithic slab is least likely to be penetrated by termites,the suspended slab is intermediate and the floatingtype slab is most easily penetrated.

Metal termite shields — A good metal shieldplaced on top of a foundation and piers is a goodinspection tool because it will force termites to buildtubes out in the open where they can be seen wheninspections are made. Metal termite shields can aid inprotection of the structure if properly designed, con-structed, installed and maintained. However, goodshield construction, installation and maintenance arerare. Metal shields should not be relied upon solely toprotect a structure from termites. They should be usedin conjunction with a conventional soil treatment orother methods described in this publication.

Particle-sized barriers — Termite researchershave found that particle-sized rocks of basalt (basaltictermite barrier) or granite may provide a physical barrierto termites. The rock is ground into a specific size, whichis too big for the termite’s mandibles to move and toosmall to allow movement between the grains. Sandbarriers are used in Hawaii, although they can addthousands of dollars to the cost of the home. It may bedifficult to prevent tree root intrusion and other disrup-tions to these types of barriers. We have no data on theeffectiveness of these products in Tennessee.

Stainless steel mesh — Termi-Mesh™ (Termi-Mesh™ Australia Pty Ltd., Malaga, Australia) is a

marine grade stainless steel, wire mesh that is laiddown as a barrier during the preconstruction phaseto prevent termites from entering the structure.Pipes, posts, foundations and trenches are alsofitted. These are currently undergoing evaluation inthe United States.

Treated lumber — Chemically treated lumbershould be used for the foundation plate, mudsill andall lumber used as partition framing and furringstrips below ground. For maximum protection, thewood should be pressure treated with an approvedpreservative. Brushing, spraying or soaking thelumber with the chemical usually gives only limitedprotection.

Borates can be used as another barrier or layer ofprotection when applied to wood in contact with thefoundation or support piers. Several borate formula-tions containing disodium octaborate tetrahydrate(Tim-bor® or Bora-Care®) are available to treatunfinished wood. In a six-year USDA study, termitesdid not successfully tunnel over floor joists treatedwith Bora-Care®. Therefore, in addition to a chemicalsoil barrier, a 2-foot band of Bora-Care® or othersimilar products applied to wood where the termitesmay enter the structure (box sills, above piers, etc.)could deter termites from tunneling over these woodpieces into the structure.

Soil termiticides - Treatment of the soil aroundand under the foundation with one of theEPA(Environmental Protection Agency)-approvedsoil termiticides is one of the best methods of pre-venting termite attack. Soil treatment should be usedas a supplement to good construction, NOT as asubstitute for it. Treatment is needed in four areasduring construction:1. Treatment of the entire soil surface under any area to

be covered with concrete, including garage floors,entrance platforms and filled porches.

2. Treatment with additional amounts of chemical tothe soil beneath those areas that lie adjacent tofoundation walls, beneath interior walls, aroundsewer and utility openings and at other possiblepoints of entry.

3. Treatment of footings and backfill against outsidefoundation walls and inside walled area wherethere is a crawl space.

4. Treatment of empty spaces or voids in concreteblocks or similar materials.

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Insecticides - EPA requires a new termiticide toshow five years of field effectiveness before the agencywill register it as an insecticide for conventional soiltreatment. Currently registered termiticides can be groupedas “repellent” or “non-repellent” termiticides. Repellenttermiticides include bifenthrin, cypermethrin, fenvalerateand permethrin. The newer non-repellent insecticidesinclude imidacloprid and fipronil. Chlorpyrifos appears tohave an intermediate level of repellency. (Over the nextfour years, chlorpyrifos uses are being withdrawn from themarket.) Imidacloprid disrupts the social behavior (groom-ing) of termites and renders them more susceptible topathogens. Fipronil’s residual activity looks very promis-ing. Subterranean termites have not penetrated through soilor damaged wood at any of the USDA testing sites, as ofthis writing, when the soil was treated with labeled rates offipronil. The newer non-repellent termiticides havebecome popular because they are reported to kill largenumbers of termites as well as protect the structure. Expectto see other “non-repellent” termiticides enter the market.

The termiticides recommended are for use byindividuals/firms certified or licensed by the TennesseeDepartment of Agriculture to apply termiticide prod-ucts. The pest control professional must read and followspecific instructions on the container label of thepesticide concentrate. The label will also providedirections for use, list the personal protective equipmentrequired, as well as other information. If the consumerhas a questions pertaining to the use of a pesticide, he orshe may ask the pest control professional for a copy of

the label. Chemicals should not be applied to water-soaked or frozen soils, because the chemicals will notbe distributed appropriately and the desired controlmay not be obtained. Do not treat when it is raining.

Application Methods —Preconstruction.

See Table 2 for amount of diluted termiticide tobe applied to each area — horizontal areas, verticalareas and hollow voids.

Monolithic slab— After grading iscomplete and before the slab is poured, treat allvertical critical areas such as bath traps, plumbingand electrical entries, etc. A horizontal barrier shouldbe created by applying a termiticide to the entire areawhere the slab will be poured. The treated soil mustnot be disturbed between the time of application andlaying of a vapor barrier and concrete.

Also apply termiticide as the backfill is beingreplaced. If this is not possible, treat the outsidefoundation soil after all grading is completed bydigging a trench 6 inches wide and about 12 inches (aminimum of 6 inches) deep, but do not dig below thebottom of the footing. The trench should angle towardsthe foundation. Where the footing is less than 6 inchesbelow the top of the grade, the trench should extend tothe top of the footing. If the top of the footing is more

Table 2. The instructions below apply to diluted insecticides:

If you are applying to: Apply this amount:

Horizontal areas to be covered by concrete(slabs, attached entryways, garages, carports,porches and terraces)

1 gal./10 sq. ft or 1 gal./ 10 sq. ft. if soil is porous or fill iscoarse gravel

Vertical critical areas (around sewer, plumbingor utility openings).

4 gal./10 linear ft/foot of depth

Other vertical areas (backfill againstfoundations walls; support piers; insidefoundation walls if crawlspace)

4 gal./10 linear ft/foot of depth to footing

Voids in foundation blocks(If preconstruction, apply before capping.)

2 gal./10 linear ft.

Heavy, clay-type soils are often found in Tennessee and may not hold the above described amount of dilutedinsecticide. Most manufacturers have amended their labels so the volume may be reduced, but there must be acorresponding increase in the concentration of insecticide so the same amount of active ingredient is applied to thesame area of soil. The rates given above typically apply to the lowest concentration listed. Pest controlprofessionals must not apply pesticide at a lower or higher concentration than listed on the label.

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than 12 inches below the surface, the soil must betrenched or trenched and rodded to a minimum of 4feet, but not to exceed the footing. Professionals use arodding tool inserted into the trench at 6-12 inchintervals, as close to the foundation as practical(within a few inches), and inject the termiticide as therod is forced through the soil. When the soil isreplaced in the trench, it must also be treated.

Suspended (supported) and float-ing slabs including basement homes —Treat the soil in the bottom of the footing trenchesprior to pouring the footings. If the footing has beenpoured already, treat voids in the masonry elements ofthe foundation wall. Trench or trench and rod to treatsoil with a termiticide around the interior perimeterfoundation and all other interior walls within the slab(Figure 13). After grading is complete and before theslab is poured, treat all vertical critical areas such asbath traps, plumbing and electrical lines. A horizontalbarrier should be created by applying a termiticide tothe entire area where the slab will be poured. Thetreated soil must not be disturbed between the time ofapplication and laying of vapor barrier and concrete.Also apply termiticide as the backfill is being replacedagainst the outside foundation as described above inTreating the soil outside the foundation.

Crawl space — After the grading iscomplete, apply termiticide to the soil in the bottomof the footing trenches prior to pouring the footingfor the foundations wall, pillars, piers, chimneys, etc.If footing is already poured, then treat the voids inthe masonry foundation elements. Trench or trenchand rod the soil along the interior walls and outsidewalls of the foundation as well as other verticalcritical areas such as around pipes (Figure 14). SeeTreating the soil outside the foundation fortrenching instructions.

Control in ExistingStructures

Inspection — A thorough inspectionshould be conducted at least annually by a profes-sional to detect possible termite activity such asmudtubes, swarmers’ wings or live termites in anactive infestation. To inspect for termites, wood(especially the plates, header joists, ends of floor

joists and any hardwood flooring) near the foundationor soil is probed with a screwdriver or similar instru-ment. The pest control professional may also use aboroscope. Damaged wood will be soft, channeled,unsound and may possibly reveal the termite infesta-tion itself. Presence of earthen “shelter tubes” onfoundation walls and wood is also evidence of infesta-tion. Termites build the tubes from bits of soil, whichthey also use to close up breaks in the surface ofinfested wood. Professionals should also use a mois-ture meter to help detect the presence of termites.Termite activity will increase the moisture readingrelative to uninfested areas. Occasionally, moisture-damaged wood in roofs can support an aerial infesta-tion and no mud tubes may reach to the ground.Therefore, attic inspections can be very important too.If termite damage is found, do not be pressured intopurchasing pest control services without doing yourhomework because there are many treatment options.

Termite control — post construction—Subterranean termites typically nest in the soil, whichprovides the necessary source of moisture. They feedon cellulose, which is usually obtained from wood.The correct application of an appropriate insecticidecreates a barrier between the termites in the soil andthe wood in the house. Baiting options for controllingtermites are discussed following these directions fortermiticide use.

Slab-on-ground houses — The control ofinfestations occurring beneath concrete floor slabs onthe ground is difficult and sometimes hazardous. Thisis another reason it should generally not be done bythe homeowner. This is especially true where radiantheat is installed, because pipes are apt to be buried inthe concrete and may be damaged when drilling holesin the floor through which an insecticide is poured totreat the soil below.

When pipes are not present in the slab, holes 1/2inch in diameter usually are made in the slab. Holesare placed about 12 inches apart (no more than 24inches) and 4-6 inches from the wall (Figure 15A).The insecticide is applied with a pump and pressureless than 25 psi through a hose and rod or sub-slabinjector. Drilling holes in the slab may require pullingback carpet, moving furniture, etc., or drilling throughwood flooring. Intact monolithic slabs do not usuallyneed to be drilled near the exterior walls as describedabove. Treatment should also be made to breaks in

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Figure 13. Application of termiticide to a supported slab foundation.

FillerConc. slab

Poisoned soil1 gal./10sq. ft. overall

Masonry wall

Poisoned soil (trenched)4 gal./10 ft. minimumVoids treated

2 gal./10 lin. ft.

Poisoned soil (trenched)4 gal./10 ft. minimum

Ground level

Figure 14. Application of termiticide to a crawl space foundation.

Fin. grade

Soil grade

1 Poured concrete wall PlumbingMasonry pier

24 4 3 3

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the slab including vertical critical areas such asexpansion joints, bath traps, plumbing and electri-cal entries, and cracks often caused by settling.Construction elements such as sidewalks, patios,dirt/sand filled porches (Figure 15B), steps, andchimneys should also be drilled and termiticideinjected adjacent to the foundation wall. After thetreatment is finished, the holes are sealed with anon-cellulose plug.

Termiticide may also be applied as a foam toimprove coverage. Foam disperses the termiticidelaterally in the space between the slab and fill. Foamcan also be used in wall voids of stone foundations,concrete block, behind brick veneer (Figure 15C) andother places including above-ground feeding sites.

An alternative method to drilling through theslab to treat near inside expansion joints consists ofdrilling the holes through the outside foundation wallsso the chemical can be injected into the soil justbelow the slab and against the inner foundation wall.The holes are made about 6-12 inches apart andinjected just a few inches beyond the inner founda-tion. This horizontal rodding allows the interiorfoundation wall, the hollow block foundation andpossibly the brick veneer to be treated. Verticaldrilling usually provides better coverage than hori-zontal drilling.

Along the exterior foundation wall, treat asdescribed in Treating the soil outside the founda-tion. Drill and treat all voids of masonry elementsextending from the structure to the soil.

Crawl space houses — Treat along interior andexterior foundation walls or around supporting piersof houses with crawl spaces, taking care not to gobelow the top of the footing. If the land slopes or iffooting is deeper than the trench, less than 6 inches orat grade level, trench and treat as described in Treat-ing the soil outside the foundation. Treat aroundother vertical critical areas such as pipes. Drillattached construction elements such as sidewalks,patios, dirt/sand filled porches, chimneys, slabfoundations, etc. and inject termiticide adjacent to thefoundation wall. All voids of masonry elementsextending from the structure to the soil should bedrilled and treated.

Basement houses — A basement is a specialcase of a floating slab. See Slab-on-ground housesfor directions on drilling the slab near the innerfoundation wall, attached slabs (patios, sidewalks,dirt/sand filled porches, steps and chimneys) andother vertical critical areas (expansion joints, bath

traps, plumbing and electrical entries, and cracks oftencaused by settling). Drill and treat all voids of ma-sonry elements extending from the structure to thesoil. Termites may come from beneath the concretefloor in the basement. If so, remove any wood thatmay extend into the ground, treat the soil and thenseal cracks or holes with a dense cement mortar. Inhouses with full basements, it is necessary to treat thesoil along the exterior foundation to a greater depththan is required for other types of houses. The trenchis prepared in the same way, but termiticide is injectedthrough the rod down to the top of the footing to aid inproper distribution of the chemical to all parts of thewall. This is especially important when masonry mortarjoints are below grade and may be susceptible totermite attack. If the footing is deeper than 4 ft.,industry standards allow rodding to a minimum of 4 ft.

Wood can be treated after an infestation occursas a supplement to a soil treatment, but should not berelied upon for sole control. Infested wood can besprayed, brushed or injected into wood where termiteshave been detected. Small holes are drilled intosuspected areas and termiticide injected at low pres-sure, often with an aerosol system. Wood can also betreated with a foam formulation.

More detailed explanations of termite treat-ments can be found in the National Pest ControlAssociation’s (Dunn Loring, VA 22027) 1998publication of Pest Management Library: Subterra-nean Termites.

Termite baits use small amounts of insecticide toreduce populations of termites foraging in and aroundthe structure. Some baits may even eradicate entiretermite colonies. Termite baits include paper, card-board or other termite food, combined with a slow-acting substance lethal to termites. If the bait kills tooquickly, sick or dead termites may accumulate in thevicinity of the bait stations, increasing the chance ofavoidance by other termites in the area. Delayedaction also enhances transmission of the lethal agentto other termites, including those that never fed on thebait. Theoretically, entire colonies could be eliminatedin this manner, although total colony elimination maynot be necessary to afford structural protection. Acomprehensive baiting program then seeks to maintaina termite-free condition on the customer’s property.

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Figure 15. Drilling slabs in basements (A), porches (B)and brick veneer (C).

A. B.

C.

Monitoring, and rebaiting as needed, must continueafter termites are no longer found in the baits be-cause, in most cases, a traditional soil treatment wasnot applied to protect the structure. Regardless ofwhich bait is used, the customer must be prepared andwilling to accept the possibility of a lengthy baitingprocess and continued monitoring.

Some bait products are inserted below groundout in the yard, whereas others are installed aboveground level on the inside of the structure. Baits areapplied below ground by enticing termites to feed onwooden stakes, cardboard or some other cellulose-based material. The toxicant-laced bait can either beinstalled initially, or substituted after termites have

been detected in an untreated monitoringdevice. The more belowground baitsinstalled, the better the chances oflocating termites. Planning, patience andpersistence are requisites for success-fully using belowground termite baits.

Termite baits may also be installedaboveground in known areas of termiteactivity. Typically, the stations areinstalled directly in the path of activetermite tunnels after the mud tubes havebeen broken.

The Sentricon™ System.This method of termite baiting hasbeen the most extensively tested ofthose currently on the market. TheSentricon Colony Elimination Sys-tem™ was developed by DowElanco

(now Dow AgroSciences, Indianapolis, IN; 800-888-5511 or http://www.sentricon.com/) and issold only through authorized pest control firms.The RecruitII™ bait contains hexaflumuron, a slow-acting ingredient that disrupts the normal growthprocess in termites (i.e., termites die while attempt-ing to molt). Termite control with the SentriconSystem ™ involves a three-step process: (1) initialmonitoring to “pinpoint” termite activity, (2)delivery of the bait and (3) subsequent monitoringto provide on-going protection. Recruit AG™ is atermite bait for use as an aboveground deliverysystem for elimination of subterranean termitecolonies. Recruit AG™ can only be used in conjunc-tion with the Sentricon Colony Elimination Sys-tem™ and is not available as a separate program.

Firstline™. Another termite bait is theFirstLine™ Termite Bait Station, manufactured byFMC Corporation (Princeton, NJ, 800-321-1FMC orhttp://www.fmc-apgspec.com/firstlin.htm). Theproduct is intended for aboveground baiting ofactive termite tubes. The station includes a semi-transparent plastic housing (4x4x1inches) with openslots at the base. Contained within is corrugatedcardboard treated with a slow-acting ingredient(sulfluramid) lethal to termites. Firstline™ GT™

(“GT” stands for ground treatment) was originallyintroduced for belowground use. The latest versionis GTX™. Label directions emphasize placement ofbaits in areas where termite activity is known orsuspected, i.e., installation may not involve insertion

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of baits at fixed intervals around the entire perimeterof the building as is required with the Sentriconsystem. FMC suggests that homes be protected fromtermites using the six elements of the SystematicTermite ControlSM Program: (1) inspection, (2)moisture management, (3) food source management,(4) termiticide, (5) termiticide foam and (6) termitebaits. Additional research and field experience withthe product are needed to delineate effects againststructural infestations.

Terminate™ is a termite bait product sold tohomeowners over-the-counter in garden stores. Theactive ingredient is identical to the FirstLine™ prod-uct, but Terminate™ was developed completelyindependently of FMC and without FMC’s knowl-edge or approval. The formulation was not tested byuniversity researchers to determine how well itworked when applied according to label directions.On October 15, 1998 a complaint was filed in U.S.District Court in Baltimore, MD by nine attorneysgeneral, the Federal Trade Commssion and theDistrict of Columbia, alleging that the company’sclaims about the product’s use and effectiveness weredeceptive and lacked adequate substantiation. Thefollowing is an excerpt from The Federal TradeCommission Press Release of March 18, 1999 on anUnited Industries Settlement (http://www.ftc.gov/opa/1999/9903/termsetl.htm):

As part of the settlement, United Industries willnot make any claims about the effectiveness of

TERMINATE unless it has reliable scientificevidence to support those claims. The company alsowill disclose in any advertisements or promotionalmaterial that claim that TERMINATE kills termitesthat the product is “Not recommended as sole protec-tion against termites, and for active infestations, get aprofessional inspection.” ...In addition, any consumerdissatisfied with Terminate may seek a refund within15 months of the purchase. ...

Exterra™ Termite Interception and BaitingSystem™ is a new termite bait developed by Ensystex(888-EXTERRA or http://www.exteris.com/). Use ofExterra™ is a multi-step process. The first step is theplacement of stations in the ground around theperimeter of the structure. The next step is inspectionof the stations and baiting of active stations withLabyrinth™ (bait that contains the active ingredient).Reinspection of stations and replenishment of con-

sumed bait follows. When termite activity in thestation is eliminated, the station is refurbished and thecycle of inspection and baiting begins again. The toxicbait in Labyrinth™ is diflubenzuron, a chitin synthesisinhibitor that causes termites to die while attemptingto molt. The biggest advantage of Exterra™ is thatstations can be monitored or refilled with bait withoutdisturbing termites in the station.

This is the most common question fromhomeowners trying to decide which form of treatmentto purchase. The question is a difficult one, consider-ing the industry’s limited amount of experience withthe new bait products. Liquid barrier treatments havebeen the standard method for controlling subterraneantermites for decades. Performance failures and otherproblems have occurred with barrier treatments, butfor the most part, these treatments have affordedadequate termite protection. Although baiting clearlyhas potential advantages (see below), the approachdoes not yet have as long a track record as barriertreatments on which to base its performance. Otherfactors to consider in the purchasing decision include:

Has the structure already been treated (un-successfully) using conventional methods?

Some structures have construction features thatinterfere with conventional soil treatment methods,e.g., wells, cisterns, plenums, subslab heating ducts,drainage systems, inaccessible crawl spaces, stonefoundations, etc. Buildings with hard-to-treat con-struction or chronic re-treatment histories are logicalcandidates for termite baits. With baits, gaining accessfor treatment is seldom a problem since foragingtermites are as likely to encounter belowground baitstations around the foundation exterior as beneath thestructure.

Are you opposed to having your floors drilled,and furniture/stored items/carpeting moved?Baiting requires fewer disruptions than does conven-tional barrier treatment. Installation and subsequentmonitoring of bait stations generally does not evenrequire the technician to come indoors. Noise, drilldust and similar disruptions associated with conven-tional treatment are avoided.

Are you strongly opposed to the use of pesti-cides around your home? Chemically-concernedhomeowners may find the concept of baiting moreattractive. With baits, the total amount of pesticide

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applied is minute in comparison to the high number ofgallons needed to achieve a thorough and effectivesoil-barrier treatment. In respect to contamination ofwells, heat ducts, drainage systems, etc., baits are ofnegligible risk and can be used in the most sensitivetreatment situations.

How much are you willing to spend fortermite protection? Termite treatments are ratherexpensive. Along with the initial treatment fee,homeowners are advised to purchase a renewableservice agreement in case the termites return. Depend-ing upon the circumstances, a baiting program mayend up costing more than a conventional treatment —the reason being that baiting programs require mul-tiple visits to the property for ongoing monitoring ofbait stations. This is especially true in respect topurchase of the renewable service agreement.Whereas conventional treatments typically entail asingle annual follow-up inspection, baiting contractsmay require three or more visits per year, for as longas the agreement is in effect. (Thus the annual re-newal fee for baiting typically will be as much as twoto three times higher than for conventional treatment).Homeowners should consider both the initial treat-ment price and renewal fee in making their purchas-ing decision.

Assuming my home will be baited, should Ialso request a supplemental barrier treatment?The need for supplemental soil treatment depends onthe circumstances. Property owners with a serioustermite problem, or those involved in a real estatetransaction, may not want to wait two to six months(sometimes longer) for baits to suppress or eliminatethe infestation. With comprehensive baiting programssuch as Sentricon™ and Exterra™, liquid applications(when deemed necessary) are usually made as partialtreatments to infested areas, rather than to the entirestructure. Other bait products (e.g., FirstLine™) aremore suited for spot-treatment of active tunnels,feeding galleries and localized areas in the soil. Suchproducts are typically used in conjunction with moreextensive barrier treatments.

The “art” and “science” of termite baiting are inan evolutionary state. The use of products in theSentricon™, Exterra™ and FirstLine™ systems mayhave changed and more baits will have entered themarket place since this publication was written. Askfor a current pesticide label for a product before it is

installed so you can understand the baiting system.Many questions about baits are still without

answers. One thing we do know is that the productswill not perform by simply hammering a few baitsinto the ground and walking away. Success willrequire thoughtful installation and diligent monitoringby an experienced service technician, backed by aresponsible pest control firm.

Choosing aPest Control Company

One of the most important steps to obtainingcontrol of a termite infestation is procuring theservices of a trained and experienced pest controlprofessional. Use the following items as a guide inselecting professional help:• Ask for referrals from trusted acquaintances who

were satisfied with their termite treatment. Call atleast three of these pest control companies and askfor price quotes, the chemical to be used and howthe company plans to treat your house.

• Ask for copies of the inspection letter and map.Keep these records.

• Read the contract carefully. Different options areavailable. Some companies will offer to re-treat ifthere is a failure, while others may provide adamage repair clause. Read both sides of a contractto understand what you are getting.

• An annual renewal fee for inspections is usuallyoffered. It is usually a good idea to contract for thisservice.

• Study the bids, a description of the work to be doneand details of any guarantees and then make yourdecision.

• Be wary of prices that seem too low. Highly spe-cialized equipment and training is needed tocontrol termites and a low bid may mean lowquality.

• Call the Better Business Bureau to learn of com-plaints against a potential provider of services.

• In most cases, the materials to be used for termitecontrol are only available to a certified applicator.The certified applicator should posses a certifica-tion card and a charter number should be presenton a company’s truck to indicate the TennesseeDepartment of Agriculture has licensed the owner.

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Visit the Agricultural Extension Service Web site at:http://www.utextension.utk.edu/

PB1344-3M-4/01(Rev) E12-4615-00-032-01

Precautionary StatementTo protect people and the environment, pesticides should be used safely. This is everyone’s responsibil-

ity, especially the user. Read and follow label directions carefully before you buy, mix, apply, store or dispose ofa pesticide. According to laws regulating pesticides, they must be used only as directed by the label.

Disclaimer StatementPesticides recommended in this publication were registered for the prescribed uses when printed. Pesti-

cide registrations are continuously being reviewed. Should registration of a recommended pesticide be canceled,it would no longer be recommended by The University of Tennessee.

Use of trade or brand names in this publication is for clarity and information; it does not imply approvalof the product to the exclusion of others which may be of similar, suitable composition, nor does it guarantee orwarrant the standard of the product.

This publication was modified from the following sources:

Burgess, E. 1992. Pesticide Labels and Labeling. E&PP Note 300. The University of Tennessee AgriculturalExtension Service

Koehler, P. and T. Weissling. 1998.Termite Baits. http://extlab1.entnem.ufl.edu/PestAlert/gcb-0414.htm. Univer-sity of Florida.

Oi, F. and T. Shelton.1997. IPM tactics for subterranean termite control. Alabama Cooperative Extension System.ANR1022.

Potter, M.F. 1998. Do-It-Yourself Termite Baits. Kentucky Pest News August 3rd edition, The University ofKentucky Entomology Department.

Potter, M.F. 1997. Termite Baits: A guide for Homeowners, Extension Entomologist University of KentuckyCollege of Agriculture.

Potter, M.F. 1997. Termites. In Handbook of Pest Control, 8th edition, ed. dir. Stoy Hedges, Mallis Handbook andTechnical Training Company.

The authors extend their gratitude to Orkin Exterminating Co. and Johnson Pest Control for allowing us tophotograph their technicians during conventional termite treatments. A special thank you to Gary Dagnan for thedesign and layout of this publication.

The Agricultural Extension Service offers its programs to all eligible persons regardless of race,color, national origin, sex, age, disability, religion or veteran status and is an Equal Opportunity Employer.

COOPERATIVE EXTENSION WORK IN AGRICULTURE AND HOME ECONOMICS The University of Tennessee Institute of Agriculture, U.S. Department of Agriculture,

and county governments cooperating in furtherance of Acts of May 8 and June 30, 1914. Agricultural Extension Service

Charles L. Norman, Dean