Circular [Apr. 1932]

GA _
AtJDO. Eo
C~o.42., OFFICE OF STATE ENTOMOLOGIST

ATLA TA, GEORGIA

M. S. YEOMANS

State Entomologist

rIR!'''ULAR NO. 42

APRIL, 1932

TERMITES IN BUILDINGS
By
TOM O'NEILL, Entomologist
A swarm of "flying ants", appearing in the house some warm day in early spring, is usually the first indication the housekeeper has that the house is infested and possibly being damaged by termites. Even then, the insects are often regarded as only a temporary nuisance, and are treated with fly spray and swept up, or are allowed to disperse naturally. No more thought is given the matter until the performance is repeated the following season.
The "flying ants" usually appear first in basements and thence work their way up into the house, although they often come out of cracks in concrete porches around outside doors. The life-history of the insect, given later, will explain this habit. The insects are black and ant-like, with clear narrow wings about twice as long as the body. The wings are readily detached, and after the insects have disappeared piles of cast wings may often be noticed around the places where the insects emerged.
These insects are termites and not ants, but because they are somewhat ant-like in appearance and because the white workers live in large colonies or nests in the ground or in wood, they are often called "white ants" and the winged forms "flying ants". Another common name for the species is "wood-lice".
There are several kinds of termites, but since the subterranean or underground kind is the only one that occurs commonly in Georgia, this discussion will be confined to that type. Termites feed on wood and cause an incalculable amount of damage by destroying the supports, timbers and flooring in residences, warehouses and other structures. Such damage is generally ascribed to "dry-rot" and regarded as unavoidable, both of which conclusions are erroneous. While timber rots are often present in the damp, unventilated places preferred by termites, the wood will usually be found to be honeycombed or eaten out to a mere shell by the grayish-white insects found within it. Wood affected by rot, although showing checks and cracks, is punky but solid, and does not show the hollowed out chambers, longitudinal gal-

leries, or tunnels of insects. And both termite and rot injury can be prevented.
Termites are not new insects, but man-made conditions have brought them into prominence as destructive pests. They have existed for ages in the soil of forests, burrowing through the earth in search of dead wood on which to feed. Twigs or branches lying on the ground are entered from a point when they are in contact with the soil, and the inside eaten out. When stumps or fallen logs are encountered they are attacked in a similar manner, large numbers of the insects moving to or being reared. in such favorable places.
Living plants are seldom attacked, the exceptions mainly being crops which are grown in newly-cleared land, where an abundance of chips, roots, etc., provide for termite propagation. When such food material has been consumed, the termites then turn their attention to the growing plants, and are sometimes troublesome for a year or two until the disturbance caused by frequent cultivation, or the failing supply of satisfactory food causes them to die out.
When buildings or other structures are erected on termite-infested soil, the insects readily transfer their attention to the wood in these if they can gain access to it. Unfortunately, modern methods of construction usually make this easy.
TERMITE DAMAGE INCREASING
Not counting the fact that persons now-a-days are better informed and recognize and report termite damage more often than formerly, it is believed that termite damage has increased during recent years. Some of the causes of this increase are:
CARELESS, CHEAP, HASTY CONSTRUCTION. This includes the leaving of stumps under buildings, the leaving of form boards around foundation concrete work, the leaving of temporary wooden supports under floors, the inclusion in dirt fills of scraps of lumber and the failure to destroy or dispose of scraps of lumber under and around the structure.
FAULTY CONSTRUCTION. Use of wooden supports which rest on the earth, sometimes having been placed before a concrete floor was laid and extending through the concrete. Cellar stairs sometimes the same.
Foundations too low so that floors are but a few inches off the ground. In some cases, particularly in added rooms, sills are laid directly on the ground or on cinders, or tarred paper.
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Lack of sufficient ventilation under buildings, particularly objectionable in connection with low foundations.
The most prevalent fault in modern home construction seems to be the use of concrete or tile porches filled beneath with dirt nearly or completely up to the level of the house sill. Such a fill allows the termites easy access to the timbers of the house and more infestations may be traced to this defect than to any other.
FURNACES, by heating basements, allow termites to remain active all the year. Moreover, a great many people close their basement ventilators in winter to conserve heat, and thus allow the basements to remain damp. Heat does not destroy moisture, for moisture cannot be destroyed-it can only be removed.
The clearing of land and the erection of building thereon cannot be regarded as a cause of recent termite increase since the process has been going on ever since this country was first settled. Such procedure, however, does change the role of the termite from that of an unimportant scavenger to a pest of great economic importance.
Lest the foregoing create the impression that termites are a menace only in newly cleared areas, it may be stated that the insects have adapted themselves to present conditions and may now be found practically anywhere in the soil, in cities, suburbs and country. The abundance of wood in or on the ground, whether from natural sources such as dead trees, fallen limbs or twigs, weed stalks or roots, etc., and from artificial sources such as building operations, fence posts and fire wood, provide ample food material for maintaining the insects in practically all localities. Infestations of economic importance may be anticipated anywhere, when structural defects are such as to invite attack.
HABITS OF TERMITES
At this point, a brief further account of the habits of termites will possibly better explain their depredations and assist in the understanding of the control measure given later.
Termite colonies, which may number from only a few insects to tens of thousands, are composed of individuals of several forms, principal among which are the reproductive forms, the workers and the soldiers, together with the young of all of these. Eggs/ are laid not only by the queen which founded the colony, but by other wingless females which develop later. The workers outnumber all other forms. They make tunnels in the soil, excavate galleries in wood, carry moisture when necessarY, care for
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the eggs and young, (although the young are active and capable of feeding themselves soon after hatching) and perform such other tasks as are necessary for the life of the colony. The oldiers, a form possessing elongated heads, are defen e units effective mainly through their ability to block entrance holes to the nest with their heads, presenting toward intruders a pair of long stout mandible.
Subterranean termites live underground where dampness prevail or in wood which is damp or which they moisten with water ecured from the soil. All members of the colony except the fully developed reproductive forms are white or light colored and so thin-skinned that expo ure to the outside air will cause their death, through drying, within a short while. Likewise, in colonies exi ting in wood above ground, cutting off their access to moisture will also insure the death of the colony. This is one of the principal methods employed in controlling infestations in buildings. Termite shun the light and when they encounter, above ground, some object too hard to be penetrated, theY construct over its surface shelter tubes or tunnels of earth and bits of wood, within which they travel.
In dark places under infested buildings it is not unu ual to find these earth shelter tubes winding up foundation walls from the earth to the timbers above. Much Ie s frequently, tubes hanging perpendicularly from timbers show where termite in the timbers, having been cut off from their supply of moisture, have attempted to reestablish a connection with the ground. Such tubes are rarely more than a foot or 18 inche long, and if the soil is not encountered within that di tance, the in ects apparently give up the attempt or die before completing it.
As already indicated, termite work through the soil earching for wood on which to feed. Wood resting on the surface of the soil is readily entered and the interior portion eaten out, although termites carefully refrain from extending their operations through to the outside. The remaining hell, often les than 1-8 inch in thicknes , gives no external evidence of infestation and suspected woodwork must be pounded or probed to determine its condition. Small hole, from which fine awdust is extruded, are not a sign of termite, but of another woodboring insect, the powder-po t beetle.
Termite , entering timbers of buildings at the oil line, may extend their galleries in the woodwork a far a the second floor, always dependent on being able to secure water somewhere with which to maintain moist conditions in their working. Excavation of the wood sub-
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stance usually follows the softer layers of the wood and sheets of the "grain" or harder part are left. Such damage to supports allows the settling of the buildings with the attendant cracked plaster, and ill fitting doors; floor may ~ag or the flooring be so hollowed out that heavy furniture penetrates it. Damage of this nature, being so apparent, is repaired long before complete collapse becomes possible, but if conditions which allow infestation are not corrected, there ensues a cycle of never-ending need for repair.
While termites show a preference for the softer parts of a piece of wood, sections of dense heartwood are often invaded. There is also a preference for certain varieties of wood, but no variety of wood commonly used in this country, unless chemically treated, is immune to attack. Products made of wood, including fiber board and paper, are likewise subject to attack.
The question is often asked as to the amount of time it takes a termite colony to cause appreciable damage. There are so many factors involved that no definite answ'er can be given. The size of the colony concerned is a most important factor, as is the accessibility of the wood and the temperature. It should suffice to say that some particularly susceptible parts of structures have needed replacement within six months and that damage has occurred in buildings not over two years old.
In the spring, and occasionally at other time, large numbers of winged males and females are produced, and these, the "flying ants" swarm out of some convenient opening in the nest. Their bodies are black and much harder than any of the underground forms so that these individuals can live in the drier outside air. ew colonies are started by a pair of the winged insects which have found a favorable place to lay eggs, and such colony grows slowly for several years. It is believed that very few new colonies are succe sfully established, as many of the swarming insects become the prey of natural enemies after leaving the shelter of the home nest. Not many of them succeed in finding sites for new nests that include the necessary features of food, moisture and protection against their enemies. New infestations are generally due to the extension of some older colony in the neighborhood.
Swarms of "flying ants" then are not considered as dangerous in themselves but such swarms do indicate the presence of a strong colony which should be located and treated immediately. Likewise, the finding of workers in woodwork which is being repaired or replaced calls for investigation and steps which will prevent the recurrence of the trouble.
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CONTROL OF TERMITES
Termite control, as a rule, is neither easy nor cheap, but is easier and cheaper than constant repair.
The basic principle of control is the insulation of woodwork from the ground and, therefore, from the termites. This practice may be supplemented by the use of chemicals.
o two infestations are exactly alike, and for that reason no set of recommendations can be given that would be effective in all cases and still not be excessive and wasteful in many. Each case must be studied, with the habits of the insects and the control principles in mind, and then methods of treatment employed which seem to best fit the conditions as found.
Whether the infestation is only suspected, or has been definitely indicated by the appearance of "flying ants" or the finding of other forms, the first step is a thorough inspection under the building to locate the colony. For this work, a hammer, screwdriver and flashlight or extension cord are suggested. The actual time of emer.gence of a swarm of "flying ants" may not oCCUPY more than 15 or 30 minutes, but is often helpful in locating the nest. Lacking this feature, the basement should be carefully examined for wood in contact with the ground, for earth shelter tubes over walls, and for damaged timbers, remembering that woodwork will not show external evidence of infestation but must be thumped or sounded for interior damage.
AT PRESENT THERE IS NO TREATMENT K OWN TO BE PERMA E TLY EFFECTIVE IN PREVE TING TERMITE DAMAGE TO THE WOOD IN BUILDINGS EXCEPT CONSTRUCTION OR RECO STRUCTIO WHICH WILL EFFECTIVELY INSULATE THE WOODWORK FROM THE GROU D. Chemical treatment should be considered only as a supplementary treatment following the reconstruction. Where reconstruction is impractical, proper chemical treatment, which should give protection for several years, is recommended. Spraying or brushing an insecticide on timbers in place is not an effective treatment, nor is fumigation as ordinarily practiced, since practically no penetration of the wood is secured by these methods. With the above in mind, suggestions on treating some of the various types of infestations are given.
Many infestations will be found to be confined to scraps of boards, firewood, or old lumber lying on the ground, or stumps or other wood in the ground, with no infestation of the house timbers. The removal of this mat-
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ter generally takes care of such an fnfestation. The ground under the building should be raked clean and the refuse burned. Firewood should not be allowed to remain on the ground or floor very long at a time, but should be elevated on some solid support such as masonry, concrete or iron, where it will keep dry. Even here, it should not be kept too long. Old lumber is better stored in a rack suspended from the timbers above. Stumps should be removed, but this is sometimes impractical by reason of their being deeply buried by fills or covered with a concrete floor. In such cases they can be allowed to remain, bearing in mind the fact that they constitute a permanent menace, and that when finally consumed, the termites that they have harbored will make determined efforts to invade the woodwork of the house before dying out or being forced to move.
Next in degree of importance are probably the infestations originating .in wooden supports, either temporary 01' supposedly permanent, cellar stairs, partition walls, window frames and other similar structures which extend from the ground or near the ground to the timbers above and afford ideal means of access to these timbers. Such supports should be removed, and those which are necessary replaced with rna onry, concrete or iron, or if wood be usee!, it should be set on an 18 inch base of such material. Board or fiber partition walls should likewise be set up on some base, and metal window frames should be substituted for wooden ones which come close to the ground line, either inside or out.
The infestation in the timbers or flooring above these "leads" will not, as a rule, require further treatment. When the insects are cut off from their supply of soil moisture they will dry up and die. They may attempt to span the intruded insulating material with earth shelter tubes, both from above and below, and these should be swept down as often as they appear until the builders are discouraged. An application of creosote here is often effective as a repellant.
Another manner in which termites gain access to woodwork, a type found most often in dark, damp places under buildings, and particularly when the foundation walls are low, is by earth shelter tubes built over the foundation wall. Treatment of such a case should include providing additional ventilation until the Government recommendation of 2 sq ft of ventilator opening per each 20 lineal feet of wall is attained. It should be noted that ventilation alone is not sufficient, but is helpful. The shelter tubes should be kept down, and the ground along the wall spaded or broken up and saturated to some depth with one of the insecticides described later. The treat-
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ment of all the soil under a building is impractical and is not recommended.
Treatment of infestations in sills lying next to concrete or tile porches present the greatest difficulty. The dirt fill under such porches allows the termites to readily enter such timbers, while the repair man is faced with a difficult and costly job in gaining access to them.
One plan is to remove the sills from the inside and replace them with chemically-treated sills which are immune to attack. Where the floor joists run parallel to the sill, this work can usually be done at from 50c to $1.00 per lineal foot, but joists heading into the sill must be cut off and later patched, and such work may cost four times as much.
Hardly so satisfactory is the method of opening up the concrete porch floor along the sill on the outside and applying a rich concrete mixture which will effectually seal the wood, at all points, from the earth of the fill. Perfect contact, with no cracks, between the concrete and the sill and upper part of the foundation wall, must be secured. It is possible that a concrete form which would hold liquid asphaltum againt the face of the foundation wall and the sill would be more satisfactory.
Treatment of the infested sills and the earth of the fill, as could be practiced by the householder, would probably be of only temporary value. Treatment by one of the first class termite-exterminating companies who are equipped with the necessary machinery would be more satisfactory. Poisoning the ground all around an infested sill might be satisfactory, but in the absence of definite information on this point, it cannot now be recommended.
Concrete or brick work used for protection against termites must be of good quality. Termites are naturally fitted for digging their way through hard ground, and they have little difficulty in penetrating crumbly mortar or concrete. Sometimes they work their way up to the woodwork through poor foundation walls, cracks in walls or along the cavities of hollow tile. Treatment of such cases requires the filling of the cracks with cement or asphalt and the capping of the wall with a layer of impervious concrete. It is not necessary to jack up the house to do this-a few bricks at a time can be removed from the top tier and the concrete placed.
CHEMICALS FOR TERMITE CONTROL
CREOSOTE for termite control is useful principally for impregnating wood. Wood properly treated at a creosote plant seems to be permanently immune to termite damage or rot, and this wood may be used in locations where such protection is necessary. Painting creosote on
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timbers is not effective, although a degree of immunity that may last several years can be secured by applying five heavy coats, with proper drying intervals, to every surface of the timber.
Creosote is al 0 used as a repellant on walls over which termites are building shelter tubes, and i frequently helpful but not alway entirely effective for this purpose. It is also used, diluted with 3 part of kerosene, for treating the oil and is of some value in this connection, but not permanently so. The odors from small quantities of creosote used about a building are not objectionable, but from large quantities are decidedly unpleasant and may remain so for a con iderable period.
KEROSENE may be used for soil treatment. It i also fairly effective in infe ted timbers if forced, with an oil gun or large syringe, into small holes bored to connect with the termite chambers within. The fire risk of using kerosene must be remembered and this treatment u ed only under well ventilated buildings and at a time when the furnace, water heater or pilot light are not in use.
ORTHODICHLOROBE ZI rE i a liquid which gives off a heavy ga deadly to in ects, but not particularly injurious to man, although heavy concentrations of the gas will cause orne smarting of the eyes and the liquid spilled on the skin also causes irritation. It peneh'ates wood better than any other insecticide in common' use, although it cannot be counted on to kill termite inside of woodwork unle s it be injected into a boring which intersects the termite gallerie . It evaporates within a hort time and treated woodwork is subject to reinfestation. A spray of orthodichlorobenzine in a confined space is considired inflammable and explosive in the presence of flame or parks. This material is useful mainly as a ground fumigant where stump cannot be taken out or where strong colonie exist in the earth along foundation wall or support and per i t in building helter tube back up to timber that have been infe ted.
Orthodichlorobenzine i understood to be the ba e or carrying agent of a very ati factory termiticide originated and used by one of the larger exterminating companies, other toxic substance in the mixture which are depo ited on evaporation giving more permanence to the treatment.
Orthodichlorobenzine i not stocked in this locality and supplies can only be secured by ordering through one of the local drug or chemical upply house. The cost in large lots is approximately 75c per gallon - small amounts might be expected to cost in the neighborhood of $1.00 per gallon.
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PARADICHLOROBENZI E, sometimes called by a trade name "Paracide" is a crystal obtained from orthodichlorobenzine and has similar insecticidal properties. It evaporates slowly giving off gas that sinks down through the soil. Tons of this mate-rial are used in this State every year to fumigate the soil around peach trees for borers in the roots and more recently it has been found useful for fumigating furniture, clothing, etc., for moths. It is available from drug stores and seed stores at 50c to 60c per lb., larger quantities from chemical supply houses may be obtained at 35c per lb., while in peach sections an agricultural grade should be obtainable at 20c or less.
Paradichlorobenzine may be used for timber or ground fumigation the same as orthodichlorobenzine, and if desired in liquid form may be dissolved-2 lbs. in one gallon of kerosene or mineral spirits.
SODIUM ARSENITE in a 107< solution, has long been recommended for poisoning the soil along the inside of foundation walls where strong colonies of termites persist. Recently a 5 % solution prepared by dissolving 1 lb. of the chemical in 2% gallons of water, has been found to be about as satisfactory. Some difficulty has been experienced in securing sodium arsenite locally since only the expensive pure grade is stocked by drug companie . .Some tree-killing preparations, obtainable from seed stores, contain 35 to 40?( sodium arsenite and these may be used diluted with about 7 or 8 parts of water. Sodium arsenite is a violent poison to animals and plants and should not be used outside the building where it may reach plant roots. Under buildings, treated ground should be covered with fresh earth.
COPPER SULPHATE (Bluestone) and ZI C CHLORIDE have been used extensively for a number of years to impregnate or surface-treat wood for the prevention of rot. Both are water soluble and will leach out of wood which is repeatedly wetted. These substances are known to be poisonous to insects under certain conditions, and while they have not been thoroughly tested against termites, it is believed that either one will be found satisfactory for soil treatment. They are readily obtainable and cheap enough to be used in generous quantities. The recommended solution (10 ) is obtained by dissolving 4 lbs. of the chosen chemical in 5 gallons of water.
BORAX at half the above strength has also been recommended.
TERMITE EXTERMINATING COMPANIES
In recent years a number of commercial termite ex-
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terminating organizations have eeen formed. Some of these, through highly exaggerated sales talk and ineffectual or injurious methods of treatment, have robbed home owners of thousands of dollars, and caused the Federal Government to issue a warning against patronizing exterminating companies that were not known to be thoroughly reliable.
If the building owner is not willing or able to carefully supervise the application of the control measures outlined in this paper, or if the reconstruction necessary for termite-proofing cannot be undertaken, treatment by one of the better companies may be expected to give relief, although the permanence of such treatment has not been established by observations extending over a necessary number of years. This treatment should embrace the removal of stumps, litter and vulnerable woodwork where possible, and the providing of adequate ventilation, followed by chemical treatment of infested woodwork and foundations, and of the soil adjacent to foundations near infestations and under filled porches or terraces. This Office has not been convinced that the treatment of the entire under part of a building is always, or even usually, necessary. Many infestations are confined to comparatively small units of the structure, and it is believed that intensive "spot treatment" of these points and of a safety factor zone around them would be equally effective, and much more economical.
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