Insect-Proofing During Building Construction
Total Page：16
File Type：pdf, Size：1020Kb
INSECT-PROOFING DURING BUILDING CONSTRUCTION W. EBELING * R. E. WAGNER - D. A. REIERSON TRUCTURAL AND HOUSEHOLD PEST mental evidence of efficiency of soil treat- foundation walls or piers. Specific in- S CONTROL in the United States re- ment have been the investigations of the structions for treatment for slab-on- quires annual expenditures of hundreds Southern Forest Experiment Station of ground, raised-foundation, and basement of millions of dollars and the services of the Forest Service, U. S. Department of construction may be obtained in publica- 27,000 licensed pest control operators. Agriculture. These investigations showed tions of the federal or state agricultural Preventive measures against structural that currently recommended dosages of experiment stations or among the tech- and household pests should be taken dur- certain chlorinated hydrocarbons formed nical releases of the National Pest Con- ing the construction of a building, be- a compIetely effective barrier against sub- trol Association. cause such measures are most effective terranean termites for a period of 18 and economical at that time. Preventive years in heavily infested forest soil in Prevention measures fall into two general categories, Mississippi, and may continue to be effec- Some househoId pests, including cock- depending on whether they are directed tive for many more years. The pest con- roaches, silverfish, odorous house ants, against (1) subterranean termites, which trol industry has successfully used soil plaster beetles (Lathrididae) , psocids, invade a building from colonies in the treatment for many years. and rat mites, spend all or a major part soil and which first attack in the sub- Currently recommended insecticides, of their time in hidden areas of a house structure; or (2) a number of other in- and concentrations include 0.5 per cent such as the attic, wall voids, soffit voids, sect species that spend either all or a aldrin, dieldrin, or heptachlor, or 1 per or in voids under cabinets or built-in considerable part of their life in the attic, cent chlordane. The dosage of dilute appliances. In larger apartment and com- wall voids, or in other enclosed spaces in emulsion recommended is 1 gallon per mercial buildings these pests often live various parts of the building. Construc- 10 sq ft as an overall treatment where also in suspended ceilings, hidden radi- tion procedures and other measures to slab and attached porches are to be ators, underfloor raceways for electrical prevent insect attack and damage differ poured, 4 gallons per 10 linear ft along and telephone wiring, elevator shafts, and considerably depending on which of the foundation walls, and 2 gallons per 10 in other hidden floor-to-floor and room-to- groups of pests they are directed against. linear ft in the voids of all unit masonry room passageways. Other pests such as Termites Gravel on which concrete slab is to be poured, and pipe and Soil treatment consists of applying forms, are sprayed with a dilute emulsions of insecticides to the long-lasting residual insecti- soil (see photo). The insecticides and cide in photo below. Pressur- dosages to be used are those recom- ized water-type fire extin- mended by federal, state, and industry guisher used for wall applica- agencies. The greatest sources of experi- tions of dusts for insect-proof- ing during construction. 4 CALIFORNIA AGRICULTURE, MAY, 1969 Insect proofing at the time of construction offers new challenge and opportunity the treatment of wall voids, soffit voids, to the building and pest control industries. It provides the opportunity for preven- and voids under cabinets and built-in ap- tion, which is generally less expensive and always more satisfactory than cure. pliances at the time of construction. Spe- cial equipment was designed to blow the Some insects such as house flies and mosquitoes are not amenable to control by dust into these voids. Dri-die can be this method-their control is primarily a community or regional problem. Some blown under built-in ranges and refrig- other insects such as ants, sowbugs, fleas and clover mites, may gain entry into erators as a protection against cock- buildings through areas where they don’t have to cross the inorganic powders roaches, silverfish, and other cryptobi- applied during construction. Nevertheless, insect proofing during construction pro- otic insects. Against cockroaches Dri-die vides the means by which a high degree of long-term control of certain important works mainly as a repellent, because most structural and household pests can be effected. of these insects will avoid contact with the dust. However, treated areas are thus eliminated as harborage and breeding drywood termites, carpenter ants, Argen- widely used by termite operators for the places for this important pest. tine and other ants, and wood wasps control of drywood termites. No other Boric acid (Siricidae), may crawl over the inner desiccant is known to have such high in- surfaces of these voids in search of nest- secticidal activity and such low bulk Recent work has shown the superiority ing sites or to reach the “living space” of density as Dri-die 67. The dust is blown of boric acid powder for cockroach pre- the building. When leaving their larval into attics, usually from the crawl hole, vention when applied at the time of con- tunnels in the studs, wood wasps enter at the rate of 1 lb per 1000 sq ft of attic struction. Boric acid has been the least and leave the wall voids through the wall space. It may be applied with an electric repellent to cockroaches of all powders plaster. Both types of pests may succumb blower or water-type fire extinguisher. tested. The insects will repeatedly enter to an insecticide applied uniformly over The dust is usually applied after a fumi- deposits of boric acid and, if the boric surfaces that are likely to become infested. gation, or after other treatment for dry- acid is thoroughly applied, they can be Insecticides can be most rapidly and wood termites to prevent further infesta- satisfactorily controlled. (See Cdifornia thoroughly applied as dust formulations. tion. The Dri-die 67 cannot destroy the Agriculture, Feb. 1969.) Like Dri-die, Also an insecticide deposited as a dust termites in their galleries in the wood- boric acid powder is inorganic and its rather than as a spray is less likely to be this must be done by other types of treat- insecticidal action will continue as long lost by penetration into the treated sub- ment such as fumigation-but it can pre- as it is left in place and remains dry. The strate (wood, Masonite, plaster, brick, vent the winged reproductives which application of boric acid is particularly etc.) and therefore it possesses longer leave the infested wood in the fall months, appropriate in areas of a building in residual efficacy. or those which enter the attic from the which cockroaches are expected to be the outside, from establishing new colonies principal pest. Inorganic dusts in the attic. Even though not all the ter- The application of dust into voids and Ideally an insecticide dust applied to mites are killed in their galleries by a enclosed places at the time of construc- areas in which it can remain indefinitely treatment, the proliferation of colonies tion can be done with a water-type fire should be inorganic, for such a dust, within the attic will be prevented. extinguisher that is now commercially since it cannot be lost by decomposition, The practice of protecting exposed available. The entire contents (3 gallons) may be able to indefinitely eliminate wood members of a structure from attack of the extinguisher can be blown out with structural voids as harborage and breed- by drywood termites by applying a film one pressurization with air to 100 p.s.i. ing places for cryptobiotic insects. With of Dri-die dust was extended to include This kind of blower generates air of this goal in mind a procedure was devel- oped for blowing an inorganic desiccant Ground-level frame duplexes at Ventura Town House were also insect-proofed at time of construc- dust into attics for prevention of drywood tion (see cover photo). termites, Incisitermes minor. Desiccant dusts kill insects by absorbing a portion of the thin protective layer of lipid that covers the entire body surface of an in- sect (with most insects this consists of a hard wax, averaging about 0.25 micron in thickness, but cockroaches are covered with a mobile grease about 0.G micron thick). When the lipid layer is removed, a lethal rate of water loss results. Dry- wood termites most commonly enter into houses via the attic. A thin film of desic- cating dust over the entire inside surface of an attic prevents thein from even at- tempting to attack the dusted wood, and in fact they die within a few hours. In 1958 a fluorinated silica aerogel which later became known as Dri-die 67, was found to be the most highly insecti- cidal of the desiccating dusts and is now CALIFORNIA AGRICULTURE, MAY, 1969 5 enough velocity and volume to dust attics tive areas for cockroaches. A layer of dust where cockroaches can be expected to be as well as wall or subcabinet voids. under and behind these appliances will a dominant problem, Dri-die should prob- When dusting wall voids that have no eliminate them as harborage and breed- ably be applied only in attics and wall insulation or fire blocks, one should inject ing places. voids, to keep cockroaches from living the dust upward from about 4 or 5 ft The seven-story concrete building (see and breeding in these areas and to pre- above the floor level through +&inch photo) contains a large kitchen, storage vent them from moving from room to holes made in the plaster lath with a small room, and dining room.