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Application of integrated pest management to library, archival, and collection pest problems
Surveying the pest pressures on the structure
and collections
Initiating an integrated pest management program
Fireproof safes and filing cabinets
Surveying the pest pressures on the structure and collections
Inspections for and evaluation of possible insect infestations and other visible pests in library and archival storage areas and collections have become more important in recent years as Integrated Pest Management (IPM) has moved to the forefront. This approach, with its movement away from purely chemical control measures, makes the inspection a cost-effective method within an integrated program.
The inspection of a facility or incoming collections for insect infestations or potential infestations should be routinely scheduled as a part of the total IPM program. Members of the Pest Control Committee must maintain vigilance in looking for insects, insect harborages, improper storage, mold, and other situations conducive to insect survival and reproduction. Minimal training will qualify personnel to perform these inspections. These individuals must be familiar with pests of libraries and collections, their habits, and the dangers posed to the collections. Recognition of such threats can then be brought to the attention of the committee for appropriate action.
Preplanning
Inspection personnel should be completely familiar with the layout of the facility. Floor plans are helpful for conducting inspections so that no areas of the structure are omitted from the inspection. The inspector must insure that he or she has keys for every closet and storage room or area of the structure. Pest problems often begin in areas not frequented by library personnel.
Proper equipment
Copies of floor plans should be utilized for taking notes as the inspection proceeds. Pencil should be used for note taking. A flashlight with fresh batteries that throws a strong spot or beam of concentrated light is essential. A small screwdriver is helpful for opening access panels and digging into cracks and crevices. Small screw-cap viles filled with alcohol may be used for collecting specimens.
The inspection
The inspection of the facility should begin on the exterior. Careful attention should be placed on locating insect and rodent harborages as well as those areas that act as highways into the building for vermin. Doors, windows, freight docks, garbage receptacles, screening, lighting, discarded debris, and structural integrity should be noted in the inspection.
Inspection of the interior should follow a logical flow from the time materials enter the building until they are stored or displayed. Equipment, light fixtures, shelving, cabinetry, overhead ledges, cracks and crevices, fire hoses, air filters, window ledges, wall-floor and wall-wall junctions, floor drains, corners, closets, mechanical rooms, and elevator shafts should be inspected. During the interior inspection rodent traps and glueboards can be updated and replenished. At the same time vending machine areas, garbage disposal and trash containers, eating facilities and kitchens, and food storage areas may also be inspected.
Reporting
The inspector should give a verbal report at the conclusion of the inspection and follow this with a short written report of findings and recommendations. Copies of this report should be given to maintenance directors, collection curators, and the food-service department to insure that recommendations are carried out. The Pest Control Committee will then oversee the implementation of the recommendations. These inspections and reports should be carried out at least every 6 months, or more frequently as pest pressures dictate.
Initiating an integrated pest management program
Not all facilities will have the same kinds of pest pressures on the structure and collections. To detail IPM prevention and control procedures more specifically, many will be itemized for specific pest problems as they may be encountered.
Silverfish. - Control and prevention of silverfish damage to library materials can be effected in a variety of ways:
1. Thorough vacuuming of the perimeters of rooms where silverfish like to hide beneath the toe moldings and baseboards during the daytime.
2. Use of insect sticky traps or glueboards in areas where silverfish seem to be a problem. Each night, when silverfish are active, they will be trapped on the glueboards.
3. Use of silica gel in a finely powdered form in the void space beneath the bottom shelf or drawer of storage cabinets. A 1/4-inch drill may have to be used to gain access to the voids beneath the cabinets. Silica gel is a desiccant and kills silverfish by drying them out. If silica gel powder (sometimes in combination with Pyrethrum insecticide) is placed beneath the cabinets, silverfish can't crawl up into the cabinet without encountering it, thus being repelled or killed.
4. Use of insecticide resin strips in enclosed spaces, particularly in manuscript, rare book, and print collections. Insecticide resin strips contain the insecticide Vapona (DDVP). This material volatilizes from the resin strip and fills a confined space with molecules of insecticide. It is a mild fumigant and in time will kill all stages of insects within the enclosed space. The normal rate of application is one strip per thousand cubic feet of space. This type of chemical application is for enclosed spaces only, such as cabinets, vaults, and small storage rooms, and is not designed to be used in open, public spaces or where ventilation would carry the fumes out of the space.
5. Application of residual, liquid insecticidal sprays to perimeters of rooms and at the base of all stack shelving areas, paying particular attention to the crevice where the floor meets the wall and baseboards.
6. Crack and crevice injection of small spot applications of liquid insecticides to the backs of cabinets where they are attached to walls.
7. The control and elimination or moisture such as leaky plumbing, around laundry areas, in bathrooms, and workrooms where a silverfish population can thrive because of the high moisture situation.
8. Reduction of potential sites of harborage by the use of caulking compounds and patching plasters.
Bookworms. - Control of bookworms in a library can be effected with a combination of approaches. An IPM approach would be:
1. Screen all entries from the exterior to prevent beetles from flying into the building.
2. Do not allow dried flower arrangements in the library. They often import eggs and larvae into the library. The larvae will consume the dried vegetable matter of the arrangement as well as the glue that generally holds the flower arrangement together.
3. Do not allow spices or other leafy vegetable matter to be stored in the library. Cigarette beetles are particularly fond of red spices, such as cayenne, paprika, and chili powder.
4. Do not encourage the storage or display of botanical collections in the library. If a collection is to be stored or exhibited within a library, it should be disinfested by heating to 130° F for 3 hours, to kill all stages of cigarette beetles in the sheaves of the specimens. After treatment stored collections should be housed in cabinets with Vapona resin strips to prevent possible reinfestations. Botanical specimens should be displayed in plexiglas enclosures to keep insects out.
5. To disinfest an entire structure of insects, heat the space with commercial gas burners. This approach has been successful in the past and is being used today by large cereal grain processors. All insect stages can be killed if the heat is distributed throughout the building with electric fans and a temperature of 140° F (60° to 63° C) is maintained for 6 hours. Loosen the books and materials to allow the air to circulate around them. This technique not only controls cigarette beetles in books, but all stages of insects in the entire structure (Cressman 1935).
6. Use plants that are preferred by gravid female cigarette beetles to control infestations. Whole leaf tobacco plants, for example, can be placed in strategic locations in an herbarium to act as bug traps. As the plants become infested with eggs and larvae, they can be removed and burned before the larvae have a chance to pupate and emerge as adult beetles (Merrill 1948).
7. If a localized, limited infestation is found in a library, isolate the infested books and subject them to a heat treatment. By placing the books in a standard oven at the lowest temperature possible (130° F for 3 hours) and placing wet newspaper or a pan of water in the bottom of the oven to maintain humidity inside the oven chamber, all stages of this insect, and in fact any insect, will be killed. This technique is commonly used in herbarium collections in various parts of the world. It is much easier to kill all stages of insects with heat than it is by freezing. If a source of humidity is supplied in the chamber, the books should not dry out during treatment. Only active infestations should be treated in this manner. Dark exit holes that have no powder associated with them indicate that the infestation has long since died out and does not require treatment.
8. If a library has an active bindery, sometimes it is possible to mix a pesticide with the glue as the damaged books are bound. In some parts of the world, the insecticide dieldrin is used for this purpose. A cigarette beetle larva consuming some of the glue would then be killed before it has a chance to develop and emerge as an adult beetle.
9. Eliminate pigeons' nests from the building. In one instance, drugstore beetles were emerging from pigeon nest debris and gaining access to a library through loose-fitting windows. The larvae of the beetles were feeding on undigested grain and other food products found in the manure layers of the pigeon nests.
10. Use fans to keep air circulating in the stacks and to keep the books dried out as an aid in controlling infestations. Attempt to keep moisture levels between 50 and 60 percent relative humidity at all times.
11. Inspect the stacks regularly with a flashlight to pinpoint areas of infestation by locating the piles of fine powder drifting from the books onto the shelving.
Cockroaches. - Integrated Pest Management approaches to the control of the large species of cockroaches include:
1. Installation of a gravel 4-foot barrier around the perimeter of the library to prevent ingress from outdoors.
2. Elimination of all vines and ivy from the building.
3. Installation of proper screening for all windows and doors.
4. Installation of exterior lights so that they will shine on the building from a distance rather than being fastened to the building and attracting insects during the night to the exterior walls of the building.
5. Removal of all debris, leaves, and twigs around the exterior of the library as well as cleaning out debris from gutters on the roof of the building.
6. Elimination of cockroach harborages and entries by caulking and sealing.
7. Installation of sticky glueboards which will trap insects on their nightly forays around the library. These insect traps can be installed in false ceilings, basements, elevator shaftways, and closets to intercept insects as they travel looking for food.
8. Use of insect baits, such as 2% Baygon Cockroach Bait, applied sparingly to quiet zones of the interior of the library. This bait, which looks like sawdust, is bran mixed with molasses and contains 2% Baygon. It is a favorite of large cockroaches and will easily bring populations into control. Whenever insect infestations are found, a common attempt at their control is by insecticidal treatments with an aerosol or fog. Insecticidal fogs or aerosols should never be used in any collection. Such formulations are oil-based. During application small droplets of the oil-insecticide mixture are dispensed into the air and will eventually settle on the entire collection. This kind of treatment irreversibly damages collections.
9. Perimeter fan spraying with residual insecticides, paying particular attention to those areas adjacent to pipe chases, elevator shafts, storage areas, and mechanical rooms. In the case of the American and Australian cockroaches, perimeter, exterior power-spraying of the walls and overhangs may be required, particularly in tropical zones.
10. Installation of thresholds and rubber flaps on exterior doors to prevent ingress by cockroaches from the exterior, particularly at night.
11. Use of copper wool in holes and openings leading from drainage and sewer systems to prevent cockroach ingress.
12. Use of fiberglass insect screening for basement and first floor level floor drains to prevent cockroaches from entering the building via the sewer system.
Psocids or Booklice. - Control of booklice is difficult. Several approaches must be considered.
1. In enclosed spaces a Vapona resin strip may be used to control psocids.
2. Lower the moisture in materials and in the room to prevent mold growth. The use of fans and climatic controls to keep the relative humidity within a range of 50 to 60 percent and temperature from 68° to 72° F will aid in reducing psocid populations.
3. For archival materials in "dead storage" place the material in a large polyethylene plastic bag with several cups of dried, powdered silica gel wrapped in muslin or cheese cloth. Moisture within the bag will be lowered to the point where mold will not grow and psocids will be eliminated.
4. Use paradichlorobenzene (PDB) as a fumigant to control book lice in heavily infested, moldy books. A very tightly confined space must be used, such as a weather stripped cabinet or closet or a heavy-duty polyethylene bag, and sufficient quantities of PDB crystals to obtain air concentrations that will effectively kill the insects. A rate of one pound of crystals per one hundred cubic feet of space for a period of at least 2 weeks is the minimum necessary for complete kill. Paradichlorobenzene used in this manner will also kill surface mold and spores on the materials. After fumigation the materials should be aired thoroughly.
Carpet Beetles and Clothes Moths. - Control of carpet beetles and clothes moths is not difficult provided the staff is involved in the IPM program. Such measures are:
1. Thorough vacuuming on a regular basis of all library areas paying particular attention to the edges of the room where adults find dead insects on which to deposit their eggs. Biannual inspection and vacuuming of false ceilings, attics, closets, maintenance areas, mechanical rooms, and elevator shaft pits are necessary to eliminate reservoirs of food sources and carpet beetle larvae.
2. Placement of sticky traps to intercept insects as they crawl into the library helps to keep carcasses of insects at a minimum. Keep in mind, however, that carpet beetles can fly into a sticky trap, lay eggs on a dead insect, and fly out of the trap without being trapped themselves. The larvae can proceed to devour the carcass of the insect on the sticky trap, pupate, emerge as an adult beetle, and fly out of the trap without being mired in the glue of the trap. This situation necessitates the removal of traps, with an accumulation of insects, on a regular basis and replacement with a fresh trap.
3. Screening of all windows and doors to prevent ingress of adult beetles from the exterior of the building. Plantings of shrubbery around the building should not include plants whose flowers are white or blue and whose flowers contain high amounts of pollen. Crepe Myrtle and Spiraea are very attractive to adult carpet beetles, where they feed on pollen.
4. Elimination of all birds' nests on and around the building. Carpet beetles become entrenched in such nests, where they feed on dead birds, feathers, and other debris.
5. Elimination of rodents and rodent nests for the same reasons given in number 4.
6. Use of residual sprays may help to some extent for carpet beetle control, but are usually of little value, particularly in warm, humid climates.
7. Use of Vapona resin strips in vaults, closets, and enclosed storage spaces to eliminate all stages of carpet beetles within these spaces.
8. Use of polyethylene bags to totally enclose susceptible materials and keep fabric pests from attacking valuable items. As long as the items do not contain high amounts of moisture when placed in the bag, the threat of mold on the interior of the bag is minimal.
Subterranean Termites. - As discussed in an earlier section, the subterranean termite colony lives in the ground, and workers make their way up into the structure to feed on cellulosic materials. The key to subterranean termite control is to make a structure less conducive to their attack by physical alteration and to establish chemical barriers in the soil through which they cannot penetrate. Chemical soil poisoning as a means of subterranean termite control should be carried out by a professional firm. Physical alterations may include:
1. Elimination of all wood-ground contacts. All wooden elements including posts, stairwells, exterior ornamentation, wooden skirting, interior support posts, grade stakes, and form boards should either be removed or set on concrete bases.
2. Installation of proper guttering and grading to carry water away from the building, making it less conducive to termite invasion.
3. Insure that wood siding is at least 6 inches from the ground.
4. Insure that earthen crawl spaces are no closer to floor joists than 18 inches.
5. Removal of all debris from crawl spaces including stumps, tree roots, scrap wood, form boards, wood chips, and paper materials.
6. Insure that cellar hatchways are constructed of solid concrete, concrete blocks, or metal instead of wood.
7. Insure that frames of cellar windows be made either of metal or pressure-treated wood.
8. Insure that vent and foundation opening frames be constructed of metal or pressure-treated wood.
9. Installation of metal permanent termite shields on tops of foundations before wooden elements are secured to them.
10. Insure that all areas where pipes penetrate a slab on grade are totally encased in concrete.
Drywood Termites. - Making a building as tight as possible will help reduce infestations of drywood termites on the interior. The following actions may be helpful in preventing drywood termite attack:
1. Maintain proper screening of all windows and doors.
2. Insure that foundation vents and windows are made of materials not conducive to drywood termite attack.
3. Inspect attic vents for proper screening.
4. Insure that the roof line where the exterior wall meets the roof is tight to prevent drywood termite ingress.
5. Provide proper lighting on the exterior as discussed in a previous section.
Mice. - Mouse control in a library is important and should be dealt with in the following ways:
1. Seal the building on the exterior as tightly as possible with copper wool and caulking compounds.
2. Never use a toxic baiting program for mice on the interior of a library. The mice will die in the walls, floors, and ceilings and provide food for carpet beetles.
3. Use mechanical control techniques. Snap traps baited with cotton balls smeared with peanut butter can be used to trap mice. Multiple-catch live traps are available on the market, such as the "Ketch-all" trap. These are capable of catching more than one mouse at a time without the use of bait, relying on the innate curiosity of the mouse. Glueboards can also be used to trap mice. Soon after they are trapped they will die, and the glueboard can then be discarded.
4. Inspect the building thoroughly with a flashlight on a periodic basis to identify those areas where mice are present. The presence of droppings is a clear indication that control measures should be undertaken in the exact spot. Two or three weeks after a control program has been instituted, remove all droppings so the progress of the trapping program can be determined.
5. In temperate regions institute trapping programs in late summer and early fall so they will be in place when the mice naturally tend to invade structures.
Rats. - Rat control is aimed primarily at the exterior of the building and may include:
1. Maintaining adequate rat bait stations on the exterior perimeter of the building.
2. Inspecting the grounds, shrubbery, and ground covers for evidence of rodent activity, such as rat burrows, runways, and droppings. Make bait placements directly into the rodent burrows.
3. Clearing debris, piles of lumber, old equipment, and other harborage sites away from the building.
4. Installing and maintaining a gravel 4-foot barrier around the perimeter of the library to prevent ingress from outdoors.
Molds and Mildew. - The following actions will be found useful in correcting mold and mildew problems in libraries:
1. An air-handling system should be installed that will drop the humidity from the air and then reheat it to desired levels. This system should be designed to handle incoming outside air as well as recirculated air. Such systems must be carefully thought out and sized to accept incoming loads with humidity levels of the exterior air as well as the amount of moisture contained in the interior air. The aim is to maintain an interior environment in the library of from 50 to 60 percent relative humidity and 68° to 72° F at all times.
2. If such air handling systems are not available or cannot be installed, fans can be used to keep the air moving, particularly near outside walls and close to floor levels, in an attempt to lower moisture content of library materials and to eliminate pockets of high humidity.
3. Waterproofing basements and walls below grade on the exterior to prevent moisture from wicking through the walls and into the interior will aid in keeping humidity levels down on the interior of the building.
4. Earthen floors in basements and sub-basements should be sealed with concrete to prevent the wicking of moisture up into the building. At the very least, earthen floors should be covered with 4- to 6-mil polyethylene film to lessen the amount of moisture being volatilized into the interior air.
5. Water-sealant paints or epoxies can be applied to floors and walls to prevent ingress of moisture to the interior of the building.
6. Attic vents and fans can be installed to pull air through buildings where no air-handling systems are available and where tropical climates require windows to be opened throughout the year. With such installations at least air can be kept moving throughout the building.
7. Open trenches and drains in mechanical rooms and areas adjacent to stack areas should be covered to prevent evaporation of liquid into the interior space.
8. Except for drinking fountains, interior fountains or waterfalls should not be permitted in a library.
9. Do not allow indoor planted areas in a library. Keep ornamental and hanging plants to a minimum to reduce the amount of water released into the interior air.
10. Heavy mold infestations resulting from flooding, water damage, leaks, and fires is an entirely separate topic and cannot be dealt with within the scope of this paper.
11. Regular inspection of the collections with a flashlight to pinpoint trouble areas is a necessity. Localized infestations of mold may be temporarily arrested with topical applications of chemicals until other modifications can be made.
12. Thymol is commonly used as a mold-control chemical on books, paper, and other library materials. The use of thymol, either as a mist or spray, or as a fumigant volatilized by heat, does not impart residual mold control to library materials. Thymol will kill some species of mold spores and mycelia upon contact. Taking the materials out of the atmosphere of thymol will leave them vulnerable to mold spore deposition and possible germination.
In the United States thymol is not registered with the Environmental Protection Agency as a mold-control chemical. It is often used, however, by library technicians and museum conservators. A wet mist is applied by dissolving thymol crystals in ethyl alcohol (ethanol). A 1 percent finished dilution is normally used. The technician wears a respirator approved for organic chemicals as well as goggles when using thymol. To protect from dermal irritation, the techician should also wear rubber gloves.
Some institutions have designed small chambers for the use of thymol for fumigations. Thymol crystals are placed on a metal tray and heated with several light bulbs. The space within the enclosed chamber becomes saturated with thymol molecules, fumigating the materials in this space. The same precautions apply for the operator as previously mentioned. Goods fumigated in such a way should be aerated thoroughly in a fume hood or outdoors to volatilize any remaining thymol before the materials can be safely handled. As stated previously, after the materials have been aerated, no thymol will remain on the materials to provide protection against subsequent mold development.
Paradichlorobenzene (PDB) has been used in enclosed spaces as a mild fumigant for mold control. Where a thymol fumigation takes no more than 24 hours for the application phase, a PDB fumigation will take up to 3 weeks unless the crystals are volatilized by heat. As before, PDB does not give residual mold control to the library materials.
Ortho phenylphenol (OPP) is another phenolic chemical that has been used for non-residual mold control on library materials. This chemical is not registered for use for mold control in libraries in the United States, but has been used in the past for extensive mold infestations brought about by flooding and fires. Repeated applications of the diluted material in alcohol have been made by spraying or fogging this solution onto the library materials.
Repeated applications are made over a series of days. These types of applications are usually performed by professional pest control operators or those who are thoroughly trained in the use of this chemical.
Alcohol and dilute bleach solutions have been used by technicians for spot applications to library materials, shelving, walls, and floors. Any strong oxidizing agent will kill mold spores, but none will impart residual chemical control.
Fireproof safes and filing cabinets
Often valuable collections and records are stored in fireproof safes and filing cabinets. These thick-walled storage containers have insulation in their walls to prevent fire from damaging the items housed within.
Two types of insulation are used for these kinds of storage cabinets. One is a dry insulation which gives superior protection, but is higher in cost. The second type of insulation is termed a wet insulation and is generally found in lower priced, consumer safes and filing cabinets.
The most common type of wet insulation is a mixture of Portland cement, Vermiculite, diatomaceous earth, and glass fibers. During manufacture this mixture is poured between the walls of the cabinet and allowed to cure. In the curing process moisture is retained by the Vermiculite particles and the diatomaceous earth. During a fire the heat of the fire turns this moisture into steam, which is generated into the interior space of the filing cabinet or safe.
Unfortunately, often moisture is continually generated by the wet insulation and creates a very high humidity inside the safe or filing cabinet, even without a fire. These types of fireproof safes and filing cabinets continue to cure over long periods of time. In the meantime they may create severe mold problems on the goods stored within the cabinet.
Many people have found that they must leave the drawers open almost continually to prevent excessive moisture buildup inside the cabinet. This practice makes the cabinet useless as a fireproof cabinet and requires continual attention on the part of the staff. The solution to the problem is to purchase fireproof safes and cabinetry that have dry insulation and therefore do not have these problems with moisture release and high humidity.