Pests can cause enormous damage to library materials.
InsectsInsects pose a serious threat to collections of all types. The environment that is the most damaging to collectionshigh humidity, poor air circulation, poor housekeepingis the most beneficial to insects. Libraries and archives can provide insects with food, water, and shelter if the building is accessible and conditions welcoming. If insect damage is evident in a library collection, a careful survey should be conducted using sticky traps to see what types of insects are causing the problem.
Various methods have been used to eradicate pests, with differing degrees of success. These include ethylene oxide (ETO), methyl bromide, formaldehyde, and, more recently, gamma radiation. Most chemical fumigants require that the materials be enclosed, a vacuum chamber in the case of ETO and plastic sheeting or tarpaulins in other cases. Gamma radiation, used to deal with both insect and mold infestations, has the advantage of no residual effectsa major disadvantage with chemicalsbut studies have demonstrated that gamma rays damage cellulose, the building blocks of paper. More recently, tests have shown the advantage of both cold and heat to kill harmful insects. Temperature manipulation is preferred to toxic chemicals.
Make the building inhospitable from the outsideThe building itself can be made inhospitable to insects. The following sensible precautions can be taken to reduce and control insect populations:
Making the building inhospitable from the insideYou can also deter the entrance of insects by using solid, impermeable construction materials such as brick, stone, concrete, and steel. If possible, observe these additional steps:
Keep food consumption and preparation areas away from collection areas—ideally in a separate building. It is preferable that food and drink not be consumed in reader and staff areas, although this is often difficult to control. Spills and food debris should be carefully removed and waste receptacles emptied regularly. Receptions and events involving food and drink should not be held in a reading room or adjacent to a collection area.
Refrigerators and appliances that combine heat and moisture are popular habitats for insects. Areas under and around appliances should be regularly cleaned, and sticky traps placed if necessary.
Inside fittingsIf insects have secured a foothold within the building, you can impede their mobility by securing inside doors, especially those leading to areas such as a kitchen or restroom. Consideration might be given to fitting these doors with a weather seal. Other steps to take:
• Cracks in inner walls or the floor should be filled to prevent insects from entering and infesting cavity areas.
• Exhibit cases and special storage cases should be fitted with gaskets to ensure tight-fitting seals.
• Fittings, cases, and room corners should be regularly vacuumed and the vacuum bags checked for insects. Filled vacuum bags should be disposed of outside the building immediately after removal.
Killing insectsA freezer set at or below -20° C (-3° F) can be used to kill insects, which should be exposed for three to four days. Books should be placed in plastic bags and, on removal from the freezer, conditioned under a constant air current from a fan. Freezing is best for occasional infestations, not for routine treatment. A simple chest freezer can be used.
Heat can also be used to kill insects in infested materials. Temperatures of 50°C (120°F) will dry out insect bodies. In tropical areas, infested books can be placed in a metal container wrapped in black plastic and left in direct sunlight for a few hours.
Because of the possible health risks, insecticides should be used with great care and with full knowledge of the effects on humans and library materials.
Research is being conducted on safe and natural insect repellents, such as compounds made from Neem, which will help to render collections safe. Combined with freezing and heat treatment for small infestations, natural repellents can help to control insects while maintaining an environment safe for humans.
Harmful insectsThere are numerous insect types that can be damaging to library and archive materials, and most are found all over the world. Only a few species can be described here, but the discussion can be extrapolated to cover others.
CockroachesThese insects seem to be found in every part of the world, and they are tenacious. There are 3,500 types of cockroaches, and they can be divided roughly into urban types, that live exclusively indoors, and outdoor types, that breed and survive outdoors in tropical regions, but which often move indoors when conditions are favorable. The four types associated with damage to library materials: the American cockroach, the Australian cockroach, the Oriental cockroach, and the German cockroach. All four species have large mouth parts and a fondness for starch, thus book cloth and paper are especially vulnerable. Cockroach damage can be recognized by multiple light patches on book cloth surfaces—sometimes down to the thread—and ragged edges on paper leaves. Cockroach droppings can also be detected in the feeding area in the form of pellets.
The American cockroach (Periplaneta Americana) hides in dark areas during the day and emerges at night. This species regurgitates a sexual attractant in the form of a brown liquid (atar), often seen on library materials. Approximately 40 millimeters in length, it is reddish brown. It is largely an indoor insect, preferring moist, warm areas.
RodentsRats and mice are the most common rodents librarians are likely to encounter. Rats are difficult to control because they are capable of gnawing through cinder block, lead and aluminum sheeting, wood, plastic, and sheetrock. The most common rats are the Norway rat (Rattus norvegicus) and the roof rat or black rat (Rattus rattus). The house mouse (Mus musculus) is very common and extremely difficult to eradicate entirely. Both rats and mice use paper to make their nests, and many fine books have lost chunks of text through their jagged gnawing. Rodents' fecal matter and urine are especially damaging. It is generally better to trap rodents than to use a poison that will allow them to crawl into building crevices and die, for rodent carcasses are breeding grounds for insects that also damage library and archival materials.
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