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Care and Conservation of Natural History Collections

Title: management, prevention and control Author(s): Pinniger, D. B. & Harmon, J. D. Source: Pinniger, D. B. & Harmon, J. D. (1999). Pest management, prevention and control. In: Carter, D. & Walker, A. (eds). (1999). Chapter 8: Care and Conservation of Natural History Collections. Oxford: Butterwoth Heinemann, pp. 152 - 176. URL: http://www.natsca.org/care-and-conservation

The pages that follow are reproduced with permission from publishers, editors and all contributors from Carter, D. & Walker, A. K. (1999). Care and Conservation of Natural History Collections. Oxford: Butterworth Heinemann. While this text was accurate at the time of publishing (1999), current advice may differ. NatSCA are looking to provide more current guidance and offer these pages as reference materials to be considered alongside other sources. The following pages are the result of optical character recognition and may contain misinterpreted characters. If you do find errors, please email [email protected] citing the title of the document and page number; we will do our best to correct them. NatSCA supports open access publication as part of its mission is to promote and support natural science collections. NatSCA uses the Creative Commons Attribution License (CCAL) http://creativecommons.org/licenses/by/2.5/ for all works we publish. Under CCAL authors retain ownership of the copyright for their article, but authors allow anyone to download, reuse, reprint, modify, distribute, and/or copy articles in NatSCA publications, so long as the original authors and source are cited. 8

Pest management, prevention and control

D. B. Pinniger Entomologist and Consultant, A.V.R. 83 Westwood Green, Cookham, Berkshire SL6 9DE. UK

J. D. Harmon Manager and Entomologist, Urban Entomology Associates, 1008 North Hidalgo Avenue, Alhambra, San Gabriel, CA 91801, USA

Introduction many of the pests, we are accustomed to this approach through tradition. Pests in a museum, library or archive environ- chemical applications directly on to ment can cause serious damage to highly objects may damage or destroy these items and valuable and irreplaceable materials. Natural produce undesirable residues. (Zycherman and history collections are particularly vulnerable to Schrock, 1988; Dawson, 1992). In addition, pest attack because much of the collection is certain methods involving the use of composed of edible plant material or non-chemical controls such as freezing or protein. Mammal and bird skins and and heating may also harm the materials if they are herbarium specimens are frequently damaged not used with due regard to the care of the by , and the risk of infestation is well objects. Therefore, a more preventive and known. However, many other objects in natural proactive approach to this problem is needed to history museums and other institutions are also control and prevent infestations and reduce the vulnerable to attack or may act as reservoirs for possibility of damage to materials. Many other pests. Wool in carpets, wool felt in displays or factors must also be considered such as door linings and dead flies in attics are as hazards to humans, and the environ- acceptable to insect pests as museum ment. specimens and the risk to the collection from these sources must be recognized. The majority of facilities deal with pests in a reactive way, Integrated pest management such as fumigating objects to kill the pests after (IPM) the infestation has occurred or monthly spraying by a pest control company (Quek et al., In today's society, an increasing emphasis is 1990; Spivak et al., 1981). Such reactive being placed on environmental sensitivity and approaches to pest control typically involve the the reduction in use of traditional . application of some type of pesticide to control Worker and public safety is also becoming a or prevent infestations. Although the routine greater concern with the increasing likelihood of application of pesticides to a museum will not lawsuits and litigation over past exposures to prevent infestations of potentially hazardous materials (Linnie, 1990).

152 Pest management, prevention and control 153

Rather than decide to abandon all attempts to should be very flexible so that it can be modified control the pests, less hazardous alternatives to at any time to suit each situation. It should also the traditional methods should be considered. be practical and achievable as it is useless Proactive approaches to pest problems are embarking on a grandiose scheme which then relatively simple and cost-effective over a long fails through lack of staffing, commitment or period of time. This requires the use of funding. A major point to remember is that integrated pest management (IPM) principles implementation of only one of the control or and practices (Linnie, 1996). IPM involves the management techniques will result in use of various types of control and management programme failure. To be successful, an IPM procedures to prevent pest invasion and to programme must include a multifaceted discourage insects from becoming established. approach. which is specific to each situation Procedures may include improving buildings, and part of the collection in terms of control, modifying the environment, placement of eradication and, especially, prevention of pest monitoring traps, and training of staff to assist infestation. Overall, a well designed IPM in the prevention of a pest im asion. IPM also programme will be a major contributor to the uses control procedures, including pesticides, efficient and environmentally conscious preser- but these are targeted to specific problems and vation of collections. are only used when necessary. IPM works with the environment, not against Basic IPM programme components it, to protect valuable collections and to maintain a clean, healthy and safe working Looking at the IPM components separately, it is environment. important to remember that each one is only a part of the whole programme and cannot stand Principles alone. Each part of the programme must be carefully examined and planned to be effective. IPM principles use the understanding of pest Different components may be selected biology and the museum environment to keep depending upon the problems encountered, the pests away from the collections and facilities use of a room, pests involved or administrative and to prevent them becoming established. constraints. Different parts of the museum Typically, there are many facets to an IPM collection or institution may initially require programme which are all interrelated. The different approaches depending upon the success of the programme depends on each part priorities. Other components can be added or of the programme being properly planned, deleted later as necessary. adhered to and supported at all levels. Included within the discussion of each component will be recommendations to correct Cost versus benefits the problems. These recommendations are meant as guidelines or as a starting point to The cost of an IPM programme may seem think of new remedial measures. The main prohibitive at first. Initial start-up costs will be objective is to correct current problems in order higher than a current monthly service from a to prevent worse situations later. pest control company which is where the largest The key stages in an IPM programme are as amount of time and money is spent. After follows:, implementation, the cost for maintenance is relatively low and primarily consists of time · Recognizing and identifying priorities for spent inspecting and identifying pests. A typical action. benefit of using an IPM programme approach for · Identifying responsible staff. the management of pests would be the discovery · Taking action on the high priorities. of a pest and implementation of control · Establishing procedures for forward procedures prior to the development of a major planning, financing and review. infestation and subsequent damage. An IPM Below is a list of the IPM principles that are programme will also eliminate or minimize employed in a typical programme. Each will be routine pesticide applications. IPM discussed separately in later sections: 154 Care and Conservation of Natural His/my Collections

· Knowledge of the pests. depending upon the type of the collection and · Surveys and inspections. the local climate. Some pests are easily recog- · Exclusion. nized by the damage that they have caused. · Cleaning/sanitation. Although a summary of the major pests and · Vegetation removal. vulnerable natural history materials is given in · Pest monitoring. this chapter, it is strongly recommended that · Environmental modification and the user makes reference to a good text on manipulation. insect identification. Examples include: Mound (1989); Peacock (1993) and Smith and Whitman · Education/training. (1992). · Record keeping. · Treatment. Pests attacking wool, fur, feathers and Pest identification textiles Major destruction of mammal and bird skins Identification of the of pest causing the and insect specimens can be caused by certain problems is the cornerstone and the initial part and pests. A number of different of an IPM programme. Incorrect identification species of carpet , museum beetles and may result in large amounts of time and leather beetles (which all belong to the family resources being wasted in controlling the wrong ) are widespread in many museums pest. and stores throughout the world. Some pests are general feeders whereas others will attack only a limited range of Carpet beetles and fur beetles materials (Table 8.1). There are also major The most common carpet beetles found are differences in pest importance and status Anthrenus sp. and sp. There are Table 8.1 Summary of pest risk to specimens Specimen type Pest Signs of Damage

Dried insect collections, Anthrenus, Attagenus, , Loose wings, fatty bodies eaten, particularly large and Reesa frass, and larval skins in cases Coleoptera Loose legs, frass and larval skins Dried arachnids and Crustacea, Anthrenus, Attagenus in cases particularly poorly cleaned decapods Bird skins Anthrenus, Attagenus. Tinea, Stripped feathers, webbing and frass Mammal skins Anthrenus, Attagenus. Tinea, Loose hair. webbing, cast skins and Tineola frass Anthrenus, Attagenus, Ptinus, Loose hair, round emergence Freeze-dried mammals and birds Stegobium, Lasioderma Tinea, holes, webbing, cast skins and Tineola frass Reptiles, pal1icularly poorly cleaned specimens Anthrenus, Attagenus Cast skins and frass Bones and horns when poorly cleaned Anthrenus, Attagenus, Dermestes Cast skins and frass Clean skeletal material Not attacked Rarely attacked Spongse Not attacked Round emergence holes, globular Dried plants, pal1icularly seeds Stegobium, Lasioderma, Ptinus pupal cases and frass and seed heads and some fungi

Cryptogams Rarely attacked Dust and frass Fungi Liposcelis, Stegobium Pest management, prevention and control 155

many different species of Anthrenus which are round, 2—3 mm long and covered with patterns similar in appearance and habits, including the of grey and gold scales. There are also many museum beetle Anthrenus museorum, the species of Attagenus including the fur beetle varied carpet beetle Anthrenus verbasci (Fig. Attagenus pellio (Fig. 8.1E) the black carpet 8.1A) and the furniture carpet beetle Anthrenus beetle Attagenus unicolor, the wardrobe beetle flavipes. All adult Anthrenus are Attagenus fasciatus and the brown carpet

D

E F

L

K

Figure 8.1 (A) Anthrenus verbasci adult; (B) Stegobium paniceum adult; (C) Dermestes maculatus adult;. (D) Lepisma saccarbina adult; (E) Attagenus pellio adult; (F) adult; (G) Ptinus tectus adult; (H) Blattella germanica adult; (I) Anthrenus sp. ; (J) Dermestes sp. larva: (K) Attagenus sp. larva; (L) Liposcelis bostrychophilus adult; (M) adult. NB Not to scale — size is given in text. Based on illustrations © The Natural History Museum. 156 Care and Conservation of Natural History Collections beetle Attagenus smirnovi. Attagenus adults are wasp beetle Reesa t.'espulae, which is more oval in shape and are very variable in size, parthenogenetic and causes serious damage to from 3 to 6 mm. insect collections in some European countries, All carpet beetle species have active. hairy and the odd beetle Tylodrius contractus, found in larvae often referred to as `woolly bears'. Larvae mammal and bird skins in the USA. of Anthrenus are short and fat (Fig. 8.11) whereas those of Attagenus are longer and more Clothes torpedo-shaped, often with a tuft of bristles at A number of species of moth will attack and the posterior end of the body (Fig. 8.1K). All are damage animal specimens and textiles. The voracious feeders and will rapidly demolish case-bearing Tinea pellionella (Fig. animal specimens, fur and feathers and woollen 8.1M) and the common or webbing clothes moth textiles (Plates 24 and 25). Many of these Tineola bisselliella are two of the most important beetles can be found in natural situations such species and they have a wide distribution. They as birds' nests and animal burrows and they are small, dull, grey-fawn moths, 5—7 mm long, thrive on dead insects such as flies and wasps. which scuttle around rather than fly and when In some museums they have a direct route into at rest fold their wings along their back. Clothes the premises from birds' nests in attics and moths hide in dark areas, shun light and lay chimneys. Once established, they can be batches of eggs on fur (Plate 26), feathers (Plate difficult to eradicate because the larvae are able 27), skins, wool or soiled silk. The larvae spin to forage widely and may take some years to silk webbing. complete development. Localized favourable The larva of the case-bearing clothes moth conditions may encourage rapid development Tinea pellionella spins a `cocoon' around itself which increases levels of damage. When larvae leaving the ends open so that it can use its jaws hatch from the egg they are extremely small and legs. It then eats as it traverses the material (less than 1 mm) and can gain entry to display carrying its case, leaving a trail of grazed textile cases and storage boxes through very small or fur with some fragments of excreta or frass. cracks. As the larvae grow, they leave empty When fully grown the larva pupates within the cast skins which may blow around and indicate case and eventually the adult moth emerges to the first signs of attack. Adult beetles fly and mate and lay eggs. may frequently be found wandering around on The common or webbing clothes moth Tineola window sills. They can be found outside where bisselliella has different habits. The larva also they mate on flowers before returning indoors to spins silk but it leaves this as a tunnel or sheet lay batches of eggs secreted in cracks and of webbing across the attacked material under crevices. which it grazes. Damage by this species is accompanied by copious webbing tubes which Hide and leather beetles frequently include large amounts of frass, and Hide or leather beetles eat animal protein such infestations appear far more `messy' than as dried animal carcasses and, as the name damage caused by Tinea pellionella. Adult moths suggests, they will also attack untanned leather can fly in through windows or open doors and and skins. There are a number of species can also originate from birds' nests. One including Dermestes pertaianus and D. generation normally takes a year but maculatus (Fig. 8.1C). The adults are generally development is more rapid in warmer dull black and much larger than carpet beetles conditions. (6—10 mm) and the larvae are also large and The pelleted excreta or frass produced by the very hairy (Fig. 8.13). Dermestes will breed in larvae of clothes moths is frequently mistaken poorly cleaned skeletal material and some for moth eggs. However, frass pellets are hard institutions use cultures of Dermestes for and opaque whereas moth eggs are very small cleaning animal carcasses to prepare skeletons. and translucent and vulnerable to physical If dermestids are kept for this purpose, they damage. Contrary to popular opinion, eggs will must be well segregated with strict controls to not remain dormant and then hatch many prevent them invading vulnerable areas. months later. Damage by moths is more Other dermestid beetles which are found only concentrated in dark areas and in crevices or in certain countries include the American Pest management, prevention and control 157 creases where specimens are stored touching a distinct lines on the elytra The larvae tunnel in wall or on a shelf. Clothes moths occasionally food leaving similar exit holes to the biscuit attack large insect specimens. It has been beetle. noticed that textiles soiled with food or urine are preferentially attacked and that a stained General detritus feeders, mould feeders area may be more damaged than an adjacent and scavengers clean one. Clean cotton materials are not at risk from attack by clothes moth, or carpet There are very many different kinds of insect beetles. species in this category. They generally cause nuisance and low levels of damage but Pests of herbarium specimens occasionally populations of insects can build up to levels sufficient to cause serious damage. Some of these beetles are also important pests of the food processing and storage industries Spider beetles and can be introduced into the museum on Spider beetles and particularly the Australian specimens or food. spider beetle Ptinus tectus (Fig. 8.1G), are widespread. They are common in birds' nests Biscuit beetles and general debris in attics, basements and The biscuit beetle or drug-store beetle stores where they will feed on a wide range of Stegobium paniccum (Fig. 8.1B) belongs to the vegetable and animal detritus including dead same family as the common furniture beetle or insects. They have been recorded as causing woodworm Auobiitm piuictatum but is much serious damage to herbarium specimens, smaller (2—3 mm). Unlike woodworm larvae animal skins and insect collections. The larvae which only eat and paper, Stegobium will are similar in appearance to those of the eat biscuits, nuts and dried plant specimens biscuit beetle and they will also bore holes (Plate 28). Herbarium specimens with before pupating in a globular silk cocoon. The nutritious seed heads and a high starch adults are 3—4 mm, hairy, superficially spider- content are particularly at risk (Plate 29). like and generally slow moving. They will Biscuit beetles will also attack papier mache tolerate lower temperatures than many other which has a high starch content, and there beetles but at higher temperatures two or three have been recent problems of damage to generations a year may be produced and freeze-dried animal specimens. Adults are very damage may be severe. Other species such as active and will fly but the larvae are not very the white marked spider beetle Ptinus fur and mobile or wide-ranging and live in tunnels the golden spider beetle Niptus bololeucus may inside the food, and when the adults leave they also cause similar damage. produce neat exit holes in objects. Development can be rapid at high tempera- Booklice tures of 30°C with generation times as short as There are a number of different species of five weeks. Biscuit beetles have an amazing booklice and Liposcelis bostiychophilus (Fig. ability to survive and breed on drugs and 8.1L) is one of the most common and trouble- spices which would be extremely toxic to other some insects. The adult of this species is animals. wingless and very small (less than 1 mm) and develops through a series of nymphal stages Cigarette beetles which feed on microscopic moulds on a range The cigarette beetle or tobacco beetle of substrates including flour, paper and Lasioderma serricorne (Fig. 8.1F) is a very cardboard. Booklice will attack some insect serious pest of tobacco but will also attack a specimens and damage book bindings and wide range of dried plant and animal material prints by grazing the surface. Squashed bodies (Plate 30) including freeze-dried animal will also stain materials and booklice are a specimens. It tends to be a more serious pest particular problem in stores which handle than Stegobium paniceum in hotter climates. books and manuscripts. These insects thrive at The adult is similar in appearance to the high which encourage mould biscuit beetle but is more hairy without growth, although Liposcelis can tolerate drier 158 Care and Conservation of Natural History Collections

cockroach species are the German cockroach Blattella germanica (10—15 mm) (Fig. 8.1H), the American cockroach Periplaneta americana (30—40 mm) and the Oriental cockroach Blatta orientalis (20—30 mm). Although they are tropical in origin and require relatively high temperatures and locally high humidities, they are very common in heated buildings in countries with temperate climates. They are extremely active and the adults of many species will fly. They are also relatively large but, as they frequent heating ducts, wall cavities and other dead spaces, the centres of infestation may be hidden. The American cockroach Periplaneta americana is probably the most abundant insect in countries with tropical and semi-tropical climates and is commonly found outside buildings. All the pest species lay eggs in cases called oothecae and the tiny nymphs hatch from these. German cockroaches hatch immediately Figure 8.2 Photograph and label damaged by Lepisma after the egg cases are dropped but American saccharhina. and oriental cockroach egg cases may remain dormant for some weeks or even months before they hatch. These cases can act as biological conditions and will develop when the relative time bombs' which can be introduced unnoticed is as low as 60%. Because it is into stores on new or returned materials and parthenogenetic, Liposcelis populations can give rise to subsequent infestation. increase very rapidly at temperatures over 25°C Infestations of cockroaches often spread from and give rise to apparent population explosions. restaurant or catering areas and they will eat a wide range of materials and cause conta- Silverfish and firebrats mination by spreading smears of excreta. They Silverfish Lepisma sp. (Fig. 8.1D) are always will also feed in toilets and drains and as they associated with damp conditions and they are known to cause allergic reactions and carry generally require localized humidity above a range of diseases, cockroach infestation can 75—80% to breed and multiply. Firebrats present a health hazard to staff. Cockroaches Thermobia sp., on the other hand, are found in are active at night and the size of infestations hotter, drier areas. They are primitive, scaly, can be underestimated if inspection is only wingless insects (10—15 mm) with forked bristles carried out in daylight. Infestations may be at the tail end. Silverfish and firebrats are difficult to eradicate even with the use of general scavengers which feed on microscopic persistent pesticides and successful cockroach moulds on a wide range of foods including glue control usually requires close co-operation and ink on paper. Lepisma saccharina has been between museum staff, catering management known to damage hooks, wallpaper, labels (Fig. and an outside pest control contractor. 8.2), postage stamps, paper currency, herbarium specimens and textiles. Insects which damage wood

Cockroaches Pests which attack wood may cause problems in World-wide, cockroaches are one of the most tree specimens, storage boxes, furniture, serious pests associated with humans and shelving or the building structure. Many of the urban development and cockroach problems most destructive pests are beetles, including have spread to museums, other institutions and associated stores. The most common Pest management, prevention and control 159 the common furniture beetle or woodworm galleries and tunnels in many directions, Aiiobiuni punctatum. Powder post beetles Lyctus frequently across the grain of the wood. sp, longhorn beetles such as Hylotrupes bajulus Channels are connected by narrow passages and bostrychid bamboo or auger borers such as which are clean and smooth. Although some Sinoxylon sp. However, some species of ants faecal pellets or frass are scattered in the and termites can also cause serious damage in passages, they are often stored in chambers countries where they are endemic. which are sealed off. Drywood termites can be identified by these pellets which are the shape of Ants poppy seeds. The termites may bore small round Most of the ant species which cause problems holes in the surface of the wood and eject the are associated with decaying timber but species frass through these `toilet holes'. Timber and of Camponotus such as the Hercules or carpen- wooden objects may be extensively damaged ter ant C. berculearnis will gnaw tunnels to before infestation is noticed because a thin layer build nests in sound wood. The ants attack soft of undamaged wood may be left on the outside. spring wood and so the tunnels follow the The nests and colonies are constructed entirely growth rings, leaving thin leaves of hard within timber and they do not forage widely from summer wood. Structural timber of buildings infested material. Drywood termites will also and specimens may be damaged in the tropics. attack and destroy other cellulosic material including books. Termites Termites or Isoptera, commonly known as Dampwood termites `white ants', are the most serious and destruc- Dampwood termites, including Zootermopsis sp., tive pests of structural timber (Edwards and are usually associated with wood which is Mill, 1986). In many museums, infestation of already being attacked by fungus and their the buildings can spread to display and storage presence indicates advanced decay. The tunnels furniture and artifacts where termites can cause and galleries are similar to those made by serious damage. Termites are not a problem in drywood termites but the interior walls are not cool, temperate countries and the most severe so clean and may be littered with pellets. problems are encountered in countries with warm, temperate and tropical climates. Subterranean termites Termites are not ants although they live in Subterranean termites need to live in contact large colonies that have a complex structure of with soil and some species build the classic different types or `castes' which may include `termite cities' with colonies in huge mounds or workers, soldiers, kings and queens, plus the spires of soil. Colonies of some species, developing eggs, larvae and nymphs. The including Reticuliterntes sp., Coptotermes sp. reproductive cycle of many termites involves the and Macrotermes sp., will spread from their production of large numbers of winged natural environment of soil and tree stumps to reproductive alates which swarm from the the woodwork of buildings. colony and then lose their wings before estab- Many species require fungi in their diet, which lishing new colonies. There are many different is produced on decaying wood within the nest. species of termites and they are generally They need to maintain high levels of moisture in divided into three types with distinctly different the colony for the development of fungi and to life styles — dryw-ood, dampwood and prevent the desiccation of the nymphs and subterranean. All three types can cause prob- workers, and this leads to the characteristic lems in museums and stores. Subterranean tube-building habit of subterranean termites. termites cause the greatest damage to buildings These tubes. which may be some metres in whereas dry-wood termites often cause the length, are constructed of soil and faecal greatest damage to artifacts. material and they protect the termites as they pass between nests in the soil to the food Drywood termites sources of wood or other cellulosic material. Drywood termites, which include the species They will line their galleries with a mud layer Cryptoterines sp. and Kalotermes sp., bore which conceals holes and covers the wood which they are excavating. 160 Care and Consecration of Natural History Collections

This habit, together with the presence of Control of the food supply will control the connecting tubes, provides the main clue to mouse problem and particular attention should distinguish colonies of subterranean termites be paid to catering and eating areas. As with from those of drywood termites with their rats, buildings can be proofed to prevent entry relatively clean galleries. A further diagnostic although mice can gain entry through very feature of damage is that subterranean termite small holes in air-bricks and under doors. galleries are restricted to softwood and do not cross growth rings. As their name implies, subterranean termites Facility and collection surveys are found near or below ground level and seldom spread above the lower floor, and this Although identification of the pest problem is means that basement areas are particularly at the cornerstone of IPM it is only the first step risk. In addition to damage to museum objects, of a programme. The second step is to conduct the enormous amount of timber which can be a survey commencing with the outside and consumed by subterranean termites can be then the inside of the facility. The aim is to sufficiently severe to cause structural collapse gain a thorough knowledge of the facility so of buildings. The eradication of termites from that action can be taken to prevent pest entry, museums and their subsequent exclusion can and problem areas can be identified for be extremely difficult and usually requires the intensified monitoring. Table 8.2 presents a services of a pest control contractor specializ- suggested check-list for a survey. ing in termite problems. Planning and priorities Rodents A survey of a collection and facility is a very Rodents are easily identified by their profuse involved process. Before beginning, it is droppings, gnaw marks and habits (Bennett et essential to know what to look for and what al., 1988; Meehan, 1984) but expert advice procedures to follow. The first priority is to look should be sought if there are persistent rodent for ways that pests can enter the facility and to problems. identify areas where they may become Infestations of brown rats Rattus norvegicus established. There are very large differences are usually only found in museums when the between the different functional areas in a rats have considerable and easily accessible museum such as galleries, stores, laboratories sources of food such as food stores near the and offices. Given the huge number of museum or catering facilities with poor refuse specimens in most natural history collections, disposal systems. When the sources of food are it is impossible to check each item on a regular controlled, the rat problems will disappear. If basis. Therefore, an overall assessment of the there is a high risk of rat invasion, in an inner collection must be carried out to identify high city area for example, then parts of the risk areas in the building and the most building can be proofed to prevent entry of rats vulnerable parts of the collection. A scale through eaves and pipe runs. diagram of the facility will be necessary during The house mouse Mus domesticus can be a the survey. As problems are noted, they should major cause for concern although in many be indicated on the diagram. Noting areas that museums and institutions the fear of infesta- could support pests prior to infestation will be tion is greater than the reality. If mice are given helpful in preventing future problems. A undisturbed areas with access to food supplies thorough record with detailed notes of the then they will breed rapidly and cause serious survey will be crucial when instructing damage by shredding paper and textiles to personnel in the resolution of these problems. make nest bedding. They will not discriminate The following equipment will be required between valuable objects, packing and rubbish. during an inspection: a strong flashlight for Mice produce prolific quantities of small, looking into corners and dark areas, a hand pointed droppings as they run around and so lens or magnifying glass for identifications, signs of fresh infestation are easy to recognize collection tubes and forceps and paper and if areas are kept clean. Pest management, prevention and control 161

Table 8.2 Survey checklist: this list is a basic guide and may not include everything found in your museum or facility — look carefully and make additions (or deletions) to the list where necessary

EXTERIOR Doors: Treatment area Roof and walls: In good repair Reference insect collection Roof type — flat, pitched or other Effectively seal off rooms areas Reference collection maintained Clean and in good repair Seal tight at sides. bottom, top pest-free Standing water Close properly Specimens for identification in Type of construction Walls and floors: pest-free drawers or containers Cracks or crevices in walls Holes in walls, floors or ceilings Galleries: (especially where two buildings Cracks at skirting baseboard Cleaning schedules meet) junction Are areas free of dust and dirt Ventilation air-bricks Blocked off fireplaces Types of display Chimneys — are they blocked off Vents screened off to prevent Do open displays contain External heating, air-conditioning animal and bird harbourage vulnerable material more at risk or other mechanical unit Plant rooms: Are materials going into and out Windows and doors: Standing water in rooms of galleries checked for pests Glass complete and secure Evidence of pest presence, insect Are food and drinks allowed in Screens in good repair or rodent carcasses, insect or galleries Weather-stripping rodent faeces Are there catering areas in the Seals tight Pipes galleries Opened regularly In good repair, leaks Are they clean Rubbish/trash: Pipe traces open or sealed Gift shop: Museum waste Air conditioning/ventilation Standard of cleaning Office waste plant Materials checked for pest Catering waste Mechanical rooms free from presence Bin storage debris and water Staff eating/rest areas: Skips dumpster storage Cracks 'crevices holes in walls Where is food allowed Regularity of emptying Openings to outside Refrigerator clean Loading-dock area: Signs of birds or birds' nests Sink and counters in good repair Clean Vents screened off to prevent and clean Dock doors tight and sealed animal and bird harbourage Presence of insects or rodents Doors left open regularly Conduits and conduit lines open Microwave oven clean or filthy What part of building does dock or sealed Rubbish bin 'trash can with liner lead into Collection storage: Emptied routinely Washed Vegetation around facility: Type of storage furniture regularly Proximity of the plants to the Condition of doors and drawers Floors regularly mopped, dusted facility How well sealed or vacuumed What is the ground material — Space under/behind units Water sources, sinks/lavatories, soil, gravel, hark, mulch How often inspected leaks Are there flowering plants Cracks crevices in walls Office areas: When do they bloom Temperature and humidity Carpets — wool or synthetic Are there wall-climbing plants Monitored Standard of cleaning Trees and leaves Normal daily range of values Live plants Outside eating areas: Environmental controls working Supply cabinets Siting Control of material moving into Types and length of storage Cleanliness and out of area Food allowed Water sources: Are food and drinks allowed in Trash — where deposited Drain-pipes and gutters stores How long in depository Water pipes Loans/acquisitions: Public catering areas: Good condition and not leaking Route through facility Standard of hygiene in food Leaks, stains, water spots Erosion Procedure for examining preparation areas problems incoming materials Trash cans Standing water around facility Identification of pests damage Where Regularity of emptying and Rodents, birds, bats: Isolation of suspected materials washing Evidence of infestation Procedure for treatment of Eating areas History and what types infested objects Regularity of dusting, vacuuming Contributing factors to their Location of freezers etc. or mopping continued presence, e.g. staff Regular inspection and EFK fly control units, are they feeding them identification of materials with emptied regularly External lighting: infestations Attic and basement areas: Type of unit used Isolation of these areas from Lsed for `unofficial' storage Mercury vapour sodium primary collection storage Standard of cleaning vapour other Registration: Leaks Procedure for pest identification, Openings, holes to outside INTERIOR isolation and who to contact Birds and birds' nests Windows: Separate room from collection Wasps' nests Sealed tight storage Pipe traces sealed Glass complete Conservation laboratories and Ducts screened off at top Opened regularly preservation offices: Damaged wood members Weather-stripping Separate room(s) from collection Screens — in good repair storage and other areas

162 Care and Conservation of Natural History Collections pencils for notes. It also helps to have a small along the top and side edges of the doors to screwdriver and pliers for opening things and provide the needed seal. poking debris out of cracks. Sinks and other pipes often have a much Prior to conducting the survey, several larger hole in the wall than the pipe itself, questions must be answered, to establish the which leaves a ready-made highway for pests history of the building and prior pest infesta- to enter the area. Gaps around pipes should be tions. filled with steel or copper wool and caulking placed around the edges. All plumbing should · Where and when have there been pest be inspected and repairs made as needed. Any problems in the past? other openings should be sealed using fine · Which pests were involved? copper wool or caulking. · What type of collections or other materials were infested? Lighting · What was done to solve the problem? · Who took care of these problems (e.g. pest Outside lights should be positioned so that control company, in-house department)? they are physically away from the building, · How often are collections surveys pointing towards it. Lights attract many types conducted and by whom? of insects which, while they may not harm the · What is the current procedure for dealing collection, provide food for dermestid beetles with infested materials? and other scavengers. Diffusers on internal fluorescent lights may also trap flies and other insects which provide food for pests, and they Exclusion should be regularly removed and cleaned. If pests could be prevented from gaining entry Effective use of lights may include the place- to the facility in the first place, then most of ment of UV light-traps at loading-dock entry the problems would be solved. Information doors. This will stop the insects that are gathered in the survey will indicate where the attracted to the light, such as flies and certain entrance points are. An additional bonus is moths. The catch trays must be emptied that some facilities have achieved up to 5% weekly or more often if necessary. savings in their utility bills after sealing openings. New acquisitions Windows which are never opened should be sealed but those which need to be opened need Collections and materials entering a facility can to be fitted with insect screening. This is not easily transport pests. Most facilities have a always possible, particularly on historic quarantine area devoted to new acquisitions buildings where it may not be acceptable for and returned loans (see Chapter 9 on policies aesthetic reasons. and procedures). There may be a specific Doors present special problems in excluding registration area in some museums and in the pests. Depending upon the door type (rollup, receiving area in most libraries. Unfortunately, sliding, single or double doors) sealing all of staff working in these areas are often not the openings may prove extremely difficult. trained to inspect for insect damage or to Gaps occur around most doors when closed respond appropriately if insect activity is and the bottom of the door is usually the most found. problematic area. This ineffective seal not only All staff should be trained in the recognition allows pests to enter the facility, but also of objects that have been damaged by insect allows heat or conditioned air to escape. All attack. Training should include recognizing doors should close tightly with no openings signs of damage by biscuit beetle and cigarette around the edges. Problems can be corrected beetle, silverfish, moths, dermestid beetles, by installation of door seals or sweeps (rubber wood boring beetles and rodents. The presence or brush) as necessary, depending upon the of frass (faecal pellets), webbing, old cocoons, construction of the door and frequency of use. insect carcasses and cast skins and various Weather-stripping, easily obtainable through holes or tunnels will be key indicators. most hardware stores, should be installed Pest management, prevention and control 163

undisturbed on an object in a sealed drawer or cupboard. Some museums have devoted time and resources to the design of storage drawers and cabinets which preclude entry by invading insects. The results clearly show decrease or elimination of damage to specimens stored in these units compared to those stored in old and badly sealed units. Investment in good storage furniture is therefore a key component in I1'M and the care of collections (see Chapter 7 on the collection environment). Storage areas are full of dead zones, such as corners, underneath bottom shelves and behind furniture, that insects and rodents love so much. These are areas which may be overlooked in routine cleaning schedules, as cleaning staff tend to miss them when sweep- ing and dusting. Particular attention must be paid to routine cleaning of storage rooms. Dust, dirt, hair, paper and other debris tend to accumulate in inaccessible areas. A good `spring cleaning' should be carried out every year and some climates may warrant such a cleaning every three months. Cleaning staff should be told where problem areas are located and how thoroughly they should be cleaned. Shelving units are notorious for sheltering pests. Pest monitoring traps (see below) should be placed among the shelves and checked routinely. Infrequently used boxes of materials stored on shelves should be sealed in Figure 8.3 Quarantine strategy for a museum. polyethylene bags and labelled. During a storage room inspection, checks should be made on, under and behind shelves for any Staff should be given written procedures to piles of fine dust (indicative of wood-boring follow if an infestation or damaged material is beetle adult emergence), shed skins of insects, found. The instructions should be both simple casings and other debris, rodent faeces, and and specific. An example can be found in Fig. dead or live insects. 8.3. Conservation laboratories Storage areas The conservation laboratory and. or preserva- As most collections have the majority of their tion office are of significant concern because articles in storage, this is the most important these areas may hold damaged collections area for implementation of IPM. Material may awaiting treatment, including insect eradica- remain undisturbed for many years and this tion. Treatments on both uninfested and provides an ideal haven for insect pests. infested objects may be taking place in the Storage furniture may range from open same locality. The last thing that is needed are wooden shelving to well sealed metal cabinets. more pest problems. It is important to remember that objects are Where feasible, it is best to have a `dirty' more vulnerable to pest attack in open storage room isolated from collections for infested but they may also be damaged if pests are allowed to breed undiscovered and 16-1 Care and Conservation of Natural History Collections objects and a separate clean room. Those galleries are used for corporate entertainment objects which are infested and/or undergoing then all food residues must be removed after the treatment should remain in a different room event, otherwise the debris will provide food for from pest-free objects. Sticky monitoring traps pests. should be placed in all doorways and windows. Food preparation, handling and consumption Weekly inspection of these traps should be areas must be kept scrupulously clean and conducted. While a stray insect may be found in monitored on a regular basis. All waste/trash the dirty room, nothing should be entering the disposal must be carefully controlled to prevent clean areas. build-up of food waste. Caterers may have a separate pest control contract, and this must be Museum galleries checked and integrated with the pest policy in the museum. Museum galleries, which may have objects in cases or on open display, are potential sites for Gift shops infestations to develop and transfer to the collections storage areas. They may also contain Almost every museum has some sort of gift shop objects borrowed for an exhibition from outside or book store housed within the facility. Such the facility. Well lit objects will be less vulnerable shops often contain objects and materials to attack but darkened areas of the galleries will similar to those on display in the galleries, tend to encourage infestation and harbourage of including textiles, basketry, wooden sculptures pests. Exhibition openings and corporate and other items. These materials may be stored entertainment functions with catered food undisturbed for long periods of time during services can introduce pests and result in food transit to and at the museum and therefore the debris which may remain in the gallery to chance of pest infestation is high. Shops are provide food for insects and rodents. often located directly adjacent to galleries, Sticky monitoring traps should be placed collection storage or food service areas, inconspicuously throughout the exhibits. All increasing the likelihood of an infestation gallery staff should be briefed on the IPM spreading from the gift shop into the collections. programme (and given explanatory leaflets) to All gift shop managers and staff should be answer any visitor questions about the traps. trained in the recognition of pest damage and Areas where mammal and bird skins are given information about IPM and the danger of displayed should have moth traps around them. insects to the collections. All infested material Areas where dried plant materials will be should be refused if discovered before entrance displayed should also be monitored with beetle into the facility, or bagged and removed traps. Inspections of the traps should be immediately upon discovery. conducted on a monthly basis. Because some Monitor traps should be placed discreetly objects on display may be less accessible than throughout the gift shop, its office and the shop collections in storage, regular inspection of the storage areas. Monthly checks should be monitoring traps is essential. conducted of these traps.

Catering facilities Vegetation

Most museums are under increasing pressure to Plants are very comforting to have in and provide food and eating facilities for visitors. As around a facility as they lend warmth and a the requirements for this are almost in direct sense of calmness to the work environment. opposition to the provision of a safe Unfortunately, there are a number of pests that environment for the collections, this has to be of infest or are attracted to plants. Flies will often major concern. When catering is provided is infest potted plants that are over-watered. should ideally be in a separate building but, if Diseased or weakened plants are open avenues not, it must be very carefully controlled. for serious insect infestations and healthy There should be no consumption of food or plants may also attract insects to their flowers drink allowed in gallery or collection areas. If or fruit. Pest management, prevention and control 165

Cut flowers and dried plant material should development of insect pests. Low humidity is not be allowed in the facility under any not so limiting for some species such as biscuit circumstances. Many insects find their way into beetles and carpet beetles, but relative humid- buildings by hitchhiking on plant material, ity below 55% will prevent the development of especially plants and flowers brought in from pests such as silverfish. Good air circulation home gardens or the outside landscape. Well- and consistent control of temperature and meaning staff members wanting to share their relative humidity will prevent mould and success at horticulture also share their pest discourage insects. problems. Carpet beetle adults feed on the pollen found in some flowers and, because they Water sources are very small, would probably not be noticed during picking or transport. Flowers from a Important water sources include rest-rooms commercial grower or florists shop for a (sinks, urinals and toilets) and water leaking temporary display usually do not present the from outside, pipes or fire extinguishing same problems as they can be sprayed with systems. All of these areas should be investi- before being placed in the museum. gated for leaks and any repairs made immedi- However, the water in flower vases can support ately. Standing water in the building can the breeding of small flies and is a ready water produce high humidity and subsequent mould source for cockroaches and other pests. and mildew growth. Dried flower arrangements are even worse The basement of a building is a common for harbouring and transporting carpet beetles source of water. Often, collections are stored in and other pests. Often the plant material is basement areas due to space constraints or purchased already infested but, even if it is building design. As a temporary measure, not, it will serve as a magnet for any future dehumidifiers may be used to control humidity infestations and supply ample food and and objects may be sealed in polyethylene bags harbourage for pests. to prevent water damage (see Chapter 7 on the collection environment). However, the objects should not be bagged at high humidity as condensation can occur inside the bag and Environment cause mould growth. In storage areas without Temperature and relative humidity climate control a packet of silica gel, encased Collection storage areas should be kept as cool in unbleached muslin and conditioned to 50% as is practically and economically possible. relative humidity, should be sealed in the Temperatures lower than 20°C should slow polyethylene bag to keep the relative humidity insect growth substantially, although some constant. The silica gel will have to be checked insects such as spider beetles have adapted to periodically and reconditioned. A small lower temperatures. If storage areas which have hygrometer or humidity indicator strip can be climate control can be kept below 15°C, this placed in the bag to facilitate monitoring. will eliminate insect problems. Galleries are often very warm and large numbers of visitors Hygiene may raise temperatures and humidities to even higher levels which encourage rapid breeding Depending upon the pest, food sources may be of insects. found anywhere in a facility. Most of the Control of relative humidity is critical to the beetles may prefer a specific food but many are suppression of mould and mildew. If the opportunistic and will eat anything. Discarded relative humidity rises above 75%, then growth human food, breadcrumbs, hair, nail clippings, of mildew and other fungi starts. Mould and and even shed skin cells may provide a more fungi are wonderful food for many insects and than adequate food source. Special attention support a wide range of species. Damp areas should be paid to cleaning in any kitchen and caused by moisture migration and condensa- food areas. tion should be avoided where possible as Many insects prefer dark areas where they humidity above 65% will also encourage are undisturbed for long periods of time. An 166 Care and Conservation of Natural History Collections old display board covered in wool felt left in a population without being noticed. After the first side-room for years will provide a wonderful food few inspections, certain areas that have proved source for moth and beetle populations to to be free of pest problems and that do not develop. Dead insects, birds' nests and debris contain vulnerable material, may not need to under shelves and in old ducting will all sustain be surveyed each time. pest populations, and so the highest standards of cleaning should be aimed at everywhere. Traps and observations Remember that insect populations can start from a very small source but will increase and Traps are used to monitor rooms and collec- then grow too large for the food source. When tions continuously. Pests will blunder into this happens, they will exit the area and seek them as they move about the area in search of out new food sources in the collection! food, mates or shelter, and pests in the traps Garbage is to many pests what a grocery will indicate their presence in the area. Once store is to us. The garbage area is typically a pests are discovered, the number of traps can quiet zone, and pest populations can develop be increased to pin-point where the infestation unnoticed. Decaying garbage presents a health is located. The correct identification of the pest threat: cockroaches and other insects will will assist in decisions to continue inspections transport bacteria and germs on their bodies or implement control measures. Sometimes from the garbage area to human food. Food outdoor pests will be caught but seldom cause waste tends to support all types of pests but any damage to the collections and die before control of where the waste is placed and becoming established. During the building frequent removal of rubbish reduce the risk of inspection and collection survey, it is important infestations. to check for any signs of pest presence, All rubbish bins/trash cans and recycling damage, droppings, carcasses, etc. containers should be lined with plastic bags. Observations should be noted on the inspec- The bags should be closed with a twist-tie or tion/survey check-list. other such device at the end of each day and Traps may be very successful in catching replaced regularly. The liner makes removal and insects, but they will not give control of transport of the materials easier and keeps the insects. They are only useful as a monitoring containers clean. If food is consumed outside device. designated catering areas then there should be bins designated for food waste only. Insect trap selection and placement

There are many types of trap available in Monitoring and inspections different countries. Non-specific sticky traps should be used as basic monitoring devices for When to inspect insects such as silverfish, booklice, cock- Inspections and surveys should be done as often roaches, crickets, ground beetles, carpet beetle as practically possible. They should be thorough larvae and other crawling insects. These traps and regular but the frequency will be do not have a attractant although determined by resources. As a general guide, a some have a general food bait. Sticky blunder check of collection areas and traps should be traps are good for monitoring the residual carried out at least four times a year. Do not population of insects in a building to assess the underestimate the time it takes to carry out a risk to the collection. They will also indicate the thorough survey. It is better to carry out a level of ingress of crawling pests into a room or proper survey every year than to start off with building. They should be placed in a regular the intention of doing it every month and then grid pattern against wall/floor angles, failing. During the initial inspection, each and preferably in corners where they will catch every room in the facility must be checked. Too more wandering insects. Some traps are low in often, a pest problem will develop due to an height and can be tucked under shelves and incomplete inspection, allowing pests to build storage units. Numbers should be matched to up their the priorities of the collection and resources, and a trapping programme should not exceed the resources available to check the traps. Pest management, prevention and control 167

Figure 8.4 (a) A. 1 r and Attagenus larvae ,ught on a sticky trap. (b) Monitoring traps on a window-ledge.

(a)

(b)

Pheromone traps contain lures to attract a species is suspected. Pheromone traps are also particular species of insect. They are therefore available for a variety of other stored food specific for the target pest. Traps and lures are product pests. available for the clothes moth Tineola bissel- Pheromone traps should be placed in a grid in liella, furniture beetle punctatum, the same way as blunder traps. Because the cigarette beetle Lasioderma serricorne and lure is more attractive to flying insects, the traps biscuit/drug-store beetle Stegobium paniceum. may be attached to walls or hung from units. (Gilberg and Roach, 1991; Child and Pinniger, The range of the attractive effect depends upon 1994; Cox et al., 1996). Placement of these temperature and air movement. It is sometimes traps should be in areas where there is a high possible to pin-point sources of infestation by risk to valuable objects or where one of these increasing the number of traps in the area 168 Care and Conservation of Natural History Collections

Figure 8.5 Typical sketch to show placement of traps in a museum store.

immediately adjacent to where the pest was removable) should be removed and the speci- caught, to narrow down the area where the pest men recorded and discarded. Numbers of. dead originated. For larger populations of pests, insects on traps are food for other insects such increased number of traps may actually exert as dermestid beetles. Replacement of the trap some control of the pest, by confusing the males will also simplify recording of later trap catches and catching them before they get a chance to and reduce confusion. mate. However, this is of no real practical value Keep track of where you place the traps and as considerable damage will be caused by the what type they are. It is helpful to have a remaining insects. As some insects may only fly schematic diagram of the floor plan with for short periods each year it is necessary to displays and the furniture drawn in. Add all consult the manufacturer's recommendations trap locations to this diagram. Keep an extra for timely trap replacement. copy of the master drawing in a safe place. An With all sticky traps, once an insect is caught example of such a diagram can be found in Fig. (Fig. 8.4), the trap (or sticky surface, if 8.5. Pest management. Prevention and control 169

Record keeping to become re-infested. Keep treated and pest- free objects separate from actively infested Record keeping is crucial to the success of IPM materials or storage areas. Placing of infested programmes. Accurate and complete records of materials in plastic bags and sealing the bags pest presence and activity will allow the is one of the best ways to achieve this goal. In programme co-ordinator to modify the environmentally controlled storage areas, clean programme as needed, identify seasonal occur- objects which are particularly susceptible to rences and devote attention to problem areas. insect attack can be placed in clear The most important information to record is polyethylene or heat-sealed bags to prevent the correct identification of the pests found. them from being re-infested. Secondly, the number of individuals caught per trap and life stages of those individuals Treatment of objects should be recorded. This information should be kept in a log hook or spreadsheet. Plans Consideration must be given to the object's should also be used to record the distribution general condition and composition. Each and presence of pests; these will be useful as control method should be evaluated and, if references in future surveys. there is any question about whether a control Comparisons of trap catches over time can method is appropriate for a certain kind of enable trends in pest emergence and invasion object or material, a conservator should be to be tracked. In addition, `hot spots' (areas consulted. Consider the materials the object is that consistently show pest activity) will made of, the pest and its biology (life cycle and become evident. These active areas are where behaviour), and the different control methods you will want to concentrate control activities. available before selection. The use of an Comparisons of inspection observations will inappropriate method can cause damage to show what is going on, how effective the collection materials and serious health hazards controls are, and what modifications need to to the staff and public. be made to the control programme. A simple spreadsheet programme on a PC will allow Freezing easy production of tables and bar charts to Freezing kills insects by exposing them to a show trends in trap catches. rapid temperature change. This technique is now widely used for treatment of natural history specimens but unless proper proce- Treatment strategies for pest dures are observed then some damage can removal occur to specimens (Nesheim, 1984; Florian, 1986, 1989, 1990; Strang, 1992). Temperatures Choosing the pest control method best suited in the freezer should be around -18 to -40°C. It for a particular problem can be a difficult is better to use a deep-freeze unit rather than a decision. Prevention is better than cure and all common household freezer, and self defrosting the points made in the section on preventing freezers should never be used. The freezer pests should be the first priority. However, should be capable of reducing the temperature when pests are found in objects or in the in the objects very quickly, within 24 hours, to building then some remedial action may be be effective. If the items have been stored in a necessary. Remedial action when pests are cold climate and are frozen very slowly, some found is as follows: insects will become acclimatized and will not · Isolate any objects suspected of being succumb to freezing. It may take much longer infested to prevent spread of infestation to for the cold to penetrate large objects or tightly other objects. rolled skins and the temperatures in the centre · Clean infested areas and destroy insect of test materials should be recorded to check bodies and debris. that the target temperature has been achieved. · Decide on the most appropriate treatment The objects must be sealed in plastic bags to for the object and environment. prevent damage by relative humidity change and moisture migration. An absorbent organic Remember, once the treatment is completed, care must be taken not to allow the material 170 Care aid Conservation of Natural History Collections buffering material such as paper-towels can be The drawbacks are the high cost of the radiation added to the bag to help control the relative unit together with the stringent safety humidity. Place the object in the freezer for at precautions necessary for its operation. There is least two weeks at -18°C or for at least three also evidence that gamma radiation has days at 30°C. It is not advisable to freeze wet deleterious effects on some materials such as specimens unless this is to prevent decay. plastics and glass and may therefore adversely After freezing, objects must not be unsealed affect natural history specimens. until they have regained room temperature to prevent condensation problems. Buffering materials will help prevent condensation. Nitrogen has proven to be very effective and safe for treatment of sensitive objects (Reichmuth et Heating al., 1991; Rust et al., 1996; Valentin and Heating will kill insects much more rapidly than Preusser, 1990; Valentin, 1991; Gilberg, 1990: freezing but it is essential to ensure that Hanlon et al., 1992). The procedure relies on elevated temperatures do not harm the objects exclusion of which then kills insects by involved. In the past a number of museums anoxia and is relatively simple to conduct. have used ovens to `disinfest' insect collections Oxygen levels must be very tow, less than 0.10/0, and this often resulted in brittle specimens and and this can only be achieved in a special cracked drawers. Recent work has shown that chamber or in individual bags made of an damage due to shrinkage and distortion can be oxygen-barrier film. Large objects can be treated eliminated by controlling the humidity around using nitrogen from cylinders. Small objects can the object (Strang, 1996). The Thermo Lignum be treated in sealed bags using an oxygen process uses a special chamber in which the scavenger such as Ageless*. humidity is accurately maintained at a set level Building a nitrogen treatment chamber may be of, for example, 550/o during the entire expensive because of the need for absolute eighteen-hour cycle from ambient temperature gas-tightness. Conversion of an existing fumiga- up to 55°C and back. Many objects, including tion chamber used for ethylene oxide or methyl books, furniture, textiles and natural history bromide is feasible but can also be expensive specimens, have been successfully treated because of the need for additional sealing and (Child, 1994). Strang (1.996) has demonstrated pipe-work. The cylinder and hag method is that if objects are bagged when they are heated, cheaper to set up initially although an accurate then humidity in the enclosure is stable and the oxygen meter must be purchased and gas cylin- object is not damaged. This offers possibilities ders must be stored in compliance with local fire for rapid and safe treatment of natural history and safety regulations. An important consid- specimens. There are some questions regarding eration is that the relative humidity of nitrogen the effect of heat treatment to 55°C on plant and gas is extremely low, between 5 and 100/0, which animal DNA and, if this is of prime importance ss ould he detrimental to the materials being in the specimen, then heat treatment would not treated. It is therefore essential to add a be advisable. humidification system to the gas supply-line Microwaves have been used for rapid treat- (Rust et al., 1996). The speed of the treatment in ment of herbarium specimens but there can be killing insects is dependent upon temperature, undesirable side-effects as the heating may be at temperatures of 25°C and above, two to three uneven and localized and overheating may weeks should be sufficient to kill pests. However. occur (see Chapter 3 on Vascular plants). In at temperatures of 20°C or below, very long addition, unnoticed metallic objects such as exposures of four or five weeks may be needed paper-clips may cause sparking and ignition of to kill some species such as woodborers. specimens and paper. A number of museums now use Ageless, a scavenger of gaseous oxygen, for treatment of Gamma radiation Gamma radiation will kill insects at high doses and is used in some Eastern European Ageless is the trademark of the Mitsubishi Gas countries for treatment of museum specimens. Chemical Company. Pest management, prevention and control 171 individual specimens (Gilberg, 1989, 1990, during the exposure period. Levels of CO, need 1991; Lambert et al., 1992; Valentin et al., 1990). to be about 60% and, unlike for nitrogen, some Ageless is composed of moist, active iron oxide leakage of oxygen into the enclosure will not powder encased in a porous packet. Oxygen in make the treatment ineffective. Because of this, the atmosphere penetrates the packet and CO, is used for large objects and enclosures. In further oxidizes the powder, forming iron oxides some countries CO, is registered as an and hydroxides. A slight amount of heat is and can only be used by produced by the reaction but, if the packets are professional operators. spaced for enough apart and kept out of contact with objects, this never builds up enough to Other gases damage the material being treated. Ageless will and other inert gases have been used work effectively only if there is a finite amount of with varying degrees of success but, because oxygen to be absorbed. This is achieved by they are more expensive than nitrogen or enclosing the object to be treated in a clear , it is difficult to justify their use. oxygen-barrier film bag. The bag should be big enough to accommodate the object to be Fumigation treated, with 3 to 4 inches spare. The excess space will become the seam of the bag and also Fumigation involves the introduction of a toxic provides extra room for the Ageless packets. The pesticidal gas into an enclosed space. Fumigant number of packets to be used is calculated from gases will penetrate materials and will kill all the type of packet and the volume of the bag. An insects within the target objects but the treat- indicator called Ageless eye can be used to show ment provides no residual protection. Because that levels of oxygen below 0.1% oxygen have of the hazards associated with fumigants, only been achieved. Objects should be left for at least trained and licensed professionals must three weeks at 25°C. With this system, set-up conduct this type of treatment. Many of the costs are lower than with the cylinder treatment products in the fumigant category such as but costs of Ageless may be high if large objects ethylene oxide, carbon disulphide, carbon are treated. Ageless will also slow any degrada- tetrachloride and ethylene dichloride have been tive processes requiring oxygen, such as mould abandoned, phased out or made illegal due to growth or oxidative chemical reactions. Thus, safety and environmental concerns. this system has applications for collection care Specialized equipment must be used in other than insect eradication. conjunction with fumigation, including some type of gas containment equipment such as a Carbon dioxide gas-proof sheet or bubble or a gas-tight Carbon dioxide treatment has been widely chamber. Chambers are commercially available accepted in the stored grain industry for many but the price is too high for most institutions to years. Grain in bins and other structures has consider buying one. The use of a vacuum been routinely treated with carbon dioxide to chamber greatly increases the efficacy of the eradicate insect infestations. The insect will treatment through increased penetration of the open up its spiracles when exposed to high fumigant. Also required are gas detection levels of CO, and this decreases the time to devices to test the concentration of the death, probably due to rapid dehydration. fumigant in the enclosure and in the atmos- The procedure used for CO2 is similar to that phere during aeration. High-powered fans are used for nitrogen in chambers or bubbles needed to move the gas and evacuate it once (Valentin and Preusser, 1990; Valentin, 1991). the fumigation is complete. In some countries As with nitrogen, the gas works slowly, partic- regulations forbid the venting of gas directly to ularly at low temperatures, and some treat- the atmosphere and traps or scrubbers must be ments add slight heating of the chamber to 30°C used to clean the exhaust air. to increase insect metabolic rates. This method also requires the use of a meter to monitor the Sulphuryl fluoride or Vikane percentage of CO, in the chamber Sulphuryl fluoride or Vikane is a fumigant which is widely used in some countries for the treatment of termites. It has also been used for 172 Care and Conservation of \aliiral History Collections museum objects and archival materials (Derrick The concentration builds up slowly until it is et al., 1990). There is some concern over high enough to kill insects and this means that deleterious effects of Vikane such as etching of the strips are most effective in enclosed cases glass and tarnishing of silver, brass, bronze and or cupboards and are ineffective when hung in copper. In addition, sulphuryl fluoride reacts ventilated areas. DDVP is not a penetrative with strong bases, and will dissolve slightly in fumigant and is unsuitable for control of certain organic solvents and cooking oils. There insects such as wood-borers, which live inside are further concerns that the material may materials (Williams and Walsh, 1989). The deposit residual fluorides in and around strips will eventually exhaust their supply of leathers and oiled stains, but definitive evidence DDVP in three to six months depending upon is not yet available (Dawson, 1992). temperature. As the DDVP vaporizes, the resin strip starts to break clown and produce a Methyl bromide discharge. This discharge is yellow in colour Methyl bromide has been used world-vvide for and may cause discoloration or staining of many years as a fumigant in the food and objects in direct contact with the strip. If used, agricultural industries as well as in museums. DDVP must be used at the correct dosage and Because of its effect on the ozone layer it has the strips should be wrapped in cheesecloth or been targeted for restrictions and will soon be muslin to prevent direct contact with objects. phased out of use in North America and Europe, Dichlorvos is animals and its very toxic to but many museums had already sought humans and use is being reviewed and alternative treatments because of the hazards restricted in some countries. and residues associated with methyl bromide. Liquid methyl bromide will react with a variety Repellents of sulphur-containing materials such as leather, wool, rayon, vinyl, rubber, hair, feathers and A number of chemicals such as , photographic chemicals. This reaction produces and para-dichlorobenzene have a sulphurous or rotten egg-like smell from been used for many years as repellents and materials, which is impossible to remove. passive fumigants. They are crystalline solids which slowly vaporize and, to be effective in Phosphine killing insects, the vapour must be contained Phosphine gas is evolved slowly from solid at a high concentration in a storage case, aluminium or magnesium phosphides in the drawer or bag. At lower concentrations there is presence of moisture. Because of this it does not some repellent effect on booklice, moths and require the use of complicated delivery beetles. Due to the rate of volatilization, apparatus or measuring devices. The gas must vapours tend to move out of the enclosed air- be contained in a gas-proof sheet or chamber space to contaminate the surrounding areas. and exposures must be longer as it kills insects The health hazards to humans from these more slowly than other fumigant gases. Five chemicals are high enough that it is advisable clays may he sufficient at temperatures of 25 C to investigate alternative methods. but at lower temperatures of around 15°C, two weeks may be needed. Although it has been Para-dichlorobenzene (PDB) used successfully for treatment of mammal and PDB will kill insects at high concentrations but bird skins, there have been reports of is known to adversely affect articles containing phosphene causing corrosion of metalwork at such materials as zinc white, lithopone, scarlet high humidities. pigments and some dyes used on cellulose acetate. It will severely shrink polystyrene Vapona, DDVP or Dichlorvos foams and plastics and will structurally DDVP typically comes packaged in a plastic weaken resins. PDB will also discolour the resin strip. The strip contains the active ingre- ultramarine pigment and contribute to the dient 2,2-dichlorovinyl dimethyl phosphate yellowing of paper and fading of ink. Dawson which slowly vaporizes into the atmosphere. (1992) states that this is caused by the chlorine in PDB. The use of PDB is being phased out Pest management. prevention and control 173 as it is now regarded as a health hazard and Applications of contact pesticides, both natural long-term exposure may cause serious health and synthetic, have been used for many years, problems. often in the form of the routine application of a pesticide by a pest control company to kill any Naphthalene insects in the area. Although some treatments Naphthalene is still widely used in homes and have a value, all pesticide use in collections museums to repel and control fabric insect should be questioned and only used if pests. Although there is some repellent effect on appropriate and targeted on the pest (Pinniger adult moths and beetles at lower concentrations, and Child, 1996). the levels required to kill insects are high. High Pesticides may present a hazard to objects in concentrations may be encountered during the the collections due to undesirable side effects initial placement of the chemical or upon (Dawson, 1992) and many pesticides have been opening of containers such as storage bags, withdrawn due to health and environmental boxes or chambers. Naphthalene will produce concerns. These include compounds discoloration in wool and may dissolve fats in and dusts, hydrogen cyanide, mercuric biological specimens (Dawson, 1992). compounds, lindane, , heptachlor and other organochlorine . Camphor Originally obtained from tree resin but now Pyrethrins and synthesized from pinene, camphor has been Pyrethrins or pyrethrums are natural botanical used for many years as a moth and beetle derivatives of the chrysanthemum flower-head. repellent. Although effective at high concen- Only a specific variety of this flower can be used trations, there are concerns relating to safety of to yield the desired commercial grade of the use because of its toxicity. The short-term and material. Pyrethrins are a combination of long-term occupational exposure limits in the different chemical constituents (pyrethrums) USA and the UK are lower for camphor than for derived from this process. Some of these naphthalene or para-dichlorobenzene. components cause rapid knock-down of insects and others cause the death of the insect. Plant-derived repellents Although safe, their usage is very limited due to Plant products such as lavender seed heads and the rapid degradation of the material when cedarwood oil have traditionally been used to exposed to ultraviolet light. protect objects from attack by moths and Pyrethrins are usually dissolved in a petro- beetles. With the demise of many synthetic leum distillate base solvent system and applied pesticides, attention has again been focused on as an aerosol. The particles that are produced these products. Certain oils derived from are approximately 80—100 pm (microns) in lavender and cedarwood do have repellent diameter. While this sounds very small, the effects on insects, but it must be remembered particles will stay suspended in the air only a that many are also quite toxic to humans and few hours. The pyrethrins are also very photo- may have deleterious effects on objects. More sensitive and degrade rapidly in sunlight due to research is needed before they can be the UV rays. A realistic lifetime for pyrethrins recommended as safe alternatives to protect applied in a room is about twenty minutes and collections. this means that they have little value in museums except as an emergency treatment for invading insects such as flies or wasps. The Treatment of the collection environment — petroleum distillates in the solvent systems are contact insecticides a disadvantage as they can damage by staining An important part of the IPM strategy may be or by dissolving oily and fatty substances. insecticide treatment of a part of the building to The pyrethroids, which include , stop the spread of insects from infested objects cypermethrin and , are synthetic or to attempt to eradicate them from analogues of pyrethrins which are much more harbourages in the storage furniture or in the stable in the environment, but are also more structure of the building. 174 Care and Consolation of Natural History Collections toxic. These are very effective insecticides arsenic. It is always advisable to take precau- against a wide range of insect pests and are tions when handling old specimens which may widely used as residual sprays and dusts to have been treated, to prevent absorbence control crawling insects. through the skin and inhalation of toxic dust (Linnie, 1990) (see also Chapter 9 on policies Other residual insecticides and procedures). A number of other insecticides are used as Whenever the use of pesticides is contem- residual treatments in museums. These include plated it is essential to ensure that the product carbamates, such as bendiocarb, and is registered for museum use and that it is organophosphates, such as chlorpyrifos. The appropriate for the pest and the environment effectiveness of these depends upon the siting of and will have no undesirable effects on the the treatment and the type of formulation used. collection. Sprays are more useful for treatment of walls and floors, and dusts may be more appropriate for treatment of dead spaces in ducting and Implementation of IPM under units. Most dust formulations have a true insecti- An IPM programme should not be set in tablets cidal effect but desiccant dusts also have of stone at the beginning but is essentially an another effect on the insect by removing the evolving process which should apply local waxy coating on the exterior of the insect's body. knowledge and respond to changing needs and The waxy coating is used to retain water and, priorities (Rossol and Jessup, 1996). without it, the insect dies from dehydration. Implementing an IPM programme in a large These dusts are safe and long-lasting and can museum or collection can be a daunting task. be very effective for treatment of wall voids, It is therefore important to identify priorities under cabinets and shelving units and in other and plan to cover the museum or institution in dead air-spaces. The dust may sometimes be achievable steps. In many cases it has taken impregnated with natural pyrethrins to speed some years to develop and implement a up killing of the insects. programme in a large national collection (Hillyer and Blyth, 1992). This has been Effects of treatment on objects and staff achieved by initially selecting one department or collection area, demonstrating that IPM is Many treatments may have some undesirable effective and achievable in that area, and then side-effects. These may be from the insecticide's adapting the programme for other areas until active ingredient or the other chemicals used in all parts are covered. the formulation. Such effects include damage to The following list gives a summary of IPM objects and books from water- or oil-based procedures: sprays and fogs. Colour changes, staining and loss of structural integrity can all result from § Obtain a plan of the building or collection careless application of a pesticide. Some or make sketches. formulations such as micro-emulsions have § Carry out a preliminary survey to identify been designed to have minimum impact on high-risk areas and objects. materials (Pinniger et al., 1994). Others such as · Include the outside of the building, micro-encapsulated formulations have been galleries, stores and all other areas. developed to adhere to structural surfaces and · Place monitoring traps in a grid. then release the pesticide only when it is picked § Plan a detailed inspection schedule. up by the insect. § Check cleaning regimes. Some consideration must be given to the · Check existing pest control contracts. possible contamination of objects by previous Examine the movement of objects in and treatments. In the past, many objects were out of the museum. directly sprayed or dusted with insecticides · Plan a quarantine strategy if one is not in such as lindane and DDT. In addition, many place. herbarium specimens were treated with · Explain to key people the objectives of IPM. mercuric chloride and mammal skins with Pest management, prevention and control 175

· Form a small team to aid communication and Gilberg, M. (1989). Inert atmosphere fumigation of museum objects. Studies in Conservation, 34, 1—84. spread the IPM load. This can, for example, Gilberg, M. (1990). Inert atmosphere disinfestations include conservation, collection management using Ageless oxygen scavenger. Ninth Triennial Meeting and buildings management. of ICOM. Committee for Conservation. · Examine training and awareness needs. Gilberg, M. (1991). The effects of low oxygen atmospheres on museum pests. Studies in Conservation, 36, 93—98. · Write an outline strategy for short-term and Gilberg, M. and Roach. A. (1991. The use of a commercial long-term IPM. pheromone trap for monitoring Lasioderma serricorne (F.) · Identify budgets that may contribute funding infestations in museum collections. Studies in Conservation, 36, 243—247. for IPM. For example, training, buildings Hanlon, G., Daniel, V., Ravenel, N. and Maekawa, S. (1992). maintenance, collections care, storage Dynamic system for nitrogen anoxia of large museum furniture etc. objects: a pest eradication study. Second International Conference on Biodeterioration of Cultural Property, Because of the effects of some chemicals on staff, Yokohama. Hillyer, L. and Blyth, V. (1992). Carpet beetle — a pilot study objects and the environment there will be in detection and control. Conservator, 16. increased pressure to move away from persistent Lambert, F.L., Daniel, V. and Preusser, F.D. (1992). the rate and toxic insecticides. As you implement and of absorption of oxygen by Ageless: The utility of an maintain an IPM programme in your facility, oxygen scavenger in sealed cases. Getty Conservation Institute, Marina del Rey, California. staff will begin to work with you once they see Linnie, M.J. (1990). Conservation: pest control in museums the merits of the programme. The development of — the use of chemicals and associated health problems. an IPM programme based on the principles Museum Management and Curatorship, Professional Notes. 9, 419—423. outlined in this chapter will enable collections to Linnie, M.J. (1996). Integrated pest management: A be cared for in ways which are safe and effective. proposed strategy for natural history museums. Museum Management and Curatorship, 15, 135—143. Meehan, A.Y. (1984). Rats and Mice. Rentokil Library, Rentokil Ltd, West Sussex. References Mound, L. (1989). Common insect pests of stored food products. A guide to their identification. British Museum Bennett, G.W.. Owens J.M and Corrigan R.M. (1988). (Natural History) Economic Series No. 15, London. Truman's Scientific Guide to Pest Control Operations, 4th Nesheim, K. (1984). The Yale non-toxic method of eradi- edn. Purdue University/Edgell Communications. cating book eating insects by deep-freezing. Restaurator, Child, R.E. (1994). The Thermo Lignum process for insect 6, 147—164. pest control. Conservation News, 72, 9. Peacock, E.R. (1993). Adults and larvae of hide, larder and Child. R.E. and Pinniger, D.B. (1994). Insect trapping in carpet beetles and their relatives. Handbooks .for the museums and historic houses. IIC 15th International Identification of British Insects, Vol 5. Royal Entomological Conference on Preventative Conservation. Practice, Theory Society, London. and Research. Ottawa. Pinniger, D.B. (1994). Insect Pests in Museums, 3rd edn. Cox, P.D., Pinniger, D.B. and Mueller, D. (1996). Monitoring Archetype Press, London. populations of the webbing clothes moth, Tineola Pinniger, D.B. and Child, R.E. (1996). Insecticides: optimis- bisselliella, using pheromone lures. Second International ing their performance and targeting their use in museums. Conference on Insect Pests in the Urban Environment, Third International Conference on Biodeterioration of Edinburgh. Cultural Property, Bangkok. Dawson, J.F.. (1992). Solving museum insect problems: Pinniger, D.B., Morgan, C., Child, R.E. and Lankford, W. chemical control. Canadian Conservation Institute (1994). A novel micro-emulsion formulation of permethrin Technical Bulletin, 15, 1—26. for the control of museum insect pests. TIC 15th Derrick, M.R., Burgess, II.D., Baker, M.T. and Binnie, N.E. International Conference on Preventative Conservation, (1990). Sulfuryl fluoride (Vikane): a review of its use as a Practice, Theory and Research. Ottawa. fumigant. journal of the American Institute of Chemistry, Quek, L.M.. Razak, SI. and Ballard, M.W. (1990). Pest 29, 77—90. Control for Temperate vs. Tropical Museums: North Edwards, R. and Mill, A E. (1986). Termites in Buildings. America vs. South America, Vol. II, pp. 817—820. ICOM Rentokil Ltd, West Sussex. Committee for Conservation. Florian, M.-L. (1986). The freezing process — effects on Reichmuth, C., Unger. W. and Unger, A. (1991). The use of insects and artifact materials. Leather Conservation News, nitrogen to control wood destroying insects in works of art. 3, 1-13, 17. Restaurator, 4, 246—251. Florian, M.-L. (1989). Freezing for museum insect pest Rosso], M. and Jessup, W.C. (1996). No magic bullets: safe eradication. Collection Forum, 6, 1—7. and ethical pest management strategies. Museum Florian, M.-L. (1990). The Effects of freezing and freezedrying Management and Curatorship, 15, 145—168. on natural history specimens. Collection Forum, 6, 45-52. Rust, M.K.. Daniel, V., Druzik, J.R. and Preusser, F.D. (1996). The feasibility of using modified atmospheres to control insect pests in museums. Restaurator 17. 176 Care and Conservation of Natural History Collections Hanlon, G. (1992). Progress in project on the feasibility of Smith, E.H. and Whitman.R.C. (1992). Field Guide to using modified atmospheres for museum pest eradication: Structural Pests. National Pest Control Association, An overview. J. Paul Getty Museum. Malibu. California. London. Harmon, J. and Coleman, C. (1993). Pest management and Spivak. S.M.. Worth. J. and Wood. P.E. (1981). Assessing disaster preparedness. Conservation Administration News, the effects of pesticidal chemicals on historic textiles. In 52, 6—7. Preservation of Paper and textiles of Historic and Artistic Mallis. A. (1982). Handbook of Pest Control. Franzak and Value II, pp. 333—343, Advances in Chemistry Series Foster Co. 193. American Chemical Society. Washington. DC. Morgan, C.P., Pinniger, D.B. and Bowden, N.S. (1993). The Strang. T.T.K. (1992). A review- of published temperatures effectiveness of residual insecticides against the varied for the control of pest insects in museums. Collection carpet beetle Anlhrenus verbasci and the implications for Forum, 8, 2. the control of this pest in museums. International Strang, T.J.K. (1996). The effect of thermal methods of pest Conference on Insect Pests in the Urban Environment, control on museum collections. Third International Cambridge. Conference on Biodeterioration of Cultural Property. Parker, T. (1988). Study on Integrated Pest Management for Bangkok. Libraries and Archives. Gen. Info. Prog. and UAISIST, Valentin, N. and Preusser, F. (1990). Insect control by inert Paris, UNESCO. gases in museums, archives and libraries. Restaurator, Pinniger. D.B. (1996). Insect control with the Thermo Lignum 11. 22—23. treatment. Conservation News, 59. Valentin. N. (1991). Controlled atmosphere for insect Pinniger, D. and Winsor, P. (1998). Integrated Pest eradication in library and museum collections. Management. Museums & Galleries Commission, London. International Seminar on Research in Preservation and Smith. R.D. (1984). The use of redesigned and mechanically Conservation, Arden House. modified commercial freezers wetted books and Valentin, N., Lidstrom, M. and Preusser, F. (1990). Microbial exterminate insects. Restaurator, 6, 165-190. control by low oxygen and low relative humidity Webb, E. A. et al. (1989). Integrated pest management at the environment. Studies in Conservation, 35. 222—230. Denver Museum of Natural History. Collection Forum, 5, Williams, S.L. and Walsh, E.A. (1989). Developing chemical 52-59. pest control strategies for museums: effects of DDVP on pests and materials. Curator, 32, 3-i 68. Zycherman. L.A. and Schrock, J.R. (eds) (1988). A Guide to Museum Pest Control. Association of Systematics Collections.

Suppliers

Further reading We recommend that when seeking advice about Berkouwer, M. (1994). Freezing to eradicate insect pests pest control companies or products, pesticide in textiles at Brodsworth Hall. Conservator, 18, 15—20. regulation authorities such as the Health and Brezner, J. and Lunen, P. (1989). Nuke 'em! Library pest Safety Executive in the UK or the Environmental control using a microwave. Library Journal. Sept. 15. 60-63. Protection Agency in the USA should be Daniel, V. and Hanlon. G. (1996). Non-toxic methods for pest contacted. control in museums. Third International Conference on Biodeterioration in Cultural Property. Bangkok. Ebeling, W. (1978). Urban Entomology. University of Monitoring traps California. Florian, M.-L. (1987). Methodology used in insect pest Agrisense-BCS Ltd. Treeforest Industrial Estate, surveys in museum buildings — a case history. Eighth Pontypridd, Mid Glamorgan CF37 SSU, UK. Triennial Meeting of ICOM Sydney. Museum Trap, Historyonics, 17 Talbot Street. Cardiff CF1 9B NV, UK

Monitoring traps are also available in most large suppliers catalogues.

Plate 24 Insect specimens damaged by Anthrenus verbasci (David Pinniger).

Plate 25 Reptile damaged by Anthrenus sarnicus (David Pinniger).

Plate 26 Lioness severely damaged by Tineola bisselliella (David Pinniger).

Plate 27 Feathers damaged by Tinea pellionella (note larval cases) (reproduced with kind permission of the Central Science Laboratory, York).

Plate 28 Dried manioc cake eaten by Stegobium paniceum (reproduced with kind permission of the Central Science Laboratory, York).

Plate 29 Herbarium specimens damaged by Stegohium paniceum (David Pinniger).

Plate 30 Parrot damaged by Lasioderma serricorne (reproduced with kind permission of the ( catral Science Laboratory, York).