THE DREADED LEPISMA SACCHARINA. Margit J Smith Presented at the 16th Care and Conservation of Manuscripts Symposium, Copenhagen, April 13-15, 2016. (Revision of an earlier article) PHYSIOLOGY Ubiquitous as it is, lepisma saccharina, also known as silverfish, Silberfischchen in German, lepisme saccharine or petit poisson argenté (French), peixe prateado (Portuguese) and pececillo plateado (Spanish), has probably been encountered by anyone who works in a museum, library or archives setting, has books at home, collects papers, or any type of printed material (ill. 1) Illus. 1. Engraving from Robert Hooke: “Of the small silver-colour’d book worm.” Illus. 2 The adult silverfish Ninety-three years before Linnaeus classified and named the insect in 1758, Robert Hooke described it in 1665 rather elegantly as “…a small white silver-shining Worm or Moth, which I found much conversant among Books and Papers, and thus suppos’d to be that which corrodes and eats holes through the leaves and covers; it appears to the naked eye a small glistering Pearl-colour’d Moth, which upon the removing of Books and Papers in the Summer is often observ’d very nimbly to scud, and pack away to some lurking cranney, where it may the better protect it self from any appearing dangers. Its head appears bigg and blunt, and its body tapers from it toward the tail, smaller and smaller, being shap’d almost like a Carret. [It] exhbits a conical body, divided into fourteen several partitions, being the appearance of so many several shells, or shields, that cover the whole body, every of these shells are again cover’d or tiled over with a multitude of thin transparent scales, which from the multiplicity of their reflecting surfaces makes the whole Animal appear of a perfect Pearl-colour.” End of quote. To continue the physical description: The two long antennae on its head contain sensilla, sensory receptors used in mechanoreception, namely reception of sound, movement, change in air pressure, and changes in the environment. Their nerve endings serve also as chemoreceptors, responding to smell, taste, and the presence of chemicals. At the end are three tail-like appendages, long bristles called cerci, the longest referred to as the terminal filum; two of these point to the sides, the one in the middle points backwards. They transmit sound and vibration Silverfish have compound eyes, with 12 facets each to provide a wide-angle view, detect movement and in some cases light. Illus. 3. Compound eyes Their mouths are simple and similar to those of cockroaches, with two pairs of strongjaw-like mouthparts, especially adept at grazing over the surface of material. Illus. 4. Rasping mouth and compound eyes Lepisma saccharina belong to the family Lepismatidae, their order comprises the most primitive and oldest of all insects – Urinsects – nearly 400 million years old and considered living fossils, older even than cockroaches. Their taxonomy is: Kingdom: Animalia; Phylum: Arthropoda; Class: Insecta; Order: Thysanura; Family Lepismatidae; Genus: Lepisma; Species: saccharina They lack wings and are therefore flightless. Three types of silverfish infest houses, the Lepisma saccharina; the gray silverfish Ctenolepisma longicaudata lives mainly in damp, cool places especially in basements and kitchens around plumbing fixtures; the fourlined silverfish, Ctenolepisma lineata, prefers extremely dry or moist conditions inside and outside the home. Lepisma saccharina is the most common. To mate, the male deposits sperm on a silk thread between the ground and a vertical object and coaxes the female to walk under it. She picks up the spermatophore with the cerci, transferring it to her genital opening. Only two or three fertilized eggs, .08- 1.9 mm long, are laid at one time in cracks and crevices with 100-150 eggs being produced in the female’s lifetime. Hatching takes three to six weeks with the young looking like small versions of adults. Silverfish molt every two to three weeks depending on the temperature is also responsible for the speed of maturation with silverfish in the warmer southern US maturing faster than those in the cooler northern areas. Their lifespan is variously reported as from 2-3 years, up to seven years and it may take two years for the young to reach the adult stage HABITATS Since silverfish readily adapt to hot, 80-90F, cool, dry and wet environments 80-90% RH, and can digest a wide variety of food, their distribution is almost worldwide: in the US alone more than thirteen species have been identified. Hiding in dark, moist or humid areas they remain as much as possible undisturbed, behind furniture, under carpets, around books, near sinks and plumbing and in attics and basements. Outdoors they are found where leaf-litter, rocks, bird’s nests and natural crevices, for instance in tree bark, provide good hiding places. When exposed to light they move quickly and stop suddenly; due to this sensitivity to light, silverfish are active predominantly at night. Even in arid areas Silverfish have the ability to absorb moisture from the air by capillary condensation, through mouth and rectal regions. Searching for food and water they frequently become trapped in sinks and bathtubs from which they cannot escape because of the smooth walls; this is often the first sign of their presence. FEEDING HABITS Carbohydrates (more specifically polysaccharides, hence their name), proteins and cellulose are their main food sources. These are found in paste, glue, wallpaper paste, sizing, gum, bookbindings, paper - particularly glossy paper, photographs, starch in clothing, cotton, linen and rayon. In addition they eat cellophane and the microscopic mold growing on plaster walls and drywall. They also feed on silk, dandruff, hair, and dead insects including other silverfish. Readily available substances such as sugar, flour and breakfast cereals as well as the non-organic materials have enabled them to find food in most inhabited and uninhabited areas, although they have been known to go up to a year without food. DAMAGE Of all insects that damage books and paper-based materials, silverfish are the most destructive, however, very little has been reported in the literature about their infestations and ensuing destruction of materials. With their simple mouths, and without being able to take bites out of the paper, damage begins with abrasion produced by grazing over the top layer of paper in a rasping fashion. (ill. 2) Illus. 5 Cover damaged by silverfish. http://thoughtsvsun.blogspot.com/2014/08/bookworm-problem-59452-actual-bookworms.html Repeated often enough this rasping action will finally lead to holes in the substrate and eventually a page can resemble a piece of lace. Illus. 6. Lace-like damage to paper Illus. 7. Rasping damage and holes in paper http://pestvic.softcorp.ca/wp-content/uploads/2013/03/DSC02251.jpg In this instance the lighter areas indicate the damage by rasping before producing a hole in the paper. Illus. 8. Book damaged at the edges http://www.uky.edu/Classes/ENT/574/insects/homes/fshc/fshc_damage.htm The book edges are completely eaten away. Silverfish are mainly introduced through the spine of a book where it is dark and food in the form of paste or glue is easily accessible. In especially advanced stages of destruction, the page or book cover can crumble when picked up. Illus. 9. Book damaged extensively throughout http://www.bluestarpest.com.au/silverfish.html. As reported in a study that examined the amount of damage silverfish can cause, the results were as follows: Groups of 5 silverfish were placed in containers with various food sources, namely papers and parchment. Within about 20 weeks the insects ate 5 square cm of silk paper, weighing 16 – 18 mg. If this result is multiplied to 100 silverfish it amounts to 100 square cm of handmade paper or 700 square cm of silk tissue within a year. Only the softer, rougher side, meaning the flesh side of the parchment was damaged, but not the skin side. In some cases the damage may be confined to the ink of the letters following their outline exactly, as observed on a blue buckram cover with white printing – the materials in the white ink was what attracted the insects. An area often overlooked as harboring silverfish may be the attic. Here, blown-in insulation consisting of shredded paper, as well as the storage of paper, old clothes, wooden and cardboard boxes, curtains, etc. provide a prime location for the insects. NON-CHEMICAL CONTROL Two paragraphs addressing the difficulty of eradicating an infestation are worth quoting in full from instructions for Integrated Pest Management (IPA) for libraries “In temperate climates, silverfish tend to migrate vertically depending on the season of the year. In the hot months of summer, silverfish will migrate down into the cooler, moister portions of the building, and in the fall and winter they will tend to migrate to attics and higher levels. Drying out a building with heat in the wintertime will help to reduce silverfish populations. The heat also eliminates the microscopic mold that grows on plaster walls and drywall providing a food source for silverfish. In cool, moist basements, and commonly in poured-concrete buildings, silverfish are a year-round problem. It is impossible to eliminate bringing silverfish into a library. Silverfish are a very common problem in cardboard box and drywall manufacturing facilities. Silverfish lay eggs in the corrugations of cardboard boxes, one of their favorite areas for egg deposition. With every cardboard box coming into a library, a new load of silverfish and their eggs is bound to arrive. Upon hatching, silverfish go through many molts throughout their long, up to three years, lifespan.” End of quote. Although it is impossible to control all introduction of the insects into a facility, several precautions can be taken, such as visual inspection of materials, and shaking books and newspapers etc. to dislodge living or dead insects and their eggs. A first step in combating Lepisma saccharina is to identify the areas where they are active. Since they are nocturnal the infestation may be fairly large before its presence is noticed. To monitor and gauge the severity of the infestation, sticky traps, commercially available, can be used. These traps consist of a substrate impregnated with a sticky substance from which the silverfish cannot escape. Traps can also be made by covering the outside of a glass jar with masking tape to let the insects crawl up and fall into the jar from which they cannot escape. To make the traps more effective, a small amount of food, e.g. oatmeal or dried meat, or a few drops of water, can be added. The jar is then placed where an infestation is suspected and monitored regularly. Presence of the insects is indicated by small piles of black dust-like frass, being their excrement, which is deposited in corners and areas behind books and boxes, along toe-boards, in closets and cupboards, and can be seen with the naked eye; also visible are remnants of a molt, namely the silvery-gray particles of their exoskeleton. Damaged fabrics will show feeding signs on individual fibers, also yellow stains that are most noticeable on linens where the insect has begun to feed. Illus. 10. Damage to textile cap Wallpaper paste is especially attractive to silverfish and a loose or damaged section of wallpaper may indicate an attack of the insects. The most important aspect of silverfish management is to increase regular housekeeping routines, vacuuming and dusting, that will create a less inviting environment. Especially corners where debris collects are breeding grounds and need to be cleaned and washed with diluted bleach occasionally. As much of the insect’s life depends on water and high humidity, eliminating dripping pipes and areas of standing water is a simple and effective response. If possible, control temperature and humidity with air conditioning, a dehumidifier, natural ventilation and airflow. Dark areas must be lit, old papers, bags, cartons, etc. removed, all foodstuffs have to be sealed and spilled food cleaned up promptly. Although it happens infrequently, food contaminated by silverfish can create human allergens that may become dangerous for persons with allergic rhinitis and asthma. Two other non-chemical possibilities of eradicating silverfish are available, though, unless there is access to a commercial freezer facility and large microwave ovens, these will be restricted to small infestations, but suitable for use in the home. Exposure to microwave radiation for 30 to 60 seconds will kill silverfish. Caution is advised for books with colored plates or that are in a fragile condition. Another method is freezing for which individual books are placed into freezer bags with a zipper closure. For large books heavy-duty polyethylene bags may be used and sealed with adhesive tape that is impervious to water. Freezers without ice build-up are recommended because moisture will end upon the books during defrosting. “Frost free” freezers are not recommended because they cycle on and off and the temperature is not constant. At least 72 hours are needed, but to be sure all insects are killed, it may be necessary to leave them in the freezer for two to three weeks. A gradual thawing is necessary by turning off the freezer and leaving the door open. The book should remain wrapped for several weeks and the plastic must be inspected carefully for tiny holes as new insects may have hatched after the freezing treatment and are eating their way out of the plastic enclosure. Eggs are especially difficult to kill. CHEMICAL CONTROL Once an infestation is discovered its treatment depends on its severity. Infestations will respond to control with products such as boric acid and diatomaceous earth two of the most effective insecticides against silverfish. Since they are very low on the scale of toxicity they are suitable for use in the home and on a larger scale in the workplace. Since 1922 borates have been used to combat roaches and other pests and by 1985 more than 200 registered pesticides contained borates. Occasionally the terms borax and boric acid are used interchangeably, but there they are not the same. Borax is the basic mineral mined from the ground. After being refined and processed it becomes boric acid. Borax that is often used in washing clothes is not as finely ground and not refined like boric acid. Boric acid in a very mild solution is also used as eyewash. Silverfish belong to the type of insect that grooms itself. When boric acid is ingested because it sticks to their legs after walking over it, and since they cannot digest it, it affects their metabolism, accumulates in their digestive tract and reproductive system, and causes them to die. Boric acid is only effective when it is ingested; when ingested in sub-lethal doses it produces sterility in female insects. Diatomaceous earth is a fine, talc-like, sharp-edged powder produced from fossilized remains of very small aquatic organisms called diatoms, phytoplankton. As the insects crawl over the dust it clings to their undersides where the sharp edges of the particles cut away the natural waxy coating on the body. This leads to their death by dehydration within about 48 hours. As long as the powders are kept dry they remain active indefinitely and are safe for humans, however, it is advisable to keep children and pets away. An extensive laboratory study conducted in Germany compared the effectiveness of boric acid and diatomaceous earth in killing silverfish. The tests used boric acid with sugar-bait; diatomaceous earth with sugar-bait and a combination of the two materials with sugar-bait. Boric acid combined with sugar-bait in a 50:50 ratio lead to 100% mortality of the insects within a few weeks. Boric acid with diatomaceous earth and sugar-bait worked even faster and killed the insects within about 20 days. Higher proportions of boric acid or diatomaceous earth lead to even faster eradication.(14) The most effective way to distribute these powdered insecticides is by using a bulb blower to blow them into storage areas, crevices, wall voids and other areas that harbor the insects. Depending on the size of the infestation it may take several weeks to show its overall effectiveness. Dusting serves especially well for larger areas as attics, basements, around furnaces etc., however, contrary to Jane Greenfield’s advice dusting on shelves seems to be less desirable as the powder is easily dislodged and can be transferred to the materials on the shelves and users’ hands when books and other stored materials are removed and replaced. A product widely available in the United States and by ordering online is the DekkoPak, a silverfish bait, containing 20% borax with 80% inert ingredients. Illus. 11. DekkoSilverfish Pak Box (Photo: Smith) The packs measure 2 ½ x 3” and look like a single layer of thick corrugated paper sandwiched between two layers of plain paper, with all four ends open. Taking this package apart shows that the paper in the center has small amounts of a hard, white substance applied to it, which sticks the center layer to the upper layer. The lower layer is attached simply with several dots of glue along the long edges. The corrugated layer is impregnated with boric acid and a pheromone attractant that, once the insects ingest it, will cause their death from dehydration. Illus. 12. Construction of the DekkoPaks (Photo: Smith) Following this recommendation silverfish were eradicated in the Special Collections at Copley Library at the University of San Diego where I was responsible for the preservation of our stacks materials. To prevent movement of the DekkoPaks on the shelves when removing and re-shelving books, they were taped to the upright ends of the ranges facing the books. After six months all packs were replaced in the same way. When I left the University about three years after that, the area was still free of silverfish. The size of the infested area for which two to three packs are sufficient is not mentioned on the packaging. From my experience, two to three packs per 36” x 48” drawer have eliminated silverfish from my paper storage cabinet that houses papers from various geographic areas, as well as from my husband’s print collection. Many commercially available pest eradication products list silverfish on their labels, but should be used with caution, as some have not been scientifically tested for their effectiveness and safety. Products containing synergized pyrethrin, including boric acid or silica gel products are very effective against silverfish if applied directly to the pests. Since the insects are nocturnal this seems to be a haphazard way of eradicating a large number, although there is some residual effectiveness in the areas sprayed when aiming at the silverfish. Other pesticides approved in various states in the US for use on silverfish include cyfluthrin, deltamethrin, lambda-cyhalothrin, d-limonene, and permethrin. Several natural materials are mentioned as repulsive to silverfish: cinnamon, whole cloves, cedar oil, cucumber peel, and lavender. They may be useful in a home setting, less so in a library or archive. To support the claim that cedar oil is a repellant, a report in the Journal of Wood Science points to the very effectiveness of this oil extracted from the needles of Cryptomeria japonica, a fast growing species of cedar tree native to Japan. The researchers recommended using it in products that control various pests, including silverfish. In the case of a serious and widespread infestation the services of a reputable pest management firm should be engaged. In the worst-case scenario, and as a last recourse fumigation of the building or part of a building may have to be resorted to, requiring evacuation for several hours or even days, and tenting, and has to be done by experienced professionals. In the past the chemical ethylene oxide (ETO) was frequently used in fumigations. It is the only product that is an insecticide, bactericide and fungicide in one, and smells like ether. Since its carcinogenic properties were recognized it is now very rarely used and was replaced with sulfur fluoride and methyl-bromide, which is highly toxic and also potentially hazardous to health. For several years a number of electronic insect repellents have been advertised and get favorable reviews. And although they are mainly used to chase rodents from the building, they are also effective against insects of all kinds, including silverfish. They produce sound waves inaudible to humans and pets which travel through electrical lines and work by confusing the pests to the point that they simple evacuate the area. As long as the device is plugged into an electrical outlet it remains active. Several customer reviews speak very highly of these devices. If is does all it is advertised to do, and at a price of $ 49.95 this seems a real bargain! Illus. 13. Pest Repeller Ultimate AT To sum up: Although I have not been able to find any report addressing the monetary cost of silverfish damage, it is well known that they are responsible for a considerable amount of deterioration to materials in collections world-wide. Irreplaceable books, documents and other paper-based objects and textiles have been lost. The need to combat Lepisma saccharina and its relatives requires constant vigilance and the knowledge of how, and with what materials, to affect their eradication. Basic, consistent and periodic sanitation of areas infested by silverfish are primary steps of defense against them. Non-toxic or low-toxic natural products such as boric acid and diatomaceous earth, both inexpensive and easily available, are second in line of managing the problem. Pesticide sprays and fumigation may have to be used as in worst-case scenario and as a last resort to rid an infested building or rooms. ADDENDUM, June 30, 2016 An interesting sidelight is provided by the medieval way to keep insects away from books, as explained to me by Archivist Wilhelm Schweizer during a visit to the Prädikantenbibliothek of the protestant church in Isny, a small town in Southern Bavaria. The library is in an upstairs room of approximately 500 square feet, without electricity and water, and is ventilated only by opening some windows. To prevent insects from invading the collection, a handful of hops was placed on each shelf behind the books. The hops remained effective for a long time in keeping the libraries pest-free and needed to be replaced only very infrequently. The same means of protecting the books is still being used today with excellent results. For more information about hops being used against insect pests, see the following article: “Not just for beer: evaluation of spent hops (Humulus lupulus L.) as a source of eco-friendly repellents for insect pests of stored foods.” https://www.researchgate.net/publication/272376948_Not_just_for_beer_evaluation_of_spent_hops_Humulus_lupulus_L_as_a_source_of_eco-friendly_repellents_for_insect_pests_of_stored_foods Illus. 14. Archivist Wilhelm Schweizer at the 500 year old Prädikantenbibliothek in Isny, Germany. Illus. 15. Hops as insect repellent is placed behind the books on the shelf. CC 16 THE DREADED LEPISMA SACCHARINA BY MARGIT J SMITH References 1. Robert Hooke. Micrographia: Or some physiological descriptions of minute bodies made by magnifying glasses. London,1665. 2. Gerhard Eisenbeis, and Wilfried Wichard. Atlas on the Biology Soil Arthropods. Berlin, Springer, 1987. 3. http://www.insectidentification.org/insect-description.asp?identification=Silverfish 4. Lopez, M. 2001. "Lepisma saccharina" (On-line), Animal Diversity Web. Accessed February 03, 2016 at http://animaldiversity.org/accounts/Lepisma_saccharina/ 5. Phillip E. Sloderbeck. “Silverfish and firebrats,” Kansas State University, November 2004. http://krex.k-state.edu/dspace/bitstream/handle/2097/21693/KSUL0009KSREEPPUBSEP123a.pdf?sequence=1&isAllowed=y 6. Wygodzinsky, Pedro W."A review of the silverfish (Lepismatidae, Thysanura) of the United States and the Caribbean area." American Museum Novitates; no.2481. http://digitallibrary.amnh.org/handle/2246/2689.) 7. Phillip E. Sloderbeck. Kansas State University. “Silverfish and Firebrats.” https://www.bookstore.ksre.ksu.edu/pubs/EP123.pdf) 8. Maja Pöschko, Dag-Ernst Petersen, Christoph Reichmuth. “Silberfischchen in Büchern: Schadenspotential und Bekämpfungsmöglichkeiten,” in Restauro, v. 103, 1997, p. 50-55. 9. T. A. Parker’s “Integrated pest management for libraries,” in Ross Harvey’s Preservation in Libraries: A Reader: p. 172. 10. Harry Ransom Center University of Texas at Austin. “Approaches to Insect Problems in Paper and Books.” http://www.hrc.utexas.edu/conservation/resources/insects. 11. “Health & the Environment are Everything.” http://www.solventfreepaint.com/boric-acid.htm. 12. The soft landing. http://thesoftlanding.com/is-diatomaceous-earth-safe-for-pets/; William Quarles. “Diatomaceous earth for pest control in "Monitoring the field of pest management. Vol. xiv, number 5/6, May/June 1992. 13. Maja Pöschke et al. “Silberfischchen.” 14. Greenfield, Jane. Books, Their Care and Repair. New York, Wilson, 1983. 15. Carolyn Klass. “Silverfish and Firebrats.” https://ecommons.cornell.edu/bitstream/handle/1813/14351/Silverfish%20and%20Firebrats.pdf?sequence=2 16. Sheng-Yang Wang et al. “Essential oil from the leaves of Cryptomeria japonica acts as a silverfish (Lepisma saccharina) repellent and insecticide” in Journal of Wood Science, December 2006, vol. 52, issue 6, pp.522-526 CC 16 ILLUSTRATIONS TO THE DREADED LEPISMA SACCHARINA By Margit J Smith mjsmith@san.rr.com https://independent.academia.edu/margitsmith Illus. 1. Engraving from Robert Hooke’s Micrographia of 1666: “Of the small silver-colour’d book worm.” Illus.2. Adult silverfish Illus 3. Compound eyes Illus. 4 Rasping mouth and compound eyes Illus. 5. Silverfish damage on book cover Illus. 6 Rasping damage and holes Illus. 7. Damage around edges – eaten all through Illus. 8. Lace-like damage to paper. Illus. 9 Illus. 9. Book damaged extensively throughout http://www.bluestarpest.com.au/silverfish.html. Illus. 10. Damage to textile cap Illus. 11. Dekko Silverfish Paks (Photo: Smith) Illus. 12. Construction of the DekkoPaks (Photo: Smith) Illus. 13. Pest Repeller Ultimate AT Additional literature: “Borax and Boric Acid for Insect Control.” http://www.dodsonbros.com/blog/borzs-and-boric-acid-for-insect-control-228.html. Ebeling, W. Urban Entomology. University of California Press, Los Angeles. Felke, Martin. “Silberfischchen (Lepisma saccharina).” Institut für Schädlingskunde. Harvey L. Sweetman. “Responses of the Silverfish, Lepisma saccharina L., to its Physical Environment.” Journal of Economic entomology. V. 32, issue 5, 1939, p. 698-700. “How to manage pests: Silverfish and firebrats,” University of California Agriculture and Natural Resources. Statewide Integrated Pest Management Program (USIPM). UC ANR Publication 7475. Insect Diagnostic Laboratory. Cornell University. “Silverfish and Firebrats.” https://ecommons.cornell.edu/bitstream/handle/1813/14351/Silverfish%20and%20Firebrats.pdf?sequence=2&isAllowed=y “Insects and Their Allies: Thysanura: Silverfish.” www.ento.csiro.au/education/insects/thysanura.html Mallis, A., and R.V. Caur. 1982. Silverfish. In: Mallis, A. (ed.). Handbook of Pest Control. Franzek and Foster, Cleveland, OH. National Park Service. “Explore Nature.” http://www.nature.nps/gov/biology/ipm/manual/silverfi.cfm. Olkowski, W., S. Daar, and H. Olkowski. Common-Sense Pest Control. Taunton Press, Newtown, CT, 1991. “[Occasional Invaders] A New Look at an Old Group.” Pest Control Technology Magazine. May 2011. Frances Ruth Weinstein. “A Psocid By Any Other Name (is Still a Pest).” Librar and Archival Security: Vol. 6(1), Spring 1984, p. 57 -63. U.S. Department of Health, Education, and Welfare. 1967. Pictorial keys to arthropods, reptiles, birds, and mammals of public health significance. U.S. Department of Health Education, and Welfare. Washington, D.C, 1967. CC 16 ILLUSTRATIONS TO THE DREADED LEPISMA SACCHARINA By Margit J Smith mjsmith@san.rr.com https://independent.academia.edu/margitsmith Illus. 1. Engraving from Robert Hooke’s Micrographia of 1665: “Of the small silver-colour’d book worm.” Illus. 2. Adult silverfish Illus 3. Compound eyes Illus. 4 Rasping mouth and compound eyes Illus. 5. Silverfish damage on book cover Illus. 6 Rasping, damage and holes Illus. 7. Damage around edges – eaten all through Illus. 8. Lace-like damage to paper Illus. 9. Damage to textile cap Illus. 10. Dekko Silverfish Paks (Photo: Smith) Illus. 11. Construction of the DekkoPaks (Photo: Smith) Illus. 12. Pest Repeller Ultimate AT Illus. 13. Hops strewn behind books in 500 year old chapel library in Southern Bavaria. Illus. 14. Interior of the chapel in Isny. 1