The whole publication in PDF - Culture in Development

Rumours about the effectiveness of microwaves for killing insects have circulated in the library and archive
community over the past several years. M icrowaves are used successfully in the food , agricultural, and textile
industries to control insects, but this strategy is not recommended for library and certainly not for archival
collections. Microwaves have a limited penetration, and may not penetrate thick books. Their effectiveness also
depends on the type of insect and the intensity and frequency of the radiation. Microwave ovens vary in intensity,
so it is extremely difficult to determine standard times and temp eratures for treatment. The primary argum ent against
microwaves is the danger of damage to treated materials. Evidence from a variety of experiments indicates that
pages and covers can scorch; metal attachments like staples can cause arcing; and adhesives can soften, causing
pages to detach from their bindings in certain boo ks. When metallic objects (staples, paperclips, sp iral binders, etc.)
are indiscriminately placed in a microwave oven cavity, the energy pattern becom es disrupted and distorted. This
condition produces arcing. Two metal objects, such as a staple and the metal cavity wall, are placed in close
proximity and subjected to an intense field of microwave energy, arcing will result. Arcing occurs because the air
between the two metallic objects becomes electrically charged, just as the air between a thundercloud and the earth
becomes charged or ionised. This ionised air becomes an electrical conductor, and electric current then leaps the gap
like a small bolt of lightning. However, lightning only lasts for an instant because it discharges or neutralises the
ionised air, but an arc in a microwave oven will continue, to a greater or lesser degree, as long as the microwave
energy is applied. At the very least, this can cause marking or pitting of involved surfaces, and at worst, can burn
a hole right through the cavity wall or object.
7.4.3 Traditional Methods
Ma n's battle against insect pests is not a battle of today. He has been fighting on this front since the dawn of history.
We know from Homeric writings that the G reeks used sulphurdioxide to poison various insect pests. Gnadinger in
his excellent book Pyrethrum F lower states that pyrethrum flowers were used as pesticides in Persia. In India
aromatic plants and their leaves were used as insect repellents since ancient times. Those known to them were
Gorbach or Shadgranth (Acorus Calamus Linn), Ashvagandha or Asana (Withania Somnifera Dun), tobacco leaves
etc. (Swarnakamal, 1975). As early as the 5th century A.D. the Chinese papermakers added an insecticide to paper,
manufactured from the seed s of the Amur cork tree. Later they were even obliged by law to add an insecticide to
paper (Plumbe, 1987c).
In the 1950s and the 1960s a common, outdated, practice to protect books against insects was to varnish the book
covers. The use of highly calendared board will also reduce infestation. Other precautions are the use of impregnated
book cloth, nylon sewing thread, polyvinyl acetate adhesive (PVA) and no paper sizing with starch, dextrin, casein
(Plumbe, 1987c).
Termites thrive in tropical and subtropical climates. It is worth recalling that termites have two deadly enemies,
sunlight and fresh air (Duchein, 1988). An old and well-tried remedy against termites is avoiding contact of storage
racks with the floor by keeping their legs in bowls containing creosote oil in kerosene oil (1 : 2) (Kathpalia, 1973;
Talwar, 1993).
Gorbach is well known as an effective insect repellent and in the Konkan districts of Maharashtra it is known
as Pandri. It contains an aromatic volatile oil and a bitter substance known as lacorin. Together they constitute a
powerful pesticide. An attack by white ants is often checked by use of powdered Gorbach. Gorbach is an erect
aromatic marsh herb , root-stock being thick and creeping. The leaves and the root-stock make a very effective
insecticide. Ashvagandha, an erect branching under-shrub 1-5 ft. high, is another plant with similar properties. It
was common practice to keep Go rbach and Ashavagandha in ancient repositories and libraries to protect books and
manuscripts from damage by insect pests. Com pounds o f lead and arsenic have also been used to preserve valuable
records. The exudation of the Indian Frankincense tree known as Gugal or Dhup is used in many parts of India and
burnt as incense. It disinfects the house and serves as a fumigant to drive out insect pests. In some Indian museums
leaves of certain aromatic plants, e.g. tobacco, Neem etc. are placed in show cases for the purpose of repelling insect
pests (Swarnakamal, 1975).
7.4.3.1 Neem and Tea Tree
Today many repellents appear that are made of plant extracts. However, current advice is to be very careful with
these traditional repellents. They are still poisonous and may be harmful to humans and the archival material. Plant
products may seem enviro nment-friendly but that does reduce po isonous cha racteristics. Conservators d o well to
remember that nature gives life as well as takes life. Some of these repellents are manufactured as insecticide papers
that come in direct contact with the archives. Other repellents are oils smeared on or impregnated into the papers.
Currently conservation scientists feel that two plant repellents are promising: extracts of the neem tree (Azadirachta
indica) and tea tree o il (Melaleu ca alternifolia). The tea tree is however poisonous because of the high contents of
volatile carbonic compounds (turpentine).
In Australia, the oil of the tea tree (Melaleu ca alternifolia) has been a time-honoured folk remedy for man and
beast. At Macquarie University the anti-microbial activity of a large number of commercial tea tree oils was
examined. Results demonstrated the importance of terpinen-4-ol for activity against microbes. The po werful antimicrobial
activity of p-cymene, a minor component of tea tree oil, was confirmed. Some micro-organisms are highly
susceptible to a combination of terpinen-4-ol and p-cymene. Tea Tree’s essential oils are very clo sely related to
turpentine, which was itself an old -fashioned and multi-use farm remedy. Less than fifty years ago turpentine was
used to cure whatever ailed people and pets. There were reports of turpentine poisoning. M ost people today realise
that turpentine is more toxic than beneficial, but as turpentine has fallen out of favour, the use of chemically related
Melaleuca oil has grown tremendously. Several studies have been published in respectable journals that back up the
folk remedy claims. For example, Tea tree oil has a proven effect against a wide variety of bacteria, fungi, and
yeasts. One study looked at the effects of the oil on normal skin bacteria versus effects on disease causing bacteria.