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5

INSECT DYES

LAC

Summary of Basic Information


Usage: Textile dyeing.
Common name of product: Lac dye.
Product type and form traded: Concentrated extract.
Botanical source: The lac insect, Laccifer lacca (super family: Coccoidea); a parasite of a large number of trees.
Synonyms forbotanical source: Kerria lacca.
Distribution: Northern India, through Bangladesh, Myanmar, Thailand, Indochina and Yunnan Province of China.
World production: Not quantifiable.
International trade: Small; possibly 10 tonnes annually.
Major producers: India and China.
Importers: No clear regular buyers.
Availability of reliable published information: Poor.

Description and Dyestuff Uses

Lac dye is the scarlet pigment present in the live, pre-emergent insects (Laccifer lacca; syn. Kerria lacca) which develop in a resinous cocoon, known as "sticklac" on the twigs of over 160 host trees in an arc from northern India through to Indo-China. The dyestuff is obtained by aqueous extraction of sticklac; the resinous residue is further processed to "seedlac" and to the fully refined "shellac".

The water-soluble dyestuff, lac dye is composed of analogues of laccaic acid, mainly in the form of ammonium salts. These pigments are present at up to 10% in sticklac which has been harvested before adult insects depart their cocoon. Processed seedlac and shellac have a low content of laccaic acids but retain a yellow water-insoluble pigment, erythrolaccin.

From ancient times, lac dye has been employed in India as a skin cosmetic and for the dyeing of wool and silk, while China has a tradition of usage for leather dyeing. The colour of the dye can be modified by the appropriate choice of mordant from violet to red and brown.

Seedlac and shellac, the major processed products of sticklac, are employed in varnishes, paints, printing inks, sealing wax, micanite compounds, as coatings for pharmaceutical and confectionery products.

World Demand and Supply Trends

International Trade

The history of substantial trade in sticklac derivatives commenced during the eighteenth century with the export of lac dye by India. Up to nearly the end of the nineteenth century the dye trade was buoyant and was still more important for India than exports of seedlac and shellac. However, the advent of cheaper and superior synthetic dyestuffs rapidly eroded demand for lac dye. Since the late 1940s, international trade in seedlac and shellac has declined also from competition by synthetic alternatives.

A minor trade in lac dye exists today but accurate quantification is difficult owing to deficiencies in the compilation of statistics by several potential exporters and importers. Only India clearly identifies lac dye in its export statistics and these reveal an irregular annual volume of shipments (0 to 15 tonnes annually over 1988-93) and of destinations.

Production and Exports

The major producers of sticklac and its derivatives today are India, Thailand and the People's Republic of China; the first two are also the major exporters of lac products and share almost equally the export market, while China's production is mainly consumed on the domestic market. Minor producers include Bangladesh, Myanmar, Viet Nam and Sri Lanka.

In India, lac dye usage is small and the bulk of the aqueous dye extract, obtained in the first step of processing of lac is allowed to run to waste. Processing of sticklac is oriented towards manufacture of seedlac and shellac, of which some 80% is exported, but this trade has declined also as a result of competition from Thailand and synthetic resins. India's annual production of sticklac was approximately 50,000 tonnes in the mid-1950s and reduced to around 12,000 tonnes by the late 1980s. Over the same period, India's exports of lac fell from 29,000 tonnes to around 7,000 tonnes per annum (predominantly of refined shellac) with the USA, Western Europe and (prior to 1990) Russia as the principal market outlets. The most recent statistics show a continuing downward trend in lac exports with a figure of 4,500 tonnes in 1992/93. While the scale of the industry has diminished in India, it remains of socio-economic importance to an estimated 3 million people, mainly tribal groups, in West Bengal, Bihar, Madhaya Pradesh, Orissa and Assam. Cultivation of sticklac is a spare-time agroforestry activity which fits in with production of staple food crops. Individual producers sell a few kilograms of sticklac which then passes through an intermediary marketing chain to processors. The majority of Indian exports are shipped from Calcutta.

Thailand's production and exports of lac commenced in the 1950s and progressively eroded India's share of the international market through keen pricing. Recent exports have been of the order of 7,000 tonnes annually, mainly of the partially refined seedlac. There is no reported export oriented production of lac dye in Thailand.

China's main cultivation area for sticklac is the province of Yunnan, where recent annual production volumes have been 4,000-5,000 tonnes of crude sticklac and 2,000-3,000 tonnes of processed shellac, together with an unspecified volume of lac dye. Production has been undertaken on a smaller scale in the province of Fujian since the mid-1950s. Exports of shellac are comparatively small at approximately 500 tonnes per annum with Japan as the principal buyer.

Prospects for New Suppliers

No upswing in demand for lac dye may be expected within developed country markets in textile applications but, new usage in food colouring is highly unlikely in view of the costs of testing for safety and the availability of established alternatives. Prospects for increased consumption within producer countries also appear slim in the textile and leather dyeing industries in the face of competition from synthetics which are in regular supply and of a more consistent quality.

Demand for lac in developed country markets appears stable but with no sign of growth prospects. Some potential may exist for increased consumption of lac within those larger developing countries with growing populations and industrial bases but on the evidence of lac's competitive status within India this may not be great.

Cultivation, Harvesting and Processing

Climate and Host Trees

Lac insects can be cultured over a fairly wide range of the tropics and sub-tropics and on a large number of host trees (see Table 10).

Insect Species

The lac insects fall under the Laccaferinae sub-family of the Lacciferidae, and of the various species the most important for commercial production is Laccifer lacca. In India, two strains are cultivated, "kusiumi" and "rangeeni", which differ in their seasonal cycle and preferred host trees. Strains in other lac producing countries are less well defined.

Production Systems

ac cultivation is a seasonal, part-time agroforestry activity which may be based on cultivated or wild host trees. In order to obtain maximum yields of sticklac, the insects are cultured, the host trees are managed and attention is given to control of parasites.

Husbandry

The first operation is pruning of the host tree in order to stimulate the growth of young shoots which provide sap as food for the insects. This is done four to six months prior to inoculation of the tree with "broodlac", a cocoon containing mature females at a stage just prior to emergence. Eggs laid on the host develop into larvae and form a resinous cocoon ("sticklac"). Harvesting is undertaken approximately six months later and the tree is subjected to a repeat treatment of pruning and inoculation.
 

Table 10: Some of the more important host trees
 
 
 Country
Common name of host tree
Species
Family
India:
(a) most common:
dhak/palas Butea monosperma (Lamk) Taubert Leguminosae
  Ber Zizyphus mauritanea Rhamnaceae
  Kusum Schleichera oleosa Sapindaceae
(b) others include: khair/cutch Acacia catechu Willd. Leguminosae
  Babul A. nilotica Willd. Leguminosae
  Arhan Cajanus cajan Leguminosae
  Sappan Caesalpinia sappan L. Leguminosae
  Pipal Ficus religiosa L. Moraceae
  Banyan F. bengalhensis Moraceae
Thailand - 
most common:
rain tree Samanea saman Leguminosae
China - include   Cajanus cajan 
Dalbergia balencea Hibiscus spp.
Leguminosae 
Leguminosae 
Malvaceae

A coupe system of management, involving resting of the trees in alternate years, has been devised by the Indian Lac Research Institute. This involves variations according to the insect strain and the host tree.

Harvesting

Harvesting involves cutting off the twig with the attached sticklac. For lac dye production, this should be done before all of the insects escape since they contain, rather than the resin, the desired pigment. The insects are killed by exposing the sticklac to the sun. When the primary objective is seedlac and shellac production, most of the insects may be allowed to escape as the quality of the product is partly assessed on its colour; the paler the better.

Processing

Twigs and other extraneous matter are first removed from the sticklac by hand picking, winnowing and sieving. Processing is undertaken as quickly as possible thereafter in order to avoid deterioration.

Lac dye is isolated as the next step, both for its deliberate production and for its discarding if the primary purpose is seedlac/shellac production. The operation involves crushing the sticklac and extraction several times with water; insects and other debris are removed also at this stage. The dyestuff is obtained as a precipitate on acidification of the aqueous extract.

The washed resin obtained after dye removal is known as "seedlac". Conversion of seedlac to the fully refined product, "shellac", can be accomplished by several processes: simple melting and filtering under pressure; melting and extrusion under pressure; and solvent extraction. Bleaching is carried out to obtain the palest form of shellac.

Yields

Sticklac yields are dependent upon various factors: the insect strain, the host tree and the management system. Annual yields of sticklac per tree reported for Bihar in India are: 6?10 kg on kusum (S. oleosa); 1.5-6 kg on ber (Z. mauritanea); and 1-4 kg for palas (B. monosperma).

Pigment contents in sticklac can be as high as 10% but the yield of isolated lac dye can be below 1% with poor quality sticklac and inefficient extraction methods.

The yield of fully refined shellac is approximately 50% of the sticklac raw material.

Developmental Potential

Lac cultivation and seedlac/shellac processing have been thoroughly researched in India. The main requirement on these topics is full implementation by producers and, where necessary, the devising of appropriate modifications in other countries (e.g., the most suitable host trees and coupe systems). Methods of improved control of lac parasites and of preventing the lac insect from developing as a pest on non-host species need further study.

Superior, more efficient means of producing lac dye certainly could be developed. But in the absence of clear evidence of the potential for a growth in market demand, investment in such research on lac dye would be difficult to justify.

Prospects for growth for international trade in seedlac/shellac are not promising. With these products, however, non-traditional producers might usefully assess demand trends within their domestic markets and the value of encouraging production ? as an additional cash crop component within agroforestry systems ? for import substitution purposes.
 

SELECTED BIBLIOGRAPHY

Production Economics and Markets

BHARDWAJ, S.P. and PANDEY, R.K. (1993). Study of production, trade and policy reform for lac cultivation in India. Bihar J. Agric. Marketing, 1(4), 404-419.

RAO, A.R. and SINGH, P. (1990). Lac cultivation and marketing. Indian Forester, 116(5), 459-463.

RATH, L.K. et al. (1992). Kusmi lac cultivation: a remunerative enterprise for the tribals of Orissa. Indian Farming, 42(9), 3.

SAHANI, D.V. (1990). Agro-climatic feasibility and economic viability of lac cultivation in Bhandara District of Maharashtra State: a micro-level model. pp. 185-202. In: Advances in Forestry Research in India, Vol. VI, ed. R. Parkash. Dehra Dun, India: International Book Distributors.

VISWANATH, S. et al. (1994). The butea tree for lac and rice production in India. Agroforestry Today, 6(2), 10.

Agroforestry Systems; Insect Cultivation, Harvesting and Processing

GHOSH, A.K. et al. (1964). Reclamation of lac dye from lac effluents. Research and Industry (India), 9(5), 129-131.

HOU, K.W. et al. (1991). Cajanus cajan intercropped with host trees of lacca insects: restoring land from shifting cultivation in Yunnan province. pp. 195-196. In: Agroforestry Systems in China, ed. Z.H. Zhu et al. Co-published by Chinese Academy of Forestry and IRDC Regional Research Office for Southeast and East Asia, Singapore.

HUANG, P.K. (1982). A brief history of the introduction of the lac insect from Yunnan into Fujian. Wuyi Sci. J., 2, 146-151.

HWANG, J.S. (1990). Uses of the lac insect in industries. Chinese J. Entomology (Taiwan), Special Publication No. 5, 147-152.

KHER, S. and LAKRA, R.K. (1989). Bioecological studies on lac insect, Kerria lacca in Haryana. J. Insect Sci., 2(2), 124-128.

LIU, F.S. et al. (1988). Relation of lac production by lac insects to the chemical composition of host plants. Scientia Silvae Sinicae, 24(1), 106-112.

SENGUPTA, S.C. (1972). Twenty-five years of research in lac. Indian Farming, 22(7), 13?23.

SHELLAC EXPORT PROMOTION COUNCIL. (1981). The Story of Shellac. Calcutta, India: Shellac Export Promotion Council (23 pp.).

TAKEDA, S. (1990). Lac cultivation and host tree plantation in northern Thailand. Southeast Asian Studies, 28(2), 182-205.
 

Dyestuff Chemistry and Applications

BHIDE, N.S. et al. (1969). Lac pigments. Indian J. Chem., 7(10), 987-995.

BOSE, P.K. et al. (1963). The Chemistry of Lac. Ranchi, India: Indian Lac Research Institute.

DEBROY, A.K. and PATHAK, B.C. (1971). Possible uses of lac dye. Indian J. Appl. Chem., 34(6), 243-8, 277-282.

NISHIZAWA, M. et al. (1985). Analysis of natural dyes III. Analysis of cochineal dye and lac dye in foods and dyes. Hokkaidoritsu Eisei Kenkyushoho, 35, 7-11 (In Japanese).

WOUTERS, J. and VERHECKEN, A. (1989). The scale insect dyes (Homoptera: Coccoidea). Species recognition by HPLC and diode array analysis of the dyestuffs. Annales Soc. Entomologique France, 25(4), 393-410.

KERMES

Summary of Basic Information


Usage: (Formerly) as a red dye for wool and silk.
Product synonyms: Kermes (English, French and German); chermes (Italian); quermes (Spanish).
Botanical source: Various species of Kermes scale insects, especially Kermes ilicis (syn. Coccus ilicis or Kermococcus vermilis) of the Coccoidea superfamily; colonizers of certain oak species, especially the kermes oak (Quercus coccifera).
Distribution: Mediterranean and Middle East region.
World production and trade: Unknown; certainly very small.
Availability of reliable published information: Poor.

History and Uses

Kermes is red-crimson dye which is obtained from females of a number of species of Kermes scale insects, of which Kermes ilicis ? a parasite of the kermes oak ? has been the most important. It has a history dating back to ancient times in the Mediterranean and Middle East region when alternatives for dyeing wool and silk were unavailable. The colour descriptors, crimson in English and carmoisine in French, are derived from the word kermes.

The pigment present in the insects is kermesic acid and this requires a mordant in the dyeing process.

Usage of kermes dye was considerable in Europe and the Middle East until the end of the sixteenth century when the cochineal insect was discovered and commercially developed in the Americas. Cochineal contains an analogue of kermesic acid as its pigment and provides a similar colour but more importantly the extractable yield of the dyestuff is very much greater from cochineal than with kermes insects. Cochineal rapidly superseded kermes in commercial dyeing.

Today, dyeing with kermes is effectively restricted to enthusiasts. Although research on kermes species (and related sources, such as "Armenian Red" from Porphyrophora hamelii and "Polish Cochineal" from Margarodes polonicus) as a dye or food colourant source has been reported periodically in the literature, there appears little realistic prospect of it regaining commercial significance owing to the high costs of collection.
 

SELECTED BIBLIOGRAPHY

BARANYVOTS, F.L.C. (1978). Cochineal carmine: an ancient dye with a modern role. Endeavour, 2, 85-92.

DONKIN, R.A. (1977). Anthropos, 72, 847.

LLOYD, A.G. (1980). Extraction and chemistry of cochineal. Food Chem., 5, 91-107.

SARIKSOV, R.N. (1984). The Ararat cochineal-biology, possibilities of maintenance and economic exploitation. Biologicheskii Zhurnal Armenii, 37(11), 916-925. (In Russian with English summary).

SARIKSOV, R.N. and SARKISIAN, S.M. (1979). Rearing of Ararat cochineal, Porphyrophora hamelii Brandt under artificial conditions - dye producing insect. Biologicheski Zhurnal Armenii, 32(3), 200-203. (In Russian with English summary).

SCHWEPPE, H. and ROOSEN-RUNGE, H. (1979). Carmine - Cochineal carmine and Kermes carmine. Carmine, 255-283.

VERHECKEN, A. (1990). Kermes and cochineal dyeing. Reply to comments. J. Soc. Dyers Colour, 106(3), 114.

WOUTERS, J. (1985). High performance liquid chromatography of anthraquinones: analysis of plant and insect extracts and dyed textiles. Stud. Consev., 30(3), 119-128.

WOUTERS, J. and VERHECKEN, A. (1991). Potential taxonomic applications of HPLC analysis of Coccoidea pigments. Belgian J. Zoology, 121(2), 211-225.

ZIDERMAN, I. (1990). Kermes and cochineal dyeing. J. Soc. Dyers Colour, 106(3), 113-114.

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