[page 32↓]

2.  Background and literature review

2.1. Sericulture as a biotechnical phenomenon

Biology of the silkworm

Silkworms are stenophagous insects that are fed solely mulberry leaves. They through four different stages, viz., egg, larva, pupa and moth for the complete the life cycle.

Adult moths have creamy white wings with brownish patterns across the front wings. The body is very hairy and the wingspan is about 50 mm. Adult females are larger and less active than males. Male moths actively crawl around looking for females. They will copulate for several hours (CISEO, 1997).

Figure 2: The life cycle of silkworm

Insertions: 1. Hatching, 2. 9 –12 days, 3. Brushing, 4. First instar, 5. Three to four days 6. First moulting, 7. 3-7 days, 8. Second moulting, 9, Third instar, 10. 3-4 days, 11. Third moulting, 12. Fourth instar, 13. 5-6 days, 14. Fourth moulting, 15. Fifth instar, 16. 6-8 days, 17. Ripe silkworm, 18. Spinning, 19. Pupation 4-5 days, 20. Pupa inside cocoon, 21. 10-15 days, 22. Emergence of moth, 23. Moth, 24. Eggs, 25. Diapause egg, 26. Non diapause egg, 27. Artificial hatching 11-14 days, 28. interring(no scale)
Source: Veda, K., et al., (1997)

[page 33↓]

After hatching from eggs, the silkworm larvae grow by feeding on mulberry leaves, except during moulting, during immature stage they moult four times then become matured larvae in about 25 days. During this period, the silk glands utilize proteins, amino acids, carbohydrates, etc., present in mulberry leaves as raw material and synthesise fluid silk which is secreted into the gland sacs. The fluid silk, thus secreted, comes out as a silk filament through the spinneret (Veda, K., et al., 1997).

The silk filament is a continuous thread of great strength measuring from 500 - 1500 meters in length. Single filaments are too thin for utilization. For production purposes, several filaments are combined with a slight twist into one strand. This process is known as “silk reeling or filature” (FAO, 1999).


Silk production encompasses planting mulberry trees up to production of eggs from moths, from supervision of single instar of silkworms until the cocooning, the harvesting of cocoons and processing to thread, yarn and fabrics. The complexity of the production activities needs manual labour force.

Sericulture activities are broadly classified into two: the agro-based sector and the industrial sector. The agro-based part involves two distinct phases of activities i.e. mulberry cultivation and silkworm rearing. Silkworm rearing is again differentiated into two: young age rearing from 1st instar to 2nd instar. The 3rd instar although an intermediate stage, is considered as young age. Rearing of 4th and 5th instars comes under late age rearing.

Photo1: Early silkworms

Photo 2: Mature silkworms larvae

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Mulberry trees (Morus spp.)

In flora categories, mulberry belongs to the family Moraceae, genus Morus. The genus Morus has many species and subspecies. Again, under the species and subspecies, there are several varieties. The natural distribution of the genus Morus covers western Africa, Middle Eastern Asia and Central and South America. It is not a natural plant of Europe (Veda, K., et al., 1997).

The mulberry tree is a quickly growing tree providing a lot of leaves. It grows in subtropics and temperate latitudes in evergreen tropics and reaches a height of up to 20 to 25 metres.

It has a wide spread expansion (see figure 3)

Figure 3: Origin and spread of sericulture and Silk Road in 8th century

Source: Sharifi (1994)

Mulberry leaves are the only foods tuft accepted by the silkworm. Therefore every single silkworm breeding activity that is planned has to make sure that a sufficient amount of mulberry trees is grown for food supply.

On the basis of usage of mulberry, the mulberry field is classified into the type utilized for rearing young silkworms and the type utilized for rearing older ones. Regarding the mulberry field for rearing young silkworms, some areas are used exclusively for spring rearing and other areas are used exclusively for summer and autumn rearing (Veda, K., et al., 1997).

The type of mulberry field is selected on the basis of weather conditions of each region, soil conditions and coordination with silkworm rearing.

[page 35↓]

Photo 3: Mulberry plants

Egg production

The production of silkworm eggs correlates closely with breeding success and is mainly carried out in specific institutions. Silkworm eggs are broadly classified into parent eggs and hybrid eggs. In the case of the parent ones, there are two types, parent eggs which are used for preparing hybrid eggs, and grandparents eggs which are used to produced the parent eggs. The hybrid eggs are known as the commercial silkworm eggs from which the larvae are used for producing reeling cocoons from which no adult moths are allowed to emerge. All other eggs are used for producing breeding adult moths.

Silkworms have a wide range of races, some of which are classified in the following manner:

Silkworms are also classified according to colour, shape and size of eggs, larvae, pupa, moth, cocoon, as well as on the basis of larval pattern, strength, course of larval period, quantity of fibre, reelability, etc. According to their utilisation, silkworms are classified, besides the race [page 36↓]used for producing silk fibres there are some which are used for high quality fabrics (fine and lousiness-free) and for special textures (Veda, K., et al., 1997).

Worm breeding

Immediately after hatching, the worms start eating mulberry leaves. A hatched silkworm larvae weighs approximately 0.45 mg and exclusively eats leaves of mulberry tree (Morus spp). The larvae develop in four stages for about 25 days, and between each of the four stages they undergo moulting and at the end they spin cocoons.

Photo 4: Cocoons processing

A silkworm is ready to spin a cocoon when it weigh’s about 5 g. First, a thread capsule is spun and after that the worm spins itself inside its cocoon. A cocoon weights about 1.25 - 2.50 g and has a filament of 500 - 3000 m long, dependent on silkworm breed and cultivation season. The cocoon spinning is completed in two days. In the next two-three days, the larvae inside the cocoons moult and become pupa. The pupa takes 10 days to transform into a moth which is white-grey coloured; The female moth produces 300 - 500 eggs.

The quantity of mulberry leaf supplied during the rearing of advanced stage larvae amounts to 90% of the total supply of mulberry (800 kg – 1000 kg) during the entire larval period.

During the fourth and fifth instar the quantity of mulberry feeding is very large and consequently the labour requirement also becomes high. Therefore silkworm rearing from the fourth instar until fresh cocoon spun is commonly accomplished by silk farmers.

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The silk yarn production begins with selecting for their quality. The cocoons will be sorted into normal and abnormal cocoons. The fresh cocoons normal are reelable to produce raw silk but the abnormal cocoons are unreelable. The abnormal cocoons are double cocoons, perforated cocoons, internally and externally soiled cocoons, thin-end cocoons, thin-middle cocoons, malformed cocoons, etc.

Photo 5: Silk yarn processing

After the first selection of cocoons, they have to be dried. The first goal of cocoon drying is the protection of cocoon quality, to preserve conditions for reeling cocoons and prevent damage that might be caused by long periods of storage. Drying kills the pupa and evaporates moisture that would otherwise ruin cocoons.

Dried cocoon storage conditions are designed to keep the raw material for long periods without any damage from moulds and pests. Cocoon storage should preferably be built with double walls. Cloth or polyethylene bags are recommended as containers for dried cocoon storage.

The technological process for silk reeling is shown in figure 4.

[page 38↓]

Figure 4: Technological process for silk reeling.

Source: Complete set of Equipment for Silk Reeling . Hangzhou Textile Machinery General Factory. The People’s Republic of China (1998), modified

In most modern factories which aim at producing high-grade raw silk, the cocoons are graded on visual inspection or by mechanical tests are actually mixed as in the required proportions. This is called cocoon mixing or blending and is done to ensure speed and uniformity of reeling as well as to obtain the desired effect in raw silk.
The reelable cocoons have then to undergo the reeling processing, after which they are either processed further to raw silk or to thrown silk. The unreelable silk is processed further to spun silk.

2.2. Origin and spread


The origin of silkworms is not definitely known. In general the Chinese Himalayan region is understood to be the origin. There are also opinions naming the north-eastern Indian Himalaya as an origin of silkworm. There is evidence using C14-Isotope-Test that silk production was occurring around 2850-2750 B. C. in China.

[page 39↓]

Development of sericulture in China

In China, sericulture seems to have had its beginning in Huango and Yangtze (Chang Jiang provinces), (FAO, 1980). Diverse literature sources tell of the development of silk production (silkworm breeding, planting and usage of mulberry trees, spinning of yarn and weaving of fabrics) reaching back to emperor Huang-ti and his wife Hsi-ling-shi around 2600 B. C. - eventually even further back to 5000 B.C. (Messerli, 1986). Others tell of exploration in the 1122 - 255 B. C. (Mell, 1955).

Sericulture extension was supported at the highest governmental level and sericulture spread out to small farmers and their education. After short time silk production had spread over approximately half of the former imperial China.

Spreading of sericulture: from China to the rest of the world

China clearly realised the value of its sericulture, not only because of the end product but due to the knowledge gained over thousands of years about silk production, moriculture and processing of silk.

Referring to Silbermann (1897, in Jakobi 1932) a Chinese princess brought eggs of silkworms inside her headdress for the occasion of her marriage to Khotan in East-Turkestan (north-western China). This led to a sericulture industry that lasted for hundreds of years. In the year 552 A. D. two Nestorian monks smuggled silkworm eggs to Byzantium, which was the first step for expansion in the western direction.

The know how of silkworm breeding and of mulberry cultivation came to Korea and Japan with Chinese immigrants in between the years 200 B. C. to 300 A. D. (Zeuner, 1967).

A further expansion came with captures, conquests and population movements of Persians and Arabs. The Moors brought sericulture later in the 9th century to Sicily and Spain. From Spain, sericulture spread to northern Italy, the region that had most of the European important producer- and trade centres in the 15th century. Through annulment of the edict of Nantes 1685, the Huguenots were exiled. They took sericulture with then to Germany, Switzerland, the Netherlands and England. Due to less favourable climate conditions, these countries created a highly developed silk industry. This was the time of separation between raw silk producing countries and those of silk industry, referring to Jakobi (1932). An figure that still dominates the geographical structure of global silk production,

[page 40↓]

Alexander von Humboldt in1809, (Beck, 1991) tells of the importation of sericulture into Central-and South America by Europeans in the 16th century. However successful implementation of some experiments secured Mexico at this time (Jahnke, et al., 2001).

Reasons for shifting of sericulture

Availability of silkworms and mulberries is related to climate and ecological conditions (rainfall, temperature, relative humidity, soil quality, etc.). According to altitude and longitude, sericulture is focussed on regions between the 300 and the 350northern latitude. These are humid to sub humid tropics. The large genetic variability concerning mulberries as well as silkworms opens up many possibilities for breeding and selection, e.g. the expansion to the Fore Asia to approx. 45th latitude degree.

Even more spectacular, sericulture reached production levels up to the 60th latitude degree, e.g. coastal regions in Norway and Sweden.

The general technical know-how was mainly spread with imports of silkworms. The most important reason for expansion and changing denotation of sericulture is moreover of an economic nature. With increasing labour costs and few mechanisation possibilities the production of raw silk became unattractive. In Europe and Japan production practically disappeared completely. In the USA breeding attempts could not keep pace with other countries. In the meantime labour diversification between production of cocoons and trade oriented commercial processing to fabrics. Therefore China, India, Turkmenistan, Uzbekistan and Kirgisistan and newly also Brazil remain, as main producer countries while main processing countries are the USA, Italy and France (Jahnke, et al., 2001).

Developments in younger time

Worldwide silk imports reached a total value of US$ 448 million in 2001 (FAO 2002). Italy and Japan are the most important silk importing countries. The export oriented silk processing industry of Italy is completely dependent on imported raw silk material, of which Italy only buys the highest quality. In Italy an amount of 50 kg raw silk has a import value of US$ 1,275. The largest supplying country of raw silk for Italy is China, at it is for the global market.

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Table 1: Silk, raw and waste production

Silk, Raw and Waste

Production (Mt)

































































Source : FAO statistics (2003) http://www.fao.org

The case of Japan is conspicuous with figures showing Japan as one of the most important global producers in 1961 (57% of world production) but decrease to 559 mt (0.004% of world production). Japanese production technology had been predominant in comparison to Chinese and Japanese international sale positions were even more superior. Since Japan’s industrialization and non-agricultural income possibilities increased, national silk production was not profitable anymore. India pushed into this market gap but China was even stronger than some other countries. In consequence, total production figures grew four times from 1961 and 2002. Nevertheless, volume of world silk production is marginal in comparison to other textile fabrics.

In future, production probably will be shifted from richer countries to poorer ones. Sericulture will be moving more and more into tropical regions. Sericulture is seen as a connoting economic approach of development for rural areas, well suited for diversification of agricultural production. As a labour intensive agricultural production branch sericulture offers agricultural working places and income possibilities but also in preliminary and downstream industrial sectors, like reeling work, weaving mills, spinneries and dyeing factories. Additionally, the products of natural silk product can support diversification of agricultural export commodities. But introduction of sericulture with high hopes of easy and quick success are amiss.

Sericulture consists of strong time controls concerning the provision of inputs to follow phase production. Therefore not only production technology but also exact production programmes and dispensation systems for supply on schedule of breed have to be evolved for [page 42↓]implementation of sericulture projects. Also fresh cocoons are perishable goods and have to be either dried or reeled one week after cocooning. Implementation of silk production to export quality requires marketing measures to be created. These should be located together with cocoon-collection quality determination facilities and, if required, cocoon drying and cocoon storage places (FAO, 1980; Sengupta, 1989).

Sericulture also requires an intensive consulting service by professional personnel. Only through a tight connection between research institutes on regional level (e.g. in China on province level) and consulting services the ascertained technology transfer can occur. Research centres have to be built up with responsibility for breeding and development of adapted mulberry varieties and silkworms as well as to find solutions for production technical problems and the development of new technologies.

Demand for capital for sericulture is evaluated as dependent on production system intensity by different authors (Meenakshisundram , 1983; Patel, 1992).

Independent of the amount of investment required is the development of suitable credit programmes for small farmers and co-operation with credit institutions for financing is indeed important (Kusnaman, 1997). Sharifi (1994) points out that silk production presents an advantage concerning loan repayment due to harvests already available in the first year of cultivation in comparison to many other permanent cultures. Thus, a more rapid start date of repayment and recirculation of loan money is possible through sericulture.

Economy: success in industrialised countries

China is an example of integrated sericulture. Chinese silkworm breeding and the correlated mulberry cultivation produce a range. Moreover sericulture can be combined with tillage, animal- and fish farming systems (Riddle and Zhong, 1988). Figure 5 shows the diverse usage possibilities of by-products and wastes from the different production branches of sericulture.

[page 43↓]

Increasing population densities made irrigated agriculture necessary for constant and higher yields. Meanwhile implementation of fishponds (aquaculture) became possible. That way, a stable and highly productive farming system is created. One system with mulberry trees is to grow them on hillsides with irrigated rice terraces, irrigated rice in shallow areas and ponds whose fish production is secured through wastes from silkworm breeding. The manifold interactions allow a maximum usage of resources (land and labour) and a stability of farming systems.

Stability or sustainability of farming system in addition to the production of silk is further advantage of sericulture in tropical regions.

[page 44↓]

2.3.  Regional view


Archaeological discoveries in the village of Ban Chiang in the north east province of Udon Thani have led experts to believe that Thailand's sericulture history may be as old as China's. An extensive burial site at Ban Chiang yielded evidence of a complex civilisation involving silk production that dated back over 4000 years.

In 1901, King Chulalongkorn made an attempt to upgrade the local silk industry by inviting a team of Japanese experts to aid production. In 1903, the Department of Silk Craftsmen was established under the directorship of Prince Phephatanapong. These early steps marked the beginning of rapid sericultural development in Thailand. Mulberry trees were planted in the northeast, local silkworms were cross bred with the Japanese variety and spinning looms were replaced by more advanced ones. Sericulture courses were taught throughout the Kingdom. By 1910, over 35 tons of silk were being exported annually
Despite the intricate role Thai silk played in high society, a flood of imported fabrics including fabulous silks from China, Persia and Japan made it difficult for local silks to compete. Thai sericulture remained a small cottage industry, most active in the Northeast around Korat, until the mid 20th century (http://iqproducts.8m.com/history)

Silk production gradually decreased over the following three decades due to a lack of government support and because of strong competition from foreign silks. An inability to improve antiquated techniques resulted in limited production.

The FAO reported that a two year project to produce disease-free silkworm seeds/hybrid eggs for sericulture farmers started in December 1997 with the additional objective to train staff of DoAE in sericulture (FAO, 2001). A special training component for the rural disabled was inserted in December 1998. Eight disabled farmers learned the method of cocoon processing with the newly developed reeling machine as well as the making of silk products for the raw silk.

The project's objective is to raise the net incomes from sericulture for approximately 8,000 farm households in the project area. The development and strengthening of farmer groups has been the foundation of all aspects of the project's fieldwork. The project works closely with the permanent staff of the DoAE including three Sericulture Extension Centres. The farmer groups are assisted in all technical aspects of sericulture production from mulberry planting to [page 45↓]fabric design and weaving. The project has facilitated contacts and marketing agreements between the farmer groups and a number of private companies.
By February 2000 the project had supported 45 farmer groups covering approximately 200 villages and 8,000 farmer members. Monitoring data show that production levels and incomes have increased significantly as a result of project activities.

In 2002 Thailand produced 1,510 mt silk (FAO, 2003).


Vietnamese sericulture began more than 3,000 years ago, probably under the influence of China, and has been practised ever since by most village families, largely for their own use and for the domestic market. Exporting started with the arrival of the French about 150 years ago and continued until the Second World War ( ITC, 1997)

In 1985, the Government launched the Silk Integrated Agro Project (SIAP) for the promotion of sericulture. The Vietnam Union of sericulture Enterprises (VISERI) was established in Bao Loc as the agency responsible for management, development and trade. VISERI is part of the Ministry of Agriculture and Food Industry.
Viseri proposed recently that Bao Loc is not the only silk production centre in Vietnam, because the climatic conditions in the Lam Dong highlands certainly make it one of the country’s most suitable areas for sericulture. The subtropical climate (22°- 29° C) contributes to the availability of fresh mulberry leaves all year round. Elsewhere in the country, fresh leaves can not be obtained for about three months in the year because of heavy rains or extreme heat, and cropping can be carried out only 7 - 8 times yearly (ITC, 1997)

The mulberry plantation increased from 36,500 hectares in 1994 to 100,000 hectares in year 2000. Many areas in the country, which are now planted with coffee or tea, could easily be used to sericulture. A shift may become attractive to farmers since the income of Sericulturists can be as much as four times as high as those of coffee or tea growers.
Sericulture is labour intensive and a one –hectare farm employs about 10 persons.
Vietnam is expected to develop into an important international supplier of raw silk and silk yarn (ITC, 1997).

The Viet Nam Sericulture Corporation (Viseri) in conjunction with authorities in Lam Dong Province recently conducted an inspection tour of all silkworm farming households in Lam Ha District, the country’s largest locality specialising in the growing of mulberry and the [page 46↓]breeding of silkworms. It was found that in May and June about 4,000 households had incurred VND216 million (US$14,000) in losses due to poor-quality silkworm eggs imported from China. This loss was largely due to degenerated species of silkworms and spoiled frozen eggs. Chinese specialists in the inspection teams agreed that spoiled silkworm
eggs are the main cause of damages to farmers and they vowed to compensate 60 per cent of losses to the farmers (Sai Gon Giai Phong, 2003)

The FAO reported that the silk production in Vietnam rose from 300 tons in 1970 to 12,124 tons in year 2002 (FAO, 2003).


Malaysia’s small sericulture industry mainly produces cocoons for export to Japan. The producer is Permit Suterasemai, a subsidiary of The Terengganu State Economic Development Corporation. The company’s 540 ha have an output of 640 tons of mulberry leaves every month. Silk eggs are imported from several countries, including Japan.
The country’s imports of silk fabrics have risen rapidly in recent years, from 19 million USD in 1992 to 89.4 million USD in 1995 (ITC, 1997).

In the year 2000 the United Nations Office for Project Services (UNOPS) reported a silkworm development project in Malaysia. The project has two major objectives:

  1. To lay the foundation for the modernisation of the sericulture sector in the country through investment support to selected less-advanced co-operative farms and institutions providing sericulture support services.
  2. To help raise incomes and improve working conditions in the selected co-operative farms, particularly for women who constitute the majority of sericulture workers.

To achieve these objectives, the project finances the following components: improvement and expansion of existing sericulture production; capacity building of sericulture support services; training and pilot activities and support for project management.
This project will benefit about 2,900 members of sericulture work teams, equivalent to about 1,500 households or 6,100 people. It would indirectly benefit about 59,800 people additionally (co-operative members and their families) through increased incomes. Average incomes for workers in project co-operatives are expected to increase by up to 30% over 9 years.

In 2001 Malaysia exported 29 mt reelable cocoons (FAO, 2003).

[page 47↓]


Attempts at developing sericulture in the Indonesian Archipelago date back to the 18th century. Zwaardecroon (1718-1725) and De Haan (1725 –1729), at that time Indonesia was a colony of Netherlander, Indonesia have produced silk yarn 34,5 lbs and exported 300 lbs to Netherlander in year 1735 (Atmosoedarjo, et al., 2000).

The modern sericulture and silk processing industry in Indonesia started in 1950 when some Indonesian war veterans supported by ex Japanese war veterans initiated the sericulture industry as a home industry to support the existing traditional silk weavers with raw silk as their raw material to produce traditional silk fabrics. The government appointed the Forestry Department to develop Mulberry Plantations and sericulture at the borders of forests, to protect the forest from people who destroyed forest for wire wood. By providing to forest workers, a barrier was created to protect the forests, especially on the island of Java (Moerdoko, 2002).

Cocoon production in Indonesia reached its highest level between 1962 and 1966, but collapsed in the 1970s due to the spread of the pebrine disease.
From the 1990´s rising cocoon prices led to a production increase. Development of silk production efforts are now concentrated on smallholder areas.

According to data obtained from the Indonesian Natural Silk Community and the Sericulture Station in Bili-Bili, South Sulawesi, the farmers involved in sericulture production increased from 7,462.00 families in 1991 to 12,631.00 in 2001 (see table 2)

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Table 2: Sericulture Developments in Indonesia 1991 – 2001




Fresh Cocoon


Raw Silk


Farmers Involved (family)
























































Source: Department of Forestry 2001

2.4. Development objectives and the economic challenge

Most developing countries are raw material producers of agricultural commodities. Income generation in developing countries is therefore often dependent on agriculture in the form of small farming systems. Rural regions make about 70 - 90% of governmental areas in most of the world’s developing countries. Table 3 shows the rural population and population density of five big developing countries in South Asia.

Table 3: Rural population and -density of developing countries in South Asia in 1999/2000

Source: World Bank Statistics (2002).

[page 49↓]

In general, the rural population is sensitive to climatic or seasonal changes and thus, changes of market prices but moreover is strictly dependent on their resources (labour and land) as a source and insurance of income.

In Indonesia income figures vary between rural and urban areas. In this case, income per capita should be differentiated into two levels of income, as the urban income is relatively higher than that of the rural population. The data for Gross National Income (GNI) and Gross National Income per capita are shown in table 4.

Table 4: Gross national income (GNI) and Gross national income per capita



GNI $ Billions

GNI per capita



























Note: per capita in 2000 Year.
Source: World Bank Statistics (2002)

For the Indonesian rural population income generation is an important aspect. From the sustainable development point of view that this kind of development assistance is a great advantage for:

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