Start a SERICULTURE (Silk) Production Unit

   

 (226). Start a SERICULTURE (Silk) Production Unit

SERICULTURE INDUSTRY AND ITS POTENTIAL IN INDIA

SERICULTURE, the technique of silk production, is an agro-industry, playing an eminent role in the rural economy of India. Silk-fibre is a protein produced from the silk-glands of silkworms.

Historically, sericulture was introduced for the first time, into China by Hoshomin, the Queen of China. For a long time, sericulture was considered to be a national secret by the Chinese Government, and as an industry it was not known in other countries. Later, it was introduced into Europe and Japan as well. According to reports available, sericulture was introduced into India about 400 years back and the industry flourished as an agro-industry till 1857, with an annual production of two million pounds of silk fibre. The industry survived the onslaught of the Pebrine disease during the period from 1857 to 1895. However, after 1928, the sericulture industry showed a decline in its production owing to the fierce competition from advanced sericulture countries, such as Japan, China and European countries. After the Independence, the industry is flourishing as an agro-industry, giving employment to over 3.5 million people in the Country.

The annual production of silk in the world is estimated at 45,000 tonnes of which Japan and China contribute 18,936 and 13,200 tonnes respectively. South Korea, USSR and India are the  other leading sericultural countries in the world. The industry has survived the stiff competition with the man-made fibres and it is now estimated by the Food and Agriculture Organisation of the United Nations that the total requirement of silk by 1980 would be of the order of 80,000 tonnes, leaving a demand of 35,000 tonnes. Japan, which is the premier silk-producing country, owing to its recent industrialisation, high cost of labour and the shortage of land available foe mulberry cultivation, has its limitations in increasing its production. Further, owing to heavy internal consumption, Japan has become an importer of silk, thus widening the gap between production and demand. This situation has given a boost to the sericulture industry in the developing countries, e.g.India and South Korea.

Among the developing countries, India enjoys a very favourable position for doubling the present status of of silk porduction of 2,969 tonnes owing to the low cost of labour. sericulture is ideally suited for improving the rural economy of the country, as it is practised as a subsidiary industry to agriculture. Recent research has also shown that sericulture can be developed as a highly rewarding agro-industry.

BACKGROUND OF THE INDUSTRY

In developing countries, e.g.India, agriculture and agro-based industries play a vital role in the improvement of rural economy.The limited availability of land, the limited cash returns, and agriculture being confined to one or two seasons in the year, have made villages to look for supporting rural industries, such as sericulture. Agriculture and sericulture are adopted simultaneously by the agriculturists in regions where the ecological conditions are favourable. In India, over three million people are employed in various fields of sericulture. It is a cottage industry and provides ample work for the womenfolk in the rural areas in rearing silk worms, while the male members work in the fields. Recently the enforcing of new ideas by research institutions both in mulberry cultivation and silk-worm-handling among sericulturists, the industry is now practised as a main profession and as a major cash crop, of the country.

Five varieties of silk worms are reared in India for producing this natural fibre. Bombyx mori, the silk worm, feeds on the leaves of Morus to produce the best quality of fibre among the different varieties of silk produced in the country. Antherea assama is confined to only Brahmaputra Valley of India in the world.It produces the famous mugasilk.Tasar silk is a product of Antherea mylitta, which feeds on Terminalia tomentosa grown in the thick jungles of Bihar, Madhya Pradesh and Orissa. The recent introduction of Antherea royeli and Antherea perniyi has enabled the country to produce the oak tasar silk, Phylosamia ricini, the eri silkworm, which feeds on Ricinus communis, is raised in Assam and Orissa commercially.

Of the total production of 2,969 tonnes of silk in India, as much as 2,445 tonnes is produced by the mulberry silkworms,Bombyx mori.

Mulberry silk is produced extensively in the states of Karnataka, West Bengal and Jammu and Kashmir. About 85 per cent of the country's production is contributed by the Karnataka state by rearing multivoltine hybrids of silkworm and this activity enables the sericulturists to harvest five to six crops a year. Jammu and Kashmir, owing to its salubrious climate during autumn and spring, is producing silk by rearing univoltine silkworms. Other states, namely, Andhra pradesh, Assam, Tamil Nadu, Uttar Pradesh,Himachal Pradesh and Punjab, contribute roughly 1.8 percent to the total production of mulberry silk in India.The State wise silk production in the country is given in Table 1.

Table1. Raw Silk Production in India (1974)
State	Production (in tonnes)	Production (in tonnes)	Production (in tonnes)	Production (in tonnes)
	Mulberry	Tasar	Eri	Muga
1.Andhra Pradesh	..	1	..	..
2.Assam	7	..	87	41
3.Bihar	..	234	3	..
4.Himachal Pradesh	2	..	..	..
5.Jammu and Kashmir	68	..	..	..
6.Karnataka	2,036	..	..	..
7.Madhya Pradesh	1	117	..	..
8.Maharashtra	..	1	..	..
9.Meghalaya	1	..	..	..
10.Orissa	..	19	..	..
11.Punjab	1	..	..	..
12.Tamil Nadu	9	..	..	..
13.Uttar Pradesh	4	..	..	..
14.West Bengal	316	21	..	..
15.Tripura	..	..	1	..
Total	2,445	393	91	41

Tasar silkworms are reared traditionally by the tribal people of Madhya Pradesh,Bihar, Orissa. These 3 states mainly contribute to the production of tasar silk in the country. The recent rearing of Antherea royeli & Antherea perniyi has enabled the country to produce the oak tasar silk in the sub-Himalayan belt & in Manipur.
Muga silk is grown exclusively in Assam & it is still considered to be a ceremonial dress by the local population.
Assam produces as much as 90% of eri silk in the country by rearing eri silkworms on castor leaves.

MULBERRY SILK

  

The systematic cultivation of mulberry, the food plant of Bombyx mori, is the first step in the production of mulberry silk. The total area under mulberry in India is 1,20,567 hectares, of which only 28,781 hectares is irrigated Whereas, mulberry is raised as a bush plantation in Karnataka & West Bengal, it is grown as trees in Jammu & Kashmir. Four Indian species of Morus, namely Morus alba, M.indica, M. serrata & M. laevigata, are raised as main food plants of silkworms.

The propagation of mulberry in Karnataka & west Bengal is through vegetative propagation, whereas root-grafting & bud-grafting are practised in the hilly areas of Jammu & Kashmir & Uttar Pradesh. Considering the ecological conditions, such as rainfall & the nature of soil, different systems of plantations for raising mulberry are practised in India.In the rain-fed areas,mulberry is planted at a distance of 7.6*7.6 cm whereas under irrigation the spacing of 5 cm* 5cm & the row system ( 4 cm between rows & 15 cm between plants) are followed. In West Bengal, a modified system of row plantation, popularly called 'Malda System' is practised even under rainfed conditions, because of the rich soil & heavy rainfall.Recently, tree plantation have ben introduced into Jammu & Kashmir.

The cost of producing mulberry has a direct impact on the cost of producing cocoons, as nearly 605 of the total cost of production of cocoons goes to the production of mulberry leaves.

Experiments conducted in the moriculture divisions of the research institutions to evolve new varieties of mulberry & improved methods of cultivation have shown that over 30,000 kg of quality leaf can be produced per annum at competitive costs against 15,000 kg by adopting the traditional methods under irrigation. Many high-yielding varieties have been introduced into the country, & they not only double the leaf yield, but also maintain the succulence of the leaves, a factor which is very important under tropical conditions.

SILKWORM-REARING

 

In India(Karnataka state), where the temperature ranges from 16-31 degree centigrade, enjoys favourable climatic conditions for rearing the silkworm Bombyx mori throughout the year, whereas in West Bengal, the multivoltine silk-worm rearing is practised even under adverse conditions of temperature. In Jammu & Kashmir, the rearing of silkworms is practised once a year during May-June.

Of a life span of 50 days of B.mori, the egg stage lasts 10 days, the larval stage lasts longest-25-30 days. The pupa stage takes 10 days. The silkworm pass 4 moults during growth. The total quality of leaf required to raise a unit of 40,000 larvae(100 dfls) is 500-600 kg by using the traditional methods. The silkworms consume as much as 95% of the food after the third & fourth moults. At the end of the larval duration, the silkworm emits silk from its mouth & constructs a cocoon on a scaffolding. The cocoons produced by hybrids are used for extracting the silk fibre. For preparing the hybrid silkworm eggs, pure races of silkworms are raised in seperate areas. The cocoons are preserved properly in the egg-producing factories, popularly called silkworm grainages. the moths are allowed to emerge. The selected combination of moths are allowed to copulate for 4 hrs. The male after the first copulation is either rejected or used for copulating with another female. Later, the female is consigned to a dark plastic 'cellule'. She lays about 400 eggs in 24 hours. At the end of 24 hours, the female is crushed & examined for hereditary diseases. Only certified disease-free hybrid eggs are reared for industrial silk production.

Considering the various factors, such as the place of origin,voltinism, the colour of the cocoons, the larval markings, the colour ,shape & size of cocoons,the silkworms are classified into different breeds. The multivoltine races & their hybrids are reared in West Bengal & Karnataka. Owing to the non-diapausing of the eggs & the copious growth of the mulberry, these breeds can be reared six times & the cocoons are harvested after 2 months. These multivoltine hybrids have a short larval duration & are generally poor yielders of cocoons. Bivoltines, because of the interruption of diapause, can have only 2 life-cycles a year. However, its possible to break the diapause artificially by treating 1-day old eggs in Hydrochloric acid of 1.064 specific gravity at 46.1 degree centigrade. By adopting this technique, it is possible to take more than 4 crops in a year. Univoltines & bivoltines require more leaves than multivoltines. However, the yield & quality of the cocoons are superior to those of multivoltines. The multivoltine silkworms yield about 25 kg of cocoons per 40,000 eggs reared, whereas the bivoltines yield 40 kgs. The average annual yield of cocoons in India is as low as 150 kg under rainfed conditions, & under irrigated conditions, it is about 400 kg.

SILK-REELING

 

The cocoons are cooked in hot water & the silk fibre is unwound from the cocoons.This process is called 'reeling'.

The silk consists of two proteins, the inner core of fibroin & an outer cover of gum sericin. During reeling, the cocoons are processed in hot water at 95-97 degree centigrade for 10-15 minutes. This process is called cooking. This cooking will enable the sericin portion to get softened & make unwinding easy without breaks. The cocoons after cooking are reeled in hot water in different types of machines. In India, 61 percent of the silk amounting to 1,320 tonnes is reeled on the country-type charka numbering 6,656. The silk produced with the country charka is of very poor quality, as the thread is not uniform, as it carries many slubs etc. The improved cottage-type basins have been introduced recently into India. Provision for button-holes & a proper croisure system to maintain the thickness of the fibre, & to control the defects of neatness in the cottage basin have facilitated the production of better-quality silk. As  much as 806 tonnes of silk is produced by 4000 cottage basins in the country.

Large-scale basins organised scientifically are arranged in filatures for the extraction of superior quality fibre. The silk produced by the filatures is superior because of the low level of defects of cleanliness & uniformity in the thickness of the fibre. Only 8% of the total production of silk in India is contributed by filatures.

The silk produced from the multivoltine races of silkworms is poor in quality & is known to have greater defects, such as lousiness, & defects in neatness & cleanliness & is of very poor quality in light of the international D grade. The silk produced by the bivoltine races of silkworms possesses superior neatness & cleanliness, is without lousiness & has high tensile strength & stands to the international A grade.

The new technology of handling silkworms in the country has shown that bivoltine silkworms, producing the international quality of silk, can be produced throughout the year in the Karnataka state in India. It has been shown that, on an average, 30-35 kg of cocoons, yielding 3-4 kg of high grade silk can be produced by rearing 40,000 eggs of bivoltines, as compared with 25 kg of cocoons & 1.4 kg of low-quality fibre from multivoltines.

BIVOLTINE COCOON HARVEST

      

Research observations have shown that the cocoon production can be increased significantly at economic costs.
It is programmed to produce 800 tonnes of bivoltine silk in Karnataka alone by 1980 & increase silk production from mulberry in India to 3,500 tonnes.

Non-mulberry silk industry
Tasar culture. Three species of Antherea are used for the extraction of tasar silk in India. They are Antherea mylitta, A. perniyi & A. royeli. In the case of the non-mulberry silk produced in India, 393 tonnes is produced from Antherea mylitta in Madhya Pradesh, Orissa & Bihar. This silkworm is reared on trees of Terminalia tomentosa,Terminalia arjuna found in the jungles of central & north-eastern parts of India. The tasar silkworms also exist in nature in jungles & are collected by the tribal people during certain seasons. The first crop, usually called the seed crop, is raised during May to July, whereas the commercial crop is raised during October-November.

Moths emerge from the cocoons of the November crop in June. The female moths are allowed to lay eggs after copulation in small baskets called manias. The eggs are collected & tied to the trees so that the hatched silkworms crawl up to reach the leaves of the food plants. Tasar silkworms are reared wild in nature & they survive exposed to the vagaries of nature & predators. They are uaually green. However, yellow, blue & white larvae are also reported. The larvae pass 4 moults before they complete their duration. At the end of the larval period, the larvae spin a ring-like structure around the twin & a long peduncle before it constructs the cocoon. The cocoons are large & brown or yellow. When the rearing is practised under cultivated conditions, the rearers protect the worms from pests & predators to harvest rich crops.

The cocoons are cooked in caustic potash & reeled to extract the fibre. They are also spun for manufacturing coarse fibre.

Tasar rearing. The recent introduction of Antherea perniyi & A. royeli on oak in Manipur has opened up new vistas for the production of superior quality tasar fibre in India. The cocoons spun by the Antherea perniyi can be easily reled & superior-quality fibre can be extracted. Antherea royeli is available in oak jungles of the sub-Himalayan belt. The cocoons are made up of 2 layers, an outer layer of thin floss & an inner thick shell of silk. The silk can be extracted only from the inner layer. Hybrids of A. perniyi & A. royeli are being exploited commercially for the production of quality tasar silk in India. A target of 650 tonnes of silk is proposed to be produced by the end of the Fifth Five-year Plan.

Muga culture. The golden-yellow silk produced by Antherea assama is found only in the Brahmaputra Valley of India. This species of silkworm is semi-domesticated in that the worms which crawl down at the end of their larval period are collected by the rearers. They are allowed to spin cocoons in the rearer's houses.

The worms are raised on Som(Machilus bombycina) & soalu(Litsaea polyantha) -trees.
A single female moth of muga lays 150-200 eggs after copulating with the male for 6-8 hrs. Usually, the female is tied to a 'kharika' for laying eggs. The larvae are reared, outdoors on trees of som or soalu.The young ones are yellowish with black markings on the body. They have the habit of crawling down the trees in groups when no leaves are left. During this time, the rearer transfers the worms to another tree. At the end of the larval period, when the worms are ready to spin the cocoons, they crawl down the tree in search of a suitable place for the construction of cocoons. Such worms are collected by the rearer & are allowed to spin the cocoons in 'jali', made of dried twigs.

The cocoon has a very weak peduncle & is golden-yellow. The cocoons are boiled in soap & soda aolution & are reeled on an appliance called "bhir". It is a tradition in Assam to raise muga silk. The total production of muga silk in India is 41 tonnes & is estimated that the country can produce 120 tonnes by 1980.

>Eri culture. The silk produced by Philosamia ricini is called eri silk. It is grown in Assam & in the eastern parts of India. The heavy rainfall & humid atmosphere in these parts are suited to eri culture. The food plants for Philosamia ricini is castor.The alternative food plants are <i<="" i="">but eri culture is mainly practised on castor.
This silk worm is multivoltine & is reared indoors. The eggs are white, hatch in ten days. The hatched larvae are mounted on castor leaves in the rearing-house & are allowed to grow by periodical feeding. The worms pass four moults during its larval period of 30-32 days. Eri silkworm is generally hardy & not easily susceptible to diseases. at the end of the larval period, the larvae crawl in search of a suitable place among castor leaves to spin the cocoons. The cocoons are usually white. However, brick red cocoons have also been observed.
The cocoons of the eri silkworm cannot be reeled, as they are made up of uneven fibres. Usually, after the emergence of the moths, the cocoons are used for producing spun-yarn. Ninety-one tonnes of eri silk is produced in the country, & it is proposed to produce 375 tonnes by the end of the Fifth Plan.</i

Research findings have shown that under the existing acreage of food plants of silkworms, it is possible to increase the silk production 3-fold, in addition to increasing its quality. The introduction of new technology of handling Bombyx mori silkworms into the major sericultural tracts of the Karnataka state has enabled the state to produce a significant quality of bivoltine silk standing to the international grades. This silk was originally imported. Its addition to the import substitution, the introduction of bivoltine silk production will enable the country to enter the export market of raw silk, opening a new directional approach to the development of sericulture in the country. It is proposed to produce over 800 tonnes of bivoltine silk by the end  of the Fifth Five-Year Plan. The impact of bivoltine silkworm-rearing has already been felt by the sericulturists in Karnataka.

In addition to the higher returns of over Rs 10,000 per acre & the quality of cocoons, there is a significant improvement in the production of the existing multivoltine silk, as the bivoltine males are used for cross-breeding with the multivoltines. a significant break-through in controlling the diseases of silkworms & mulberry has ben achieved through the efforts of the research institutes in India. It has been shown that silk production in India can be increased from the present standard of 25kg per hectare to 140 kg under irrigated conditions & from 10 kg per hectare to 25 kg under rainfed conditions & the country's production can be increased 3-fold. These observations have a significant influence on the employment potential of the rural people increasing the employment potential from 30.37 lakhs of persons to 37.94 lakhs by 1980.

Recent findings relating to the rearing of tasar silkworms on oak plants in the sub-Himalayan range & in Manipur have placed the country in a new set-up of producing a significant quantity of quality tasar silk. It has also opened up new avenues for introducing & improving sericulture. It has also enhanced employment potential to the tribal & poorer sector in the hilly areas. Thus the country is poised for a white revolution leading to the production of international-quality silk, both in the mulberry & tasar sector & increasing the total silk production to 3500 tonnes providing employment potential for 37 lakhs of rural people in various fields of silk production.

How Silk is Produced

From the Cocoon to Yarn

Silk is produced by various insects, but by far the largest quantity comes from the silkworm 'Bombyx Mori'. This is the silk worm, which feeds on mulberry leaves and forms a cocoon of Silk before pupating. The threads from several cocoons are subsequently unwound together to form a single strand of raw silk. This fine thread is the basic component of all Silk yarn and fabric. Some of the gum, which the silkworm uses to hold the cocoon together, remains to assist the delicate fibre during processing. It is subsequently washed away.

Silk Weaving

Weaving is the operation that creates a fabric by interlacing the warp yarns (lengthwise) and the weft yarns. Weaving is carried out on looms, after a series of preliminary operations including:

· Warping: this means preparing the warp by rolling all the warp-yarns on to a beam, under the same tension, strictly parallel to each other and in a certain order.

· Pirning: the weft (cross-wise) yarns are put on to a pirn, which is then placed inside the shuttle in order to lay the weft-yarn between the warp-yarns.

In the past twenty years, enormous strides have been made in improving not only the machines involved in the preparation of weaving, but in the loom itself. Non-stop weaving has been made possible by the introduction of automatic pirnchanging. And there are now shuttleless looms, (more properly called weaving machines). These machines use lances, or projectiles, or a jet of compressed air to shoot the weft-yarn between the warp-yarns, instead of the traditional shuttle, and at vastly higher speeds. This increased automation also meant that one weaving-worker can now look after 20 looms at the same time, instead of only 4 traditional looms. This has consequently led to much greater yield and productivity.

Some of the modern weaving machines are large enough to weave fabrics 3 metres wide. In addition to their greater speeds these machines also offer the advantage for the weaver of enabling him to divide this large width into several smaller widths, for example 3 times 90 centimetres.

Although modem weaving machinery has made enormous progress, certain specific types of silk can only be made on ordinary looms, as they are too complex to be woven on highly-automated machines, running at very high speeds. This is notably the case for high-novelty fabrics, and even more so for the reproduction of traditional fabrics used for wallcoverings, upholstery etc.

Many of these fabrics are produced on Jacquard looms, called after their Lyonnais inventor, who in 1801 perfected the existing system of patternweaving, by the use of perforated cards. The Jacquard loom makes it possible to weave intricate and multi-coloured patterns directly into the fabric, and thus create highly elaborate and handsome fabrics.

As soon as they come off the loom, the fabrics are thoroughly inspected so as to eliminate any defects that may have occurred during weaving.

Dyeing, Printing, Finishing

There are two main types of silk fabrics, each with its own specific characteristics:

· The first category includes those fabrics made from yarns which have been dyed beforehand: these fabrics are known as yarn-dyed or dyed-woven (eg, taffeta, duchess     satin, many pattern-woven fabrics)

· The second type includes all those fabrics that are dyed after weaving, known as piece-dyed fabrics (eg, crepes, twills, etc).

In both cases, yarn-dyed or piece-dyed, the dyeing operation is always preceded by boiling-off, a process in which the gum (sericin) is removed from the fibre. This results in a weight loss of 20-25%. In some cases, this loss is made up for by the addition of vegetable or mineral substances, which the fibre absorbs in order to have better "body" when this is required for certain end-uses.

Dying

Up until about 1815-1830, only yarn-dyed fabrics were woven, as piece-dyeing was still unknown. Yarn-dyeing still uses the same basic technique, which consists of soaking the skeins of raw silk in tanks containing the dyestuff.

Piece-dyeing, introduced in Lyon, became an industrial process around 1849, and for a long time remained a speciality of Lyon Region. There are several different processes of piece-dyeing. The fabric can be fed into the dye-bath through two cylinders, or it can be fixed to a round jig which is immersed in the bath. While the fabric is attached to the jig, the dyestuff is fixed, and then the fabric is rinsed and dried.

Printing

Printing consists of transferring a pattern to the fabric. Nowadays, printing is carried out in the following ways:

· Block-printing: wooden blocks are engraved with the pattern to be printed, and the raised parts of the block transfer the dyestuff to the fabrics. However, this process is slow and laborious, and today is only used on a very small scale for handicraft fabrics.

· Roller-printing: the roller-printing method was invented by the Scotsman Bell in 1785. The fabric is printed mechanically by passing through two rollers which have been engraved with the required design. This method is ideally suited to very long runs, and so is not used very often for silk fabrics.

· Screen-printing: sometimes knows as "a' la lyonnaise", because the city of Lyon seems to have been the first to industrialise this process around 1850. A fine gauze is stretched tightly over a metal frame, and the design to be reproduced is transferred to the gauze. By a photochemical process, the "pores" in the gauze are partially blocked off allowing the dyestuff to be squeezed through the gauze where the design is to be printed. This process enables several colours to be printed one after the other, each colour requiring one frame. The design is printed on to a white fabric, or on to fabrics already dyed with a base colour. In this case, the base colour is not fixed, so that the colours printed through the screen destroy and replace the base colour. This type of printing is particularly intended for high-novelty fabrics, which are usually produced in relatively small quantities. It is, therefore, very widely used in printing silk fabrics.

Finishing

With the exception of pattern-weavers, all fabrics have to be finished. It is the finisher who gives satin its shimmering suppleness and its "hand". Finishing gives a fabric the desired appearance and feel. There are numerous finishing processes, physical and chemical. Finishing includes treatments such as creaseproofing, water-proofing, fire-proofing, etc.

Sericulture and Silk Production

The ancient technique of rearing silkworms for production of silk yarn (and weaving it into expensive cloth) is widely practiced today. Over Rs. 1000 crores worth of silk is produced in Indian annually by more than 27 lakh people, over half of them being women. There is a huge export market too for silk cloth and garments.

However, as in so many other traditional industries, the primary producers get only a fraction of the profits which are usually cornered by middle men and trading houses. Consequently the mulberry cultivators and silk reelers, weavers, etc., continue to live in dismal conditions. They also face hardships arising from pests, non-availability or poor quality of raw materials and price manipulations.

Sericulture and silk production have an enormous potential in our country provided it is made available to rural people, especially women, and its marketing is organized independently. It can serve as an excellent mode for employment generation and augmentation of income. This requires not only providing fresh technological inputs to primary producers but more importantly,

evolving and establishing new systems of organizing production and marketing.The technology of sericulture and silk production is well-known. In brief, various aspects involved in it are as follows:

Mulberry Cultivation: Silkworms feed on mulberry leaves. Hence the rearing of silkworms involves cultivation of mulberry trees, which provide a regular supply of leaves. Worms are introduced through DFLs (Disease Free Layings, i.e. eggs) procured from a quality centre (called grainage). In India, the bulk of mulberry cultivation is done by small farmers (< 4 acres land), usually in clusters of 300-400.

Rearing: The silkworms are actually larvae of the silkmoth. They are reared in specially made trays in rooms with controlled temperature and humidity and regularly fed mulberry leaves. At a certain stage they convert themselves into cocoons. These cocoons are made from a single filament of material secreted by the pupa and wrapped around itself for protection. These filaments upon hardening constitute silk. On an average, 1 acre of plantation would yield 240 kg of cocoons in an year, starting from 100 DFLs. Depending upon whether it is dryland or irrigated mulberry, farmers can harvest the cocoons 4 to 8 times in an year. Reeling: The removal of silk yarn from the cocoons is called reeling. This is done by first cooking them in water to remove the gum, which holds it together, and then unwinding the filaments (reeling). Usually 8-10 cocoons are reeled together. There are three methods for reeling: the

charkha, the slightly more advanced cottage basin and the costly automatic machines.

Twisting: Prior to weaving, the raw silk is boiled in water to remove remaining gum, dyed andbleached, and then woven into the garment – usually on handloom. In some cases the woven cloth may be dyed and bleached.

Species of Silkworms: There are four different species of moths, cocoons of which yield differing types of silk:

Problem/Need

Technology Package

�� Mulberry Silk is the most common among them contributing to nearly 95% of world’s silk production. It is produced from the cocoons of the moth Bombyx mori. Within the species there are many varieties, mainly differentiated according to the number of generations produced annually under natural conditions. Then, hybrids of various kinds have also been developed. Multivoltine varieties (laying eggs several times a year) have been widely propagated to push up yields, but many feel that they are more vulnerable to pests and hence risky for small farmers. The government provides DFLs of various species

through its outlets.

�� Eri silkworm has two varieties – a wild one and a domesticated one bred on castor

leaves. The filament is neither continuous nor uniform. Hence the moths are allowed to emerge before commencing reeling. A white or bright red silk is produced.

�� Tasar silkworms are wild. The Indian Tasar worm feeds on trees of Terminalia species and other minor host plants, while the Japanese and Chinese worms feed on oak and other allied species. Reeling can be done as with mulberry worms.

�� Muga silkworm is found only in Assam. It feeds on two local species of shrubs – Machilus bombycina and Litsae polyantha, producing a strong, golden yellow thread.

Under the prevailing system in India, all the functions described above are usually carried out by different sets of people and there exists a well-established system of markets where the products of each stage are sold/bought. Being dominated by rich traders, it is here that most of the profits are siphoned off. Hence, in the new technology package, an alternative system is envisaged of a cooperative or collective kind where functions are decentralized yet under the larger umbrella of a people’s organization. The final products are then marketed centrally. Expert inputs are made available for both technical and managerial aspects including marketing.Consequently the high prices available for silk clothes would mean higher returns to the primaryproducers at various stages.

Rearing Equipment

Item Rate (Rs.)

Rearing Trays (3.5’ bamboo) 30

Rearing stands 300

Ant wells 5

Feeding working stands 50

Leaf chambers 350

Leaf chopping boards 60

Leaf chopping knives 50

Thermometers 50

Hygrometers 200

Sprayers (foot operated) 1000

Mats 25

Reeling and Weaving Equipments

Item Rate (Rs.)

Reeling/Spinning machine 4,000

Handlooms 5,000

Twisting machine 50,000

Warping and other accessories 25,000

Equipments and Machinery: Requirements will depend on the functions and stages of theprocess being undertaken. Variations and innovations are also possible. An illustrative list withtypical costs is given in the Table (given above). Prices are only indicative.