Silk is a natural protein fiber , some forms of which can be woven into textiles. The protein fiber of silk is composed mainly of fibroin and is produced by certain insect larvae to form cocoons. The best-known silk is obtained from the cocoons of the larvae of the mulberry silkworm reared in captivity (sericulture). The shimmering appearance of silk is due to the triangular prism-like structure of the silk fibre, which allows silk cloth to refract incoming light at different angles, thus producing different colours. 

1. SILK AND SILK CENTRES IN
INDIA
POWER POINT
PRESENTATION

2. SILK
• Silk is a natural protein fiber , some forms of which can
be woven into textiles. The protein fiber of silk is composed mainly
of fibroin and is produced by certain insect larvae to
form cocoons. The best-known silk is obtained from the cocoons of
the larvae of the mulberry silkworm reared in captivity (sericulture).
The shimmering appearance of silk is due to the triangular prism-like
structure of the silk fibre, which allows silk cloth to refract incoming
light at different angles, thus producing different colours.

3. HOW MANY TYPES OF SILK
FOUND IN INDIA?
• There are four types of natural silk produced in India for commercial purposes.
• These are known as Mulberry silk, Tassar silk, Mooga silk, and Eri silk.
• Among the four kinds, the mulberry silk contributes to more than 80% of the silk produced in the
country, with the mulberry silkworm generally being regarded as the most important.
• Tassar Silk, also known as Tassar Silk is an exquisite thread obtained from a wide-winged moth
that is yellowish-brown in colour. The scientific name of these moths is Antheraea Paphia and
they are a part of the group known as Emperor Moths or Saturnids. They are made from silk that
is produced from silkworms that breed on wild forest trees, not mulberry trees. It is cheaper than
mulberry silk.
• Mooga silk is a variety of wild silk geographically tagged to the state of Assam in India. The silk is
known for its extreme durability and has a natural yellowish-golden tint with a shimmering, glossy
texture. It was previously reserved for the use of royalty.
• Eri Silk comes from the caterpillar of Samia ricini, found in northeast India. The name "eri" is
derived from the Assamese word "era", which means "castor", as the silkworm feeds on castor
plants.

4. WHERE WE FOUND SILK?
• Geographically, Asia is the main producer of silk in the world and
produces over 95 % of the total global output. Though there are over
40 countries on the world map of silk, bulk of it is produced in China
and India, followed by Japan, Brazil and Korea. China is the leading
supplier of silk to the world.
• India is the second largest producer of silk and also the largest
consumer of silk in the world. It has a strong tradition and culture
bound domestic market of silk. In India, mulberry silk is produced
mainly in the states of Karnataka, Andhra Pradesh, Tamil Nadu,
Jammu & Kashmir and West Bengal, while the non-mulberry silks are
produced in Jharkhand, Chattisgarh, Orissa and north-eastern states.

5. HOW THHE SILK IS MADE?

6. LIFE CYCLE OF SILKWORM
• The process of raising silkworms to produce silk is called sericulture or
silk farming. It all starts with the silkworm, or Bombyx Mori as it’s
called in Latin. Its Latin name translates to ‘silkworm of the black
Mulberry tree’. The creature is also commonly referred to as mulberry
silkworm, named after its diet of mulberry leaves.
• The mulberry silkworm is responsible for over 95 percent of all the
silk produced in the world. It is a completely domesticated species
that no longer lives in the wild. During sericulture, a silkworm will go
through several of the following lifecycle stages:-

7. STAGE 1-THE EGG
• The lifecycle of a silkworm begins with the eggs of a grown silkmoth.
A female silkmoth can lay up to 500 eggs. Within a few days after
laying her eggs, the silkmoth will pass away, as its sole purpose in life
is to reproduce.
• Each of the eggs is about the size of a poppyseed and light yellow in
color. Fertile eggs will turn to a dark brown or grey color within a few
days. The fertile eggs are incubated under the optimal temperature of
about 25 degrees Celsius and a humidity of about 80 to 85 percent.
Under these conditions, the eggs are expected to hatch into larvae
within approximately 12 days.

8. STAGE 2 -THE LARVA
• Stage 2 – The Larva (Caterpillar)
• After hatching, the larvae are carefully transferred from the incubation room to the rearing room, where it’s time for them
to feast. The larvae are placed onto rearing trays with great care, as newly hatched silkworms are vulnerable to injuries.
Silkworm larvae look like tiny black hairy caterpillars, which will later shed their hair and skin and eventually turn white.
• A Diet of Mulberry Leaves
• The rearing trays are covered with freshly chopped mulberry leaves, which is the only food a silkworm consumes. The
caterpillars get fed fresh leaves twice a day. Care is taken to ensure the mulberry leaves remain moist and the trays remain
clean so that the silkworms continue to eat and stay healthy. You will be able to hear the sound of silkworms crunching on
mulberry leaves when standing near the trays. The sound of many silkworms simultaneously eating has been described as
similar to the sound of falling raindrops.
• Shedding of the Skin
• The larva stage, also known as the caterpillar stage, is the longest in the lifecycle of a silkworm. As a larva, the silkworm
will go through five instars. An instar is a developmental stage between molts, and a molt is when the larva sheds its skin.
Each silkworm will shed its skin four times before cocooning.
• The silkworm has to molt often as it grows in size exponentially. During every molt, its old skin is shed to make room for a
larger one. After its first molt, the silkworm will have already shed its hair to reveal its smooth skin. In the last days of the
fifth instar, the larva will be 10.000 times heavier than it was at hatching. After about 24 days as a larva, the silkworm is
ready to pupate. At this point, the caterpillar will have eaten its initial bodyweight about 50.000 times over.

9. STAGE 3 -THE PUPA
• Stage 3 – The Pupa
• Now that the caterpillars have finished their feast, it is time for them to start spinning
their cocoons so that they can pupate and transform into moths. You’ll know the larvae
have matured by the signs they show. They’ll no longer eat, they’ll crawl around looking
for corners to spin in, and they’ll be creamy white in color. Now the larvae are ready to
be transferred from their rearing trays to mountages.
• Mounting
• The mature silkworms are transferred to mountages by hand, making sure not to
overcrowd the mountage and to leave out any diseased caterpillars. This process is also
called mounting. A mountage is a device that looks like a frame with cubbyholes, which
allows silkworms to comfortable spin their cocoon.
• The environmental conditions during mounting should be optimal to ensure that the
cocoons are of high quality. The temperature should be no higher than 26 degrees
Celsius, and humidity should be between 60 and 70 percent. Care should also be taken
not to disturb the silkworms while they’re spinning their cocoons.

10. STAGE 4 THE ADULT
MOTH
• Stage 4 – The Adult Moth
• After about 2 to 3 weeks in its cocoon, the pupa will be ready to metamorphose into a
silkmoth. While emerging out of its cocoon, the cocoon will break, making the silk fiber
unsuitable for silk fabric production. This is why in sericulture the silkworms will never
make it to this stage. Instead, the cocoons are steamed or boiled after around a week
since the spinning of its cocoon. This results in the death of the pupae so that the silk
cocoon remains intact. At this stage in silk farming, the cocoons are ready to be
processed into raw silk.
• If the silkworms were allowed to break out of their cocoons, they would have
transformed into adult silkmoths. The life of a grown silkmoth is very short, as its only
purpose is to reproduce. Domesticated silkmoths are unable to eat or fly. They will find a
partner to mate with and then pass away after reproducing. This whole process usually
happens within a week. Male silkmoths die after mating, while female silkmoths die after
laying their eggs. The lifecycle of the silkworm then starts all over again.
•

11. HOW THE SILK IS
MADE
• 1. Harvesting
• First, the cocoons have to be harvested from the mountages. Harvesting happens around 7 to 8 days after the silkworms started
spinning their cocoons. A few cocoons can be cut in half to check if the pupae have fully formed. A fully formed pupa is hard and
brown in color. The cocoons are carefully picked by hand to ensure that no damage is done to the delicate silk fibers.
• 2. Stifling & Sorting
• The stop the pupa inside the cocoons from hatching and breaking the silk cocoon, the pupa will have to be killed. This process is
called stifling and is usually done using hot air or steam. Stifling also dries out the cocoon so that it can be preserved longer. The
cocoons can then be sorted based on quality and characteristics such as the length, shape, color, and luster of the silk fiber.
• Some cocoons may be deemed unsuitable for further processing and will be thrown out. Examples of cocoon defects include urine
stains, mold growth, and perforations.
• 3. Boiling
• After stifling, the cocoons will be exposed to heat once again to prepare them for unreeling. The cocoons are put in boiling water
to soften them. Cooking them makes it easier to find the end of the single silk fiber that makes up the cocoons. It also makes it
simpler to unwind them.
• Another benefit of boiling the cocoons is that it softens the silk. The process of cooking the cocoons sets into motion a degumming
process. Degumming is the removal of sericin proteins from the silk fiber. Sericin is a gummy-like protein that coats the other
protein in silk, which is called fibroin. Sericin enables two filk filaments to stick together. However, the sericin makes silk feel a little
rough, which consequently makes it harder to dye. Cooking the cocoons softens the hard sericin protein and makes the cocoons
smoother in texture and feel.

12. HOW THE SILK IS
MADE
• 4. Deflossing
• After cooking, the surface of the cocoons may still be covered in some loose fiber, making the
cocoons look fuzzy. This fuzzy layer consists of broken and uneven silk filaments. The loose fiber is
removed from the cocoons in a process called deflossing. Deflossing gives the cocoons a clean
look, makes it easier to process the cocoons further, and increases its market value.
• 5. Reeling
• Reeling is the step in the silk production process where silk cocoons are turned into threads of silk
yarn. Reeling is the unrolling of the cocoon and the combining of multiple silk filaments into one
single strand of silk. Reeling used to be done by hand, but is now mostly automated using
machines. During reeling, the revolving brushes of the machine grab the end of a cocoon’s silk
filament. The fast-moving reel then unravels the cocoon and dries the silk simultaneously.
• A single strand of silk is too thin to use on its own. This is why the filaments of multiple cocoons
are reeled together at the same time to create one strand of silk yarn. The number of cocoons
reeled together can be anywhere from 2 to 20, depending on the desired thickness of the silk
yarn. As silk fibers are so fine and light, you need about 2500 cocoons to produce 1 pound of silk.

13. HOW THE SILK IS
MADE
• Twisting & Dying
• Now that reeling has completed, the threads of silk yarn are removed from the
reels. The silk is then twisted into spiral circles to form bundles. These bundles of
yarn are also called skeins. The twist in a silk thread can be increased further, or
more silk threads can be added and twisted together. The amount of twisting
needed depends on what kind of fabric the silk will be woven in.
• After twisting, the silk yarn is ready to be dyed. You can choose to dye silk before
or after weaving the silk thread into fabrics. Silk is easy to dye thanks to the
structure of the fibroin proteins that make up most of the silk. The dye is easily
absorbed by silk, and the colors will look vibrant. Silk also contains both positive
and negative ions, which means that most commercial dyes are effective on silk.
• Following twisting and dying, the silk threads are wound onto spools or tubes.
The silk yarn is now ready to be sold, or to be woven into fabrics.

14. HOW THE SILK IS
MADE
• 7. Weaving
• Silk yarn is transformed into a silk fabric by weaving the threads. There are
many ways to weave silk. One of the most popular methods for weaving
silk is called charmeuse, also known as satin. The charmeuse weave is a
tight weave that results in a smooth and shiny silk fabric. Silk charmeuse
fabrics have a glossy surface and a dull back. This look is achieved by
floating the lengthwise thread over three or more transverse threads.
• Other popular types of silk weaves include silk chiffon, silk twill, silk crepe,
and silk habotai. Each of these weaves has a unique way of layering and
weaving the silk yarn, resulting in fabrics with different textures and looks.

15. • India has the unique distinction of being the only country producing all the five known commercial silks,
namely, mulberry, tropical tassar, oak tassar, eri and mooga, of which mooga with its golden yellow glitter is
unique and prerogative of India.
• Mulberry sericulture is mainly practised in states such as Karnataka, Andhra Pradesh, Assam and Bodoland
(Kokrajhar, Chirang, Baksa and Udalguri districts of Assam), West Bengal, Jharkhand and Tamil Nadu who are
the major silk producing states in the country. North East has the unique distinction of being the only region
producing four varieties of silk viz., Mulberry, Oak Tassar, Mooga and Eri. Overall NE region contributes 18%
of India's total silk production.
• India is the second largest producer of silk in the world. Among the four varieties of silk produced in 2020-
21, Mulberry accounted for 70.72% (23,860 MT), Tassar 8.02% (2,705 MT), Eri 20.55% (6,935 MT) and
Mooga 0.71% (239 MT) of the total raw silk production of 33,739 MT (Provisional).
• The silk production has been reduced in the country during 2020-21 due to the disruptions caused by the
Covid-19 pandemic. The total raw silk production in the country during 2020-21 was 33,739 MT, which was
5.8% lesser than the production achieved during the previous year 2019-20 and registered around 86.5% of
achievement against the annual silk production target for the year 2020-21. The bivoltine raw silk production
declined by 3.4% to 6,772 MT during 2020-21 from 7,009 MT during 2019-20. Similarly, vanya silk, which
includes Tasar, Eri and Muga silks, have reduced by 13.8%, 3.7% and 0.8%, respectively during 2020-21 over
2019-20. The area under mulberry has reduced by 0.8% in 2020-21 compared to previous year. (2.38 lakh
ha.)
SILK PRODUCTION IN
INDIA

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