Sericulture definition, types of silk, equipments and methods used in sericulture...

2. Bs (hons) ZOOLOGY

3. SERICULTURE
 SILK has been under use by human beings for various
purposes.
 It is known as “the queen of fibres”
 High scale production of silk in world.
 Rearing, developing and looking of silk insects is termed
as SERICULTURE

4. HISTORY
 Lotzu empress of kwang-Ti discovered the origin of
silk worm in the form of thread. But its technique was
kept in secret.
 The sericulture technique was known to only china,
and one who tried to open it, hanged to death.
 Then this secrecy was opened when two spies from
EUROPE were sent to CHINA.

5. Silk moth
 The silk producing machine is an insect called as SILK
MOTH(resham ka kira).
 Types of silk
 Mulberry silk
 Tasar silk
 Eri silk
 Muga silk

6. Mulberry silk
This is supposed
to be the superior in
quality to other
types due to its
shiny and creamy
color.
It is secreted by
caterpillar of
Bombyx mori which
feed on mulberry
leaves.

7. Tasar silk
Antheraea paphia ,
common in India,
china and sri lanka.
Catterpillar feed
on ber, oak, and fig
plant.
Cocoon is hard
and hen’s egg size
which produces
brown colored silk.

8. Eri silk
Produced by
caterpillar of
Attacus ricini
which feed on
castor leaves
Color is creamy
white like
mulberry but less
shiny.

9. Muga silk
Antheraea assama
Native place is
assam, good source
of cottage industry.
Catterpillar feed
on Machilus plant
Semi
domesticated

11. Life cycle of silk moth, Bombyx
mori

12. Physical characteristics
 It is pale, cream or ashy white in color.
 2.5 to 3 cm long and covered with small color.
 Body is divided into head thorax and abdomen.
 Head is big having large compound eyes and a pair of
antennae.
 Thorax is strong muscular three segmented structure
provided with spiracles 2 pair of wings(4-6cm long)
and 3 pair of legs.

13. Physical characteristics
 Abdomen is covered with scales and highly extended
in females whereas narrow in males.
 Sexes are seperate, sexual dimorphism exist.
 Males small in size than females
 Females live for 2-3 days but males sometimes die
during copulation, once females copulate they lay
eggs(all fertilized) till she dies.
 One moth lay eggs 400-500 eggs depending upon
climatic conditions and nutrition.

14. Stages of life cycle
Eggs
 eggs are rounded and white. With increase in time
egg become darker day by day.
 Two types of eggs are present:-
 Diapause : eggs are laid by silk worm inhabiting in
temperate regions, all vital activities are ceased.
 Non- diapause : silk worm belong to sub tropical
region like india.

15. Eggs of bombyx mori

16. caterpillar
 Hatches from egg are 5-7mm in length ,body is rough,
wrinkled and greyish in color.
 Have 12 segments, distinct into 3 parts i.e head, thorax,
abdomen
 Head is mandibulate mouth parts ,feed on leaves.
 Thorax has 3 segments bear a pair of true jointed legs.

17. caterpillar
 Abdomen has 10 segments.
 Larva feed on mulberry leaves and grow very quickly.
 Stop feeding, become inactive after 4 to 5 days then 1st
molting occur. 2nd stage larva is similar to 1st one but
slightly larger., eat for 7 days and 2nd molt occur. And 3rd
larva formed. Larva repeats this process four times .

18. caterpillar
 Maturity is achieved in 45 days since time of hatching.
And matured catterpillars are now 7-10cm.
 By this time formation of a pair of salivary gland is
completed. Salivary glands secrete silk that are also
called as silk glands.

19. caterpillar

20. pupa
 Fully formed instar larva undergo physiological
changes and become restless.
 Due to intrinsic hormonal reasons.
 Moves its head in whirling position, constantly and
rapidly rotates head at its axis & in mean time saliva
comes out through a small pore known as SPINNERET.
 Located on tip of hypopharynx in mouth. There is
continous flow of saliva through this pore.

21. pupa

22. cocoon
 White color bed of pupa whose outer thread are
irregular and inner threads are regular.
 Thread’s length is 1000-1200m, in concentric manner.
 Binding of threads round cocoon is very quick i.e 65
times/min
 Now silk worm pupa is covered with thick, oval white
or yellow silken cocoon.

24. emergence of imago
 Active metamorphic changes take place during
pupation in which abdominal prolegs disappear,
thorax develop two pairs of wings.
 Pupa is metamorphosed into young adult moth in 12-
15 days called as IMAGO
 It secrets alkaline fluid that soften one end of cocoon
and come out

25. emergence

27. sericulture
 This is multivoltine(having several broods within year)
 They are of domestic types and can b reared indoors
 Large and healthy cocoons are selected, kept in
vantilated cages emerge after few days
 Males and females are distinguishable.
 Kept in pairs in coupling jar for 24 hours copulate
 females transferred to egg laying boxes made of
cardboard
 Female lay 300-400 eggs.

28. Tools and materials
 Machana : proper place for rearing silk worm
 Rearing trays: for keeping laid eggs along mulberry
leaves
 Spining tray: for keeping caterpillars at time of full
grown stage ready for pupation.
 Dalas: for fetching mulberry leaves
 Chopping knife: cut mulberry leaves
 Baskets: distribute mulberry leaves
 Hygrometer, thermometer oven and freezers are also
used.

30. Rearing of silk worm
 5 stages for rearing
1. Supply of eggs: quality of seeds is important, only
those eggs are given that has been produced in a well
recognised grainage( where eggs are made)
2. Incubation of eggs: incubation conditions should be
optimum. For uni voltine eggs 73.5-77*F, 77*F for bi
voltine and 80*F for multi voltine.
 Humidity 75-80%
 For incubation seeds are spread on piece of paper In
rearing tree.

31. 3. Brushing of worms: to separate newly hatched worms
from shells of their eggs by means of a feather
 The process of brushing is spreading finely chopped
mulberry leaves on the egg sheet after 95% eggs are
hatched. The newly emerged worms crawl on top of
feed. & then transferred to rearing tray
4. Rearing of worms: it requires following
 Rearing room: ventilated, protect against direct sun
rays, well disinfectant with 2% formalin.

32.  Rearing appliances: wooden racks, chopping knifes,
leaf storing basket, gunny cloth pieces, door curtain
etc
 Leaves & their preservation: harvested by cutting and
plucking of leaves, preserved by keeping in basket
covered with gunny cloth.
 Feeding: feed with mulberry leaves at different
intervals, different staged larvae need different
amount of food.

33.  Cleaning: cleaning of trees is necessary to remove
excreta.
 Spacing: necessary to give proper spacing, avoiding
over crowdedness & spread of disease providing high
temp. at first two stages(80-85F) & in 3rd 4th stage 10
degree lower. With humidity 85-90%.
 Mounting & harvesting: when worm is fully grown &
appitite fails become restless and start spining out of
cocoon. Put in cocoonages

34. 5. Spinning of cocoon: period in which worm stop
feeding and start secreting a pasty substance from silk
gland.
 Worms picked up and put in spinning tray & kept in
position of slope to the sun for short period.
 Within 3 days spinning is done
 Cocoon formed
 Last stage of rearing

35. 6. quality of cocoon: depend on raw silk, filament
length ,reliability & splitting.
7. Marketing of cocoon: price of cocoon is fixed by govt.
8. Post cocoon processing: the method of obtaining silk
from cocoon is called as post cocoon processing. It
includes stifling & reeling
 Stifling: “killing of cocoon”
 8-10 days cocoon selected. Dropped in hot
water(helps in unwinding), sun exposure to 3 days

36.  Reeling: process of removing threads from killed
cocoon
 Threads are transferred to large wheel then to spools
called as reeled silk.
 Waste outer layer & damaged cocoon & threads are
separated and filaments are spun. This spuned silk is
called as spun silk.
 Raw silk is further boiled, stretched and purified by
acid or by fermentation carefully washed again &
again.

37. Rearing of silk worm

38. Diseases and enemy of silk worm
 Grasserie disease: viral, formation of polyhedral bodies
in body fluid, hypodermic infection.
Control is difficult. Preventions include sterilization of
tools, optimum temp., cleaning and proper spacing.
 Pebrine: most serious one, protozoan parasite(Nosema
bombycis), effect young larva by loss of appitite,
irregular moulting and growth.
 Muscardine disease: fungal, lose of appitite, specks
appear on skin, body become limp, elasiticity loose &
movement stop, death, appearance of white spores.

40. predators
 Tricoliga bombycis: parasite fly lay eggs near body of
catterpillar larva upon hatching feed on tissue of
caterpillar that dies.
 Canthecona fincellatta & tanchid fly: have long
rostrum with the help of which penetrate body of silk
worm, hemolymph oozes out & worm die.
 Ants, hornets, bats, kites atc feed on it.

41. Properties of silk
 Pasty secretion of silk gland; modified salivary gland
 When contact with air become hard and form strong
silk strand.
 Secretion form 2 cores of fibroin( 1) tough elastic
insoluble protein cemented together with sericin (2)
gelatinous easily soluble in warm water.
 Wax & carotenoids are also detected.

42. Uses of silk
 Silk clothes
 Synthetic fibers
 For military purposes
 Fishing fibers
 Parachutes
 Tyres of racing cars
 Insulation coils of telephones
 Medical dresses & suture material.