Sericulture

1. Economic zoology

2. GDC Mendhar
Inam ul haq

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

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,

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.