1. SILKWORM REARING
(BLPI-003)
Resource Person:
Dr. K.Kamatchi
Assistant Professor of Zoology
Vivekananda College,
Tiruvedakam West, Madurai
IGNOU - Academic Counsellor
Code: GYYPK2432J/001
Vivekananda College, Tiruvedakam West
IGNOU - Study Centre - 43016
2. Sericulture
History of the sericulture
Central Silk Board and other organizations
Morphology and anatomy of silkworm
Morphology of mulberry plant
Diseases and pests of mulberry.
Diseases and pests of silkworm
Mulberry cultivation
Rearing Facilities
Rearing Appliances
Rearing Operations
Rearing Methods
Cocoon Qualities
Silk Reeling
Silk Twisting
Silk Weaving
Dyeing
Printing
3. Synopsis
• Introduction
• Rearing Facilities
• Rearing House
• Rearing Appliances
• Disinfection
• Rearing Operations
• Brushing
• Feeding
• Bed Cleaning
• Spacing
• Care during moulting
• Mounting of mature worms for spinning
• Harvesting of cocoons
4. REARING FACILITIES
• Rearing House:
• Silkworm is domesticated animal.
• It cannot tolerate seasonal fluctuations.
• It need an ideal rearing house.
• It has separate rooms for storing leaves
• Keeping rearing appliances.
• Rearing house must be brick-walled
• Roof – non conductor of heat-RCC roof
• Cement –plastered
• Not in water logged area
• North-south orientation
• Provision of broad verandah
• Planting shady trees
• Double door system
5. Rearing Appliances
• Rural based agro industry
• Appliances – cheap and locally available
• It differ from place to place
• CSB devising novel rearing appliances
6. • Appliances used for keeping the worms
being reared.
• Rearing Stand
• Rearing Trays
• Ant wells
• Paraffin Paper
• Chop Sticks
• Feathers
9. Ant Wells:
• Placed below the legs of rearing stand
• Prevent ants – crawling up
• Water poured
• CSR&TI give –Raksha rekha
• Chalk line – base of stand.
10. Paraffin Paper:
• Thick craft paper – paraffin wax coat
• Prevent evaporation of moisture
• Maintain high humidity
• Polythene sheets
• Dried banana leaves
11. Chop Sticks:
• Thin sticks of bamboo – 20 cm.
• Used like a forceps
• Picking worms
• Particularly diseased worms
12. Feather:
• Bird feathers
• White ones – preferable
• Brushing newly hatched larvae
• Spread the young worms.
13. Appliances used for feeding:
• Leaf basket
• Leaf chamber
• Chopping board
• Chopping knife
• Mats
• Feeding stand
14. Leaf Basket:
• Bamboo baskets – convenient size
• Collecting and transporting the leaves
15. Leaf Chamber:
• Store harvested leaves.
• Wet gunny cloth is placed.
• Water sprinkled periodically on cloth
• To keep leaves fresh.
18. Mats:
• Below the chopping board
• Collect cut leaves.
• Clean paper may used.
19. Appliances used to support the
spinning larvae:
• Cocoonage or Mountage:
• Determine both quality and quantity of good cocoons.
• Weeds, straw and dry twigs
• Provide convenient space
• Not promote the formation of double cocoons
• Malformed cocoons and flimsy cocoons.
• Provision for drying of liquid excreta
• Easy mounting and harvesting
• Cheap, durable, easy to handle
• Occupy less space, allow free flow of air.
20. Chandrika:
• Bamboo spiral mountage – south india
• West Bengal and other parts of india
• 1.8m x 1.2m
• 4 – 5 cm width
• 1000 worms can be mount.
21. Types of Mountages:
• Screen type mountage
• Plastic mountage
• Polymer mountage
• Japanese low cost mountage
23. Rearing Operations:
• Disinfection
• Brushing
• Maintenance of optimum temperature and humidity in the
rearing bed
• Feeding
• Bed cleaning
• Spacing
• Care during moulting
• Mounting of mature worms for spinning
• Harvesting of cocoons.
24. Disinfection:
• It must be effective against the pathogens.
• Application must be simple, easy and take minimum time.
• Harmless to man and domestic animals.
• Cheap and easily available.
• Physical methods
• Chemical methods
26. Sun Drying:
• Expose the appliances to direct sun light
• Cheap method
• Suitable only for tropics
• Cannot suitable for temperate
• Also in winter and rainy seasons
• Some appliances damaged
27. Disinfection by Steaming:
• Good sterilizing agent
• Disinfecting the rearing room
• Initial cost is high
• Harmful to bamboo and wood.
29. Chemical methods:
• Disinfectant may be solid, liquid, gas
• It should have a broad spectrum activity
• non- toxic to man and animals.
• Have a capacity to avoid combination with organic matter
• Non-corroding and non-standing over the equipment and
surface
• Readily mix with water
• Have detergent property
• No offensive odour
• Available readily in large quantities at a fair price.
30. Disinfectants are:
• Chlorine
• Iodine
• Phenol
• Quaternary Ammonium Compounds
• Formaldehyde
• Spraying with 2% Formalin
• Spraying of Bleaching powder
• Fumigating with formaldehyde gas
31. Brushing:
• Hatching – Photoperiodic response
• Sunshine in the early morning – noon
• Newly hatched larvae – black and bristly
• Ants
• Process of separating them – egg shell
• Transferring to rearing bed
• Best time – 10 a.m.
• Unhatched eggs – return to black box
• Brushed the next day
32. Brushing from loose eggs in egg
boxes:
• 75% of eggs – blue egg stage
• Cover of box removed
• Thin muslin cloth or fine meshed net placed above
• Small amount of fresh, chopped mulberry leaves spread over
the net
• Larvae crawled up
• Feather method
• Husk method
• Cloth/paper/net method
33. Maintenance of Optimum
Conditions for Rearing:
• Productivity and Profitability depends upon healthy and
hygienic rearing.
• Giving quality leaves
• Optimum environmental conditions
• Temperature
• Humidity
35. Humidity:
Triple role
1. Affects growth of larvae and quality of
cocoons
2. Quality of leaves
3. Induces diseases
Larval age Humidity optimum
I instar 85%
II instar 85%
III instar 80%
IV instar 75%
V instar 70%
36. Feeding:
• The quality of the cocoons harvested depends – quality of
leaves fed during rearing.
• Satisfy both appetite and nutritional requirements.
• Summer six feedings / day (7 a.m., 11 a.m., 2 p.m., 5 p.m.,
8 p.m., and 11 pm.)
• Other seasons five feeding enough
• Give chopped leaves for larvae
37. Bed cleaning:
• In the rearing tray after feeding the unconsumed leaves and
the feacal matter of the larvae to be removed by this
method.
• Clean with husk
• Clean with net
• Combined net and husk method
38. Spacing:
• Silkworm developed rapidly from age to age.
• Increase several times their original weight and size.
• 15 times – hatching – I instar
• 4 to 5 times – II and III instar
• 25 times – IV and V instar
• Total increase in weight from hatching – V instar 7,000 -
10,000 times.
• So rearing space has to be extended
39. Moulting:
• Moulting occurs four times during the larval life.
• Sensitive period lasting for 15-30 hours.
• During this time worm does not feed
• Wriggles out of old skin and come out of new and soft skin.
• Bed should be dry.
• Pre-moult – worms shining body with a dark small sized
head and move to the periphery of bed.
• Moult – stop feeding.
• Post moult – large head, loose and less shiny skin – more
appetite.
40. Mounting:
• It is the final and most busy operation
• V instar larva attaining full growth.
• Let is for spinning – select suitable place
• Ripe worm
• Translucent colour
• Stop feeding – move to the edge of the bed.
• They transfer to the mountages.
41. Methods of Mounting:
• Hand Picking:
• Ripe worms are picked one by one by hand
• Collected in a tray and transferred to mountages
• Some worm to be injured
• More labours
• Worms uniformly distributed in mountages.
• Injured and diseased worms removed.
• Simultaneous mounting
• Net method
• Branch method
• Free mounting
42. Process of Spinning:
• Mature larva passes out its last excreta
• After emptying its gut, it secretes first silk droplet
• It is hardens and sticks on the mountage.
• Anchorage spot.
• Sericin – secreted by silk gland.
• 1.5 cm/ second.
43. Harvesting:
• Aim of the silkworm rearing is to harvest the cocoons
produced and sell them to the reeling agencies.
• Time of harvest – 3-4th day of mounting
• Early harvest injured the pupa.
• Late harvest – the moth emerge and pierced the cocoon.
• Cocoons are harvested by hand
• Remove faccal pellets on them
• Sorted size, defective cocoons
