Allied Sectors and Occupations

Silkworm Seed/Egg Production

Mulberry Seed/Egg Production

Disinfection of grainage and implements

Bamboo made house with thatched roof and mud-plastered wall is preferable for grainage.
Disinfect the grainage rooms and appliances prior to commencement of operation.
Wash the rooms and appliances with 5% bleaching powder solution before one day.
Dry the appliances in sun shine for 3-4 hours before one day.
Disinfect the rooms and appliances with a mixture of 2% formalin, 0.5-1% lime and 0.5% detergent solutions @ 1L/ sq.m after one day.

Pupal examination

Separate out the melted, flimsy and good cocoons.
Take out the gut portion and observe under microscope.
Reject the lot in case there is incidence of pebrine.
Disinfect the contaminated room before the arrival of new lots.

Preservation and protection of seed cocoons

Immediately after the receipt of seed cocoons, spread them on trays in a
single layer to facilitate good aeration.
Reject the seed cocoons which are melted, uzi infested, flimsy and not conforming to the characteristics of parent races.
Preserve only the healthy seed cocoons in trays for further processing.
Provide cross ventilation in the preservation room.
Maintain temperature at 25 ± 1˚C, relative humidity of 75 ± 5%, 16 hour light and 8 hour dark conditions in the cocoon preservation room.
Maintain complete darkness one day prior to emergence to avoid irregular emergence of moths.

Early eclosion/ artificial eclosion/ forced eclosion of moths

This helps in determining the disease freeness of a batch and helps in
minimizing the loss to grainage.
For early emergence of moths, 50-60 seed cocoons are taken from individual lots and placed into an artificial eclosion box.
Maintain the temperature at 32-33 0C with the help of thermostat. This accelerates the development of pupae and moth emerges early.
Examine the early emerged female moths of respective lots are under microscope to know the disease freeness of lots.

Synchronization of emergence of moths, pairing, depairing and oviposition

Keep the cocoon preservatio0n room dark before the expected day of emergence
of moths.
In case of variation in development of male or female pupae, the development of male pupae can be arrested by preserving them at 5-7 0C and 75 + 5% relative humidity for 3-4 days.
Only healthy and active moths are taken for pairing.
After 1-2 hours of emergence, the male and female moths of respective combination are allowed for 3.5 to 4 hours of pairing.
At the time of depairing, the male and female moths are to be moved side way so that the moths are separated easily without causing injury to reproductive organs.
The mated female moths are taken in a separate container and induced for urination.
Moths are placed on egg sheet and covered with cellules and kept in semi dark condition for oviposition.
Under proper preservation (5-7 0C), male moths can be used for second pairing by giving 1-2 hours rest.
Throughout the process of pairing, depairing and oviposition, optimum temperature of 25 ± 1 0C and relative humidity of 75 ± 5% should be maintained.

Moth examination

Examine the mother moth either individually or in mass for pebrine disease.

Surface sterilization of eggs

Dip the egg sheets in 2% formalin for 10-15 minutes. This helps in removal of
pathogens adhering to the egg shell and further prevents secondary
contamination.
Wash the eggs in formalin solution. It helps in firm adherence of eggs to the sheet.

Incubation eggs

Maintain temperature of 25 ± 1˚C, relative humidity of 75 ± 5%, 16 hours of
light and 8 hours darkness.
During the pinhead stage or before two days of hatching, maintain total darkness
for uniform development of embryo and hatching of larvae at a time on a single
day.

Source

Directory of Sericulture Technology 2008, Karnataka State Sericulture
Research and Development Institute, Bangalore- 5 60 062.

Muga seed/ egg production

Grainage hall

Bamboo made house with thatched roof and mud-plastered wall is preferable for grainage.
All round varanda is suitable for keeping the temperature down.

Material required for grainage operation

Chemicals: Formalin, Bleaching powder, Lime powder, Potassium hydroxide.
Equipment and Accessories: Spray machine, BOD incubator, Microscope,
Micro-slides & cover slip, Moth crushing set, Mask and Gloves, Moth cage, Foam
pad, Measuring cylinder, Balance (readability- 0.1 g) Scissor, Muslin cloth,
Bucket , Thread, etc.

Disinfection

Disinfection should be done 3-4 days prior to receipt of seed cocoons and
immediately after completion of grainage operation.
Drench the walls of the hall and grainage appliances with 5% bleaching powder solution.
Seal the grainage hall airtight and put all appliances inside.
Apply fresh disinfectants in the grainage hall and keeps the room closed for 24 hours.
Amount of disinfectants to be used @ 1 l/ 2.5 sq. m floor area.
Open the hall one day prior to consignment of seed cocoons.
Use mask and hand gloves during disinfection.

Selection, collection and transportation of seed cocoons

Select well-formed healthy cocoons for seed production (Male: 4-4.5g, Female:
5-6g) at a female:male ratio of 60:40.
In case of cocoons taken from the early part of spinning, keep the early spun cocoons in BOD incubator for 4-5 days at 10 0C to synchronize moth emergence.
Before selection of seed cocoons, pupal gut test must be done to ensure disease freeness of the lot.
Cocoons from highest ripening day or one day prior/ after are preferable.
Transport seed cocoons after complete pupation avoiding direct sunlight, rain, jerk, etc.

Storage of seed cocoons

Keep seed cocoons in moth cages in single layer to facilitate proper aeration
and easy emergence.
Maintain proper aeration in the grainage hall.
Temperature between 26 to 28 0C and relative humidity of 80±5% are suitable for grainage operation.

Moth emergence and coupling

Emergence usually takes place at dusk and continues till midnight.
Place emerged male and female moth in mating cage at 1:5 ratio for easy coupling and put the cage in a well aerated dark and cool place.
Allow 7-8 hours of coupling. Female moth should be put into netlon oviposition pouch individually (9 x 3 x 3 cm in size) for egg laying.

Oviposition

Arrange the pouch in a rack (50 cft in volume ) in the grainage hall.
Allow to lay egg for 3 days.

Moth examination

On the 4th day, resort to individual mother moths examination for detection of
pebrine disease.
Conduct two-tier examination of mother moths crushing the midgut of the mother in 2% Potassium solution.
Burn perbrinzed and other diseased moth along with diseased eggs and Kharika.

Surface sterilization of eggs

Wash the eggs with soap solution and then carry out surface sterilization by
putting the eggs in 2% formaldehyde solution for 2-3 minutes.
After sterilization, wash the eggs in running water till smell of formalin goes off.
Dry the eggs in shade.

Incubation of eggs

Keep the dried eggs in BOD incubator at 261 oC with 855% RH.
Put some saturated solution of calcium chloride at the bottom of the BOD incubation to keep the RH within the required range.

Egg transportation

Avoid stuffing of egg packets inside bags/poly bags.
Transport dfls in separated perforated paper packets.
For transportation in bulk quantity, make bags for 50 dfls with muslin cloth/ cotton mosquito net and fit individual bag in a wooden frame.
Carry the bags in plastic baskets avoiding heat, jerk, etc.

Hygiene

Burn dead and melted cocoons.
Dispose-off pierced cocoons as soon as possible.
Dispose the crushed materials, moths, grainage waste, etc. in soak pit treating with 5% bleaching powder solution or burn them.
Wash hands with alkaline soap and then with 2% bleaching powder solution before entering into grainage hall.
Keep a foot mat soaked with 5% formalin in front of the grainage hall

Source:

1. Package of practices of Muga, Eri and Mulberry Sericulture for North Eastern
region of India, 2005, Central Muga Eri Research & Training Institute,
Lahdoigarh, Jorhat, Assam.
2. Directory of Sericulture Technology 2008, Karnataka State Sericulture
Research and Development Institute, Bangalore- 560 062.

Eri Seed/ Egg Production

Seed cocoon selection

Select cocoons based on physical characteristics e.g. compactness, shape, size and number of cocoon per kg (not more than 350 cocoons/kg).

Disinfection of grainage room

Wash the grainage room and appliances with 5% bleaching powder solution, 3 days before consignment of seed cocoons.
Same disinfection procedure should be adopted after completion of grainage.
In the event of pebrine incidence during grainage, fumigate with 5% formaldehyde solution under high humid condition with the appliances inside.
Open the room after 24 hours.

Transportation of seed cocoon

Transport the cocoons in plastic trays during early morning or in the evening hours to avoid direct exposure to sunlight.

Storage of seed cocoon

Seed cocoons are stored in single layers @ 500 cocoons per tray (size 3ft x 2ft) arranged in racks.

Emergence of moths and sorting of couplings:

Moth emergence occurs after 17-18 days of spinning in summer and 30 t0 35 days in winter.
Moth emergence takes place in the evening hours as well as in the morning hours.
Collect the emerged moths in moth cage approximately in the ratio of male :
female at 60 : 40. The paired moths are allowed to couple for 6 hrs.
Decouple the moths and allow the female moths to lay eggs on kharika/pouch.

Moth Examination

Conduct microscopic examination of mother moths on 3rd day for basic and 0n 4th day for commercial seed following Fujiwara technique.

Harvesting of eggs

Collect all the disease free layings alongwith the kharika in a tray for harvesting. Transfer the harvested eggs to a piece of nylon net for washing.

Degumming and surface sterilization of eggs

Dip the eggs in 0.2% bleaching solution for 5 minutes.
Wash the eggs with fresh water and soap and finally with fresh water.
Spread the sterilized eggs on a blotting paper for drying in the shade.
Weigh the dried eggs and pack in specially designed egg boxes for supply.

Source

Eri Silkworm Seed Production Centre, Azara, Guwahati