• 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:

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