SILKS
Sericulture Information Linkages
And Knowledge System

Central Silk Board, Minisitry of Textiles, Government of India, Bangalore
Chirang, Assam

Techniques of Rearing Silkworm

Rearing of Eri Silkworm, Samia ricini (Donovan)
Rearing house
  • Eri silkworms are reared indoor.
  • The plinth area 10 m x 5 m size rearing house having tin or thatch roofing with 1.5 m varandah all aroundis ideal for accommodating 100 dfls for commercial silkworm rearing per crop.
  • Rearing house should be well ventilated and fly proof.
Disinfection and prophylactic measures
  • Disinfection before and after each rearing is considered the key for a successful cocoon harvest
  • Disinfect the rearing house at least 7 days before and soon after the rearing.
  • Disinfection should be carried out on bright sunny days.
  • Wash the rearing houses and appliances with 5 % bleaching powder solution before rearing. Sprinklingof 2 % bleaching powder-lime mixture in the surroundings of the rearing house is equally effective.
  • Fumigate with 5% formaldehyde solution under high humid condition.
  • Open the room after 24 hours.
  • Windows and ventilators should be kept open for proper aeration and free circulation of air.
Season:

Rearing can be done throughout the year. However, March-April and September-October are the best seasons for eri rearing.

Egg incubation:

Incubate the dfls at 24-26°C and 75-85% relative humidity.

Brushing
  • Wash hands with 2% formalin solution and then with water.
  • Brush newly hatched worms on tender leaves (preferably castor) during morning hours.
  • Use paraffin paper and water soaked foam pad in rearing tray to maintain temperature andhumidity.
Late stage rearing

  • Rear maximum 300 nos. of 5th instar worms per 3 ft x 3 ft diameter tray.
  • Low cost bamboo platform rearing equipment is the best for rearing late stage worms considering thelimited rearing space and frequent bed cleaning. The structure with 6ft (L) x 5.5 ft (H) x 3 ft (W) dimensions

    can accommodate 25-30 dfls.

Feeding
  • Feed 1st instar worms on tender, 3rd and 4th instar on semi-matured and 5th instar on maturedleaves.
  • Feed the worms’ minimum 4 times a day with castor or kesseru leaves.
Bed cleaning :

Resort to bed cleaning daily.

Ripe worm collection
  • Ripe worms become yellowish white and start roaming for selection of site for cocoon formation.
  • While picking up the matured worms and rubbing in between fingers, a sound of hollowness isproduced.
  • Mature worms are collected and put to cocooning mountages.
  • Besides traditional Jali, bamboo chandraki, bamboo stripe type mountage and plastic collapsiblemountage are used for cocooning
Source:
  • Package of practices of Muga, Eri and Mulberry Sericulture for North Eastern region of India, 2005,Central Muga Eri Research & Training Institute (CMER&TI), Lahdoigarh, Jorhat, Assam.
  • Dr. M.C. Sarmah, Shri B.N. Sarkar, Shri S. A. Ahmed, Dr. K. Neog, CMER&TI, Lahdoigarh.