Eri is reared entirely indoors, which makes the rearing house itself the primary disease and pest control — mesh, doors, ante-chambers and ant wells do work that a muga rearer has to attempt with field sanitation.
Rearing house and appliances
- Well ventilated and fly-proof with a 1.5 m verandah; plinth 10 m × 5 m per 100 dfls; sited 10–20 m from the living house.
- Platform system for 100 DFLs: disinfection sprayer (1), rearing stands 2 × 1.8 × 0.5 m in three tiers (10) or a 1,000 sq ft multi-tier platform, feeding stands 1.0 m (2), bamboo collapsible or plastic mountages (150), thermostat heater covering over 500 sq ft (1), humidifier to 1,000 sq ft (1), ant wells of 15 cm diameter (20), leaf preservation chambers 1.5 × 1.0 × 0.75 m (2).
- Chemicals: formalin, bleaching powder, slaked lime, Asthra, detergents and soaps.
Disinfection schedule
| When | Activity |
|---|---|
| On completion of rearing | First disinfection of house and appliances — 0.05 % Asthra or 2 % bleaching powder solution |
| 3 days before rearing | Cleaning and washing of building and appliances |
| 2 days before rearing | Second disinfection — 0.05 % Asthra or 2 % bleaching powder solution |
| 1 day before rearing | Dust 5 % bleaching powder in slaked lime around the house; open windows to ventilate and clear accumulated gases |
Bleaching powder solution: 2 kg of ISI-grade powder (32 % chlorine) with 0.3 kg slaked lime per 100 L water; paste first, add the balance of water, stand 10 minutes, use the supernatant. Apply at 1 litre per 2.5 m² of floor area. Construct a dipping tank near the rearing house for small appliances.
Rearing operations
| Stage | Practice |
|---|---|
| Egg treatment | Surface-sterilise in 2 % formalin and dry at room temperature. Incubate at 25 °C, spread in thin uniform layers, followed by black-boxing to synchronise hatching. |
| Pigmentation | Eggs darken to deep blue two days before hatching; hatching follows 8–10 days after oviposition. |
| Brushing | Feed tender chopped leaf to newly hatched worms. Wash hands with 2 % formalin before every operation. |
| Bed cleaning | Essential in tray rearing, not in platform rearing where bed extension and lime application keep the bed dry. I and II instars: once, the day before moult. III instar: three times — after the second moult, mid-instar and before the third moult. IV and V instars: once daily. |
| Moulting | Pre-moult — body stout, head small relative to body, feeding reduced, skin tight. At moult — feeding ceases, no movement. Post-moult — head pale yellow and enlarged, worms active, skin loose and wrinkled. No disturbance during the moult; resume feeding when 95 % have emerged. |
| Lime dusting | Before first feeding in each instar and during each complete moult; in the fifth instar on days 2, 4 and 6. |
| Maturity and spinning | Body softens as silk glands swell, gut empties, worm shrinks and turns restless. Spin in chandrakie or dry leaves at about 25 °C — three days in summer, five in winter. |
| Harvest | Lift carefully after pupation and clean. Discard double, melted, flimsy and poor cocoons. |
Rearing methods
| Method | Description |
|---|---|
| Tray | Bamboo or wooden trays. Young age (I–III instars): wooden 50 × 60 × 5 cm or bamboo 70 cm diameter. Requires systematic bed cleaning. |
| Bunch | 10–12 castor leaves or kesseru branches tied and hung on a horizontal support; a fresh bunch beside the exhausted one lets worms crawl across. |
| Platform | Shelves in two tiers 30 inches apart or three tiers 27 inches apart, nylon mesh or bamboo mat seats, ideal size 5 × 7 ft. For mass rearing of late-age worms, not less than 100 dfls. No bed cleaning needed. |
Platform rearing eliminates bed cleaning entirely — the single most labour-intensive
operation in tray rearing — and holds roughly three times the worms in the same floor
space. The institute’s 2005 platform technology accommodates 7,200 worms from 25–30
dfls on three bamboo-strip platforms of 1 × 2 m.