DISINFECTION
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Spray 2 % formalin with 0.3% slaked lime or 2.5 % chlorine dioxide with 0.5 % slaked lime @ 2 l/m2 area for disinfecting the rearing house immediately after completion of rearing and three days before brushing.
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Dip the rearing equipments in 2 % bleaching powder solution and sun dry before use.
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Dust 5% bleaching powder with slaked lime powder @ 200 g/m2 around the rearing house and passages and sprinkle water @ 1 lit / m2 floor area.
Incubation of egg and hatching
- The egg sheets should be spread out as a single layer in a chawki tray.
- Temperature of 25oC and humidity of 80 per cent are maintained. For this, paraffin papers and wet foam pads may be used.
- When the eggs come to head pigmentation stage (about 48 hours before hatching), they should be kept in dark condition by wrapping them in black paper or by keeping them in a box (black boxing). On the expected day of hatching, eggs are exposed to light, early in the morning to ensure uniform hatching. This facilitates uniform development of embryo.
- Most of the eggs (90 to 95 per cent) will hatch in about 2 to 3 hours.
Low cost method of preservation of eggs
- The eggs can be kept in an earthen incubation chamber.
- Draw the diagram and observe how humidity is maintained in the chamber.
Brushing
- The hatched larvae should not be starved and they must be brushed on a paraffin paper in a rearing tray or blue polythene sheet (Rearing bed).
- This is done by sprinkling chopped tender mulberry leaves of size 0.5 to 1 cm2 over the hatched larvae. The larvae crawl on to the leaves.
- After 8 to 10 minutes, the egg sheet is inverted over rearing tray and gently tapped.
- Worms that are still attached to the egg sheets should be gently removed to the tray with a feather.
- A rearing bed is prepared and some more chopped leaves, if necessary, are sprinkled.
- To prevent drying of leaves and to maintain the required humidity in the rearing bed, wet foam pads and paraffin paper covering are provided.
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