Write short note.
Sericulture: The rearing of silkworms to obtain silk fibre is known as sericulture. The methodology of sericulture includes five steps:
Collection of eggs − The ripened cocoons are collected and adult moths are allowed to come out of them and mate. The females are then collected and kept in a bag with mouth sealed and within some time, they die after laying their eggs, which are recovered for further process.
Incubation of eggs − The obtained eggs are spread evenly on tray and kept in incubator at 65°F. The temperature is slowly increased day after day and eggs hatch at 77°F. Larvae are recovered from the incubator.
Rearing of larvae − Larvae are reared in special rooms maintained at 77°F. They feed on mulberry leaves and become double their size in 4-5 days. During this 40 days larval period, 4 cycles of sleep followed by moulting is encountered.
Recovery of silk from cocoon − The larva is then transferred to the spinning trays where silk is released from the silk glands of larvae to form a cocoon. It takes 9-10 days for spinning to complete. Cocoons are preserved and are passed on to steam treatment. On steam treatment, the pupa inside the cocoon dies. Thereafter, drying treatment is done, which dries up the pupa.
Reeling and spinning − The process of removing the silk thread from the killed cocoon is called reeling. The silk so obtained is the raw silk, which is boiled and purified by acids to bring lustre.