Assam is the only place in the world where all commercially exploited varieties of silk viz. Mulberry (Pat), Eri, Muga and Oak tasar silk are produced.
The life cycle of mulberry silkworm completes in 45-55 days, consists of stages egg, larva, pupa and moth. Egg stage is lasting for 9-10 days, larval stage which is 24-28 days, pupal stage 8-10 days and moth stages 3-4 days.