Answered Date (09 May 2020 05:37 PM)Translated Date (-)
The technology of sericulture and silk production is well-known. In brief, various aspects involved in it are as follows: Mulberry Cultivation: Silkworms feed on mulberry leaves. Hence the rearing of silkworms involves cultivation of mulberry trees, which provide a regular supply of leaves. Worms are introduced through DFLs (Disease Free Layings, i.e. eggs) procured from a quality centre (called grainage). In India, the bulk of mulberry cultivation is done by small farmers (< 4 acres land), usually in clusters of 300-400. Rearing: The silkworms are actually larvae of the silkmoth. They are reared in specially made trays in rooms with controlled temperature and humidity and regularly fed mulberry leaves. At a certain stage they convert themselves into cocoons. These cocoons are made from a single filament of material secreted by the pupa and wrapped around itself for protection. These filaments upon hardening constitute silk. On an average, 1 acre of plantation would yield 240 kg of cocoons in an year, starting from 100 DFLs. Depending upon whether it is dryland or irrigated mulberry, farmers can harvest the cocoons 4 to 8 times in an year. Reeling: The removal of silk yarn from the cocoons is called reeling. This is done by first cooking them in water to remove the gum, which holds it together, and then unwinding the filaments (reeling). Usually 8-10 cocoons are reeled together. There are three methods for reeling: the charkha, the slightly more advanced cottage basin and the costly automatic machines. Twisting: Prior to weaving, the raw silk is boiled in water to remove remaining gum, dyed and bleached, and then woven into the garment – usually on handloom. In some cases the woven cloth may be dyed and bleached. Species of Silkworms: There are four different species of moths, cocoons of which yield differing types of silk: Problem/Need Technology Package ¾ Mulberry Silk is the most common among them contributing to nearly 95% of world’s silk production. It is produced from the cocoons of the moth Bombyx mori. Within the species there are many varieties, mainly differentiated according to the number of generations produced annually under natural conditions. Then, hybrids of various kinds have also been developed. Multivoltine varieties (laying eggs several times a year) have been widely propagated to push up yields, but many feel that they are more vulnerable to pests and hence risky for small farmers. The government provides DFLs of various species through its outlets. ¾ Eri silkworm has two varieties – a wild one and a domesticated one bred on castor leaves. The filament is neither continuous nor uniform. Hence the moths are allowed to emerge before commencing reeling. A white or bright red silk is produced.¾ Tasar silkworms are wild. The Indian Tasar worm feeds on trees of Terminalia species and other minor host plants, while the Japanese and Chinese worms feed on oak and other allied species. Reeling can be done as with mulberry worms.¾ Muga silkworm is found only in Assam. It feeds on two local species of shrubs – Machilus bombycina and Litsae polyantha, producing a strong, golden yellow thread.
