Short Essay on Sericulture in about 300-400 words.
Answers
Silk is the protein secreted by the larvae of certain Lepidopteran moths. It is fibrous in nature, and widely used for the manufacture of art clothes. The silk is derived from silk moths mainly belonging to Bombycidae and Saturuidae families of lepidoptera.
The origin of silk industry is a controversial topic. According to one source the origin is from India during 200 B.C. (Himalayan region). Whereas another view holds that it originated from China. The knowledge of silk production spread for and wide by the passage of time. Today many Western nations along with Japan, Russia, and Persia. Africa and India are practicing the culture and production of silk
Sericulture is the art of rearing silk worms under artificial or domesticated conditions and extraction of the silk fiber from their cocoon.
The moths belonging to two major families, Bombycidae and Saturnidae of Lepidoptera group of insects produce commercial silk in India Based on the quality and lusture of the silk fibers 4 types of silk are produced by die different forms of silk secreting moths. The main species of silk secreting moths are Bombyx sp. Attacus sp. and Anthracea sps.
Essay # 2. Types of Silk:
Silk industry in India is supported by different types of silk worms. The qualities of the silk produced by these worms vary. Though there are different types of silk worms, the commercial silk are of 4 types.
Information’s regarding the silk varieties; the respective silk worms and their food plant are given in the following table:
Essay # 3. Physical and Chemical Properties of Silk:
The silk fibre quality and quantity depends on the size and robustness of the cocoon. It is estimated that on an average a cocoon gives silk filament of 600-1200 m. To produce 1 lb. of raw silk about 2300-2600 cocoons are required. In terms of weight about 11 kg., of cocoon’ may yield 1 kg., of raw commercial silk and 1.5 kg of waste silk for spinning. The thickness of the silk filament produced by Bombyx mori varies from 0.018 mm.
The filaments have great tensile strength (tensile strength of silk 64,000 lb/ssq. Inch and that of iron 90,000 Ib/sq. inch) and good elasticity (the silk fibre can stretch one fifth of its original length). These two properties of silk owe much of its excellence as a textile material.
Silk filaments are formed of an inner core of material called fibroin covered by another substance called sericin. Fibroin constitutes about 70-80% of the filament. It is an amphoteric colloidal protein of formula C15 H22 N5 O6. Fibroin when heated burns and gives the smell of burned feather. This property is used to distinguish genuine silk from artificial silk. Sericin is also a protein of albuminous nature.