CHAPTER 1
INTRODUCTION 

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The origins of sericulture and silk production are closely associated with the emergence of China as one of the great civilizations. It is believed that sericulture evolved gradually and by the middle of the third millennium BC was already being used by humanity.

Silk is an animal fibre, produced by caterpillars belonging to the genus Bombyx. A single silk filament is the product of a series of stages derived from the cultivation of mulberry trees for feed to the propagation of the domesticated silkworm, Bombyx mori. During the caterpillar phase, the worm wraps itself in a liquid protein secreted by two large glands in its head. This secreted protein hardens upon exposure to the air. The resulting filament is bonded by second secretion, sericin, which forms a solid sheath or cocoon. Under natural conditions, a moth eventually breaks through the cocoon. In sericulture, the larva is killed in the cocoon by steam or hot air in the chrysalis stage before its metamorphosis. Sustained heat processing softens the hardened sericin so that the filament can be unwound.

The silk filament is a continuous thread of great strength measuring from 500-1 500 metres in length. Single filaments are too thin for utilization. For production purposes, several filaments are combined with a slight twist into one strand. This process is known as "silk reeling or filature".

Silk is a premium priced agricultural commodity, although its sheer volume is less than 1 percent of the market for natural textile fibres (Table 1). The international demand for high quality silk has multiplied. Appropriate cocoon-drying techniques and reeling operations are vital to supply good quality silk. Although new technologies are applied among major silk producing countries in Asia, many newcomers to the industry including non-traditional producers have not been transitioned to the methods that ensure high quality silk for export.

World production of raw silk reached nearly one hundred thousand tonnes in 1993. In contrast to strong declines in Japan and the Republic of Korea to roughly 3 900 and 500 tonnes respectively. China for the first time surpassed the 66 000 tonnes and India raised its output to 14 000 tonnes. Outside Asia, Brazilian output exceeded 2 500 tonnes per year, with the then USSR output lingering around 3 000 tonnes yearly. When compared to these three countries, production figures in some traditional sericulture countries have declined.

Recently, China experienced a striking decline in output to 59 000 tonnes in 1996; however a slight recovery was anticipated in 1997. At this time, China’s production will be sustained around 60 000 tonnes per year. Output in India also diminished from nearly 14 000 tonnes in 1994 to less than 13 000 tonnes by 1996 (Table 2). Still over 70 percent of global output are attributed to China, followed by India as the second largest producer.

Source: I.S.A. Bulletin (* Estimated)

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