Silkworm farming, silk farming or sericulture is the cultivation of silkworms to produce silk. Although there are several commercial species of silkworms, Bombyx mori (the caterpillar of the domesticated silk moth) is the most widely used and intensively studied silkworm (these eggs may need to be imported into SA as its native to Asia). While South Africa is home to its own variety of silk worm – namely the Mopane Worm (Gonometa rufobruuea) – this worm spins a very rough cocoon that is unsuited for silk manufacture.
How to farm silk
Silkworm larvae are fed with mulberry leaves, and, after the fourth moult, they climb a twig placed near them and spin their silken cocoons. The silk is a continuous filament comprising fibroin protein, secreted from two salivary glands in the head of each larva, and a gum called sericin, which cements the filaments. The sericin is removed by placing the cocoons in hot water, which frees the silk filaments and readies them for reeling. This is known as the degumming process. The immersion in hot water also kills the silkworm pupa.
Single filaments are combined to form thread, which is drawn under tension through several guides and wound onto reels. The threads may be plied to form yarn. After drying, the raw silk is packed according to quality.