Farhan Ali, Ijaz Ashraf, Umair Talib
Faculty od Agriculture, University of Agriculture, Faisalabad
Silk is a natural fibre and was amongst the earliest fibres discovered by man with others being wool, hemp, linen and cotton. Silk is a fibre made of proteins “fibroin” and “sericin” secreted in the fluid state as single filament by a caterpillar known as “silkworm”. These silkworms feed on the selected food plants and spin cocoons as a protective shell to prolong the life. Being an eco-friendly, biodegradable and self-sustaining material; silk has assumed special relevance in present age.
Silkworm has four stages in its life cycle viz., egg, silkworm (larva), pupa and moth (adult). Man deals this life cycle at the cocoon stage to obtain the silk. It is a commercial fibre of animal origin other than wool.
Silk is a salivary secretion produced
when a full grown silkworm larva spins its cocoon for pupation. It is known as
“Golden fibre” or “Golden Queen of textile”. Silk products are wonderfully light,
soft, strong and smooth and universally accepted by world top fashion designers
for its beauty, colours dyeing affinity, thermo tolerance, and water absorbance.
Silk is used in the manufacture of various weaves like plain, crepe, georgette
and velvet, knitted goods such as vests, gloves, socks, and stockings. Silk is
dyed and printed to prepare ornamental fabrics for saries, ghagraas, lehngaas
and dupattas, jackets, shawls and wrappers, cushions, table cloths, curtains,
parachutes. Silk is used to manufacture fishing lines, sieve for flour mills,
insulation coil for electric and telephone wire. An important function of silk
is that it is used in surgical sutures especially in heart surgery because it
attaches with heart and become its part after sometime. Silk is used in the
manufacturing of insulation coil for electric and telephone wire and also in
tyres of racing cars.
Commercial rearing of silk producing silkworms
is called sericulture. Sericulture is an agro-based cottage industry involving
interdependent rural, semi-urban and urban-based activities in which estimated
participation of women is about 60%. So, in contrast to any other agro-based
profession the role of women in sericulture industry is dominating which will
be helpful for improving the status of women in family enterprises.
Promotion of sericulture can help in
ecosystem development as well as high economic returns. Sericulture industry
comprising three main components:
i) Cultivation of Food plants of Silkworms
ii) Rearing of silkworms
iii) Reeling and Spinning of silk
First two components are agricultural and last one is the industrial. All these sections or components of sericulture industry provide a large scale employment. It is a source of livelihood for the rural and tribal people.
Silkworm is selected for research studies because the rearing of silkworm is a labour-intensive, welfare oriented, and village-based cottage industry capable to stop the migration of people from villages to cities. It provides employment and helps in improving the socio-economic status of rural inhabitants.
The history of silkworm is as old as the history of mankind. It was started in China nearly 5000 years ago. It was first discovered by Chinese Queen in 2640 B.C. While making tea she accidentally dropped a silkworm cocoon into a cup of hot water and found that the silk fibres could be loosened and unwound. Fibres from several cocoons could be contorted together to make a thread that was strong enough to be woven into cloth. Thereafter, Chinese Queen discovered not only the means of raising silkworms but also the manners of reeling silk and of employing it to make garments. The Chinese kept this discovery secret for about 3000 years and was spread across the world through secret ways.
Now the sericulture is being practiced in many countries. At present Japan, China, Korea, Italy, Soviet Union, France, Brazil and India are the chief silk producing countries in the world.
The annual world production of raw silk is about 65000 tons with China producing half of the world supply followed by the India, Korea and Japan. The worldwide demand for raw silk during 1960-70 was 2.5% per annum which later increased by 5% per annum. Although 46.5% of world demand is met by artificial silk; the demand for natural silk is on rise and the global supply is increasing day by day due to its superiority over artificial silk.
Sericulture in Pakistan is an industry of nomads and the reason is that there are a few research institutions working on this and also because of small land holdings by farmers and untrained persons. It is reported that annual production of silk in Pakistan is about 550 tons while in our neighbour country India the Production is 26500 tons per annum.
A research study was carried out by Department of Agricultural Entomology; University of Agriculture Faisalabad in their sericulture laboratories.
The selected Mulberry plants i.e. Morus levigata were treated in the field with three different methods (stem injection, foliar spray and soil application) with nine doses of micro and macronutrients which are N (0.2pc), P (0.1pc), K (0.3pc), Ca (0.1pc), Mg (0.1pc), Zn (0.15pc), Cu(0.05pc) in various combinations.
The eggs of Pakistani strains are purchased from Forest Department. These eggs can be hatch about 28-30°C for hatching. The newly hatched larvae are of dark brown or blackish in colour and are fed on chopped leaves at 4 hours interval. In next instars as silkworms growing they were fed on whole leaves gregariously or voraciously.
