Silkworm Mountage and Harvesting Techniques
Mountage
Mountage, also called cocoonage, is a device that helps or supports the silkworms for comfortable spinning their cocoons. It is round or rectangular-shaped and is formed of bamboo mat supported by split bamboo reapers on all sides. Bamboo strips are fixed in a spiral/circular fusion on the bamboo mats. It has a capacity of 1,000 worms.
Screen-type Mountage
It is made of bamboo or wooden or plastic reapers on which longitudinal strips with triangular peaks are placed. It can be folded and stored, needing less space and is well-ventilated, producing good quality cocoons.
Plastic Mountage
It is made of plastic and is similar in shape to chandrika. They are easy to clean, not prone to rodent attack, and produce fewer double cocoons, but are costly.
Japanese Low Cost Mountage
It is made up of a wooden frame of four longitudinal rods attached by means of cross-spokes at two ends to a central axis. Each rod has a number of pegs placed at equal distances. The pegs are connected by long threads twisted rice straw. It is cheaper, more durable, and decreases the spread of disease.
Bamboo Strip Mountage
It is made up of bamboo strips which are nailed on wooden reaper or placed in grooves of reaper. They are stacked above the other. The bottom frame is placed on four uniform bricks or wooden blocks, making it cheap, durable, easy to handle, and harvest the cocoons.
Bottle Brush Mountage
It is made up of a thick coconut or jute fibre rope into which 6 9″ sticks (midribs of coconut leaves) are inserted very closely. The worms spin the cocoons in the space between the sticks.
Plastic Bottle Brush Mountage
It is formed of plastic ropes. Each plastic rope has 8 branches with two sub-branches. The branches are equally distributed at a distance of 1 cm at the base and 4 cm at the ends of the branch in a circular shape.
Harvesting of Cocoon
Collection and gathering of cocoon from the spinning trays, called mountages.
Period
The cocoons are generally harvested on the 6th day after pupation, when the integument of the pupa has turned brown, dry, and hard. This condition will be suitable for safe handling and transportation of cocoons. It is better to check the condition of pupae by slit opening a few pupae. Premature harvesting may lead to loss of silk content of the cocoons due to incomplete spinning or killing the delicate prepupa or pupa within the cocoons. Delayed harvesting will lead to weight loss of cocoons.
Methods
Cocoon harvesting depends upon the mountage. Before the harvesting of cocoons, litters and left-over of the leaves, dead unspun larvae, naked pupae, flimsy and molten cocoons must be removed from the mountage. The flimsy and molted cocoons spoil the good cocoons by spilling strain. Cocoon harvesting can also be done with the help of machines. Central Sericulture Research and Training Institute (CSRTI) of Mysore has developed some machines for harvesting and deflossing the cocoons.
Cocoon Drying
Cocoon drying is to protect cocoon quality, preserve condition of cocoons for reeling, and prevent damage caused by long periods of storage. Drying kills the pupa and evaporates moisture as excessive moisture within the cocoon causes putrefaction and molds. Moisture content is mainly present in the body of pupa and is about 75 to 79%. Aim of cocoon drying is to reduce it to 7 to 13% to prevent putrefaction. Methods of cocoon drying being employed in the commercial use are: Sun drying, steam stifling, and hot air drying.
Cocoon Storage
Characteristics of good cocoon storeroom: Air space for ventilation must be provided at the bottom of the storage room to prevent moisture coming up from underground. The cocoon store should be built with double walls or walls should be as thick as possible. Windows should be small and fixed at a high level and provided with an exhaust to draw out the moisture accumulated in the room. The store room should be lined with an iron sheet. All walls, ceiling, and floor of the store room should be lined with wood paneling. Dried cocoons should be stored in cloth or polyethylene bags. Shelves should be provided in 3 to 4 tiers to store the cocoon bags. Bags should not be piled together. A cocoon storage bin “Honey Comb Tub Type” is used to reduce the fungus growth during storage, especially during humid conditions. Humidity should not be allowed to exceed scattering calcium chloride or silica gel on the floor or by use of a heater if required.
Disinfectants
Formaline solution, chlorine dioxide, slaked lime, bed disinfectants, and RKO are used for fumigation and disease control in sericulture.
Silk Glands
These are one pair of unique and conspicuous glands present in the fourth to eighth segments of the abdomen of silkworm larva on ventrolateral sides of midgut. When fully formed at the end of the fourth moult, each silk gland is about 5 times the length of the larva, a highly convoluted structure, while its weight becomes two-fifths of the body weight. On maturity, silk glands become golden-brown colored. Silk glands are modified salivary of labial glands of silkworm.
Silk Route
Silk route, also called Silk Road, was an ancient network of trade routes used from the second century BC through 14th century that extended from China to the Mediterranean. It refers to both terrestrial and maritime routes. The original silk route was established during the Han Dynasty (207 B.C. to 220 A.D.) by Zhang Quian, a Chinese official and diplomat. The silk route was most popular during the Tang Dynasty, from 619 to 907 A.D. Travelers used camel or horse caravans to travel the Silk route. Travelers along the Silk route’s maritime routes stopped at ports for fresh drinking water and trade opportunities. In 2013, then president of China XI Jinping officially revived the historic Silk route as “One Belt, One Road.” In June 2014, UNESCO designated the Chang’ an – Tianshan corridor of the Silk Road as a World Heritage Site.
Sericulture
Sericulture, also called silk farming, is the process of commercial rearing of silkworms (i.e. caterpillar larvae of silk moths) for the production of silk. About 2,700 B.C., prince Hoang-ti of China directed his wife, Si-ling-Chi, to examine the silkworm and test the practicability of using the thread. She discovered the means of raising silkworms, but also the reeling the silk and employing it to make garments. So Si-Ling-Chi was honored as “The Goddess of Silkworms.” The technique of silk production was kept secret by the Chinese for more than 2,000 years. Knowledge of sericulture reached Japan through Korea during the early part of 300 A.D. Knowledge of cultivation of the silkworms was established in India shortly after 300 A.D. The eggs of silk moth and seeds of the mulberry tree were carried to India concealed in the headdress of a Chinese princess. In 522 A.D., secrets of sericulture were smuggled to the Roman Empire by two Persian monks who learned the technique of rearing the silkworms and preparing the silk in China and smuggled some eggs of the silk moth. Rome, the art of sericulture was well established in western Asia and eastern European countries. In the 18th century, England innovated improved silk-weaving looms, power looms, and roller printing, and led Europe in silk manufacturing. In 1801, Joseph Jacquard, a Frenchman, developed a more advanced silk weaving machine. In 1870, Louis Pasteur discovered that epidemic Pebrine disease of silkworms could be controlled by prevention through simple microscopic examination of adult moths. Present status of Sericulture: China is the largest producer of silk in the world. India occupied the second position in silk production. China, India, and Japan together accounted for 87 per cent of the global silk production.
Types of Silkworms
Bombyx mori (Mulberry silkworm) – It is most extensively reared in many countries like China, India, Japan, Korea, Italy, France, and the USSR. In India, it is cultured on mulberry leaves in a number of states like Kashmir, Punjab, West Bengal, Karnataka, and Tamil Nadu, which together account for 92% of the country’s total mulberry silk production. Antheraea paphia (Tassar silkworm) – It is commonly distributed in forest areas of China, India, and Sri Lanka. In India, it is mainly produced in the states of Jharkhand and Chhattisgarh. Antheraea assamensis (Muga silkworm) – It is the native of Assam state of India. Philosamia ricini (Eri silkworm) – It is the native of East Asia. In India, these silkworms are commonly reared in Assam and N.E. States. Antheraea pernyi (Oak silkworm) – It is the native of China and Japan. In India, it is found in abundance in the sub-Himalayan belt covering the states of Manipur, Himachal Pradesh, Uttar Pradesh, Assam, Meghalaya, and J & K.
Voltinism
Voltinism is the ability of organisms to produce a number of generations produced in a year. Mulberry – uni, bi, multivoltine; muga and eri – multivoltine.
Taxonomic Position of Silk Moth
K-animalia P-Arthropoda (Jointed legs and sclerotised exoskeleton) sub p-Mandibulata (Mouth parts with strong mandibles.) C-Insecta (Hexapoda) (Body divided into head, thorax, and abdomen; thorax with 3 pairs of legs) Subclass-Pterygota (Presence of wings) O-Lepidoptera (Both pairs of wings membranous and caterpillar larva) Family-Bombycidae (Domesticated silkworms) Genus-Bomby Species-mori
Central Sericulture Research & Training Institute (CSRTI), Mysore
It is the research institute in the field of tropical sericulture. It was established at Chennapattna is 1961 but was shifted to Mysore in 1963 under the administrative control of Central Silk Board (CSB). It is aimed for the overall development of silk industry in the country. Now it has grown to a full-fledged center of excellence and provides commendable support to enhance silk productivity and quality ensuring generation of higher income for the farmers.
Central Silk Board
It is a statutory body under the administrative control of the Textile Ministry of Government of India. It was established in 1949 with its headquarter in Bangalore. It has been entrusted with the overall responsibility of developing silk industry covering all the activities from development of food plants to cocoon production; production of silk yarn, formation of policies governing import and export of silk. It is basically an R & D organization and is also involved in undertaking, assisting, and encouraging scientific, technological, and economic research in the silk sector.
National Silkworm Seed Organization
It is a separate entity under CSB, established in 1975 to supplement the efforts of State Governments in supplying high-quality Bivoltine and Multivoltine silkworm seeds to the farmers. Its main targets are to maintain, multiply, and supply authorized silkworm stocks, production and supply of quality industrial silkworm seeds; and transfer of technologies in the field to improve the productivity and quality of silk.
Silk Mark Organization of India
“Silk Mark Scheme” was launched in June 2004 by the Ministry of Textiles of Government of India. The main aim of the scheme is to protect the interests of the consumers and other stakeholders of the silk value-chain. It signifies that the product is made of pure silk.
Indian Silk Export Promotion Council
It was established by GOI in 1983. Its prime object is to promote and regulate the exports of natural silk goods and to promote India’s image as a reliable supplier of high-quality silk goods like fabrics, ready-made garments, machine-made carpets, etc.
Central Sericulture Germplasm Resources Centre
It is a premier center of conservation and utilization of Seri-biodiversity in the country. It is recognized as a National Active Germplasm Site (NAGS) for mulberry as well as silkworms. It is located at Hosur (Tamil Nadu) and was established by CSB in 1991. It is concerned with biodiversity mapping, collection, characterization, and pest-free conservation of mulberry and silkworms in different geographical regions of India. Effective utilization of their genetic resources in crop improvement programs rests mainly on its systematic characterization and evaluation, identification of potentially useful germplasm, high yield, alkaline and stress tolerance, water and nitrogen-use efficiency, etc.
Sericulture Biotech Research Laboratory
In was established by the Central Silk Board (CSB) in 1993. It was established to take advantage and harness the benefits of emerging applications of molecular biology and genetic engineering to address various problems being faced in the production of international grade Indian silk by conventional breeding. It is mandated to provide biotechnological solutions to sericulture industry and to support improvement of silkworm races and the host plants for the production of quality silk.