Sericulture in India | Silk Rearing & Production | IBPS AFO & NABARD Exam

Silk, often regarded as the "Queen of Fibers," is one of the most exquisite and luxurious natural fibers globally. Renowned for its fine, lightweight, and soft texture, silk is also incredibly strong, boasting high elasticity. This natural marvel is produced by the silkworm, specifically the silk moth. Although numerous species produce silk, only a select few are cultivated for sericulture.

Types of Silk

There are four main types of silk, each produced by different species of silkworms:

1. Mulberry Silk (Bombyx mori): The most superior in quality, mulberry silk is known for its shining, creamy white colour. It belongs to the Bombicidae family and feeds exclusively on mulberry leaves.
2. Tasar Silk: Produced by the caterpillar of species such as Antherea mylita, A. paphia, and others, Tasar silk is copper-colored. These caterpillars feed on the leaves of arjun, sal, oak, and various other plants.
3. Eri Silk: This creamy-white but less shiny silk is produced by Phylosomia ricini, which feeds on castor and keseru leaves.
4. Muga Silk: Characterized by its golden yellow color, Muga silk is obtained from the caterpillar of Antheria assama, which feeds on som, suwalo, champa, and mejankari plants.

Life Cycle of Silkworms

The life cycle of silkworms involves several stages, starting from egg-laying to the emergence of adult moths. This cycle is quite similar across the different types of silk moths:

1. Eggs: Female moths lay eggs, which are of two types: diapause and non-diapause. These eggs are incubated and eventually hatch into larvae, known as caterpillars.
2. Caterpillar: The newly hatched caterpillar is a voracious feeder, primarily consuming mulberry leaves. As they grow, they undergo several molts, eventually developing salivary glands to produce silk.
3. Pupa: Once fully grown, the caterpillar stops feeding and begins to secrete silk from its glands, creating a cocoon around itself.
4. Cocoon: The silk cocoon is composed of continuous threads that can be up to 1200 meters long. After about 10-12 days, the pupa transforms into an adult moth.
5. Emergence of Imago: The moth emerges from the cocoon after undergoing metamorphic changes. The adult moths mate, and the cycle begins again.

Economic Importance of Silk

Silk is highly valued for its use in textiles and clothing. While the use of pure silk has declined due to its high cost, silk blended with other natural and synthetic fibers remains in high demand globally. Beyond fashion, silk is also used in various industries, including the military, for applications such as parachutes, fishing lines, insulation coils, and medical sutures.

Key Statistics for Silk Production in India

• Global Ranking: India is 2nd largest silk producer globally after China. (~30% of the world’s total).
• Annual Production: 30,000 to 35,000 metric tons of raw silk.
• Types of Silk:
• Mulberry Silk: 80-85% of total production.
• Tasar Silk: 10-12% of total production.
• Muga Silk: 2-3% of total production.
• Eri Silk: 5-7% of total production.
• Major Silk-Producing States:
• Karnataka: 60% of India’s total silk output.
• Tamil Nadu: 20% of total production.
• Andhra Pradesh: 10% of total production.
• West Bengal and Assam: Combined 10%, with Assam as a major producer of Muga and Eri silk.

Silkworm Diseases

The sericulture industry faces threats from various diseases affecting silkworms, including:

• Pebrine (Nosema)
• Flacherie (Bacterial disease)
• Grassarie (Viral disease)
• Muscardine (Fungal disease)
• Maggot Disease (Tricolyga sorbillans)

Rearing of Silkworms

Rearing silkworms involves much more than just feeding the caterpillars. It requires meticulous care from the egg stage through to the production of the cocoon. This process, known as grainage management, ensures the production of high-quality silk.

Post-Cocoon Processing

Once the cocoon is formed, the silk thread is extracted through a process known as post-cocoon processing, which includes:

• Stifling: Killing the pupa inside the cocoon to prevent the emergence of the moth.
• Reeling and Spinning: Extracting and twisting the silk threads to create raw silk, which is then purified and processed into various silk products.

Conclusion

Sericulture is a fascinating and economically significant industry that produces one of the most luxurious fibers in the world. Despite challenges such as diseases and the high cost of production, silk continues to be a sought-after material in fashion and other industries.