Introduction
Efficient silkworm management ensures high silk yield and quality. The two key components of silkworm management are proper housing and nutrition, which create optimal conditions for growth, health, and cocoon production. This guide provides detailed instructions on housing design, rearing practices, and nutrition, enriched with the latest research and best practices.
Housing Management
Rearing House
For the rearing of silkworms, a dedicated house is considered ideal. The house is typically built on an elevated and shaded site, with dimensions such as 18 feet x 12 feet x 10 feet for accommodating 100 dfls (disease-free layings). Features of an effective rearing house include a three-foot-wide balcony, sufficient windows and ventilators for air circulation, and nylon netting over openings to prevent the entry of pests like houseflies. The direction of the house often faces east-west to avoid direct sunlight.
A rearing house may include a main hall for rearing, an ante-room, and a leaf preservation room. It is built to maintain optimal environmental conditions, including a temperature range of 26–28°C and relative humidity (RH) of 60–70%, facilitating efficient silkworm growth with minimal costs.
Key Principles
Conditions to be avoided in the rearing house include dampness, air stagnation, direct strong drafts, and bright sunlight exposure. Conditions to be ensured include maintaining equable temperature and humidity levels and ensuring good ventilation.
Trees planted around the rearing house may help in maintaining a favorable environment. A washable floor and other features that facilitate effective disinfection are considered important during construction.
Disinfection Practices
Disinfection of the rearing house and appliances is often undertaken before each rearing cycle. Solutions such as 5% bleaching powder or 2% formalin are prepared and sprayed on all surfaces three days before rearing begins. After disinfection, the house is closed for 24 hours and ventilated thoroughly to eliminate any residual traces of chemicals.
Rearing Equipment
Rearing requires various equipment designed to maintain ideal conditions. Items such as sprayers, rearing trays, stands, foam pads, paraffin papers, and nets play key roles in the process. Specialized tools for leaf chopping, cleaning, and handling silkworms are also part of the setup.
Equipment for egg incubation includes bamboo trays, paraffin papers, and wet foam pads to retain moisture. The maintenance of temperature at 25–26°C and RH at 80% during incubation ensures uniform hatching.
Nutrition Management
Collection and Preservation of Leaves
Fresh and succulent mulberry leaves are generally harvested to feed silkworms. Leaves are often wrapped in wet gunny cloth or stored in bamboo baskets lined with similar material to preserve moisture.
Feeding Practices
Feeding practices vary with the developmental stages of the silkworms:
- 1st Instar: Tender leaves (2nd and 3rd from the branch tip) are chopped into small pieces for easier consumption.
- 2nd Instar: Slightly larger leaves (3rd and 4th from the branch tip) are chopped for feeding.
- 3rd Instar: Whole leaves, after washing and drying, are provided.
- 4th and 5th Instars: Whole branches are fed directly, avoiding over-mature or diseased leaves.
The composition of mulberry leaves supports the nutritional needs of silkworms across their lifecycle.
Chemical Composition of Mulberry Leaves:
Component | Range (%) |
---|---|
Moisture | 65-78 |
Protein | 19-25 |
Sugars | 10-15 |
Reducing Sugars | 1.2-1.9 |
Rearing Practices
Chawki Rearing
Early-stage rearing (1st and 2nd instars) involves providing tender and nutritious leaves. Room conditions such as a temperature of 27–28°C and RH of 80–90% are maintained. Bed cleaning is performed once during the first two molts and daily during the third stage using cleaning nets.
Late-Stage Rearing
For later stages, mature leaves from 60-day-old plantations are fed. Feeding practices are adjusted, such as increasing the bed space and reducing the larval density to 60–70 larvae per square foot. Regular bed cleaning ensures a hygienic environment.
Environmental Conditions by Instar Stage:
Silkworms progress through several developmental stages, each with specific environmental requirements:
Instar | Humidity (%) | Temperature (°C) | Space per 100 dfls (sq. ft.) |
---|---|---|---|
1st | 85–90 | 26–28 | 4–14 |
2nd | 85–90 | 26–28 | 15–45 |
3rd | 80–85 | 25–26 | 46–90 |
4th | 75–80 | 24–25 | 91–100 |
5th | 75 | 23–24 | 81–360 |
Mounting and Harvesting
Fully ripe silkworms are often identified for mounting, and suitable mountages like rotary or bamboo designs are used. Conditions such as 27–28°C and RH of 60–70% are maintained during this stage. Cocoons are generally harvested on the fifth day after mounting, with careful selection to ensure quality.
Hygiene Practices
Stringent hygiene practices are typically followed during silkworm rearing. These include regular disinfection, limiting entry to essential personnel, and proper disposal of diseased worms. Cleaning of the rearing house and equipment is often carried out using bleaching powder or other disinfectants.
Conclusion
Proper silkworm management requires attention to housing, nutrition, and hygiene. Implementing these practices ensures optimal growth conditions and maximizes cocoon yield and quality. Adherence to these guidelines will contribute to sustainable and profitable sericulture.
References
http://silks.csb.gov.in/anjaw/wp-content/themes/Common_District/trs-frame.html
https://agritech.tnau.ac.in/sericulture/seri_silkworm1_rearing%20house.html
Saha, Sajal & Kumar, Pravesh & Raj, Shubham & Choudhury, Babita. (2022). Sericulture: management and practices of mulberry silkworm. 2456-4494. 10.35629/7781-07023546.
http://www.csrtimys.res.in/sites/default/files/ebooks/1990-1.pdf
https://vietnamagriculture.nongnghiep.vn/visit-to-the-model-silkworm-breeding-house-d387196.html
https://www.researchgate.net/publication/307583005_Solar_passive_silkworm_rearing_house
https://justagriculture.in/wp-content/uploads/2024/12/41.-Techniques-For-Rearing-of-Silkworm.pdf
Further reading
Beekeeping Equipment: Covering the basic tools & protective gear needed for beekeeping
Influence of Rearing Substrate on Black Soldier Fly Larvae Nutritional Value for Animal Feed
Food Insecurity in Africa: Can Insect Consumption Bridge the Protein Gap?