Effect of different stifling methods on cocoon quality parameters: A comparative study

In the present study, rearing of bivoltine silkworm, Bombyx mori L. hybrid CSR₂ × CSR₄ was conducted under standard recommended practice. After harvesting, cocoons were stifled and dried with four methods viz., open sun drying method, open sun drying with black cloth, barrel steaming and hot air oven drying to study effect on quality parameters of silkworm cocoons viz., average filament length, average non- breakable filament length, average denier, raw silk percentage, renditta and reelability percentage. The cocoon dried by hot air-drying method showed significantly higher average filament length (1138.02 m) and higher non-breakable filament with a value of 817.34 m as compared to all other treatments. Non-significant difference in overall denier among all the experimental treatments was observed. The best renditta was recorded in hot air drying with a value of 6.64. The raw silk percentage and reelability percentage of cocoons dried under hot air-drying method showed significantly higher percentage of 39.50 and 84.78%, respectively compared to other treatments. Thus, stifling of cocoons with hot air-drying method showed cocoon characteristics significantly better as compared to other stifling methods. Exposure of cocoons to direct sunlight deteriorates the quality of the cocoons. Cocoon parameters were observed inferior in open sun drying method.