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Chandrika and plastic mountages

Mountages are spinning frames onto which mature fifth-instar silkworms are transferred so that they can spin their cocoons in well-defined cells. The chandrika, a traditional bamboo mountage, and the plastic collapsible mountage developed by the Central Silk Board are the two principal forms used in Indian sericulture.

Composition and design

The chandrika is a rectangular bamboo mat fitted with a spirally wound bamboo tape that creates the spinning cells. A single chandrika accommodates about 1,000 worms and is widely used in South Indian rearing households. The plastic collapsible mountage, recommended by the Central Silk Board and CSRTI, is a polypropylene frame of about 11 folds, each approximately 6 cm high, fitted onto a 60 x 90 cm tray.

Mode of use

Ripe worms are picked by hand or by phototropic methods and uniformly distributed on the mountage at recommended density. The mountages are kept in a well-ventilated, draft-free spinning area within the rearing house (Silkworm Rearing Shed); ambient temperature and humidity are maintained to promote uniform shell formation. Cocoons are harvested after the pupa has hardened, usually on day 5 to 7 after mounting.

Target use and dose

Both mountage types are sized for late-age larvae of mulberry silkworm including bivoltine hybrids (Bivoltine Silkworm). The plastic mountage offers approximately 69% cocooning efficiency compared with about 64% for the older jali (bamboo) type, with a lower incidence of double cocoons and deformed shells.

Safety and adoption

The plastic mountage is rodent-proof, easily disinfected with formalin-bleach solutions between batches, and reusable for many seasons, making it preferred in commercial bivoltine operations. The chandrika continues in use for its low capital cost but rising bamboo prices and its fragility have made it less common.

See also: Bivoltine Silkworm, Silkworm Rearing Shed, Cocoon Marketing Csb Auction, Whole Shoot Feeding, Chawki Rearing Centre.

References

  1. Mountages used in Sericulture for Quality Cocoon Production. Biotica Research Today.
  2. Mountage: Meaning and Types. Notes on Zoology - Sericulture.
  3. Harvesting and Marketing of Cocoons. eGyanKosh, IGNOU.