Rearing technology of eri silkworm (Samia cynthia ricini) under varied seasonal and host plant conditions in Tamil Nadu.
The eri silkworm, Samia cynthia ricini highly preferring castor as a host plant followed by tapioca and also the suitability of other alternative host has been found out for the continuous rearing during unseason of crop. In laboratory study we were used 10 plant species, viz., Calotropis gigantean, Nerium odourm, Leucaena leucocephla, Parthenium hysterophororum, Annona squamosa, Pongamia pinnata, Coconut leaf, banana leaf, Sesbania grandiflora, and Terminalia catapa for feeding the 5th instar larvae of eri silk worm after pre-starvation period of 30 min. In case of Calotropis gigantea, the larvae started feeding initially than stopped in a short period and showed 100% larval death with in an hour. In all other cases except the country almond Terminalia catapa and subabul Leuciana leucocephala, the worms were not feeding at all, or they just nibbled and started wandering. On the other hand, the feeding was moderate and continuous on subabul and country almond. In another experiment the larval duration on CRNB variety was minimum 23 days and it extent to 25 days in CPDB, CGDB, Co.2-CPDB, Co.2-CGDB, H.165-CPDB. Twenty-six days were required in castor-tapioca combination to complete the larval development and a maximum of 28 days on the tapioca (TV 1&2) host plant. The moulting period for all the larval stages ranged from 3.5 to 4.5 days on different host plants and combinations. It was short in favorable plants.