Rearing performance of Eri silkworm, Samia ricini reared on Carica papaya leaves during different seasons in Kokrajhar, Assam

Abstract

Samia ricini is one of the most common silkworms reared in Kokrajhar district. Samia ricini is known to feed on a variety of host plants however, the rearing performance and silk quality of the silkworm depends primarily on the type of food plants used for rearing. Castor plant is regarded as the primary host plant, but it is not commonly available throughout the year. Therefore, an attempt was made to study the rearing performance of Samia ricini which was reared using Carica papaya leaves during different seasons. The growth parameters and cocoon characters of the silkworms reared on Carica papaya leaves were comparatively normal. The larval duration ranged from 30.11±0.942 to 41.88 ±1.135 days in Carica papaya fed silkworms and 21.55±0.906 to 35.78±1.534 days in R. communis (castor) fed silkworm. The pupal duration in silkworms fed with C. papaya ranged from 14.44±1.011 to 17.89±0.699 days and 11.11±0.699 to 13±0.894 days in R. communis fed silkworms. The effective rate of rearing (ERR%) emergence rate (ER%), survival rate (SR%), cocoon weight (g), shell weight (g), shell ratio (%), hatchability (%) and fecundity (nos.) of the silkworms fed with C. papaya leaves were also found to be normal as compared to the silkworm fed with R. communis leaves. However, the growth duration and overall performance of the silkworm was found to be better during S2 (summer) and S3 (autumn)and lower during S4 (winter). The present study indicates that the economic and growth parameters of Eri silkworms reared using C. papaya leaves was comparable with those reared using castor leaves therefore, C. papaya may also be considered as a potential host plant for the rearing of Samia ricini.