Rearing Performance of Different Eco-races of Eri Silkworm (Philosamia ricini Donovan) during Spring Season of Uttar Pradesh

The rearing performance of different eco-races of eri silkworm, Philosamia ricini was studied during spring 2007 and 2008 in Uttar Pradesh. The rearing performance of different eco-races namely Borduar, Titabar, Dhanubhanga and Mendipathar was analyzed based on their hatching (%), larval duration (d), weight of full grown larvae (g), cocoon yield (by number and weight), single cocoon weight (g), shell weight (g), shell ratio (%), cocoon shape variability, pupal period (d), pupation rate (%), and leaf silk conversion rate (%). The Borduar eco-race of P. ricini showed better rearing performance compared to Titabar, Dhanubhanga and Mendipathar eco-races. The rearing parameters such as weight of full grown larvae, yield, single cocoon weight, shell weight, shell ratio, cocoon shape variability, pupation rate of different eco races of eri silkworm differed significantly.