The eri silkworm, Samia ricini (Donovana) is a polyphagous vanya silkworm and castor (Ricinus communis) is the most suitable primary food plant. However, being annual in nature, the castor requires huge investment in maintenance and recurring plantation which makes the ericulture is lesser lucrative among poor farmers. Hence, the experiments on rearing performance of eri silkworms feeding on different perennial food plants revealed the superiority of the combination of Castor (Ricinus communis) with Borpat (Ailanthus grandis) leaves feeding in early and late stages of silkworm, respectively. The lowest larval duration, higher mature larval weight, single cocoon weight, single shell weight, cocoon yield per disease free laying (dfl) in numbers, effective rate of return (ERR) and cocoon shell yield per 100 dfls were found the highest in treatment of Castor in combination with Borpat, which was at par with the treatment Borpat alone i.e. feeding from brushing (1st instar) till spinning (5th instar). The lowest performances in all economic characters such as higher larval duration and the lowest mature larval weight, single cocoon weight, single shell weight, cocoon yield per dflin number and cocoon shell yield per 100 dfls were recorded in the treatment of eri silkworm feeding from 1st instar till spinning on Kesseru plant. The highest fecundity was recorded in the treatment of Castor in combination with Borpat, which was at par with the treatment of Castor in combination with Borkesseru. Similarly, the higher hatchability, moth emergence and lower cocoon: dflratio was recorded in the treatment of Castor in combination with Borpat. Adoption of Borpat tree for rearing of eri silkworm among eri rearers will help in commercialization of ericulture and will overcome the problem of non-availability of sufficient leaves throughout the year besides mitigation of deforestation and affects of climate changes.