4-Methylthiobutyl Isothiocyanate or Erucin obtained from Eruca sativa (Mill.) (Thell) seeds were investigated for its effect against the second instar larvae of common cutworm, Spodoptera litura (Fab.) by conducting artificial diet bioaasays and topical assays. The artificial diet bioassays conducted at different concentrations (40mg/l, 81mg/l, 121mg/l, 161mg/l and DMSO as control) showed inhibitory effects on percentage of pupation rate and percentage of adult emergence. Topical application of 161mg/l concentration of erucin to the larvae of S. litura delayed the larval and total development period and decreased the percentage adult emergence. These findings indicate a possible insecticidal role of erucin in insect pest management.