The Relative toxicity of methyl-o-demeton, spinosad, acetamiprid, chlorfenapyr and fipronil were evaluated against mustard aphid, Lipaphis erysimi (Kalt.) on Gobhi sarson var. DGS-1 during 2017-18. The LC50 values of insecticides viz., methyl-o-demeton, spinosad, acetamiprid, chlorfenapyr and fipronil were , , , and ppm, respectively by direct spray method indicating that acetamiprid exhibited greater toxicity among the tested insecticides. | Relative toxicity of some newer insecticides against mustard aphid Lipaphis erysimi Kalt. on Gobhi sarson