Control of green peach aphid (Myzus persicae), a globally important pest, using plant-derived oils is a promising alternative to conventional insecticides. Although various plant-derived oils are potentially useful for insect control, dose–response studies and efficacy comparisons among oils have not been widely reported. Our objective was to compare M. persicae control by plant-derived oils, focusing on oils derived from Brassicaceae species that exhibit rotational and environmental quality benefits. We thus applied sprays of emulsified ethyl esters from the seed oils of yellow mustard (Sinapis alba), oriental mustard (Brassica juncea) and rapeseed (Brassica napus) to M. persicae in a laboratory bioassay. A dose–response relationship was modelled for the S. alba spray yielding LD50/LD95 values of 18.2 ± 0.87/128.1 ± 5.10 μg ester per cm2 (P < 0.0001). Ethyl esters of oils from all three species and soybean (Glycine max) ethyl ester were compared to determine the efficacy of Brassicaceae oils relative to the dominant plant-oil spray currently available. All ethyl esters were equally efficacious despite measured differences in fatty acid profiles among the oils. Oils derived from mustards B. juncea and S. alba are potentially useful feedstocks for the production of insecticidal sprays, and testing on additional insects is warranted.