Worldwide, the bird cherry-oat aphid, Rhopalosiphum padi, (R. padi) affects wheat, sorghum, and other grain crops, and conventional pesticides to control this aphid negatively affects the surrounding environment. Therefore, knowing the entomotoxicity of different chemical compounds against R. padi is an important step to control these pests. Thus, we aimed to evaluate the toxicity of different nicotinic acetylcholine receptor modulators (thiamethoxam, imidacloprid, acetamiprid, and sulfoxaflor) and the octopamine receptor agonists’ (ORAs hereon) synergistic effect (chlordimeform and amitraz) on the selected pesticides’ toxicity against R. padi adults. We found that chlordimeform was more effective than amitraz (LC50: 144.01 and 238.33 μg/mL, respectively), after 24-h of exposure. Sulfoxaflor was the most toxic pesticide (LC50 values were 4.61 and 0.44 μg/mL), whereas we identified acetamiprid as the least potent one (LC50 values were 111.82 and 88.69 μg/ mL). Thiamethoxam was the most effective neonicotinoid pesticide among those we used. Chlordimeform and amitraz had synergized effects with the surveyed pesticides, with amitraz showing the highest synergistic ratio. These findings indicate that ORAs are promising tools to increase the selected pesticides’ effectiveness on R. padi control, which may contribute to the decrease in the use of generic pesticides, the emergence of resistant strains, and, consequently, their impacts on the environment.