Objective To investigate the toxic activity of perilla essential oil(PE-EO)and PE-EO nanoemulsion on larvae and pupae of Culex pipiens pallens.The findings of this study will provide a scientific basis for the development of safe and effective plant-derived mosquitoicides.Methods The larvicidal and pupicidal activity,the duration of action of PE-EO nanoemulsion against Cx.pipiens pallens,and toxicity to non-target organisms were determined using a series of laboratory bioassays.Results The LC50 of PE-EO against L1,L2,L3 larvae was 25.4,43.0,46.6 mg/L,while those of nanoemulsion-PE-EO against L1,L2,L3 larvae was＜25.0,35.1,38.1 mg/L respectively.At all larvae stages,the larvicidal activity of the nanoemulsion was significantly greater than that of pure EO at the same concentration.In pupal stage,the mortality of PE-EO at 24 h and 48 h were 1.3％and 2％,while that of nanoemulsion-PE-EO were 34.7％and 40％.The larvicidal activity of the essential oil(EO)is limited to a period of 1-2 days,whereas the nanoemulsion can maintain its efficacy for up to 5 days.Neither the EO nor the nanoemulsion exhibited any toxicity towards aquatic plants.However,the toxicity of the PE-EO mixture towards fish was significantly reduced following nanoemulsion encapsulation.Conclusion In comparison to PE-EO,the nanoemulsion displays enhanced stability,which has resulted in augmented killing activity against mosquito larvae and a reduction in toxicity to non-target organisms.Nanoemulsion-PE-EO has the potential to serve as an environmentally friendly,sustainable and efficacious larvicide for mosquito vector control.