Abstract: 【Aim】 This research aims to evaluate the fumigation activities of the essential oils (EOs) from Cinnamomum caphora fruits, Cinnamomum pedunculatum leaves and Sabina chinensis var. chinensis leaves, and their mixtures against the adults of the housefly, Musca domestica, so as to provide theoretical basis for developing botanical insecticides. 【Methods】 The fumigation and knock-down toxicities of these EOs extracted by steam distillation and their mixtures against the 5-day-old adults of M. domestica were detected with the erlenmeyer flask method. 【Results】 The median lethal concentration (LC₅₀) values of the three EOs against M. domestica adults were 5.28, 16.86, and 14.54 μg/cm³, respectively, and the median knock-down time (KT₅₀) values in the treatment of LC₉₀ were 12.03, 16.56, and 13.37 min, respectively. The fumigation toxicity of EO from C. pedunculatum leaves against M. domestica adults showed strong synergistic effect when it was mixed with EO from S. chinensis var. chinensis leaves at the LC₅₀ value ratio of 9∶1, with the co-toxicity coefficient (CTC) as high as 367.95. 【Conclusion】 The EO from C. caphora fruits has strong fumigation and knock-down toxicities against M. domestica adults, followed by EO from S. chinensis var. chinensis leaves and then EO from C. pedunculatum leaves. Mixtures of EO from C. pedunculatum leaves and S. chinensis var. chinensis leaves have synergistic effect on their fumigation toxicities against M. domestica adults. The three EOs have the potential to be developed as environmental insecticides.

Key words: Musca domestica, essential oil, fumigation toxicity, mixture, co-toxicity coefficient, knock-down toxicity, synergistic effect