Abstract: 【Aim】The aim is to explore the bioactivity of Coriandrum sativum essential oils against Myzus persicae, and its synergistic effects on imidacloprid, as well as the response mechanism of M. persicae to C. sativum essential oil stress. 【Methods】 The median lethal concentration (LC₅₀) values of 24 h fumigation activity (essential oil concentrations of 200, 100, 50, 25, 12.5, and 6.25 μL/mL) and 24 h contact activity (essential oil concentrations of 12.5, 6.25, 3.125, 1.563, and 0.781 μL/mL) of seed essential oil and leaf essential oil of C. sativum against M. persicae adults were evaluated, respectively. M. persicae adults were treated with imidacloprid solutions at the concentrations of 40, 20, 1.0, 0.5, and 0.25 mg/L containing 0.05% volume fraction of leaf essential oil and seed essential oil of C. sativum, respectively, by leaf-dipping method to determine the synergistic effects of leaf essential oil and seed essential oil of C. sativum on imidacloprid at 48 h after treatment. The activities of the protective enzymes superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD), detoxification enzymes carboxylesterase(CarE) and glutathione-S-transferase (GST), and acetylcholinesterase (AChE) in M. persicae adults at 48 h after contact treatment with LC₅₀ concentration of leaf essential oil and seed essential oil of C. sativum were determined. 【Results】 The 24 h contact LC₅₀ values of seed essential oil and leaf essential oil of C. sativum against M. persicae adults were 1.63 and 3.72 μL/mL, respectively. The 24 h fumigation LC₅₀ values of seed essential oil and leaf essential oil of C. sativum against M. persicae adults were 1469 and 3415 μL/mL, respectively. The synergistic experiment results showed that the LC₅₀ values of imidacloprid against M. persicae adults were 0.99 and 1.51 mg/L after adding 0.05% volume fraction of seed and leaf essential oil of C. sativum and the synergistic ratios were 478 and 313, respectively. The activities of the protective enzymes SOD and CAT in M. persicae adults at 48 h after the contact treatment with seed essential oil and leaf essential oil of C. sativum at the LC₅₀ concentration were significantly increased, however, those of POD had no significant change as compared with those of the blank control group. The activities of the detoxification enzymes CarE and GST, and AChE in M. persicae adults at 48 h after the contact treatment with seed essential oil and leaf essential oil of C. sativum at LC₅₀ concentration were significantly increased as compared with that of the blank control group. The activities of SOD, GST, and AChE in M. persicae adults treated with the C. sativum seed essential oil were 1.58-, 1.20-, and 134-fold as high as those of the treatment group of the C. sativum leaf essential oil, respectively. 【Conclusion】 Seed essential oil and leaf essential oil of C. sativum have contact activity and fumigation activity against M. persicae, and also show synergistic effects on imidacloprid, with seed essential oil displaying stronger effect. M. persicae can respond to the stress of insecticidal components in C. sativum essential oil by increasing the activities of the protective enzymes SOD and CAT, as well as the detoxification enzymes CarE and GST, and AChE.

Key words:  Myzus persicae, Coriandrum sativum essential oil, insecticidal activity, synergism, protective enzyme, detoxification enzyme