Insecticidal Activity of a Component, (-)-4-Terpineol, Isolated from the Essential Oil of Artemisia lavandulaefolia DC. against Plutella xylostella (L.)

SIMPLE SUMMARY: Plutella xylostella (L.) (Lepidoptera: Plutellidae) is the most destructive pest of cruciferous crops around the world. The inappropriate use of insecticides to manage it has brought the development of resistance to several pesticide active ingredients. Keeping in view the resistance problem and long-term application, essential oils of plants may provide an environment-friendly solution to manage pests. Although the essential oil of Artemisia lavandulaefolia DC. was proven to exhibit promising insecticidal activities against P. xylostella, which components have insecticidal activities are unknown. In the present study, four bioactive components were identified from A. lavandulaefolia essential oil by GC/MS, and their insecticidal activities against P. xylostella were also evaluated. Among them, (-)-4-terpineol was proven to be mostly responsible for its insecticidal activity against P. xylostella. This effect was associated with decreased activity of GST, CAT, AChE and Na(+)/K(+)-ATPase. Overall, our findings indicated that (-)-4-terpineol may offer an alternative source for the control of P. xylostella. ABSTRACT: Plutella xylostella (L.) is one of the most serious pests of cruciferous vegetables. Our previous work demonstrated that the essential oil of Artemisia lavandulaefolia DC. exhibits promising insecticidal activities against P. xylostella. This study further characterizes the key components that are responsible for the insecticidal effect. In total, 47 compounds (96.52% of the total compounds) were identified from the total oil using GC-MS, and the major compounds were eucalyptol (21.57%), D(+)-camphor (17.33%), (-)-4-terpineol (9.96%) and caryophyllene oxide (10.96%). Among them, (-)-4-terpineol showed significantly larvicidal and fumigant activities against P. xylostella. The LD(50) of (-)-4-terpineol was 43.15 mg/mL at 12 h and 31.22 mg/mL at 24 h for 3rd instar larvae, and the LC(50) for adults was 8.34 mg/mL at 12 h and 7.35 mg/mL at 24 h. In addition, the adults treated with (-)-4-terpineol showed varying degrees of inhibitory activity toward glutathione S-transferase, catalase, acetylcholinesterase and Na(+)/K(+)-ATPase at different post-treatment intervals and concentrations. The results indicate that (-)-4-terpineol has promising insecticidal activities against P. xylostella, and it has good inhibitory effects on the four enzymes of P. xylostella adults.