Identification of Repellent and Insecticidal Constituents of the Essential Oil of Artemisia rupestris L. Aerial Parts against Liposcelis bostrychophila Badonnel

The aim of this research was to determine the chemical composition and insecticidal and repellent activity of the essential oil ofArtemisia rupestrisL. aerial parts against the bookliceLiposcelis bostrychophilaBadonnel and isolation of insecticidal and repellent constituents from the essential oil. The essential oil ofA. rupestriswas obtained by hydrodistillation and analyzed by GC-MS. A total of 30 components of the essential oil ofA. rupestriswas identified and the principal compounds in the essential oil were α-terpinyl acetate (37.18%), spathulenol (10.65%), α-terpineol (10.09%), and linalool (7.56%), followed by 4-terpineol (3.92%) and patchoulol (3.05%). Based on bioactivity-guided fractionation, the four active constituents were isolated from the essential oil and identified as α-terpineol, α-terpinyl acetate, 4-terpineol and linalool. The essential oil ofA. rupestrisexhibited contact toxicity againstL. bostrychophilawith LD50value of 414.48 µg/cm2. α-Terpinyl acetate (LD50= 92.59 µg/cm2) exhibited stronger contact toxicity against booklice than α-terpineol (LD50= 140.30 µg/cm2), 4-terpineol (LD50= 211.35 µg/cm2), and linalool (LD50= 393.16 µg/cm2). The essential oil ofA. rupestris(LC50= 6.67 mg/L air) also possessed fumigant toxicity againstL. bostrychophilawhile the four constituents, 4-terpineol, α-terpineol, α-terpinyl acetate and linalool had LC50values of 0.34, 1.12, 1.26 and 1.96 mg/L air, respectively. α-Terpinol and α-terpinyl acetate showed strong repellency againstL. bostrychophila, while linalool and 4-terpinol exhibited weak repellency. The results indicate that the essential oil ofA. rupestrisaerial parts and its constituent compounds have potential for development into natural insecticides or fumigants as well as repellents for control of insects in stored grains.Keywords:Liposcelis bostrychophila;Artemisia rupestris;contact toxicity;fumigant toxicity;repellency;essential oil composition