Evaluation of repellency of some Chinese medicinal herbs essential oils against Liposcelis bostrychophila (Psocoptera: Liposcelidae) and Tribolium castaneum (Coleoptera: Tenebrionidae).

The screening for repellency against the booklouse, Liposcelis bostrychophila (Badonnel), and the red flour beetle, Tribolium castaneum (Herbst), from 14 Chinese medicinal herbs showed that the essential oils of Curcuma longa L., Epimedium pubescens Maximouwicz, Lindera aggregate (Sims) Kostermans, Nardostachys chinensis Battandier, Schizonepeta tenuifolia Briquet, Zanthoxylum schinifolium Sieber et Zuccarini, and Z. officinale Roscoe exhibited strong repellency against L. bostrychophila and T. castaneum. A total of 35 components of the essential oil of E. pubescens were identified by gas chromatography and gas chromatography-mass spectrometry. Beta-Eudesmol (14.89%), alpha-pinene (13.38%), borneol (9.56%), (R)-carvone (7.89%), and menthol (7.45%) were the main components of the essential oil of E. pubescens. From the essential oil of E. pubescens, four monoterpenoids and one sesquiterpenoid were isolated by bioassay-guided fractionation. The compounds were identified alpha-pinene, borneol, menthol, carvone, and beta-eudesmol. (R) -carvone, menthol, borneol, and beta-eudesmol were strongly repellent against L. bostrychophila at concentration of 8.5 nl/cm2 after 2 h exposure whereas alpha-pinene exhibited moderate repellency. (R)-carvone exhibited stronger repellency against the booklouse than the positive control, N, N-diethyl-3-methylbenzamide (DEET). Moreover, (R)-carvone also possessed stronger repellency against T. castaneum than DEET. The other four constituents, menthol, borneol, and beta-eudesmol also showed repellency against the red flour beetles but weaker than DEET at lower concentrations.