Acaricidal activities of the active component of Lycopus lucidus oil and its derivatives against house dust and stored food mites (Arachnida: Acari)

Abstract

Recent studies have focused on materials derived from plant extracts as mite control products against house dust and stored food mites because repeated use of synthetic acaricides had led to resistance and unwanted activities on non-target organisms. The aim of this study was to evaluate the acaricidal activity of materials derived from Lycopus lucidus against Dermatophagoides farinae, D. pteronyssinus and Tyrophagus putrescentiae. The LD50 values of L. lucidus oil were 2.19, 2.25 and 8.45 µg cm(-2) against D. farinae, D. pteronyssinus and T. putrescentiae. The acaricidal constituent of L. lucidus was isolated by chromatographic techniques and identified as 1-octen-3-ol. In a fumigant method against D. farinae, the acaricidal activity of 1-octen-3-ol (0.25 µg cm(-2)) was more toxic than N,N-diethyl-m-toluamide (DEET) (36.84 µg cm(-2)), followed by 3,7-dimethyl-1-octen-3-ol (0.29 µg cm(-2)), 1-octen-3-yl butyrate (2.32 µg cm(-2)), 1-octen-3-yl acetate (2.42 µg cm(-2)), 3,7-dimethyl-1-octene (9.34 µg cm(-2)) and benzyl benzoate (10.02 µg cm(-2)). In a filter paper bioassay against D. farinae, 1-octen-3-ol (0.63 µg cm(-2)) was more effective than DEET (20.64 µg cm(-2)), followed by 3,7-dimethyl-1-octen-3-ol (1.09 µg cm(-2)). 1-Octen-3-ol and 3,7-dimethyl-1-octen-3-ol could be useful as natural agents for the management of three mite species.