Acaricidal Activity of Essential Oils Derived from 10 Cupressaceae Species against Stored Food and House Dust Mites

Acaricidal activities of essential oils obtained from 10 Cupressaceae species against Dermatophagoides farinae, D. pteronyssinus, and Tyrophagus putrescentiae were examined using direct contact method. Based on $LD_{50}$ values, most toxic plant oil was Chamaecyparis obtusa against D. farinae ($LD_{50},\;15.8{\mu}g/cm^{2}$) and D. pteronyssinus ($LD_{50},\;14.1{\mu}g/cm^{2}$), and T. orientalis L. ($LD_{50},\;22.8{\mu}g/cm^{2}$) against T. putrescentiae. D. pteronyssinus may be controlled more effectively by applying oils of C. pisifera var. filifera Beiss et Hart., C. obtusa S. et Z., C. pisifera Endl., J. chinensis L., J. chienesis var. sargentii Henry, J. virginiana L., and T. orientalis L. than D. farinae. D. farinae may be controlled more effectively by oils of J. chinensis var. aureo-variegata Rehder, J. chinensis var. globosa Horn., and J. chinensis var. kaizuka Hart. than D. pteronyssinus. Acaricidal activities of leaf oils extracted from C. obtusa S. et Z. and T. orientalis L. were significantly higher than those of fruit and branch oils against D. farinae and D. pteronyssinus. Acaricidal activities of oils of C. obtusa S. et Z. fruit and T. orientalis L. branch were significantly higher than those of leaf and branch oils of C. obtusa S. et Z., and fruit and leaf oils of T. orientalis L. against T. putrescentiae. Acaricidal activities of essential oils of C. obtusa S. et Z. and T. orientalis L. were comparable with that of N,N-diethyl-m-toluamide. Naturally-occurring acaricides, C. obtusa S. et Z. and T. orientalis L. could be useful as new acaricidal agents against Dermatophagoides spp. and Tyrophagus spp.