Acaricidal activities of traditional Chinese medicine against the house dust mite, Dermatophagoides farinae.

Objective. This paper assessed the potential of traditional Chinese medicine (TCM) preparations for using as environmentally acceptable and alternative commercial acaricides. Methods. 22 kinds of TCM, which contained abundant essential oils and showed insecticidal effects, were collected. Samples extracted with petroleum ether, ethyl acetate and methanol were tested against house dust mites Dermatophagoides farinae and their toxicity assessed. Results. The results showed that 3 TCM of Cinnamonum cassia, Eugenia caryophyllata and Pogostemon cablin have higher activity, and the parallel tests showed that the petroleum ether extract had higher activities (0·0046 mg/cm 2 , 0·005 mg/cm 2 and 0·006 mg/cm 2 respectively, 24 h, LD 50 ) than the extracts of ethyl acetate and methanol. The acaricidal activity of the ethyl acetate extracts from C. cassia , P. cablin and Asarum sieboldii (0·00144 mg/cm 2 , 0·00347 mg/cm 2 and 0·05521 mg/cm 2 respectively, 24 h, LD 50 ) were almost comparable to that of benzyl benzoate and dibutyl phthalate. However, the methanolic extracts of were less effective. Conclusions. This study shows the use of extracts with petroleum ether of C. cassia , P. cablin and E. caryophyllata as eco-friendly biodegradable agents for the control of the house dust mite.