The acricidal potency of some essential oils can be applied to the control of house dust mites. But it is more effective keeping the house dust mites away than killing them because they remain as allergens even after death. The most efficient repellent concentration of lavender and tea tree in 10㎕ against house dust mites (Dermatophagoides farinae and D. pteronyssinus) were experimented by direct contact bioassay method at various doses ; 2.5, 1.25, 0.625, and 0.3125% and at vairous exposure times ; 15, 30, 60, 120, and 180 minutes. The most effective dose of essential oils (lavender and tea tree) against house dust were 0.625% and the repellent effectiveness at the mowt effective dose of 0.625% were 95.6% for lavander and 96.2% for tea tree, respectively. These results suggest that lavender and tee tree can be effectively used in the control of house dust mites.

The insecticidal potency of some essential oils have been suggested that they may find an application in the control of house dust mites. We compared the repellent effect of four essential oils ; lemon grass (Cymbopogon nardus), lavender(Lavandula vera), rosemary(Rosmarinus officinalis) and ylang ylang(Cananga odorata). The oils were exposed at different doses(0.1, 0.05, 0.025, 0.0125, and 0.00652 ㎕/㎠) and different times(1, 2, 3, 4, 5 hours) on house dust mites(Dermatophagoides farinae and D. pteronyssinus). The repellent effects(%) of essential oils that were exposed at 0.1 ㎕/㎠ and for 1 hours against house dust mites were lemon grass(63.3%) and rosemary(61%), lavender(40%), ylang ylang(40%) in the order named.

Quality stability of the herb pill coated with edible oils containing rosemary was investigated. Herb pills were made of herb powders such as Panax ginseng, Cinnamomum cassia, Lycium chinense, Zyzyphus jujuba and Zingiber officinale. Rapeseed oil and lubriol were used as edible coating oil. After herb pills coated with edible oils with or without rosemary were stored at 40℃ for 180 days, the microbial viable cell counts and peroxide values(POV) of the herb pill were investigated. After 180 day storage, POVs of herb pills with only rapeseed oil or lubriol were 0.51 and 0.49 meq/kg, respectively. However, when rosemary was added in herb pills the POVs were decreased to 0.30 and 0.39 meq/kg, respectively. The addition of rosemary to the rapeseed oil and lubriol tended to decrease the microbial viable cell counts of the herb pill. The microbial viable cell counts of rapeseed oil and lubriol were 940 and 820CFU/g, respectively after 180 days of storage. However, these levels were suppressed to 720 and 640CFU/g by the resemary addition. On the other hand, the ginseng saponin content of herb pills was not affected by the rosemary addition during storage.