Fumigant toxicities of 20 plant essential oils, and fumigant and contact toxicities of the components of active oils and their analogues against adzuki bean weevil, Callosobruchus chinensis (L.) were investigated. Fumigant toxicity varied with plant essential oils and concentrations. The 24-h LC50 values against adult C. chinensis were 3.14, 6.68, 8.59, 8.90 and 10.23 mg/L air concentration for Gaultheria fragrantissima, Illicium verum, Croton anisatum, Aniba roseodora, and Bursea delpechiana, respectively. To elucidate structure-activity relationship of methyl salicylate (MS) and trans-anethole (tA), fumigant and contact toxicities of MS, methyl 3-hydroxybenzoate (M3HB), methyl 4-hydroxybenzoate (M4HB), methyl 2-methoxybenzoate (M2MB), methyl 2-acetoxysalicylate (M2AS), methyl benzoate (MB), salicylic acid (SA), trans-anethole (tA) and 1-methoxy-4-propylbenzene (PB) were investigated. The 24-h LC50 values of fumigant toxicity were 3.48, 5.36, 6.39 and 9.27 mg/L air concentration for MS, MB, tA and PB, respectively. The 24-h LD50 values (µg/beetle) of contact toxicity were 28.89, 33.27, 33.56, 44.81 56.31, 38.59 and 69.20 for MS, M2AB, M2MB, MB, SA, tA and PB, respectively. Structural differences were identified that may contribute to understanding the insecticidal activities of methyl salicylate and trans-anethole.

The acaricidal activities of Illicium verum fruit-derived materials against adults of Dermanyssus gallinae were examined using the direct contact application method. Based on laboratory tests, an acaricidal constituent of I. verum fruit was determined because of its potent activity. Results were compared with those of the currently used acaricides such as dichlorvos, diazinon, and carbaryl. The acaricidal principle of I. verum fruit was identified as (E)-anethole using a GC-MS. Its acaricidal activity was compared with those of 12 compounds having a similar chemical moiety. Based on the LD50 values, the acaricidal activities of (+)-or-(–)-neomenthol were the strongest (0.01 ㎎/㎠]) and (E)-anethole, (+)-or-(–)-menthol, (±)-isoborneol, (–)-menthone, and (1S)-endo-(–)-borneol showed similar results (0.02 ㎎/㎠), and (1R)-(+)-camphor and (+)-menthone also gave good activities (0.03 and 0.04 ㎎/㎠, respectively). These compounds showed more toxic acaricidal activities than diazinon and carbaryl, 0.05 and > 0.2 ㎎/㎠, respectively, but were not comparable to that of dichlorvos with 0.0002 ㎎/㎠. These results indicate that the I. verum fruit-derived materials and tested compounds descried as poultry red mites-control agents could be useful for managing field populations of D. gallinae.