Acaricidal and Repellent Activity of Zanthoxylum myriacanthum (Rutaceae) Fruit Extracts Against Tetranychus urticae and Tetranychus truncatus (Acari: Tetranychidae)

This work investigated acaricidal and repellent activities of Zanthoxylum myriacanthum Wall. ex Hook. f. (Rutaceae) extracts against Tetranychus urticae Koch and Tetranychus truncatus Ehara (Acari: Tetranychidae). Acaricidal activities were tested by spraying the extracts on adult females and eggs, and repellent activity was assessed in paired-choice tests with filter paper treated with the extracts by using adult female mites. Adult mortality 24 h after application of a 12% (w/v) concentration of the hexane extract was 73.3% for T. urticae and T. truncatus, whereas application of the methylene chloride extract caused 85.8% mortality of T. urticae and 85% mortality of T. truncatus. Lower concentrations (6-12%) of the methanol extract yielded low efficacy against T. urticae but exhibited high efficacy against T. truncatus (73.8- 95.8%). In general, egg hatch was reduced <50% by 5 d following application of the extracts. Only the 6-12% concentration of the hexane extract caused higher levels of T. truncatus egg mortality ranging 55.4-68.7%. All extracts repelled adult mites over 64% from 5 to 72 h after exposure. However, the percentage of repellency showed no statistical differences in all treatments. Gas chromatography-mass spectrometry (GC-MS) analysis identified that the major chemical compounds in the hexane extract were DL-limonene (29.75%) and sabinene (9.76%), whereas limonene (40.70%) and sabinene (16.60%) were the principal constituents of the methylene chloride extract. Our results demonstrate that Z. myriacanthum dried fruit extracts have potential for controlling T. urticae and T. truncatus and might be developed as acaricides for integrated pest management programs.