title: Control of Tetranychus urticae Koch by extracts of three essential oils of chamomile, marjoram and Eucalyptus.
abstract: OBJECTIVE
  To evaluate the acaricidal activity of extracts of three essential oils of chamomile, marjoram and Eucalyptus against Tetranychus urticae (T. urticae) Koch.
  
  
  METHODS
  Extracts of three essential oils of chamomile, marjoram and Eucalyptus with different concentrations (0.5%, 1.0%, 2.0%, 3.0% and 4.0%) were used to control T. urticae Koch.
  
  
  RESULTS
  The results showed that chamomile (Chamomilla recutita) represented the most potent efficient acaricidal agent against Tetranychus followed by marjoram (Marjorana hortensis) and Eucalyptus. The LC50 values of chamomile, marjoram and Eucalyptus for adults were 0.65, 1.84 and 2.18, respectively and for eggs 1.17, 6.26 and 7.33, respectively. Activities of enzymes including glutathione-S-transferase, esterase (α-esterase and β-esterase) and alkaline phosphatase in susceptible mites were determined and activities of enzymes involved in the resistance of acaricides were proved. Protease enzyme was significantly decreased at LC50 of both chamomile and marjoram compared with positive control. Gas chromatography-mass spectrometer (GC-MS) proved that the major compositions of Chamomilla recutita are α-bisabolol oxide A (35.251%), and trans-β-farersene (7.758%), while the main components of Marjorana hortensis are terpinene-4-ol (23.860%), p-cymene (23.404%) and sabinene (10.904%).
  
  
  CONCLUSIONS
  It can be concluded that extracts of three essential oils of chamomile, marjoram and Eucalyptus possess acaricidal activity against T. urticae.
authors.affiliation: Department of Biochemistry, Faculty of Agriculture, Cairo University, P. Box 12613, Gamma St, Giza, Cairo, Egypt.
authors.forename: M R Afify
authors.initials: MR
authors.lastname: Abd El-Moneim
authors.forename: S Ali
authors.initials: SA
authors.lastname: Fatma
authors.forename: A F
authors.initials: AF
authors.lastname: Turky
mesh_terms: D056810:Acaricides / Q000302:isolation & purification / Q000494:pharmacology*; D000818:Animals; D020843:Chamomile / Q000737:chemistry*; D004351:Drug Resistance; D004798:Enzymes / Q000032:analysis; D005052:Eucalyptus / Q000737:chemistry*; D005260:Female; D008297:Male; D009822:Oils, Volatile / Q000302:isolation & purification / Q000494:pharmacology*; D031341:Origanum / Q000737:chemistry*; D016019:Survival Analysis; D040102:Tetranychidae / Q000187:drug effects* / Q000201:enzymology
chemical_list: D056810:Acaricides; D004798:Enzymes; D009822:Oils, Volatile
keywords: Alkaline phosphatase; Chamomile; Enzymes; Eucalyptus; Glutathione-S-transferase; Marjoram; Non specific esterase; Plant essential oils; Protease; Tetranychidae