Control of Tetranychus urticae Koch by extracts of three essential oils of chamomile,marjoram and Eucalyptus

Objective:To evaluate the acaricidal activity of extracts of three essential oils of chamomile,marjoram and Eucalyptwi against Tetranychus urtiaie(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 LC_(50)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-Stxansferase,esterase(α-esterase andβ-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 LC_(50)of both chamomile and marjoram compared with positive control.Gas chromatography-mass spectrometer(CC-MS)proved that the major compositions of Chamomilla recutita areα-bisabolol oxide A(35.251%),and trans-3-farersene(7.758%),while the main components of Marjorana hortensis are terpincne-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.