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Acaricidal property of the essential oil from Lippia gracilis against Tetranychus urticae and a natural enemy, Neoseiulus californicus, under greenhouse conditions

Author:
Born, Flávia de Souza, da Camara, Claudio Augusto Gomes, de Melo, João Paulo Ramos, de Moraes, Marcilio Martins
Source:
Experimental & applied acarology 2018 v.75 no.4 pp. 491-502
ISSN:
0168-8162
Subject:
Lippia, Neoseiulus californicus, Tetranychus urticae, acaricidal properties, acaricides, acarology, beta-caryophyllene, beta-pinene, carvacrol, cineole, essential oils, eugenol, fumigants, gas chromatography, greenhouse production, leaves, limonene, mass spectrometry, mites, natural enemies, oils, p-cymene, residual effects, terpinolene, thymol, toxicity
Abstract:
The essential oil from the leaves of Lippia gracilis was investigated for fumigant and residual activity against Tetranychus urticae (Acari: Tetranychidae) and Neoseiulus californicus (Acari: Phytoseiidae). The results were compared to eugenol, Ortus® and Azamax®, as positive controls. Gas chromatography (GC) and GC/mass spectrometry analysis enabled the identification of 28 compounds, accounting for 99.1 ± 0.6% of the essential oil. The major constituents were carvacrol (61%), p-cymene (11%) and thymol (11%). Mites were more susceptible to the oil in fumigant tests than in residual tests. Among the components, thymol and β-caryophyllene had the greatest fumigant and residual toxicity against T. urticae, respectively. The role of selected constituents (carvacrol, p-cymene, thymol, limonene, β-pinene, 1,8-cineole, terpinolene and β-caryophyllene) in the acaricidal properties of the L. gracilis essential oil is also discussed. Fumigant and residual effects of Lippia oil were more selective than eugenol with regard to a natural enemy of T. urticae, Neoseiulus californicus. Experiments under greenhouse conditions demonstrated greater toxicity of the Lippia oil in comparison to the positive control at 24, 48 and 72 h after treatment. The results suggest that Lippia oil is a good candidate for the formulation of a botanical acaricide for the integrated management of T. urticae.
Agid:
6105802