Atividade de óleos essenciais de plantas das famílias Burseraceae, Lamiaceae, Rutaceae e Verbenaceae em Tetranychus urticae Koch e Neoseiulus californicus (McGregor)

Abstract

Two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae), has been controlled mainly chemical synthetic acaricides. The use of essential oils can be an alternative to this method of control. The aim of this study was to determine the effect of essential oils from plants of Families Burseraceae, Lamiaceae, Rutaceae and Verbenaceae against T. urticae and the predatory mite Neoseiulus californicus (McGregor) (Acari: Phytoseiidae). Repellent and toxic activities of the oils were determined and compared to eugenol. Toxicity was evaluated by fumigation and residual effect in the laboratory and by direct contact in a greenhouse. The results showed that the oils of Ocimum basilicum L. and Thymus vulgaris L. were the most repellent, with RC50 = 3.43 x 10-7 and 2 x 10-4 μL/mL, respectively. The toxicity against eggs of T. urticae revealed T. vulgaris, Rosmarinus officinalis L., Citrus reticulata Blanco and O. basilicum oils as more active. Estimates of mortality concentration curves for fumigation of adult females of T. urticae revealed that was more toxic eugenol, with LC50 = 4 x 10-3 μL/L air. The test results showed that residual C. reticulata, T. vulgaris and O. basilicum oils present the same toxicity observed for eugenol. The toxicity tests to N. californicus indicated that all the oils are selective fumigation and that the O. basilicum, R. officinalis and C. reticulata oils were more selective by residual effect. The relative toxicity of the individual constituents of the essential oils and their contribuition to the acaricidal activity on T. urticae are also discussed. The highest average mortality on T. urticae in the greenhouse after 72 h of exposure were 100%, 98.85% and 96.59%, promoted by Citrus sinensis Osbek x Citrus reticulata Blanco, R. officinalis and Lippia gracilis Schauer oils, respectively.