Efeitos letal e subletais dos óleos essenciais de Nectandra nitidula Nees & Mart., Salvia rosmarinus L. e Ocimum basilicum L. sobre Tetranychus urticae Koch (Acari: Tetranychidae)

Abstract

The two-spotted spider mite, Tetranychusurticae Koch, 1836 (Acari: Tetranychidae), is a cosmopolitan and polyphagous pest, considered a limiting factor in various commercial, ornamental, and industrial crops. Its significant infestation occurs across diverse species worldwide and has traditionally been controlled through the use of agrochemicals. However, continuous agrochemical application has led to environmental impacts and human health risks due to toxic residues. In this context, essential oils have emerged as a viable alternative for mite control, although limited studies exist. This study aimed to evaluate the acaricidal activity of essential oils as an alternative for controlling T. urticae and to simulate the interaction between the major compounds of these essential oils and Acetylcholinesterase (AChE) using the molecular docking methodology.Three essential oils were individually tested: two commercial oils from Salvia rosmarinus L. and Ocimumbasilicum L., and one from NectandranitidulaNees et Mart, a native species from the Brazilian Cerrado. These tests aimed to determine the most effective concentrations and their impact on oviposition. The chemical composition of the oils was determined by gas chromatography coupled with mass spectrometry (GC/MS). Additionally, mites were observed using scanning electron microscopy (SEM). Mite colonies were maintained on Canavaliaensiformis L. leaves in controlled arenas. For the assays, Fragaria x ananassa leaf discs were transferred to Petri dishes, mites were subsequently introduced, and essential oil concentrations were applied using a Potter Tower.Chemical analysis of the essential oils identified sesquirosefuran (68.77%) as the main compound in N. nitidula, 1,8-cineole (50.37%) in S. rosmarinus, and methyl-chavicol (87.13%) in O. basilicum. Regarding acaricidal activity, mortality was higher within the first 24 hours for N. nitidula and O. basilicum oils compared to 48 and 72 hours, while oviposition simultaneously decreased. S. rosmarinus oil exhibited lower mortality across all evaluated concentrations. The lethal concentrations (LC50) were 3.12% for O. basilicum, 3.59% for N. nitidula, and 9.41% for S. rosmarinus. Molecular docking simulations showed that sesquirosefuran had the highest affinity (-86.74), followed by methyl-chavicol (-83.17) and 1,8-cineole (-62.37) for AChE. These results suggest that O. basilicum and N. nitidula oils are promising alternatives for the management of T. urticae and contribute to more sustainable agricultural production.