Nanoemulsion Based on Essential oil of Mentha piperita in the Sustainable Management of Oligonychus ilicis McGregor, 1917 (Acari: Tetranychidae)

The red mite, Oligonychus ilicis McGregor, 1917 (Acari: Tetranychidae), is a major pest of coffee crops ( Coffea canephora ), causing significant damage to plantations. In this context, essential oils, particularly when formulated as nanoemulsions, emerge as a promising alternative for pest management due to their high efficacy and low environmental toxicity. This study explores the acaricidal potential of a nanoemulsion based on Mentha piperita essential oil against O. ilicis . For this study, an analysis of the main chemical constituents of the essential oil (EO) was first carried out, and a nanoemulsion based on peppermint essential oil was formulated using the low-energy emulsification method, with specific surfactants employed to stabilize the particles. The proposed formulation was monitored for macroscopic stability by visual assessment of phase separation, creaming, sedimentation, turbidity, and loss of homogeneity over time before toxicity evaluation in laboratory bioassays involving the direct application of different concentrations (0.25, 0.15, 0.10, 0.060, 0.040, and 0.025% v/v) to adult females of O. ilicis . The results showed a clear dose–response relationship, with mortality rates exceeding 90% for O. ilicis at concentrations as low as 0.040%. The LC₅₀ and LC₉₀ values were estimated at 0.0257 and 0.0424% (v/v), respectively. These findings indicate that the peppermint essential oil-based nanoemulsion exhibits acaricidal activity against the red coffee mite, O. ilicis , under laboratory conditions, suggesting its potential as a botanical formulation for future integrated pest management studies.