اثرات سمی و دورکنندگی دو اسانس گیاهی و نانوفرمولاسیون آن‌ها بر کنه تارتن دولکه‌ای Tetranychus urticae (Acari: Tetranychidae)

The low solubility of plant essential oils in water, their oxidation, and instability in the presence of light, humidity, and high temperature have reduced their application. Using nanoformulation methods may improve the pesticidal efficiency of plant essential oils. In this study, the acaricidal effect of pure essential oils and chitosan-loaded nanoparticles containing the essential oils of Eucalyptus globulus and Ferula assafoetida, as well as their durability and repellent properties against adult female mites of Tetranychus urticae Koch, were investigated. The LC50 values for inhalation toxicity for E. globulus, F. assafoetida, and their nanoformulations were 53.3, 71.50, 157.72, and 8.73 µl/l air, respectively, and the LC50 values for contact toxicity for E. globulus, F. assafoetida, and their nanoformulations were 3.28, 1.74, 2.98, and 0.50 µl/cm2, respectively. In the study of the durability and persistence of the lethal effect of the essential oils and their nanoformulations, a lethal concentration of 90% (LC90) was used over 20 days. The results showed that the mortality rate of the nanoformulations was significantly higher than that of the pure essential oils over time. The results of the repellent index (RI) calculation and the response type of adult female mites to the tested essential oils at different times showed that both essential oils maintained their repellent properties for up to 48 hours. The particle size distribution analysis using Dynamic Light Scattering (DLS) estimated the particle sizes for E. globulus and F. assafoetida to be 41.2 and 28.29 nm, respectively. The surface morphology examination of the nanoparticles using a Scanning Electron Microscope (SEM) showed that the nanoparticles were almost spherical. Based on the results of this study, it can be stated that the essential oils of E. globulus and F. assafoetida have significant potential in controlling T. urticae, and the nanoformulation of these essential oils preserves their acaricidal properties for a longer period. Therefore, nanoformulating essential oils can be used to improve their efficiency in pest control.