Efecto repelente de aceites esenciales sobre el ácaro Tetranychus urticae Koch (Acari: Tetranychidae)

Introduction. Various plant extracts are used in agriculture to reduce the impact of arthropod pests. However, few studies describe the toxic or repellent action of cinnamon, citronella, and ginger essential oils on populations of phytophagous mites such as Tetranychus urticae. Objective. To evaluate the repellent effect of commercial grade essential oils of cinnamon (Cinnamomum zeylanicum), citronella (Cymbopogon winterianus), and ginger (Zingiber officinale) on a population of the mite Tetranychus urticae on sweet pepper (Capsicum annuum) plants under in vitro conditions. Materials and methods. The research was conducted between October and November 2023 at the Acarology Laboratory of the Crop Protection Research Center (CIPROC) of the School of Agronomy, University of Costa Rica, located in San José, Costa Rica. Four concentrations (1 %, 2 %, 3 %, and 4 %) of each essential oil (cinnamon, citronella, and ginger) were tested at a volume of 333 µL per leaf. To quantify their repellent effect, a choice test using paper bridges was employed. Evaluations were performed 24 and 48 hours after application. A randomized complete block design was used, and data were analyzed with a generalized linear model. Results. The three oils and their concentrations showed repellent activity above 60 %, except for citronella oil at 2 %. Higher concentrations did not always result in greater mite repellency, although this pattern varied among oils. Conclusions. Cinnamon, citronella, and ginger essential oils have repellent properties against Tetranychus urticae, demonstrating their potential as an alternative for the management of this pest.