Investigation of the effectiveness of essential oils in the control of the tomato leaf miner tuta absoluta (Meyrick, 1917) (Lepidoptera: Gelechiidae)

In this study, alternative biopreparat methods for controlling Tuta absoluta (Meyrick) (Tomato Leafminer) were investigated using formulations of essential oils derived from Pine tree (Pinus pinea), Lemon (Citrus limon), Basil (Ocimum basilicum), and Tea Tree (Melaleuca alternifolia) at concentrations ranging from 5% to 100%. The formulations were applied using spraying and dipping methods under laboratory conditions, aiming for low resistance risk, human and environmental safety, and eco-friendliness. The study was conducted on indeterminate and determinate tomato plants in incubators under long-day conditions (16:8 light cycle) at 25±1 °C and 60±5% relative humidity. The results were first analyzed to determine mortality rates using the ABBOTT formula, and then evaluated using One-Way ANOVA in the SPSS 23.0 software package (SPSS Inc., Chicago, IL, USA). As a result, all statistical analyses indicated that all essential oils used in the study exhibited lethal effects on the larvae of the tomato leafminer. Lemon oil was found to be the most effective essential oil at every doses and application methods. However, because of the phytotoxicity observed even at the lowest dose of lemon oil on tomato leaves, its recommendation is impractical. Although pine tree oil was ineffective in the spraying application, the dipping method produced better results. Basil oil was successful in both spraying and dipping methods. Tea tree oil demonstrated the highest efficacy on T. absoluta at all doses when applied by the dipping method. In addition, all oils were tested on the eggs of T. absoluta, and no larval emergence was observed although discoloration was noted in the eggs. Based on these results, tea tree essential oil is considered a promising plant-based alternative for future pest control.