Toxicity Effects of Golder and Giant Fennel Essential Oils and their mixture on Two-Spotted Spider Mite, Tetranychus urticae
Paper ID : 1026-IPCA4 (R1)
Javad Molavi Nafechi *, Faezeh Bagheri, Mohammad Ali Akrami
Shiraz University, School of Agriculture, Department of Plant Protection
The two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae) is one of the most harmful agricultural pests throughout the world. This pest in addition to feeding the plant cell contents and causing weakness in the plant makes disorders in the transpiration and photosynthesis of plants. Due to the limited number of safe pesticides in pest control, pest resistance to existing pesticides, and the danger of using chemical pesticides for non-target organisms, and the environment, there is a need to introduce natural and low-risk alternatives to conventional synthetic pesticides that leave less hazardous residues in the environment while being more acceptable than chemical pesticides. In this regard, the present study investigated the fumigant toxicity of the essential oils of two species of Fennel (Ferula assafoetida and F. persica) and one species of Golder (Otostegia persica) against two-spotted spider mite at 30±2oC, 50±5% relative humidity, and 16:8 light-dark photoperiods as a single application, double mixtures of two species of fennel, and three sets of two fennel species and one Golder species. A number of adult mites were placed on the leaf disks of the bean plant on the water agar medium. Each experiment was carried out with six concentrations and three replications. In each replicate, 20 adult mites of the same age were used. The experiment was performed using factorial in a completely randomized design on 6 cm diameter Petri dishes in a fumigant manner. The mortality value was counted after 24 hours. The results of this study showed that LC50 values for essential oils of F. persica, F. assafotida, O. persica, double mixtures of two species of fennel, and a triple mixture of essential oils of two species of fennel and Golder, were 0.054, 0.2, 11.01, 0.17 and 0.93 µl/lair, respectively. A comparison of lethal concentrations of 50% of essential oils and their mixtures at a 95% probability level showed that F. persica essential oil has significantly higher fumigant properties than other essential oils and their mixtures, and also the toxicity of the mixtures was much lower than the toxicity of each essential oil alone, which an antagonistic relationship between them was found.
Application of the mixture, Bioassay, Essential oil, Fumigant toxicity
Status : Abstract Accepted (Oral Presentation)