Chemical Composition and Acaricidal and Insecticidal Activity of the Essential Oil of Tithonia Diversifolia (Asteracea) (Hemsl.) a. Gray

Tithonia diversifolia is a plant from the Asteraceae family that, due to the large quantity of hydrogenated monoterpenes present in its essential oil, can be used to prepare a product capable of combating agricultural pests. Therefore, the aim of this study was to carry out a phytochemical screening of the components of the essential oil produced by hydrodistillation of the leaves of Tithonia diversifolia and to verify its possible acaricidal applications in the control of the spider mite Tetranychus urticae (Koch) (Acari: Tetranychidae) and insecticidal applications in the control of the corn weevil Sitophilus zeamais (Motsch) (Coleoptera: Curculionidae), both via fumigation. Gas chromatography coupled with mass spectrometry revealed the presence of 32.67% β-pinene (6,6-dimethyl-2-methylenebicycle, heptane), 24.74% α-pinene (2,6,6-trimethylbicycle, hept-2-ene) and 22.69% limonene (1-methyl-4-(1-methyleneyl)-cyclohexene), among other components, in the essential oil of T. diversifolia . Fumigation tests revealed 52% mortality of spider mites at a concentration of 20 µL/L air and 96% at 80 µL/L air. The insecticidal activity tests on the corn weevil showed no mortality, but the repellency tests on this same insect showed promising results close to 100% at a concentration of 10 µL/L air, suggesting further studies to implement its use in greenhouses to control spider mites and in silos to repel corn weevil due to its volatility.