Essential oils can be used as an alternative to using synthetic insecticides for pest management. Therefore, the insectistatic and insecticidal activities of the essential oil of aerial parts of Salvia ballotiflora (Lamiaceae) were tested against the fall armyworm Spodoptera frugiperda (Lepidoptera: Noctuidae). The results demonstrated insecticidal and insectistatical activities against this insect pest with concentrations at 80 µg·mL . This oil also increased the duration of the larval phase by 5.5 days and reduced the pupal weight by 29.2% withrespect to the control. The GC-MS analysis of the essential oil of S. ballotiflora showed its main components to be caryophyllene oxide (15.97%), and β-caryophyllene (12.74%), which showed insecticidal and , respectively.

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The effect of four nitrogen levels (KNO3: 5, 10, 15 and 20 meq L-1) on the production of ricinine was studied using a semi-hydroponic system. The insecticidal activity of methanolic extracts of Ricinus communis L. leaves against Spodoptera frugiperda Smith larvae was also tested. A dosage – response relationship showed strong positive correlation (R2 = 0.92, P ≤ 0.05) between the nitrogen concentration in the hydroponic solution and ricinine percentage in leaves. A strong correlation (R2 = 0.94, P ≤ 0.05) was also shown for nitrogen content in tissues and ricinine percentage. The use of nitrogen in the form of KNO3 increased the production of ricinine, and it also affected mortality of S. frugiperda larvae. LC50 for ricine methanolic extracts of R. communis leaves on S. frugiperda were 13,469.12, 15,754.34, 16,046.11 and 18,155.75 mg mL-1 for nitrogen concentrations of 20, 15, 10 and 5 meq L-1 respectively. Increased nitrogen concentration in the hydroponic solution associated with increments in leaf area and ricinine concentration. This indicates that nitrogen concentration can be manipulated to improve production of this alkaloid, and the extracts used for crop protection.

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Weed control in sustainable agriculture requires new bioherbicidal molecules to replace synthetic herbicides that have damaged the environment and generated resistance in weeds. This study was conducted to investigate the chemical composition of Eucalyptus globulus essential oil and to explore its bioherbicidal potential on the germination and radicle growth inhibition. The phytotoxic effects of E. globulus essential oil (1, 10 and 20 μL mL-1) were tested in comparison to those of the synthetic herbicide Glyphosate (1, 10 and 20 μL mL-1) in bioassays of germination and radicle growth of Lactuca sativa and the resistant weeds Avena fatua and Amaranthus hybridus. Gas Chromatography with Flame Ionization Detector and Gas Chromatography-Mass Spectroscopy analysis showed that major monoterpenes comprised 1,8-Cineole (86.94%), α-pinene (7.71%), d-limonene (2.65%), and p-cymene (1.48%). The seed germination and radicle length exhibited different degrees of inhibition in response to the concentration of E. globulus essential oil. At some concentrations, both the Glyphosate herbicide and the E. globulus essential oil demonstrated the same phytotoxicity against the resistant weeds A. fatua and A. hybridus. Essential oil bioactivity Lethal Concentration (LC50) in the majority of cases was lowest for A. hybridus, followed by A. fatua and L. sativa. Based on the results, it can be concluded that E. globulus essential oil possesses phytotoxic potential and could be explored as a bioherbicide for resistant weeds management programs.