Cedrela odorata L. is a plant species from the Meliaceae family that is cultivated for timber production. Although the C. odorata essential oil (EO) contains mainly sesquiterpenes, its insecticidal potential is unknown. The lipophilic properties and high degradation capacity of EOs have limited their application for use in pest control. However, the currently available knowledge on the nanoemulsification of EOs, in addition to the possibility of improving their dispersion, would allow them to prolong their permanence in the field. The objective of the present work was to develop a nanoemulsion of the C. odorata EO and to evaluate its larvicidal activity against Spodoptera frugiperda. The EO was obtained by the hydrodistillation of C. odorata dehydrated leaves, and the nanoemulsion was prepared with non-ionic surfactants (Tween 80 and Span 80) using a combined method of agitation and dispersion with ultrasound. The stability of the nanoemulsion with a droplet diameter of <200 nm was verified in samples stored at 5 °C and 25 °C for 90 days. Both the C. odorata EO and its corresponding nanoemulsion presented lethal properties against S. frugiperda. The results obtained provide guidelines for the use of wood waste to produce sustainable and effective insecticides in the fight against S. frugiperda. In addition, considering that a phytochemical complex mixture allows the simultaneous activation of different action mechanisms, the development of resistance in insects is slower.

Spodoptera frugiperda J.E. Smith (Lepidoptera: Noctuidae) is a polyphagous insect pest native to America. Due to its capacity for adaptation and migration, it is currently located in Africa, Asia, and Oceania, where it threatens agricultural crops. The ability of S. frugiperda to develop resistance to insecticides is one of the reasons for the continuous search for more effective, low-cost, and environmentally friendly control products. In the present work, the insecticidal activity of ethanolic and hexane extracts obtained from fresh and dehydrated leaves of Piper auritum Kunth (Piperales: Piperaceae), Piper umbellatum L. (Piperales: Piperaceae), and Cedrela odorata L. (Sapindales: Meliaceae) was studied against first instar larvae of S. frugiperda. The ethanolic extracts of the dehydrated leaves of C. odorata and P. auritum presented insecticidal activity as high (100% mortality at a concentration of 92 mg/cm²) as that obtained with the positive control, Melia azedarach L. (Sapindales: Meliaceae). The GC-MS analysis of the extracts revealed the presence of phytochemicals classified mainly into the groups of monoterpenes, sesquiterpenes, diterpenes, phenylpropanoids, alcohols, and fatty acids. P. auritum grows and propagates rapidly. In addition, due to its low toxicity in mammals and non-target insects, it is a plant with the potential to be used as a botanical insecticide. The exposure of S. frugiperda larvae to low concentrations of ethanolic extract of P. auritum allowed us to observe their biological activity in the development of this insect. The LC₅₀ was 22.1 mg/cm². At sublethal concentrations (LC₂₁ and LC₃₅) the low fertility of the emerging adults was noticeable.

Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) is an agricultural pest of global economic importance. Its ability to reproduce, adapt, and develop resistance necessitates the creation of effective and environmentally friendly alternative control strategies. This study aimed to evaluate the larvicidal activity of three nanoformulations (NFs) based on the essential oil (70% safrole) of Piper auritum Kunth (Piperales: Piperaceae), nanoemulsion (NE), microemulsion (ME), and silver nanoparticles (AgNPs), against second-instar larvae of S. frugiperda. The NFs were prepared using a combination of low- and high-energy methods, using Tween 80 and Span 80 as stabilizing agents. The droplet sizes of the NFs ranged from 19 to 48 nm. Stability analysis of the formulations maintained for 60 days in open systems at room temperature allowed the identification of remaining oxidized sesquiterpenes and phenylpropanoids. In in vitro bioassays, the NE demonstrated the highest larvicidal activity, with an LD₅₀ of 0.97 µg cm⁻², outperforming the other formulations by a factor of ten. Observations of morphological damage to larval and pupal tissues, along with deformation of adult specimens, confirming the toxicity of the NFs. These findings highlight the potential of essential oil-based NFs derived from P. auritum as sustainable biopesticides for integrated pest management.