Sitophilus zeamais is a primary pest of maize. Our aim was to perform a qualitative review and meta-analyses with 56 scientific articles published from 1 January 2000 to 1 October 2022 dealing with direct (topical application) and indirect (impregnation of essential oils, EOs, onto filter paper or maize grains) contact toxicity of EOs against S. zeamais. Three independent meta-analyses of single means of LD₅₀ (direct contact) and LC₅₀ (indirect contact) were conducted using a random effect model. Essential oils more frequently evaluated were those belonging to Asteraceae, Apiaceae, Lamiaceae, Myrtaceae, Piperaceae, and Rutaceae. The LC₅₀ global mean values were 33.19 µg/insect (CI₉₅ 29.81–36.95) for topical application; 0.40 µL/cm² (CI₉₅ 0.25–0.65) for filter paper indirect contact; and 0.50 µL/g maize (CI₉₅ 0.27–0.90) for maize grains indirect contact. The species Carum carvi, Salvia umbratica, Ilicium difengpi, Periploca sepium, Cephalotaxus sinensis, Murraya exotica, Rhododendron anthopogonoides, Ruta graveolens, Eucalyptus viminalis, Ocotea odorifera, Eucalyptus globulus, Eucalyptus dunnii, Anethum graveolens, Ilicium verum, Cryptocarya alba, Azadirachta indica, Chenopodium ambrosioides, Cupressus semperivens, Schinus molle, Piper hispidinervum, Mentha longifolia, and Croton pulegiodorus showed LC₅₀ or LD₅₀ values lower than the global means, indicating good insecticidal properties. Our results showed that EOs have great potential to be used as bioinsecticides against S. zeamais.

Spodoptera frugiperda is a major agricultural pest worldwide, causing significant economic loss to maize crops. Its control largely depends on synthetic pesticides, which contribute to resistance development, harm non-target organisms, and lead to environmental degradation. Essential oils and their main components offer a more sustainable and ecologically sound alternative for the management of S. frugiperda. This study evaluated the effects of selected essential oils and their bioactive compounds on the survival and behavior of S. frugiperda using toxicity and preference assays. Peppermint essential oil and its major constituent, pulegone, significantly reduced the survival of S. frugiperda, with effects similar to those caused by synthetic insecticides. Eucalyptus essential oil and its main compound, 1,8-cineole, also influenced the behavior of S. frugiperda, suggesting potential for use in repellents. These findings highlight the use of essential oils and their main constituents/active constituents as bioinsecticides and their integration into environmentally friendly pest management strategies.

Global population is expected to increase to 9x109 individuals by 2050, which highlights the need to produce more food in a more sustainable way. The demand for alternatives to synthetic insecticides is reflected in the increasing amount of research dealing with essential oils as insecticidal and repellent compounds. Argentina has large regions of tropical, temperate, and cold climates, where many essential oil-producing plants grow and develop. In this context, the aim of the present study was to revise the most relevant literature about the insecticidal and repellent properties of essential oils from Argentine aromatic flora. The first section of the present review covers those essential oils used to control insects that are important to affect human and animal health, such as mosquitoes, flies, bed bugs, and vinchucas. The second part addresses essential oils that could be used as insecticides and repellents in horticulture and agriculture such as oilseed, such as moths, bugs, fruit flies, different phloem-sap-feeding insect species that attack vegetable and fruit crops, and weevils and beetles that affect stored grains and food commodities. Throughout this review, the toxicity of the most bioactive essential oils is discussed by considering their chemical profile and their major pure compounds molecular features. This literature review highlights the enormous potential of Argentine essential oils to be included in repellent and insecticidal formulations.

Climate change scenarios predict increased temperatures, potentially impacting the development of phytopathogenic fungi and the efficacy of their control. This study evaluated the effects of four natural organic compounds—carvacrol, eugenol, trans-cinnamaldehyde, and 1-heptyn-3-ol—on the growth of Fusarium verticillioides and the survival of Sitophilus zeamais under two temperature regimes (28 °C and 32 °C). Fungal growth was assessed through the lag phase duration and mycelial expansion, while insecticidal activity was determined by mortality of S. zeamais. Carvacrol (1 ppm) produced the most pronounced inhibitory effect on fungal growth, significantly extending the lag phase and reducing mycelial area, with eugenol showing similar effects at selected concentrations. Both compounds maintained or enhanced their antifungal activity at elevated temperatures. Trans-cinnamaldehyde and 1-heptyn-3-ol exhibited moderate or low effects, depending on concentration and temperature. Regarding S. zeamais, 1-heptyn-3-ol achieved complete mortality at all concentrations under both temperature scenarios, whereas carvacrol, eugenol, and trans-cinnamaldehyde showed dose-dependent effects at 28 °C and enhanced efficacy at 32 °C. Overall, these findings highlight the potential of these compounds as sustainable, climate-resilient alternatives for managing fungal pathogens and stored-product pests.