Nanotechnology has been a promising plant protection discipline in recent years, attributed to the unique physicochemical properties exhibited at the nanoscale. In this context, silver nanoparticles (AgNPs) have been effective in various applications, including medical, industrial, and agronomic, and during the last few years, the control of insect pests has raised great interest. The present review mainly provides updated information about the use of AgNPs elaborated by different synthesis methods, such as biological (plants, microorganisms), physical, and chemical, and their effect against various insect species of agricultural importance belonging to the order Diptera, Coleoptera, Lepidoptera, and Hemiptera. The physiological and toxic effects of applying AgNPs are reported and characterized by developmental problems, mortality, weight reduction, interference with enzymatic activity, and anomalies in the life cycle. Moreover, in the final section, the action mechanisms through which AgNPs act on insects are also discussed, highlighting mechanisms such as alteration of transmembrane permeability, interruption of DNA replication, alteration of protein synthesis, and production of reactive oxygen species (ROS).

Murtilla (Ugni molinae) is a shrub native to Chile that has undergone an incipient domestication process aimed at increasing its productivity. The reduction in intrinsic chemical defenses due to the domestication process has resulted in a decrease in the plant’s ability to defend itself against mechanical or insect damage. In response to this damage, plants release volatile organic compounds (VOCs) as a means of defense. To understand how domestication has impacted the production of VOCs in the first offspring of murtilla, we hypothesized that their levels would be reduced due to the induction of mechanical and herbivore damage. To test this hypothesis, we collected VOCs from four offspring ecotypes and three wild relatives of murtilla. We induced mechanical and herbivore damage in the plants and then enclosed them in a glass chamber, where we captured the VOCs. We identified 12 compounds using GC-MS. Our results showed that wild relative ecotypes had a higher VOC release rate of 624.6 µg/cm²/day. Herbivore damage was the treatment that produced the highest release of VOCs, with 439.3 µg/cm²/day in wild relatives. These findings suggest that herbivory triggers defenses through the emission of VOCs, and that domestication has influenced the production of these compounds in murtilla. Overall, this study contributes to bridging the gap in the incipient domestication history of murtilla and highlights the importance of considering the impact of domestication on a plant’s chemical defenses.

The horn fly is an economically important hematophagous ectoparasite of cattle. Its management relies heavily on broad-spectrum pesticides, which are harmful to the environment and have led to the development of resistance. Therefore, alternative control methods are needed. Semiochemicals involved in communication between horn flies and their host are a promising alternative. Considering that the egg-laying of this fly occurs almost exclusively in fresh cattle dung, and most parts of its life cycle occur totally in dung, dung volatiles might play an important role in horn fly behavior. Therefore, the main aim of this study was to evaluate the effects of volatile blends and compounds emitted from fresh/aged cattle dung on the olfactory response and oviposition of horn flies. Dung blends were captured and analyzed by SPME-GC/MS. p-Cresol was the most abundant compound in dung blends, followed by α- and β-pinene, limonene, and β-caryophyllene, among other common dung volatiles. Fresh-dung volatiles attracted males and females in a Y-tube olfactometer, and they elicited the egg-laying of flies in two-choice tests. p-Cresol and α-pinene were attractive to females and they elicited higher oviposition, demonstrating that dung volatile semiochemicals, in part, lend to dung attractiveness and stimulate the horn fly oviposition.

The overuse of synthetic pesticides has triggered resistance in insect pests and caused severe environmental impacts, emphasizing the urgent need for sustainable alternatives in Integrated Pest Management (IPM). This study aimed to biosynthesize and characterize chitosan-coated silver nanoparticles (AgChNPs) using Galega officinalis leaf extract and evaluate their insecticidal effects against Drosophila suzukii (Diptera: Drosophilidae), a key pest of fruit crops worldwide. The biosynthesized AgChNPs (257.2 nm) were polydisperse, crystalline, and stable, as confirmed by UV-vis spectroscopy, dynamic light scattering (DLS), X-ray diffraction (XRD), and transmission electron microscopy (TEM). AgChNPs exhibited strong toxicity across multiple developmental stages. Combined larvicidal and pupicidal activity reached 48.3% and 73.3% at 500 and 1000 ppm, respectively, significantly affecting immature stages. As a consequence, adult emergence declined to 46.7%, 51.7%, and 26.7% at 250, 500, and 1000 ppm. Among emerged adults, 71.7% displayed sublethal effects, with 62.8% showing morphological malformations (deformed wings, dehydration) and 37.2% presenting cuticle demelanization. Adulticidal bioassays revealed progressive mortality over 48 h, with 96% mortality at 1000 ppm. Overall, AgChNPs caused acute and chronic toxicity, reduced adult emergence, and induced severe morphological alterations, demonstrating their potential as a sustainable nanotechnological tool for effective pest control within IPM programs.

The Argentine stem weevil (ASW), a major pest in ryegrass pastures, causes significant agricultural losses. Ryegrass can establish a symbiotic association with Epichloë endophytic fungi, which supply chemical defenses, including peramine. This symbiosis helps protect ryegrass by providing peramine, which acts as a primary defense. In addition, ryegrass can activate induced defense mechanisms, with peramine remaining the central agent in response to herbivorous insect attacks. Therefore, this study assessed the feeding of the ASW on ryegrass carrying endophytic fungus and peramine levels in aerial organs and its effects on pest performance. Argentine stem weevil adults and larvae were placed on ryegrass leaves and stems to assess feeding. Two treatments were used: endophyte-free plants and endophyte-colonized plants. After ASW feeding damage, insect consumption was measured by the leaf area consumed. To evaluate peramine production and its increase in response to ASW attack, peramine levels in leaves were analyzed using liquid chromatography. Damaged E+ ryegrass plants showed significant increases in peramine, with adult and larval herbivory raising levels by 291% and 216% in stems and by 135% and 85% in leaves, respectively, compared to controls. Endophyte-free (E−) plants experienced more ASW damage, as insects preferred feeding on them, showing reduced activity as peramine levels rose in endophyte-infected (E+) plants. An oviposition assay confirmed insect preference for endophyte-free (E−) plants. Additionally, larvae reared on endophyte-infected (E+) plants had lower survival rates, correlating negatively with peramine levels. These results emphasize peramine’s role in strengthening ryegrass defenses against ASW, impacting both feeding and larval development.

This study aimed to biosynthesize silver nanoparticles (AgNPs) using aqueous leaf extract of Galega officinalis and to evaluate their insecticidal activity against key stored-product pests. AgNP formation was confirmed through UV–vis spectroscopy, which showed a surface plasmon resonance peak at 380 nm. FTIR analysis indicated the presence of plant-derived functional groups likely involved in the reduction and stabilization of Ag⁺ ions. Dynamic light scattering revealed an average hydrodynamic diameter of 25.07 nm, a PDI of 0.39, and a zeta potential of −22 mV, while TEM images showed predominantly spherical and polydisperse particles ranging from 4.3 to 42.4 nm. Insecticidal bioassays performed on Sitophilus granarius, Tribolium confusum, Plodia interpunctella, and Ephestia kuehniella revealed concentration-dependent mortality. The highest mortality rates were recorded at 1000 ppm, reaching 100% in T. confusum, 83.33% in P. interpunctella, and 76.67% in both S. granarius and E. kuehniella. These findings demonstrate the potent insecticidal activity of G. officinalis-mediated AgNPs and support their potential as environmentally friendly alternatives for stored-product pest management, warranting further studies on safety, large-scale synthesis, and integration into pest-control programs.