While many insects have evolved mechanisms to ensure the faithful transmission of bacterial symbionts across generations, the majority of insects lack such mechanisms. Instead, many insects must acquire symbionts from their local environments. Without mechanisms for vertical transmission, insects are thought to be at risk of experiencing low fitness by acquiring low-quality symbiont strains. For example, insects dependent on environmental symbiont transmission may acquire nonsymbiotic bacteria or symbionts that are adapted to other co-localized hosts. Yet, insects often appear capable of interacting with a wide variety of symbiont strains, and environmental transmission is prevalent across diverse insect species. Therefore, it remains unclear whether the evolutionary history of a symbiont actually impacts its benefit to hosts. Here, we test whether the recent evolutionary history of a symbiont impacts its quality to an insect host by inoculating Anasa tristis De Geer (Hemiptera: Coreidae) insects with Burkholderiaceae strains isolated from a conspecific host, a distantly related heterospecific host, and from soil. We find that the soil strain offers few fitness benefits. In contrast, both strains with a recent history of host association support insect survival to adulthood, but the greatest benefits emerge from the symbiont isolated from a conspecific host, which also improves insect development rates. Overall, our study demonstrates that the evolutionary history of a symbiont may impact its quality to insect hosts and lays a foundation for future work to further examine whether environmental transmission carries costs for insect hosts.
Xylella fastidiosa Wells et al. 1987 is a vector-transmitted plant pathogen of economic importance that is widespread throughout coffee plantations in Costa Rica. Previous studies have shown the existence of a broad diversity of leafhoppers present in different coffee producing regions in Costa Rica. The presence of leafhoppers in coffee plantations with the presence of X. fastidiosa poses their role as potential vectors. To our knowledge, the vector status of leafhoppers present in coffee plantations in Costa Rica has remained unsettled. This work confirmed 8 species of leafhoppers as vectors of X. fastidiosa related to coffee in Costa Rica. Insects were collected in field in the northern part of the Costa Rican Central Valley, and leafhoppers were identified, classified, and grouped for further analysis. All the confirmed vector species belong to the subfamily Cicadellinae (Hemiptera: Auchenorrhyncha), known as sharpshooters. The ability of these specimens to survive on coffee plants for a 72-h period was assessed. In planta transmission assays were performed on X. fastidiosa-free coffee plants under greenhouse conditions. X. fastidiosa was detected in plants after one and a half years, confirming the vector status of leafhoppers. Positive plants remained asymptomatic throughout the experiment. The implication of these species as vectors strengthens surveillance actions in local and international contexts.
Aphid resistance to insecticides necessitates management strategies that improve efficacy while minimizing chemical input, including combinations of active ingredients with distinct modes of action. This study evaluated the individual and combined toxicity of pymetrozine, pirimicarb, and imidacloprid against third-instar nymphs and adults of the green peach aphid, Myzus persicae (Sulzer) (Hemiptera: Aphididae). Using a 48-h leaf-dip bioassay, insecticides were tested individually and in 1:1 binary combinations, and interactions were quantified using the combination index (CI). Sublethal effects of the most effective mixture were further assessed at the LC30 level (16.424 mg l-1) using age-stage, 2-sex life table analysis and biochemical assays. Among the tested combinations, the imidacloprid-pirimicarb mixture produced the strongest combined effect (CI < 0.5) in both developmental stages, whereas the other mixtures showed antagonistic interactions (CI > 1). This mixture resulted in LC50 values of 39.269 mg l-1 for nymphs and 122.553 mg l-1 for adults, corresponding to substantial reductions in effective concentration and active ingredient requirements compared with single-insecticide treatments. Sublethal exposure significantly (P < 0.05) reduced demographic parameters, including the intrinsic rate of increase (r), net reproductive rate (R0), fecundity, and longevity. Biochemical assays also revealed developmental stage-dependent alterations in acetylcholinesterase, esterase, and total protein levels following exposure to the mixture. Overall, the findings demonstrate that the imidacloprid-pirimicarb combination enhances toxicity against M. persicae under laboratory conditions and may contribute to reduced insecticide input, although additional studies are required to clarify the nature of the interaction and evaluate its applicability under field conditions.
Automated image-based identification of adult insects is increasingly critical to biodiversity monitoring, pest management, and vector surveillance, yet practical deployment remains limited by data scarcity, field variability, and fine-grained taxonomic challenges. We conducted a PRISMA-guided literature review of computer-vision methods for insect classification and identification. A Web of Science Core Collection search (31 August 2024) retrieved 930 records; after deduplication (n = 2) and screening, 230 articles underwent full-text quality assessment using weighted criteria for taxonomy/methods, image capture, computational technique, sample size, and performance evaluation. Of these, 111 high-quality studies met inclusion thresholds. Data were extracted on taxonomic coverage, optical devices and experimental settings, algorithms and pipelines, datasets, and outcome metrics. Deep learning dominated the field; You Only Look Once variants were common for detection and ResNet/EfficientNet/MobileNet for classification; occasional hybrids combined Convolutional Neural Network (CNN) features with traditional classifiers. CNN-based and 1-stage detectors outperformed hand-crafted pipelines; transformers and self-supervised pre-training showed promise with limited labels. Despite strong laboratory performance, generalization to field conditions was hindered by illumination, occlusion, and pose variability. Public datasets were scarce and geographically skewed, limiting reproducibility and equitable benchmarking. Taxonomic coverage concentrated on Lepidoptera, Diptera, Hemiptera, and Coleoptera. We recommend advancing the field through comprehensive reporting beyond overall accuracy, the design of lifecycle-aware and domain-adapted models validated under field conditions, the establishment of diverse benchmarks with standardized imaging protocols, and the development of interpretable architectures suitable for deployment in embedded trapping systems.
Parlatoria blanchardi Targ. (Hemiptera: Diaspididae) is a destructive scale insect that causes serious damage to date palm plantations. The essential oil (EO) of Deverra scoparia Coss. & Durieu was investigated for its insecticidal activity against P. blanchardi under different drying methods. This is the first time to our knowledge that the insecticidal activity against P. blanchardi has been reported for the plant species D. scoparia. This study evaluates, for the first time, the bioactivity of D. scoparia EO, as well as its insecticidal activity against P. blanchardi under different drying techniques (air drying, sun drying, and microwave drying at 264, 400, and 800 W). The chemical composition of D. scoparia EO was identified and characterized using gas chromatography mass spectrometry (GC-MS). In addition, the responses of the target enzyme acetylcholinesterase (AChE) and 2 key detoxification enzymes, carboxylesterase (CarE) and glutathione S-transferase (GST), in P. blanchardi were investigated to elucidate the underlying mechanisms of toxicity. Our data showed that a total of 32 compounds were identified, with myristicin (43.44% to 69.73%), D-limonene (6.61% to 12.57%), dillapiole (0.74% to 10.87%), α-phellandrene (0.47% to 8.16%), and α-pinene (4.36% to 8.10%) as the dominant constituents. Insecticidal activity varied markedly with drying technique; microwave drying at 264 W produced the most toxic EO against adult stages (LC50 = 0.12 to 0.13 µl/ml), while sun-dried EO showed the highest efficacy against immature stages. Enzyme assays revealed that microwave-derived oils significantly increased AChE activity while strongly suppressing CarE and GST activities. Our findings suggest that this plant might be efficient as a potential alternative control agent for P. blanchardi.
Insecticide resistance threatens sustainable agricultural intensification worldwide. Once regarded solely as a host-encoded evolutionary response, resistance is now known to be strongly influenced by microbial symbionts. Here, we synthesize recent advances showing that vertically and horizontally transmitted bacteria, fungi, and viruses modulate insect-toxicant interactions through 3 intertwined mechanisms: (i) direct enzymatic degradation of the active ingredient inside the gut lumen or hemocoel, (ii) transcriptional or posttranscriptional up-regulation of host detoxification gene networks (cytochrome P450s, carboxylesterases, and glutathione S-transferases), and (iii) epigenetic or immune-mediated priming that accelerates metabolic clearance while dampening insecticide-induced oxidative stress. Symbiont-mediated shifts in toxicity thresholds are context-dependent, varying with host genotype, symbiont strain, insecticide chemistry, and route of exposure. Symbionts may synergize with classical resistance mutations to produce super-resistant phenotypes, or conversely sensitize insects through pro-toxicant bioactivation. We propose an integrative "symbiont-insecticide-host" triangulation framework combining gnotobiotic manipulation, spatial metabolomics, and CRISPR-based microbial genetics to identify causal loci. Microbiome engineering through symbiont replacement, phage therapy or engineered plasmids offers a green resistance-management tool that lowers selection pressure on synthetic chemistries while preserving biocontrol compatibility. Clarifying these microbe-centered pathways is essential for predicting resistance trajectories and for designing durable, next-generation pest-control strategies aligned with food-security and environmental-quality goals.
Timely identification of biological species is often needed for various purposes, including economic reasons, and advances in DNA sequencing technologies have greatly augmented the ability to identify species through the application of DNA barcoding. One such method examines environmental DNA (eDNA) to sample the presence of organisms in an environment without necessarily having direct access to the whole organisms. In recent years, multiple high-throughput sequencing platforms have emerged, and there are differences in the efficiency, effectiveness, and economics across these platforms. In this report, we examine the application of two platforms, from PacBio and Oxford Nanopore Technologies, to sequence COI amplicons from nine barcoded yard waste samples that we previously studied for a different purpose. Here, we observed consistencies across the platforms in the identification of operational taxonomical units (OTUs) from broad swaths of life, most prominently including Bacteria, Amoebozoa, Fungi, Arthropoda, Nematoda, Spiralia, and Viridiplantae. Other taxonomical groupings were also tentatively identified. However, limitations in coverage of the diversity of COI sequences in the public databases rendered species-level identification impossible for many of the OTUs. Insect species were the best represented across all barcoded samples, and both sequencing platforms regarding percentage identity to the best BLAST hits in the databases. Following this, we took an in-depth look at the knowledge of the presence of highly matched species in the locality from where the eDNA samples were derived. Strengths and limitations of this approach in the analysis of eDNA are discussed.
The Queensland longhorn beetle (QLB), Acalolepta aesthetica (Olliff), was first detected in the Puna District of Hawai'i Island in 2009 and has since been observed to attack high value specialty crops such as cacao (Theobroma cacao), breadfruit (Artocarpus altilis), and citrus (Citrus spp.), as well as the culturally important kukui, Aleurites moluccanus. Endemic to the Australian states of Queensland and New South Wales, QLB had no pest status before introduction into Hawai'i. To address the lack of basic biological data on QLB, we conducted four pilot experiments to support pest management efforts. These included sequencing the CO1 region of the mitochondrial genome, observing beetle behavior in both a laboratory wind tunnel during scotophase and in the field using harmonic radar tracking, and obtaining QLB spatial distribution data through a citizen science web-based reporting application hosted by ArcGIS Online. Our results place QLB in a phylogenetic context, which will allow the development of diagnostic tools to differentiate QLB from other longhorn beetles. Behavioral observations suggest that QLB are largely sedentary, move mostly by walking with rare flights, and spend most of their time in trees. Citizen science reports suggest QLB populations are highest in May-July, beetle locations are largely restricted to elevations under 500 m, and population expansions are mostly occurring along the coast. These data combined can be applied to pest management efforts for this important and invasive agricultural pest. Further, we hope this interdisciplinary approach can serve as a framework for research response efforts to invasive insects generally.
Insect collections offer a unique and practical way to enrich students' education at every level. Collecting insects and identifying specimens provides an active, hands-on activity that connects students to the natural world in a way that lectures alone cannot. With the advancement of technology, non-lethal approaches to traditional museum collections can still provide an experiential learning opportunity without the need for ethical considerations. This review emphasizes the significance of insect exposure in primary school, secondary school, undergraduate instruction, and public outreach settings, utilizing both traditional and contemporary methods. The goal at all levels is to share information about the diversity and uniqueness of insects while reducing the fear and stigma surrounding entomology. While traditional insect collections have justifiable applications, newly developed non-lethal methods are just as valid. Determining the most suitable methods for the target audience is crucial for the future of entomology. This article is part of the 2025 Collaborative Publication Program organized by the Entomological Society of America Student Affairs Committee to address emerging issues in Entomology.
Maize (Zea mays L.) is a staple crop for millions of people worldwide, yet its productivity is constantly under threat from pests such as fall armyworm (Spodoptera frugiperda J.E. Smith), stem borers (Busseola fusca Fuller and Chilo partellus Swinhoe), maize aphids (Rhopalosiphum maidis Fitch), and maize weevil (Sitophilus zeamais Motschulsky). These pests can cause devastating losses of 20-50% in the field and up to 40% during storage. The pests are increasingly resistant to chemical insecticides, and there are growing concerns about environmental and health impacts. Sustainable alternatives are urgently needed. This review brings together insights from 34 studies (2000-2025) on plant-based insecticides, cultural practices, and their integration for maize pest management. Across the selected studies, larval mortality due to botanical extracts ranged from 45% to 92%, depending on the plant species used, formulation, and target pest. These values reflect the range reported in different studies rather than results from a formal meta-analysis. Cultural practices like intercropping, crop rotation, adjusting planting dates, and field sanitation lowered pest pressure by 18-80% and boosted yields by 8-45%. Combining these approaches was even more powerful, reducing fall armyworm damage by 65-88%, increasing yields up to 52%, and supporting beneficial insects. Despite these successes, challenges remain, especially in understanding how farmers adopt these methods and how they perform across different locations and seasons. Overall, this evidence shows that integrated, environmentally friendly strategies can protect maize, support farmers, and promote resilient, low-input farming systems. Future work should focus on long-term field trials, practical adoption, and socio-economic benefits to make these strategies widely accessible. A systematic literature search was conducted using databases such as Scopus, Web of Science, and Google Scholar covering studies published between 2000 and 2025.
The coffee leaf miner is a key pest of coffee in Brazil, controlled mostly by chemical insecticides. The recent introduction of isocycloseram (group 30) requires baseline susceptibility data to support resistance management programs. This study established the baseline susceptibility and monitored the resistance of coffee leaf miner populations to isocycloseram in the main coffee-producing regions of Brazil. Fourteen field populations were collected between June and October 2024 for the baseline assays, while 22 populations were monitored until 2024 and 2025. The bioassays revealed significant geographic variation in susceptibility, with lethal concentration LC50 values ranging 7.5-fold (0.95 to 7.11 mg a.i. L-1). Despite this, all populations remained susceptible, with resistance ratio (RR50) ≤ 1.0, indicating absence of preexisting resistance. The diagnostic concentration bioassays showed consistently high mortality (>90%), confirming continuous susceptibility. Efficacy trials with the label dose (150 mg a.i. L-1) resulted in mortality between 93% and 100%, with negligible probability of control failure. The diagnostic concentrations (LC99 = 39.76 mg a.i. L-1) may be used in future monitoring. The monitoring and the adoption of integrated resistance management strategies are fundamental to preserve the long-term efficacy of this insecticide.
Chemical communication in eusocial insects is crucial for colony survival and adaptation to diverse environmental conditions, contributing significantly to their evolutionary success. Pheromones, produced mainly by exocrine glands, serve as the primary means of communication among colony members. They coordinate complex social behaviors, including foraging, queen recognition, brood care, alarm signaling, and colony defense. Proper pheromone function is therefore essential for maintaining colony cohesion and efficiency. However, pathogens, particularly viruses, can influence pheromone-mediated communication through 2 main mechanisms: by altering pheromone production or by impairing pheromone perception. The impacts of viruses on exocrine glands and pheromone production have been well documented in several nonsocial insect species. Although evidence is growing for the effects of viruses on pheromone-mediated behaviors in eusocial insects, the underlying mechanisms linking viruses and pheromone signaling remain poorly understood. Here, we review current knowledge on how viral infections influence chemical communication in 2 ecologically important, eusocial insects: the honey bee (Apis mellifera Linnaeus, 1758), a nectar and pollen feeder, valued for its pollination services and honey production, and the fire ant (Solenopsis invicta Buren, 1972), an omnivore and notorious invasive pest. We further explore the ecological implications of virus-eusocial insect interactions and discuss their consequences for pollinator and pest management. Additionally, we identify knowledge gaps and highlight future research directions that could enhance our understanding of virus-pheromone dependencies. By examining these complex interactions through a chemical ecology perspective, we aim to advance the understanding of viral ecology and contribute to the development of management strategies that improve honey bee health and enable sustainable fire ant control.
The recent outbreaks of thrips in subtropical and tropical regions of the world caused serious economic losses. This has increased interest in releasing predatory insects to manage thrips in cowpea and other important crops. Therefore, we assessed the potential of the green lacewing, Chrysopa formosa Rambur (Neuroptera: Chrysopidae), a generalist predator, for controlling Megalurothrips usitatus Bagnall (Thysanoptera: Thripidae) and Frankliniella intonsa Trybom (Thysanoptera: Thripidae), the 2 major pests of cowpea in South China. Chrysopa formosa larvae displayed a type III functional response to M. usitatus. The theoretical maximum predation of a C. formosa third instar larvae on M. usitatus second instar nymphs and adults was 1054 and 570, respectively. The C. formosa second instar larvae consumed more than 71% of a mixed population of M. usitatus and F. intonsa in a cowpea field by 14 days after release. The predation of C. formosa on M. usitatus increased as the temperature increased from 15 °C to 35 °C, whereas the predator developed slower above 25 °C. There was no significant difference in the hatch of C. formosa eggs kept at 25 °C and 30 °C, and the survival of first to third instar C. formosa larvae maintained at 25 °C was more than 80%. Thus, C. formosa can effectively suppress M. usitatus and F. intonsa in cowpea.
Tuta absoluta is a major invasive pest of Solanaceous crops, largely managed through chemical interventions. Despite its economic importance, the genomic landscape of its detoxification machinery remains poorly understood. We performed a genome-wide identification of 23 GST genes (TabsGSTs) in T. absoluta, characterized by amino acid lengths of 147-289 aa and a predominantly 1- or 5-exon genomic architecture (∼65%). The identification of four tandemly arranged gene clusters highlights potential evolutionary hotspots for insecticide resistance. Phylogenetic analysis categorized these genes into seven subfamilies, with the lineage-specific expansion of the Epsilon class indicating its key role in xenobiotic metabolism. Transcriptional profiling revealed divergent responses to insecticides: chlorantraniliprole exposure (LC50) largely failed to induce TabsGST expression, whereas spinetoram LC50 treatment triggered significant upregulation of TabsGSTe6 and TabsGSTu1. This study elucidates the molecular characteristics and expression dynamics of the GST family in T. absoluta, offering vital molecular targets for resistance monitoring and the design of targeted control measures.
A new pherotype for Mediterranean populations of the long-tailed mealybug Pseudococcus longispinus (Targioni Tozzetti) has been recently identified as producing the new compound 2-(1,5-dimethyl-4-methylenecyclopent-2-en-1-yl)ethyl acetate. To study the effects of sex pheromone emission on males, the attractant efficacy of different emission rates of this compound has been studied under field conditions. For this purpose, experimental pheromone dispensers were designed, and their release profiles were studied by gas chromatography to obtain their mean release rates. Male trap captures were correlated with the corresponding pheromone release rates to explore the existence of an optimal emission value or range that maximizes the captures. The resulting correlation fitted a quadratic model, with a relative maximum of captures corresponding to a theoretical optimal emission rate of 66 μg/d. Nevertheless, no significant differences were found in male captures among emission rates between 2 and 147 μg/d, which indicates a wide range for effective trapping. The highest pheromone emission studied (502 μg/d) obtained the lowest captures, suggesting a possible repellent or male impairment effects to locate the source of the sex pheromone at high doses. The application of the results obtained for control techniques such as monitoring, mass trapping, or mating disruption is discussed.
Cicadas are a group of insects recognized for their distinctive life cycle and the stridulatory calls produced by males to attract females. While cicadas are commonly associated with thermophilic forests and xerophilic shrublands in Mediterranean regions, their distribution in temperate areas of Europe remains poorly understood. This study focuses on the cicadas of the northern Iberian Peninsula, specifically Asturias, characterized by a temperate climate. Over three years of fieldwork, we surveyed potential sites to locate cicada populations. Efforts were made to collect data on their habitat, ecology, and behavior. Acoustic recordings were used to characterize species-specific calling songs, and specimens were captured for genetic analyses. In addition, species distribution models were developed using climatic variables to assess potential habitat suitability across the region. We identified four cicada taxa-Cicada orni, Tibicina quadrisignata, Tettigettalna argentata, and Cicadetta sp.-primarily occupying forested habitats, native shrublands, and pine plantations. These species were found between 200 and 1,600 m a.s.l. and were acoustically active at temperatures above 18 to 21 °C, preferentially during sunny and low-wind conditions. Distribution models highlighted the warmest valleys of the study area as the most favorable for cicada occurrence, providing guidance for future sampling efforts. Furthermore, we provide the first genetic characterization of the cicada species detected in the region, which supports the morphological and acoustic identifications and reveals the presence of a putative new species of the genus Cicadetta. Finally, we outline conservation-relevant considerations for the preservation of cicada populations in temperate environments.
Traps containing food-based attractants are an important component of regional networks operated to detect invasive tephritid fruit flies (Diptera: Tephritidae), which pose a serious threat to fruit and vegetable production worldwide. However, food baits are weak attractants, and there is a critical need to increase their effectiveness. A recent study demonstrated that the addition of ammonium acetate crystals to an aqueous torula yeast borax (TYB, a commonly used food bait) solution significantly increased captures of Mediterranean fruit flies, Ceratitis capitata (Wiedemann), and oriental fruit flies, Bactrocera dorsalis (Hendel), but not melon flies, Zeugodacus cucurbitae (Coquillett). The present study investigated 2 alternative methods for providing ammonium acetate in TYB-baited traps. First, a cylinder containing ammonium acetate was affixed to the inner, upper surface of traps above the standard TYB solution, and this resulted in significantly higher captures of C. capitata, but not B. dorsalis or Z. cucurbitae, than observed for traps baited with standard TYB. Second, ammonium acetate was incorporated directly into field-ready TYB pellets. However, these had no effect on C. capitata and even appeared to repel Z. cucurbitae. Two additional modifications were investigated: (i) extra amounts of certain amino acids or (ii) ground brine shrimp were added to TYB. The increased levels of amino acids significantly enhanced captures of C. capitata but not B. dorsalis or Z. cucurbitae. Addition of shrimp powder did not positively influence trap catch for any species. Implications of these results for detection trapping are discussed.
To clarify the molecular responses of Trichogramma chilonis (Hymenoptera: Trichogrammatidae) to the diseased gray eggs of Antheraea pernyi (Lepidoptera: Saturniidae), transcriptome sequencing analysis of Trichogramma adults reared on gray eggs and healthy eggs was carried out using high-throughput sequencing on the Illumina HiSeq 2000 platform. Subsequent to RNA-seq, 34,404 assembled unigenes were identified, and 15,405 of these were annotated in the transcriptome libraries of T. chilonis. In addition, 101 differentially expressed genes (DEGs) were detected, including 8 significantly upregulated and 93 significantly downregulated genes. Functional classification revealed that biological process, cellular component, and molecular function categories were significantly enriched. According to the Clusters of Orthologous Groups classification, the DEGs were mainly enriched in "posttranslational modification, protein turnover, chaperone" and "carbohydrate transport and metabolism." Moreover, tryptophan metabolism, arginine and proline metabolism, and nitrogen metabolism were significantly enriched among the metabolic and signaling pathways. Fourteen downregulated genes related to insect growth, development, and immune mechanisms were identified from the annotation results. Under paired-choice conditions, T. chilonis showed a significant preference for healthy A. pernyi eggs over gray ones in terms of parasitism rate. However, no significant differences were observed in offspring emergence rate between the 2 host types. Finally, 8 DEGs were chosen for validation via real-time quantitative polymerase chain reaction, exhibiting expression trends consistent with the RNA-seq data. Taken together, these findings provide a molecular biological basis for understanding the effects of A. pernyi gray eggs on T. chilonis.
Paranosema locustae infection reduces the abundance and diversity of the intestinal bacteria in locusts, although the microbial adaptive changes and the underlying mechanism of chronic pathogenesis remain unclear. In this study, the intestinal microbial changes in Calliptamus italicus (Linnaeus, 1758) (Orthoptera: Acrididae) were analyzed with metagenomic sequencing after P. locustae infection. Results showed that the diversity of intestinal microbial communities in C. italicus declined after P. locustae infection, while the abundance of infection-specific taxa in C. italicus in the experimental groups was significantly higher than those in the control groups, irrespective of sex (P<0.05). The populations of opportunistic pathogenic bacteria such as Klebsiella aerogenes and Enterococcus faecalis increased significantly (P < 0.05). Meanwhile, the abundances of probiotics such as Pediococcus acidilactici and Enterobacter hormaechei increased significantly (P <0.05), which could inhibit the pathogenicity of P. locustae. The results suggested that the interplay of changes in the species and quantities of probiotics and pathogenic bacteria in the intestine of C. italicus after P. locustae infection was an important factor contributing to the difficulty of P. locustae in quickly breaching the host defense system and to its chronic pathogenicity.
Productivity of soybean, Glycine max (L.) Merr. (Fabales: Fabaceae), and maize, Zea mays L. (Poales: Poaceae), is reduced by several insect pests, among the most important of which is the fall armyworm, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae). Control of this insect relies mainly on chemical insecticides or transgenic plants expressing Bacillus thuringiensis Berliner (Eubacteriales: Bacillaceae) proteins, but these methods impose strong selection pressure favoring resistance evolution. Soil applications of silicon (Si) and arbuscular mycorrhizal fungi (AMF) are potential alternative tactics to enhance plant resistance and tolerance within integrated pest management programs. This work evaluated the effects of soil application of Si and AMF, individually and in combination, on the development of soybean and maize and on their resistance and tolerance to S. frugiperda. Greenhouse experiments used 4 treatments: control, Si application, AMF inoculation with Rhizophagus irregularis (Błaszk., Wubet, Renker & Buscot) (Glomerales: Glomeraceae), and combined Si + AMF. AMF inoculation significantly increased root and shoot biomass of soybean and plant height in maize, while Si significantly increased root biomass in maize. The combined AMF + Si treatment significantly reduced defoliation by S. frugiperda on soybean. AMF-inoculated soybean plants also recovered better from mechanical defoliation, producing greater shoot biomass, whereas Si-treated maize showed higher root biomass after injury. These findings demonstrate that Si and AMF soil applications can enhance crop development and contribute to resistance and tolerance against fall armyworm, offering sustainable alternatives for integrated pest management in soybean and maize.