Search Results (68)

Insect pests are a major limiting factor to producing profitable soybean (Glycine max (L.) Merr.) in South Carolina. Production practices within the soybean industry have drastically evolved over the last few decades, but treatment thresholds for insect pests have stayed the same. Evaluating treatment thresholds for insect pests typically involves simulating injury because it offers a controlled and repeatable way to evaluate an injury–yield relationship. Simulating defoliation injury in soybean typically involves methods such as hand-plucking or cutting leaflets, but these methods are not truly representative of insect feeding injury. This study describes the design, development, and validation of a novel pneumatic leaf puncher created with a 3D printer and used to simulate insect defoliation injury in soybean. The device was engineered to deliver controlled, repeatable leaf tissue removal at varying target levels (5, 15, 30, and 40%) by using interchangeable punching plates. Simulated defoliation treatments were applied to mature leaves on soybean plants at the V6 growth stage in a greenhouse study. The leaf area removed was quantified using LeafByte, a mobile app designed for measuring leaf area, and confirmed against target values. Results showed a high level of correlation between intended and actual defoliation levels, with accuracy ≥ 90%. The pneumatic leaf puncher provides a potential standardized method for administering foliar damage and offers a reliable alternative to manual clipping or herbivory feeding trials in defoliation research. Ongoing field trials at Clemson University will incorporate yield data to refine defoliation thresholds. Due to its adaptability and ease of use, the pneumatic leaf puncher could be implemented regionally, nationally, or internationally to support standardized defoliation studies across diverse cropping systems. Full article

The soybean pod borer, Leguminivora glycinivorella, is a monophagous pest that threatens soybean production. Its larvae feed concealed within pods, which limits the efficacy of conventional insecticides. Elucidating its chemosensory system is therefore essential for developing green, behavior-based management strategies. Reference-based transcriptomics across multiple tissues of L. glycinivorella identified a comprehensive repertoire of chemosensory genes, including 76 odorant receptors (ORs), 15 gustatory receptors (GRs), 18 ionotropic receptors (IRs), 52 odorant-binding proteins (OBPs), 18 chemosensory proteins (CSPs), and 4 sensory neuron membrane proteins (SNMPs). Sequence and phylogenetic analyses characterized these candidates within the context of known insect chemosensory families. Notably, canonical bitter GRs and specific IR lineages (e.g., IR100/IR85a) were not detected in our dataset, potentially reflecting adaptation to the specialized soybean-feeding habit of this pest. Expression profiling further revealed pronounced sexual and tissue dimorphism: male antennae showed significant enrichment of putative pheromone receptors (PRs) and LglySNMP1, whereas several OBPs and ORs exhibited female-biased expression, suggesting roles in host location and oviposition. Additionally, the high expression of GR43a homologs points to fructose sensing, while the lack of detectable CO₂ receptor components (except LglyGR2) suggests atypical carbon dioxide perception mechanisms. Collectively, this study provides a valuable expression atlas of chemosensory genes in L. glycinivorella and identifies sex-specific candidate genes for future functional validation and behavior-based pest management. Full article

The commercialization of genetically modified (GM) maize and soybean is advancing, with strip intercropping emerging as a promising model to enhance crop yields and resource efficiency. However, the impact of this system on target pests remains unclear. To address this, we evaluated eight different planting patterns (four different monocultures and four different strip intercropping integrations) of insect-resistant GM maize (‘RF88’) and soybean (CAL16) events and their non-transgenic parental lines (Xianyu 335 maize and Tianlong No. 1 soybean) in the Huang-Huai-Hai planting area from 2023 to 2025. Our results identified Helicoverpa armigera and Spodoptera exigua as the dominant pests on maize and soybean, respectively. We found that the GM trait significantly reduced the population density and plant damage caused by these pests. Strip intercropping also provided significant suppression across both crop lines. Furthermore, the integration of strip intercropping and the GM trait resulted in the most effective pest control. This study provides valuable insights for the top-level design and industrial layout of GM crop commercialization and contributes to promoting its safe application and sustainable pest management. Full article

Hemipteran insects such as Euschistus heros and Dysdercus peruvianus are important pests of soybean and cotton, respectively, making them relevant targets in pest management programs. This work aims to evaluate the insecticidal and chemical activity of Cymbopogon citratus essential oil (CC-EO) and its nanoemulsion against E. heros and D. peruvianus. A mixture of citral stereoisomers (59.5%) was identified as the major constituent of CC-EO The topical application of nanoemulsion resulted in 53.33% and 33.33% mortality in E. heros and D. peruvianus, respectively. Contact treatment caused 83.33% mortality in E. heros and 86.70% mortality in D. peruvianus, also inducing antennal deformities observed by scanning electron microscopy and reflected in altered behavioral responses in a Y-tube olfactometer assay. Ovicidal effects were observed in contact treatment for both species, affecting nymph emergence from eggs treated with nanoemulsion. Treatments with pure EO resulted in 100% nymph mortality and complete inhibition of egg hatching in both insects. Headspace solid-phase microextraction (HS-SPME) analysis revealed changes in the volatile profile of treated insects, showing the presence of semiochemicals related to defense and alarm, such as terpenes and alcohols. The multiple lethal and sublethal effects demonstrated by CC-EO highlight its potential as a candidate for integrated pest management programs, offering an eco-friendly alternative to conventional chemical control methods. Full article

Soybean production is a cornerstone of Brazilian agriculture but is heavily threatened by insect pests such as the soybean looper Chrysodeixis includens, capable of reducing yields by up to 70% if uncontrolled. Reliance on chemical insecticides is increasingly unsustainable due to environmental impacts and resistance, highlighting the need for eco-friendly alternatives. The alphabaculovirus Chrysodeixis includens nucleopolyhedrovirus (ChinNPV) is an important biocontrol agent largely used in Brazilian fields because of its host specificity and safety, although its persistence is limited by ultraviolet (UV) sensitivity. Here, we characterize two ChinNPV isolates, CNPSo-168 (C168) and Tabatinga (Tb), using genomic and phenotypic analyses. Whole-genome sequencing revealed circular dsDNA genomes of 139,290 bp (154 ORFs) for C168 and 139,131 bp (153 ORFs) for Tb, both encoding the 38 baculovirus core genes and sharing >98.9% identity with reference genomes. Comparative genomics identified 431 SNPs, including 132 nonsynonymous changes in structural, regulatory, and infection-related genes. At low concentrations, C168 showed an approximately 2-fold lower LC₅₀ than Tb (higher potency), while both achieved near-complete mortality within 8 days at higher concentrations. This greater potency at lower concentrations reinforces the efficacy-based rationale for selecting isolate C168 for biocontrol applications. Infection reduced larval growth, pupation, and adult emergence, often with developmental impairments. Despite genetic differences, both isolates were highly UV-sensitive, and formulation tests indicated that titanium dioxide combined with kaolin conferred partial protection. These results provide insights into ChinNPV diversity and support its development as a sustainable tool for soybean pest management. Full article

Corn–soybean strip intercropping (abbr. CSSI system) can enhance species biodiversity and ecological services for ecological control of insect pests. To improve its effectiveness and fully utilize it to improve ecological control of insect pests and crop production, two monoculture types of corn (C) and soybean (S), and two strip intercropping patterns (i.e., C3S3 and C3S4, indicating three rows of corn strip intercropped with three and four rows of soybeans respectively), were conducted to assess the CSSI system’s (i.e., C3S3 and C3S4) impacts on the abundance of insect pests and crop yields by a two-year field experiment. The results indicated that a total of 11 species of insect pests were found in the CSSI system. Compared with C or S monoculture, the community indexes of insect pests (including the Shannon–Wiener diversity index (H), the Pielou’s evenness index (E), and the Margalef’s richness index (D)) increased, and the Simpson’s dominance index (C) decreased in the C3S3 and C3S4 patterns in 2022. Compared to the C and S monoculture, the CSSI system decreased the population dynamics of total insect pests and the key insect pests Trialeurodes vaporariorum on corn and soybean plants, respectively. In the CSSI system, T. vaporariorum exhibited higher population dynamics on corn plants than on soybean plants, indicating a preference for corn plants under the CSSI system. Moreover, the corn yield per hectare in the C3S4 pattern was significantly higher than that of the C monoculture in 2022–2023. The biomass per plant and the 1000-grain weight of corn in the C3S3 pattern were significantly lower than that in the C monoculture and C3S4 pattern in 2022. The biomass per plant, the 1000-grain weight and yield per hectare of soybean in the C3S3 and C3S4 patterns were significantly lower than that in the S monoculture in 2022–2023. The land equivalent ratio (LER) was <1.0 in the CSSI system, posing yield loss risk for soybeans in the CSSI system. The competitive ratio (CR) of corn was greater than soybean in the CSSI system. In addition, the yield of corn and soybeans were not significantly correlated with the abundance of total insect pests, while the soybean yield was significantly positively correlated to the abundance of T. vaporariorum. In conclusion, it is presumed that the CSSI system can decrease the abundances of insect pests, particularly key insect pests, and maintain their community stability, thereby preventing insect pests’ outbreak. However, the CSSI system is disadvantageous for soybean yield, as it cannot fully utilize land resources and may pose a risk of system yield loss. Full article

Brazil leads tropical agriculture, yet annual yield losses from insect pests and concerns over water contamination, non-target impacts, and resistance sustain demand for safer, more efficient control tools. This review synthesizes advances in nanopesticides for Brazil’s major crops (soybean, sugarcane, coffee, and citrus) and is organized into five parts, comprising concepts and definitions; formulation families; modes of action; efficacy evidence from laboratory, greenhouse, and field studies; and environmental and human health risk considerations. Evidence indicates that nano-enabled delivery can increase on-target deposition, prolong residual activity, and match or exceed control at reduced active ingredient loads by improving foliar adhesion, transcuticular transport, plant uptake, and spatiotemporal targeting with pheromone-releasing nanofibers and other dispensers. Because nanoformulations can alter exposure pathways and environmental fate, this review emphasizes nano-specific physicochemical characterization under use conditions, fate and transport in Oxisols and Ultisols, and tropical waters, ecotoxicity panels that include pollinators, aquatic invertebrates, soil biota, and vertebrate surrogates, and scenario-based exposure assessment for applicators, residents, and consumers. The review closes with practical guidance for Brazil: head-to-head efficacy benchmarks against commercial standards, the standardized reporting of release and characterization data, and a nano-specific environmental risk assessment checklist to help realize efficacy gains while protecting environmental and human health. Full article

The whitefly, Bemisia tabaci, is a complex of cryptic species that is a significant pest of different legume hosts that inhabits various regions worldwide with diverse climates and characteristics. Its adaptability is often facilitated by the insect’s microbiome, which can contribute to both the metabolism of host plant secondary compounds and insecticide resistance. The most relevant biotypes in Brazil are Middle East-Asia Minor 1 (MEAM1) and Mediterranean (MED), because of their ability to damage different hosts. Although MEAM1 is the prevalent species in Brazil, MED has great potential to spread, and there is little current knowledge about the biology of this biotype in the country. Therefore, the objective of this study was to evaluate the development and viability of MED on two legumes, soybean and common bean, alongside cotton, bell pepper, and tomato, at temperatures of 20 °C, 23 °C, 26 °C, 29 °C, 32 °C, and 35 °C and characterize the composition of its endosymbionts. Temperatures between 23 °C and 32 °C were the most suitable for B. tabaci MED development and viability across all tested host plants, whereas 35 °C proved harmful for insects reared on legumes. We observed a temperature threshold (°C) and thermal constant (degree-days) that varied according to the host plant, ranging from 9.81 °C and 384.62 for soybean to 11.17 °C and 333.33 for bell pepper, respectively. The main endosymbionts were in a ratio of 80% Hamiltonella and 20% Cardinium. These results allow the future mapping of risk for the MED biotype on different host plants in Brazil and elsewhere in South America. Full article

Thrips flavus (Thysanoptera: Thripidae) is a Eurasian pest that primarily attacks a variety of cash crops such as soybean. Currently, there is insufficient knowledge of thrips-resistance mechanisms in soybeans and a lack of effective thrips-resistant soybean varieties. The objective of this study was to identify the correlation between the pest thrips, T. flavus, resistance levels and morphological structures of soybean varieties. A total of 41 spring soybean varieties were planted in a field in Northeast China. Observations were made regarding the infestation intensity of T. flavus, the morphological structures (compound leaf shape, leaf length, leaf width, leaf surface humidity, trichome density, length, and color), leaf SPAD value, leaf nitrogen content, etc. Specifically, leaf trichome density (regardless of whether it was on the upper or lower surfaces of the upper, middle, or lower leaves), trichome color, and compound leaf shape all showed significant positive correlations with the amount of T. flavus. Additionally, principal component analysis (PCA) indicated that, during the peak flowering stage, leaf width, trichome length, trichome density, SPAD value, and nitrogen content were key factors for evaluating resistance; meanwhile, during the podding stage, leaf length, SPAD value, nitrogen content, and leaf surface humidity made the most significant contributions. Field resistance screening using the number of T. flavus per meter of double rows, the average number of T. flavus per plant, and hierarchical cluster analysis yielded consistent results. The soybean variety “podless-trichome” is a thrips-resistant variety (high resistance), and “Jinong 29” is a thrips-sensitive variety (high sensitivity). This study provides valuable insights into the occurrence of insect resistance to thrips in soybean varieties. Full article

The tarnished plant bug, Lygus lineolaris Palisot de Beauvois (Hemiptera: Miridae), is an economically important pest of row crops worldwide. Ten isolates of entomopathogenic nematodes (EPNs) (Rhabditida: Steinernematidae and Heterorhabditidae) were evaluated against the third instar nymphal stage of the tarnished plant bug and its generalist predator, the sculpted damsel bug, Nabis roseipennis Reuter (Hemiptera: Nabidae), one of the most abundant and commonly encountered damsel bugs in cotton and soybean agroecoscapes across the Southeastern United States. The objectives of these experiments were to assess the infectivity of entomopathogenic nematodes (EPN) by direct topical exposure against the sculpted damsel bug and tarnished plant bug, whether the predator prey choice is affected by EPN infection, and if feeding on EPN-infected tarnished plant bug (TPB) prey items could result in cross-infection of the predator. Mortality rates at a concentration of 200 infective juveniles (IJs)/mL significantly differed among isolates and insect species, ranging from 30% to 93% for tarnished plant bugs and from 6% to 38% for sculpted damsels, respectively. The third instars of L. lineolaris were more susceptible to the ten nematode isolates than N. roseipennis. Higher pathogenicity on the tarnished plant bug and a low mortality potential make strains HbHP88, HbVS, Sc17c+e, and SfSN the most promising candidates for the biological control of L. lineolaris under lab and greenhouse conditions while preserving beneficial predators of the Southeastern United States. Full article

The fungus Metarhizium anisopliae is under development as a bioinsecticide for Euschistus heros. To further elucidate the effect of this fungus on E. heros behavior, we monitored the feeding activities of adults treated with the fungus at 1 × 10⁸ conidia mL⁻¹ on soybean in the pod-filling stage (R5) through electropenetrography (EPG) AC-DC. We also determined the virulence of M. anisopliae to adults and its damage to soybean seeds. M. anisopliae displayed high levels of virulence to adults even at low concentrations of 5 × 10⁶ conidia mL⁻¹ (98% mortality). E. heros females were more susceptible to M. anisopliae than males, exhibiting a lower LT₅₀ for mycosed adults (7.1 and 9.7 days, respectively). The EPG experiment showed that fungus-treated adults spent significantly less time on probing activities (reduced by 86% at day four and ceased at day five) than untreated insects, and the number of waveform events per insect significantly decreased. This information is valuable for managing stink bugs at the field level, as it shows that even though the insect is alive, its feeding is compromised, consequently minimizing the damage inflicted to the crop. This study paves the way for further research employing entomopathogenic fungi in pest control. Full article

With the search for alternative pest management strategies due to the concerns associated with synthetic pesticides, botanicals have been of increasing interest. However, the potential of plants such as soybean (Glycine max) as biopesticides is less known. Hence, this study assessed the activity of soybean extract (SBE) on insects and Phytophthora pod rot pathogens of cocoa using the filter paper contact toxicity and amended-agar plate techniques, respectively. Concentrations of 0.001–100% w/v SBE induced a mortality of 17.02–100% on the cocoa mirid Sahlbergella singularis and 2.5–90% and 5.26–100% on the ants Crematogaster africana and Pheidole megacephala, respectively. Also, 0.001–20% w/v SBE inhibited mycelial growth by 0–72% (Phytophthora palmivora isolates) and 1.17–81.03% (Phytophthora megakarya isolates). The minimum inhibitory concentration for P. palmivora and P. megakarya isolates was 1% and 0.001% w/v SBE, respectively. The median lethal concentration was 3.50% (S. singularis) and 193.73% w/v (C. africana), while the median inhibitory concentrations were 4.70 and 7.87% (P. palmivora isolates) and 1.13 and 1.48% (P. megakarya isolates). The activity of SBE on the pests was differential but non-toxic to the ant C. africana. The findings indicate the potential of SBE as a biopesticide against S. singularis and Phytophthora pod rot pathogens of cocoa. Full article

Soybean (Glycine max) is the most widely grown legume crop in the world, providing important economic value. Pest herbivory damage by insects and mammalian wildlife, in particular the white-tailed deer (Odocoileus virginianus), limits yields in soybean. Incorporating trypsin inhibitors (TIs) as plant protectant against herbivory pests has been of interest. We previously showed that the overexpression of soybean TIs in soybean conferred insect deterrence under greenhouse experiments. In this study, we examined the potential of transgenic TI-overexpressing lines in deterring insects under field conditions at Knoxville, Tennessee. Our results indicate that the overexpression of TI could lead to a significant reduction in leaf defoliation of the transgenic compared to non-transgenic lines without negatively impacting plant growth and yield under field conditions. Furthermore, we extended our study by comprehensive evaluation of these transgenic plants against the white-tailed deer herbivory in a separate field setting at Jackson, Tennessee, and with controlled deer feeding experiments. No significant differences in growth characteristics were found between transgenic and non-transgenic lines under field conditions. There were also no significant differences in deer deterrence between transgenic and non-transgenic lines in ambient deer herbivory field or controlled deer feeding trials. Our study provides further insights into more exploration of the role of TI genes in pest control in this economically important crop. Full article

Understanding plant-insect interactions can help control the harm of herbivorous pests. According to transcriptome data, transcripts of Solanum lycopersicum responding to feeding by Tuta absoluta were screened for important endopeptidase inhibitors. These genes were annotated as serine-type endopeptidase inhibitors from the potato inhibitor I family, potato type II proteinase inhibitor family, and soybean trypsin inhibitor (Kunitz) family. Based on the analysis of expression patterns, Solyc09g084480.2, Solyc03g020080.2, Solyc03g098760.1, and Solyc01g009020.1 were identified as key genes in the defense system of S. lycopersicum. The major endopeptidase genes such as Tabs008250, Tabs007396, and Tabs005701 in the larval stages of T. absoluta were also detected as potential targets of the plant endopeptidase inhibitors. The interaction mode between these endopeptidase and endopeptidase inhibitors was predicted based on the protein structure construction. This study aims to reveal the molecular response of S. lycopersicum to feeding by T. absoluta with high throughput sequencing and bioinformatics analysis. Full article

Insect pest infestations can vary due to spatial differences in microclimates and food availability within agroecosystems. Covariates can reflect these environmental conditions. This study tested whether using environmental covariates in two-phase sample optimization improved the spatial predictions for soybean insect pests. During the 2021–2022 crop season, insect pest samples were collected at 50 georeferenced points in a commercial soybean field in Brazil, alongside data on environmental covariates such as vegetation indices, soil properties, terrain topography, and distances from riparian areas. Three covariates were selected using correlation and principal component analysis (PCA). In the 2022–2023 crop season, sample designs were optimized using the iterative algorithm optimization of sample configurations using spatial simulated annealing (SPSANN) using the selected covariates, resulting in two optimized designs that were compared to a regular grid. Data from the three sampling designs comprising 50 points were evaluated using geostatistical methods, regression analysis (pest abundance), and classification (pest presence or absence) via the random forest algorithm. The data showed no spatial dependence, making using geostatistical interpolators inappropriate. However, a multi-objective optimized sampling design, tailored to refine configurations for identifying and estimating variograms and spatial trends essential for spatial interpolation, produced the most accurate predictions. Therefore, a two-phase sample optimization with prior in situ selection of environmental covariates improves pest predictions in agricultural systems, contributing to more efficient and sustainable agricultural management. Full article