Journal of Pest Science

Numerous arthropod pest species can cause significant losses in the quantity and quality of stored products. Currently, the most common pest control strategy is the use of a limited number of authorized synthetic insecticides. However, the overuse of these insecticides has led to an increase in pesticide resistance, reducing their effectiveness. Biological control using natural enemies offers an effective alternative to prevent insect populations from reaching pest status. Generalist predatory mites are noted for their potential as biocontrol agents as they can prey on a large variety of pest species and are easy to manage and apply. We evaluated the suitability of three predatory mites, Blattisocius tarsalis, Cheyletus malaccensis, and Amblyseius swirskii, for controlling several insect pests that are usually present in stored cereals. Prey acceptance and predation rates were assessed in experiments in which a known number of preys were offered to mite females in different arenas. Blattisocius tarsalis and C. malaccensis exhibited broad polyphagous behavior on insect pests commonly found in stored rice and other cereals. In contrast, A. swirskii was ineffective against these pest species. The efficacy of B. tarsalis and C. malaccensis, individually or in combination, in controlling populations of Oryzaephilus surinamensis and Sitotroga cerealella in medium-size arenas was also evaluated. Whether individually or in combination, both predatory mites reduced populations of O. surinamensis or of S. cerealella by half. These results suggest that periodic releases of these predatory mites could maintain these pest populations under control.

Species of generalist phytoseiid mites in the genus Euseius are effective natural enemies of multiple arthropod pests in various types of orchards worldwide. Cover crops increase the densities of these predators and can help reduce pest densities, but their practical roles and effects in enhancing biological control have not yet been completely unveiled yet. Here, we examined the efficacy of biocontrol of Panonychus citri (McGregor) and Aculops pelekassi (Keifer) by naturally occurring Euseius sojaensis (Ehara) in commercial Japanese citrus orchards with cover crops of Lolium perenne L. (perennial ryegrass) managed in two different ways: flowering and mowing. In the flowering plots, the numbers of windborne pollen grains and phytoseiid mites were larger, P. citri populations were smaller, and rates of fruit injury caused by A. pelekassi were significantly lower than in mown plots. In early summer, the number of E. sojaensis in the flowering plots peaked following a peak in the abundance of windborne Poaceae pollen caught on the citrus trees. These results suggest that the windborne pollen supplied from cover crops of L. perenne boosts the populations of E. sojaensis inhabiting the citrus trees and enhances the efficacy of biocontrol of P. citri and A. pelekassi. The percentage of E. sojaensis females with eggs was higher in flowering plots than in mown plots. Therefore, in conservation biological control, a perennial ryegrass cover crop flowering in early summer would be beneficial for increasing the fecundity of this predatory mite, even when prey (pest) densities are low.

Bactrocera dorsalis Hendel is one of the most serious pests in dragon fruit, requiring heat treatment before international trade. Here, a novel strategy of combining phosphine fumigation followed by forced hot-air treatment was developed and its effects on B. dorsalis mortality and postharvest quality of dragon fruit were evaluated. B. dorsalis 18-h-old eggs and third instar larvae were the most tolerant stages to heat treatment. The combined treatment demonstrated a significant synergistic effect. Probit analysis revealed that the heat treatment time of combined treatment required to achieve 50% mortality (95% CL) for eggs and third instar larvae was reduced to 72.5% and 66.5% of forced hot-air treatment alone, respectively. Gene expression analysis showed that phosphine fumigation dramatically inhibited induction of HSP genes in insects following forced hot-air treatment, indicating the synergistic effect might derive from the inhibition of heat-response genes by phosphine. Fruit soluble solids content and titratable acidity were not affected by the combined treatment, although respiration was slightly inhibited. This research demonstrated the synergistic effect between phosphine and forced hot-air treatment against B. dorsalis and indicated that compared to the heat treatment alone, combined treatment required less time and a lower temperature, providing great potential as a novel strategy for fruit phytosanitary treatment, especially in heat-sensitive fruit.

Several beneficial microbes have been shown to activate defensive mechanisms in plants, enhancing their resistance against herbivores. However, it remains unclear whether different beneficial microbes can synergize to improve defenses in wild plants, similar to their effects in cultivated plants against insect pests. Here, we investigated the effect of the endophytic entomopathogenic fungus Metarhizium robertsii, both individually and in combination with the growth-promoting rhizobacteria Bacillus amyloliquefaciens, on plant growth and volatile emissions in the cultivated Solanum lycopersicum and its two wild parents, S. pimpinellifolium and S. habrochaites. We also assessed the ovipositional preference of the destructive pest Tuta absoluta and the olfactory responses of its natural enemy, the mirid predator Macrolophus basicornis, toward these treatments across each tomato species. Both wild and cultivated plants inoculated with M. robertsii exhibited enhanced growth and emitted higher levels of specific volatile compounds than non-inoculated plants. Furthermore, T. absoluta females laid fewer eggs on S. lycopersicum and S. habrochaites inoculated with M. robertsii. Additionally, the inoculation of this beneficial fungus resulted in increased attraction of M. basicornis to the volatiles of S. lycopersicum and S. pimpinellifolium. Interestingly, the combined inoculation of B. amyloliquefaciens and M. robertsii generally did not yield an additive effect on volatile emissions and resistance against T. absoluta compared to M. robertsii alone in wild and cultivated tomato plants. These results suggest that the inoculation of M. robertsii could be a promising tool for protecting tomato plants against T. absoluta and enhancing the attraction of its natural enemy, M. basicornis.

In the ongoing pursuit of sustainable farming techniques, the constant fight against aphids remains an essential frontier. Aphids are well-known agricultural pests and they continue to jeopardize global crop production, necessitating an immediate demand for sustainable pest control methods. Conventional chemical insecticides not only harm the quality of crops but also cause environmental damage. This comprehensive review starts with a meta-analysis using PRISMA approach, to present innovative, environmentally friendly alternative technologies, the latest developments and advances in aphid control that can reduce pressure on the environment and contribute to a more sustainable aphid control. Good alternative technologies include bioengineered nanoparticles, RNAi and CRISPR/Cas9. In addition, there has been progress in the existing use of natural enemies with parasitoids and predators with increased efficacy, as well as the area of microbial control of aphids with entomopathogenic fungi and bacteria. Because monitoring is very important and a cornerstone of integrated pest management, the latest advances in artificial intelligence and deep learning in aphid control are helping to reduce pressure on the environment and contribute to a reduction in the use of chemicals, supporting the preservation of biodiversity and sustainability, which fits with the policy in many continents. Altogether, this paper aims to provide a valuable guidance for researchers, practitioners and policymakers who are involved in the complex dynamics of aphid control in agriculture.

The invasion of Hyphantria cunea, also known as “smokeless fires”, poses a significant threat to artificial and natural forest resources. Therefore, it is urgent to adopt safe and effective control strategies to prevent the spread of and harm caused by of H. cunea. In this study, potential repellent active ingredients were screened from the volatiles of Larix gmelinii and Syringa oblata, the non-preferred hosts of H. cunea. The sensitive substances were identified in the H. cunea larvae and adults through electroantennographic (EAG) and behavioral responses. The results showed that fresh branches with leaves of L. gmelinii and S. oblata had significant repellent effects on the fifth and 6th instar larvae and virgin females, which were mainly related to α-pinene and (+)-limonene and other volatile substances. 100 μL/mL α-pinene and (+)-limonene were found to significantly stimulate the olfactory nervous system of H. cunea virgin females and male adults, and could induce significant EAG responses. They could induce avoidance behavior of 4-6th instar larvae, virgin females, and male adults, and also inhibit the selection behavior of fifth and 6th instar larvae and adults to Salix matsudana, the preferred food host. So α-pinene and (+)-limonene can be used as repellents for larvae and adults of H. cunea, with an effective concentration of 100 μL/mL. The two terpenes can induce avoidance behavior of H. cunea during the larval feeding period and before the mating of adults, thus inhibiting the outbreak and spread of the pest, providing an important control strategy for the integrated management of H. cunea.

With the rollback of insecticides, novel tools for pest control are urgently needed. Aphids are particularly a major concern with few sustainable control alternatives. Ecological intensification has been promoted as a way of “inviting" back nature’s self-regulating abilities into agricultural production systems. Although such measures enhance the presence of natural enemies in agroecosystems, we demonstrate that in an ecologically intensified apple orchard, biocontrol of rosy apple aphid was minimal. We verified why the biodiverse settings did not result in enhanced ecosystem services, i.e., biological control of the rosy apple aphid. Close monitoring of food–web interactions in thousands of aphid colonies showed that tending ants dominated responses, while those of natural enemies were weak or absent. However, application of artificial aphid honeydew diverted ants from tending aphids and flipped the myrmecophily-dominated state into favoring numerical responses of a guild of natural enemies. Responses were swift and controlled both Aphis pomi and Dysaphis plantaginea, provided intervention was synced with aphid and predator phenology. Although myrmecophily in aphids is well-known on its own accord, it has been completely overlooked in ecological intensification. To unlock the aphid-biocontrol potential provided through ecological intensification, myrmecophily needs to be disrupted. Although particularly true for perennial systems, generally practices that reduce soil disturbance favor ants and may amplify aphid pests, thereby reducing biocontrol impacts in ecological intensification efforts. Harnessing ecosystem services requires careful analysis and good understanding of agroecosystem intricacies.

In response to growing concerns regarding the adverse environmental and health effects of synthetic pesticides, there has been a notable surge in the demand for plant-based bioinsecticides. Botanicals and essential oils (EOs) are emerging as promising alternatives that offer a safer and more sustainable approach to pest management. Nevertheless, the effectiveness of these natural insecticides is often hindered by their inherent instability under environmental conditions, high volatility, and susceptibility to thermal decomposition, which necessitates frequent reapplication and diminishes their practical utility. To address these challenges, innovative formulation strategies such as nanoemulsions, microemulsions, nanoencapsulation, and microencapsulation have been developed. These advanced approaches facilitate controlled release, enhance stability, and significantly improve the efficacy of botanical- and EO-based insecticides. By providing target-specific action, these formulations not only reduce the frequency of applications and lower dosage requirements but also minimize environmental contamination and enhance overall pest management efficiency. This review offers a comprehensive exploration of these advanced formulations, including the preparation and characterization of nano-/microemulsion and nano-/microencapsulate systems and the technical challenges associated with their characterization. This manuscript examines the efficacy of these formulations in pest management, focusing on their physical and chemical stability under various storage conditions. Additionally, it addressed the impact of these formulations on nontarget organisms and their potential phytotoxicity. Despite the promising results observed in controlled settings, there is a notable lack of field studies evaluating the suitability of these formulations for different crops and their effectiveness in diverse agricultural environments. This identified gap underscores the necessity for further research to validate the practical application of these technologies. This review also discusses the scalability and cost-effectiveness of these advanced formulations, providing insights into their potential for broader commercial adoption.

The fall armyworm (Spodoptera frugiperda) is an important pest of maize, and a key target of transgenic crops expressing Bacillus thuringiensis (Bt) insecticidal proteins. These exert a strong selective pressure, so susceptible plants (refuges) are planted together with the transgenic seed to lower such pressure. The system favored in North America is to mix Bt and non-Bt seed (refuge-in-a-bag, or RIB). However, South American farmers favor structured refuges, interplanting rows of Bt and non-Bt seed. Yet, the proportion of susceptible maize must be minimized to prevent yield losses, and flight distance before mating is considered the best way to gauge the adequate distance between non-Bt rows in structured refuges, which has been estimated through mark–release–recapture experiments. The aim of this study was to compare three marking techniques and three trapping systems in laboratory and field experiments. Results suggest conventional marking techniques were not completely innocuous to the moths. UV traps drastically overrode the effect of synthetic and natural pheromones, suggesting they may not reflect normal dispersion behaviors. Marking experiments may not provide reliable measures of flight distance, and although farmers tend to resist the RIB option the data suggests it should be enforced.

Coffee leaf miner (CLM) Leucoptera coffeella stands out as a primary insect pest of arabica coffee plants in some regions of Brazil. Coffee breeding for CLM-resistance has used the species Coffea racemosa as gene donor for C. arabica, resulting in the development of the resistant commercial hybrid ‘Siriema AS1’. However, no previous study has characterized the resistance type, and whether there is variation in the levels expressed in progenies of ‘Siriema’ to CLM. This study aimed to characterize the type, by antixenosis or antibiosis, and the levels of resistance in segregating progenies of ‘Siriema’ plants to CLM. Experiments were conducted under laboratory conditions with artificial infestation of CLM adults in oviposition cages, where dual-choice preference assays compared each tested ‘Siriema’ progeny with the susceptible commercial cv. Arara (C. arabica). A follow-up no-choice assay evaluated five selected ‘Siriema’ progenies on the development of CLM compared to cv. Arara. As main results, ‘Siriema’ progenies were equally susceptible to CLM oviposition, and were overall stimulant relative to cv. Arara. However, there was low CLM larval survival and injury intensity on the selected ‘Siriema’ genotypes, indicating moderate levels of antibiosis-resistance, while cv. Arara and one ‘Siriema’ progeny were moderately susceptible. These findings further our understanding on the type and levels of resistance in ‘Siriema’ genotypes, aiding in the development of resistant coffee hybrids and deployment of management strategies to CLM.

Frankliniella intonsa (Thysanoptera: Thripidae) is a significant invasive pest that can damage numerous plants and crops and spread the tomato spotted wilt virus. During the sunflower flowering period in the primary sunflower production area in China, F. intonsa-infested sunflower heads produce kernels with marked visual damage, including peel scratches, which reduce seed quality and profitability. In this study, the behavioral responses of F. intonsa to buckwheat and sunflowers were measured in a Y-tube. Meanwhile, gas chromatography-mass spectrometry was performed to determine the volatile components of inflorescences of both sunflower and buckwheat and the behavioral effects of these components were evaluated on F. intonsa in a Y-tube. The results revealed that sunflower leaves significantly repelled adults and nymphs of F. intonsa both in olfactometer bioassays. However, F. intonsa was significantly attracted by the volatiles from the leaves and flowers of buckwheat. Interestingly, F. intonsa adults preferred sunflower flowers over buckwheat flowers. Among the four kinds of sunflower flower volatiles selected, F. intonsa was attracted by two kinds of volatiles (γ-terpinene and (R)-( +)-limonene), while one volatile (β-pinene) had the effect of repelling F. intonsa, while among the four selected buckwheat flower volatiles, F. intonsa were attracted by three kinds of volatiles (α-caryophyllene, verbenone, octane). Finally, the field-trapping effect of buckwheat on F. intonsa was verified by a sunflower-buckwheat intercropping experiment. The results of this study provide a theoretical basis for the feasibility of intercropping with buckwheat and sunflower to control F. intonsa. Thus, buckwheat can be used as a trapping plant in fields to prevent F. intonsa invasion.

The stable fly, Stomoxys calcitrans, is a globally important pest causing stress, economic losses and transmission of pathogens in livestock. Control on commercial farms relies predominantly on the use of insecticides, with pyrethroids being the most frequently used class of insecticides in industrialised countries. Here, laboratory isolates were obtained from four dairy farms in Brandenburg (Germany) and tested for phenotypic resistance to deltamethrin in comparison to a susceptible reference isolate using topical application. Individual flies were subsequently genotyped using allele-specific real-time PCRs. Phenotypic resistance was observed in all four field isolates with resistance ratios between 46 and 119 compared to the susceptible laboratory strain. At position 1014 of the voltage-sensitive sodium channel, allele-specific PCRs detected the wild-type, kdr-his and kdr genotypes encoding leucine, histidine and phenylalanine, respectively. In the susceptible laboratory isolate, only the wild-type was identified. On the farms with very high LD50 values, the kdr variant was most prevalent and logistic regression analysis revealed that the kdr variant increased the odds to survive exposure to deltamethrin more than the kdr-his genotype. Flies carrying two resistance alleles were less susceptible than flies that also carried one wild-type allele. In three out of four field isolates, the allele frequencies were significantly different from the expectations of the Hardy–Weinberg equilibrium suggesting ongoing selection. The data show that the phenotype can be largely explained by the kdr genotype and represent high frequencies of the L1014F kdr and L1014H kdr-his variants conferring high levels of resistance in northern Germany.

Due to their potential role in pathogen transmission, invasive mosquitoes pose considerable threats to human and animal health. Several studies have identified the most important ecological drivers mediating the establishment and spread of key mosquito species (e.g., Aedes aegypti, and Ae. albopictus), and made predictions for future distribution. We evaluated the effect of an exhaustive list of environmental predictors on the distribution of three invasive species in Hungary (Ae. albopictus, Ae. japonicus, and Ae. koreicus) by using the same standards for data collection based on citizen science observations. Current distribution maps of these species were generated from a 5-year survey, then were compared with various predictor maps reflecting climate, habitat type, food supply, traffic, and interspecific competition by using a boosted regression trees approach that resulted in a subset of variables with the strongest impact. The best predictor sets were used to predict the probability of occurrence of the focal species for the whole country, and these predictions based on citizen science were evaluated against the results of an independent recent field surveillance. We uncovered species-specific patterns and found that different predictor sets were selected for the three different species, and only predictions for Ae. albopictus could be validated with direct trapping data. Therefore, citizen science informed distribution maps can be used to identify ecological predictors that determine the spread of invasive mosquitoes, and to estimate risk based on the predicted distribution in the case of Ae. albopictus.

Phosphoinositide-dependent kinase PDK, a key component of the insulin signaling pathway, plays an important role in the regulation of insect growth and development. However, the functional significance of the PDK gene in Tuta absoluta, a destructive invasive tomato leaf miner, remains unknown. In this study, we identified and characterized a PDK gene (designated TaPDK) and analyzed its physiological roles in molting and reproduction of T. absoluta. Our results showed that the TaPDK expression levels were elevated in the 5- and 6-day-old pupae before ecdysis and declined immediately after eclosion. TaPDK was predominantly expressed in the head, midgut and abdomen. When the TaPDK was knockdown, the larval-pupal molting and female reproduction were severely affected. Injecting dsRNA of TaPDK into 2-day-old female pupae resulted in severe phenotypic changes (cuticular shrinkage) in 31.29% of pupae, ultimately leading to death. Knockdown of TaPDK significantly reduced the 20E titer and chitin content and downregulated the expression levels of genes involved in the 20E pathway and chitin metabolism. Further investigation revealed that the suppression of TaPDK impaired ovarian development, resulting in significantly reduced fecundity and hatchability. In addition, the JH titer and vitellogenin content of TaPDK-deficient females were reduced, and the expression of Vg, VgR, and JH signaling pathway genes were significantly decreased. Collectively, our study provides a deep insight into the PDK-mediated regulation of pupal ecdysis and female reproduction in T. absoluta.

The Fall Armyworm, Spodoptera frugiperda, invaded China late in 2018 and was responsible for substantial crop losses, especially to maize. This work focuses on the suitability of climate across China for Fall Armyworm survival and spread. It uses climate metrics derived with guidance from experts to enable assessment of the risks posed by Fall Armyworm on maize production in different regions of China. The locations and time of year when temperature conditions are within a viable range for Fall Armyworm survival (minimum temperature higher than 9.7∘$^\circ$C and maximum temperature lower than 39.2∘$^\circ$C) are used to estimate the spatial distribution of winter breeding and overwintering zones, which helps understand the regions and timing of Fall Armyworm migration risk into northern maize production regions. In addition, meridional wind conditions across the Yangtze River basin area are assessed, and a metric of migration potential from the winter breeding and overwintering regions in the south towards northern regions with maize production is established. Results show that temperature during the winter months currently limits Fall Armyworm winter breeding populations to the very southern regions of China (and bordering countries to the south). However, due to the consistent timing and direction of the East Asian Summer Monsoon winds, the Fall Armyworm could easily be directed northwards to the Yangtze River basin during summer months with a peak in July. For this reason, pest management actions against the Fall Armyworm on summer maize should be taken.

The egg parasitoids, Trichogramma evanescens Westwood and T. pinto Voegelé (Hymenoptera: Trichogrammatidae), play central roles in the management of lepidopteran crop pests. However, their effectiveness highly depends on the employment of compatible pesticides, with a particular focus on novel insecticides that are promising in pest control. This study investigated the lethal, sublethal and transgenerational effects of two novel insecticides, afidopyropen and broflanilide, on T. evanescens and T. pintoi in terms of biological and behavioral traits. The eggs of the factitious host, Ephestia kuehniella Zeller (Lepidoptera: Pyralidae), with parasitoids at the preimaginal developmental stages (egg-larval, prepupal and pupal) were immersed in insecticide solutions. The emergence rates of both parasitoids were negatively affected by preimaginal treatments with different concentrations of afidopyropen and broflanilide. In transgenerational experiments, broflanilide treatments significantly reduced the parasitism performance of the treated generation (F0), emergence rate of F1 and F2, sex ratio of F1 T. evanescens and the emergence rate and sex ratio of F1 T. pintoi. Afidopyropen treatments reduced the emergence rate of F3 T. evanescens adults. The longevity of the F0 females and males of both parasitoids and that of the F1 females of T. evanescens were significantly reduced by broflanilide treatments. Broflanilide also decreased the walking speed of both species while afidopyropen enhanced the resting frequency of T. evanescens. This comprehensive study provides insights into the toxicological assessment of afidopyropen and broflanilide on Trichogramma species, employing parameters corresponding to their population and behavioral dynamics. Finally, this study concludes that the integration of afidopyropen and broflanilide into integrated pest management (IPM) strategies necessitates careful consideration, particularly regarding potential non-target effects on Trichogramma species.

The papaya mealybug, Paracoccus marginatus, is an invasive pest that causes significant damage to various tropical fruits and ornamentals worldwide. Lambda-cyhalothrin, an effective insecticide in integrated pest management (IPM) strategies, can control P. marginatus. This study evaluated the sublethal effect of lambda-cyhalothrin on the life table parameters and the detoxification enzymes activities of P. marginatus. Furthermore, transcriptome sequencing analysis revealed the potential mechanisms of the detoxification-related genes associated with enzymes activities. The study reported that lambda-cyhalothrin showed high activity against P. marginatus, with LC30 values of 8.98 mg/L. Two-sex life table results showed that the development duration of the second instar nymphs, preadults, and adult female longevity was significantly prolonged, and the fecundity was stimulated in the F1-CY of P. marginatus when the parental generation was exposed to LC30 lambda-cyhalothrin. Moreover, lambda-cyhalothrin treatment significantly increased the activities of Cytochrome P450 monooxygenases (P450) and glutathione-S-transferase (GST) enzymes. Additionally, significant expression levels of P450, GST, carboxylesterase, and esterase genes were observed in P. marginatus subjected to the sublethal lambda-cyhalothrin exposure. Our findings demonstrate that sublethal concentrations of lambda-cyhalothrin influenced the development and fecundity of P. marginatus, and changes in enzymes activities and differential expression of detoxifying genes might be involved in the response and detoxification metabolism of lambda-cyhalothrin in P. marginatus. These results could contribute to a comprehensive risk assessment and provide guidance for the scientific use of lambda-cyhalothrin in IPM strategies.

Spodoptera frugiperda is a major pest in corn crops, causing significant productivity losses and exhibiting high resistance to synthetic insecticides. Essential oils (EOs) are natural substances known for their insecticidal activity against various agricultural pests. This study describes the chemical composition and bioactivity of Drimys brasiliensis EO against S. frugiperda larvae. The EO was extracted using the steam distillation method in a vat, and its chemical composition was determined using gas chromatography coupled with mass spectrometry (GC–MS). The insecticidal activity of this EO was assessed by the contact method to estimate the lethal concentration (LC50 and LC90) and to evaluate the effects on biochemical markers, including glutathione S-transferase (GST), esterase-α (EST-α), esterase-β (EST-β), superoxide dismutase (SOD), acetylcholinesterase (AChE) and lipid peroxidation (LPO), in 3rd instar larvae of S. frugiperda. Twenty-nine compounds were identified by GC–MS, accounting for 81.32% of the total chemical composition D. brasiliensis EO resulted in 100% mortality of S. frugiperda larvae at a concentration of 2.5%, with LC50 and LC90 values of 0.90 and 1.40%, respectively. Both lethal concentrations increased AChE and LPO activity, while only LC90 affected the EST-α and EST-β enzymes. Drimys brasiliensis EO exhibits insecticidal activity against S. frugiperda with neurotoxic effects, as well as cellular damage, demonstrating its potential as a control method in managing this pest in conventional and organic production methods.

Cold treatment with rigorous regulatory oversight is often mandated to manage horticultural trade-related biosecurity threats, such as invasive, cold-sensitive fruit flies (Diptera: Tephritidae). Cold treatment schedules, developed through rigorous laboratory experiments, require a set temperature and duration to ensure at least a probit 8.7 (99.99%) mortality rate, regardless of infestation likelihood. This threshold is costly to demonstrate for each pest and commodity combination and the resultant treatment may be harmful to fruit quality. Moreover, these stringent schedules do not account for cold-induced mortality already occurring in commercial supply chains. We developed a predictive temperature-dependent mortality function using 28 published cold treatment studies of pest fly species to support more flexible and proportionate use of cold treatment. The daily mortality rate was unaffected by the duration of cold exposure (0–20 days). The mortality rate varied primarily by pest species (10 species) and developmental stage (eggs and larval stages), and to a lesser extent by temperature (0–7 °C) and host (13 fruit types). Our model mostly predicted fewer days to meet probit 9.0 mortality compared to empirical results from large-scale studies, suggesting these studies can be overly conservative. By leveraging previous empirical studies, our model enables estimation of temperature-dependent daily mortality for unstudied pest developmental stage host–temperature combinations, which can then be empirically validated through targeted studies. It is hoped these results will shift cold treatment usage from highly regulated, fixed temperature treatments with a target mortality rate requirement to a more flexible approach that accounts for existing commercial supply chain practices and infestation likelihood in produce.

Single-cell RNA sequencing (scRNA-seq) has emerged as a powerful tool for studying complex cellular composition and gene expression dynamics of biological systems. In this study, we analyzed the midgut of the fall armyworm (FAW), Spodoptera frugiperda, utilizing scRNA-seq technology. scRNA-seq analysis yielded high-quality sequencing data from two replicates, showcasing robust sequencing integrity, mapping efficiency, and reproducibility. We identified twelve clusters of midgut cells, including enterocytes, enteroblasts, enteroendocrine cells, goblet cells, and stem cells, each with unique marker gene expression indicative of their specialized functions. Further analysis revealed intricate gene expression profiles and enriched biological pathways associated with each cell type, shedding light on the molecular mechanisms underlying midgut function. Additionally, lineage trajectory analysis identified the differentiation pathways of midgut cell populations, confirming canonical relationships among stem cells, enteroblasts, enterocytes, and goblet cells. Furthermore, we also studied the expression of genes coding for insecticide target sites and metabolizing enzymes in different midgut cell types. Overall, our studies provide a comprehensive understanding of midgut cellular diversity and gene expression dynamics in the FAW, offering valuable information that could be used to develop methods for managing this and other pests.

Plant secondary metabolites are crucial in affecting the interactions between insect herbivores and entomoviruses. However, there is limited knowledge regarding the impact of such metabolites on the susceptibility of insect herbivores to entomoviruses. In this study, we adopted the allicin, caterpillars (Spodoptera exigua) and nucleopolyhedrovirus (SeMNPV) as a system, and found that allicin significantly increased the mortality of S. exigua larvae infected with SeMNPV by 36.03–59.45% when infected with the virus at a concentration of 2.12 × 10³ OB·mL⁻¹. Furthermore, NPV-infected larvae together treated with allicin inhibited the growth and development of larvae, comparing to individual NPV-infected larvae. Notably, we observed a significant enrichment of differentially expressed genes involved in the cytochrome P450-mediated metabolism pathway between the NPV-infected and allicin combined with NPV-treated groups. The silencing of CYP340AA1 through RNA interference significantly increased the mortality of larvae infected with SeMNPV. This investigation indicates that allicin might be a potential candidate for improving the performance of the NPV against insect herbivores and identifies that CYP340AA1 gene is important in this process.

Diaphorina citri is the vector of “Candidatus Liberibacter asiaticus” (CLas), a bacterium associated with the citrus disease known as Huanglongbing (HLB). Previous mitochondrial genome (i.e. mitogenome) population analyses revealed the prevalence of two major mitochondrial groups (MGs) of D. citri in China, separated by elevation gradients. We assessed the population diversity of D. citri from 54 major citrus-producing areas within 11 provinces/regions of China. Additionally, endosymbiont genomes were assembled for “Ca. Carsonella ruddii” (CaCr) and “Ca. Profftella armatura” (CaPa) from next-generation sequencing of 31 new Chinese samples. Most of the D. citri diversity came from single nucleotide polymorphisms (SNPs) within five mitochondrial genes: nad3, cox2, rrnL, cob, and atp6. Nine SNPs clustered the analyzed D. citri mitogenomes into three major MGs comprising seven subgroups. Independent phylogenetic trees were generated for the endosymbionts CaCr and CaPa, and a CaPa plasmid, supporting the patterns obtained for D. citri mitogenomes while adding complexity layers. Genomic data from CaCr, CaPa, along with the plasmids from CaPa contribute to the genetic diversity—consisting of 68 SNPs and two genomic gaps—reproducing phylogenetic structures outlined by previous mitochondrial genomic studies. Additionally, both the mitogenomes and the endosymbiont genomes revealed subgroups within the original MG clusters, based on further 154 SNPs and 17 gaps. Thus, the combined genomic approach reveals further aspects about population diversity and natural history of this invasive species. Further understanding of D. citri and its endosymbionts can, therefore, aid D. citri HLB management protocols and help forecast territorial expansion events.

Since 2018, increased infestation by the fall armyworm Spodoptera frugiperda (FAW), an invasive pest worldwide, has negatively affected Asian crop production. Seasonal migratory activities drive regional outbreaks of this pest, but it remains unclear whether there is direct transboundary movement between East Asian and South Asian regions. From 2019 to 2023, FAW moth movements were monitored in Ruili of Yunnan Province, a city at the border area of China and Myanmar which is located in the insect migratory route between China and South Asian countries such as India and Bangladesh. The results showed that there was regular seasonal migratory activity of the pest, which could be divided into spring–summer (April–June) and autumn (October) peak migration periods. Further analysis using trajectory simulation model indicated that the FAW moths in spring–summer migration mostly come from Myanmar, the northeastern states of India and Bangladesh, and returns to the three countries in autumn from Southwest China. Our study clarifies the regional migration pattern of the FAW moth in China and South-Southeast Asia, providing a theoretical basis for constructing a regional early warning and management systems of this pest.

The stink bugs Edessa meditabunda, Piezodorus guildinii, and Diceraeus furcatus (Hemiptera: Pentatomidae) are major pests in the Argentinean core area of soybean production. A detailed molecular genetics comprehension of how these insects perceive odorants and respond to semiochemicals and how they detoxify chemical pesticides and plant compounds are essential to improve their management strategies. We first assembled and compared the transcriptomes from E. meditabunda, P. guildinii, and D. furcatus. Regarding sequence similarity, P. guildinii and D. furcatus are closer to each other than E. meditabunda. Then, we characterized the multigene families of odorant binding proteins (OBPs) and cytochrome P450 monooxygenases (CYP). A total of 29, 38, and 39 unigenes encoding for OBP were obtained in E. meditabunda, P. guildinii, and D. furcatus, respectively, divided into classical OBPs and plus-C OBPs. A total of 72, 63, and 76 unigenes encoding for CYP were found in E. meditabunda, P. guildinii, and D. furcatus, respectively, which were further classified into 24 families and 47 subfamilies. On the other hand, we performed for the first time RNA interference in vivo by dsRNA injection in E. meditabunda, suggesting that this molecular tool can be exploited in future physiological and functional studies in this species.