Hemiptera diversity using the mtDNA COI barcode in almond orchards in the Northern San Joaquin Valley of California.

A low-toxicity baiting program precipitates collapse of Argentine ant and ant-associated hemipteran pest populations in commercial citrus

The western tarnished plant bug, Lygus hesperus Knight (Hemiptera: Miridae) and the whitefly, Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae) are key hemipteran pests of numerous crop plants throughout the western United States and Mexico. Management in the U.S. currently relies on only a few insecticides and is threatened by the evolution of resistance. New chemistries or alternative management strategies are needed to reduce selection pressure on current insecticides and enhance control. Here, we investigated the bio-insecticidal toxicity of the French marigold, Tagetes patula Linnaeus (Asterales: Asteraceae), against both L. hesperus and B. tabaci. Assays indicated significantly reduced survival of both pest species on T. patula plants, and in diet incorporation assays containing aqueous and methanolic marigold foliar extracts. Mortality was concentration-dependent, indicating the presence of one or more extractable toxicants. These data suggest that T. patula plants have insecticidal constituents that might be identified and developed as novel alternatives to conventional chemical treatments.

Genetically modified crops that express insecticidal Bacillus thuringiensis (Bt) proteins have become a primary approach for control of lepidopteran (moth) and coleopteran (beetle) pests that feed by chewing the plants. However, the sap-sucking insects (Hemiptera) are not particularly susceptible to Bt toxins. In this study, we describe two Cry toxins (Cry64Ba and Cry64Ca) from Bt strain 1012 that showed toxicity against two important hemipteran rice pests, Laodelphax striatellus and Sogatella furcifera Both of these proteins contain an ETX/MTX2 domain and share common sequence features with the β-pore-forming toxins. Coexpression of cry64Ba and cry64Ca genes in the acrystalliferous Bt strain HD73- resulted in high insecticidal activity against both hemipteran pests. No toxicity was observed on other pests such as Ostrinia furnacalis, Plutella xylostella, or Colaphellus bowringi Also, no hemolytic activity or toxicity against cancer cells was detected. Binding assays showed specific binding of the Cry64Ba/Cry64Ca toxin complex to brush border membrane vesicles isolated from L. striatellus Cry64Ba and Cry64Ca are Bt Cry toxins highly effective against hemipteran pests and could provide a novel strategy for the environmentally friendly biological control of rice planthoppers in transgenic plants.IMPORTANCE In Asia, rice is an important staple food, whose production is threatened by rice planthoppers. To date, no effective Bacillus thuringiensis (Bt) protein has been shown to have activity against rice planthoppers. We cloned two Bt toxin genes from Bt strain 1012 that showed toxicity against small brown planthoppers (Laodelphax striatellus) and white-backed planthoppers (Sogatella furcifera). To our knowledge, the proteins encoded by the cry64Ba and cry64Ca genes are the most efficient insecticidal Bt Cry proteins with activity against hemipteran insects reported so far. Cry64Ba and Cry64Ca showed no toxicity against some lepidopteran or coleopteran pests. These two proteins should be able to be used for integrated hemipteran pest management.

Hemiptera is one of the most significant orders of insect pests, including whiteflies, true bugs, aphids, planthoppers, psyllids, and so forth, which have led to substantial economic losses in agricultural industries and have significantly affected food yields through their ability to suck the phloem sap of crops and transmit numerous bacterial and viral pathogens. Therefore, explorations of pest-specific, eco-friendly and easy-to-adopt technologies for hemipteran pest control are urgently needed. To the best of our knowledge, microRNAs (miRNAs), which are endogenous non-coding small RNAs approximately 22 nucleotides in length, are involved in regulating gene expression via the direct recognition and binding of the 3'-untranslated region (3'-UTR) of target messenger RNAs (mRNAs) or by acting as a center of a competitive endogenous RNA (ceRNA) network at the post-transcriptional level. This review systematically outlines the characterization and functional investigation of the miRNA biogenesis pathway in hemipteran pests, such as whiteflies, true bugs, aphids and planthoppers. In addition, we explored the results of small RNA sequencing and functional observations of miRNAs in these pests, and the results suggest that the numerous miRNAs obtained and annotated via high-throughput sequencing technology and bioinformatic analyses contribute to molting development, fitness, wing polyphenism, symbiont interactions and insecticide resistance in hemipteran pests. Finally, we summarize current advances and propose a framework for future research to extend the current data and address potential limitations in the investigation and application of hemipteran miRNAs.

Monitoring and identifying insect pests in museum practice: IPM experiences at the Hungarian National GalleryThe status of silverfish in the environment of artefacts and the appearance of a new alien pest species in Hungary The concept of Integrated Pest Management (IPM) was adapted from agriculture and the food industry to ensure more effective protection against pests in museums and various cultural institutions. IPM involves a holistic approach to address all pest problems collectively, rather than managing each issue separately. This strategy aims to prevent problems and crises by taking proactive actions and measures. The first IPM programme in the Hungarian National Gallery was launched in 2019, focusing on testing materials and methods for monitoring and detecting pests. Collaboration between different departments, from building management to conservators, and a comprehensive knowledge of the building and storage areas are essential for successful IPM strategies. Identifying potential entry points for pests within the building and areas that may attract pests is vital. Integrated pest management offers solutions for both vertebrate and invertebrate pests. For cost-effectiveness and sustainability, custom-made sticky traps were created using recycled cardboard and double-sided adhesive. Periodic monitoring and documentation of trapped insects are essential for evaluating the effectiveness of IPM strategies. Microscopic examination of pests is essential for identifying pests. The results of the four-year IPM programme at the Hungarian National Gallery revealed the most common pests and helped prioritise areas for intervention. Continuous improvement and adaptation of IPM strategies are necessary, especially with the emergence of new invasive species due to climate change.In 2024, a new species was identified in the Hungarian fauna, underlining the importance of IPM, especially insect trapping. While encountering various arthropods in museum settings, not all pose actual harm to artefacts. The number of known species in Hungary fluctuates due to globalisation processes such as trade, increased tourism, and climate change. Previously unknown invasive arthropods may appear in local collections, potentially unrecognised as pests, as exemplified by the appearance of the long-tailed silverfish (Ctenolepisma longicaudatum) in Hungary.Newly emerging pest species are typically synanthropic, thriving near humans. The temperature-controlled urban environment facilitates the establishment of animals not adapted to the region’s climate. The expanding distribution of the siverfish is attributed to its ability to tolerate lower temperatures and relative humidity levels. While numerous in the Zygentoma order, only a few species are addressed as museum pests in Europe. The species appearing in Hungary belong to two families: Lepismatidae and Nicoletiidae.Although the presence of native and introduced pest species in museum environments is nearly unavoidable, their establishment can be minimised with a systematic and preventative IPM strategy.

The brown marmorated stink bug, Halyomorpha halys (Stål), is an invasive species from Asia. This polyphagous, stink bug species has posed a serious production challenge in several crop species in the areas where established. The insect has spread to all the mainland states in the U.S. in about one and half decades after its first detection in Pennsylvania. The types of crops reported to have been infested by this stink bug have increased with its spread to new geographic locations. In this study, we report the first evidence of H. halys infestation in almond fruit in California. In Stanislaus County, an adult brown marmorated stink bug in an almond orchard was first observed in May 2017. The stink bug feeding on almond fruits caused excessive gumming to the developing fruits, and damage to the kernels along with typical necrotic feeding signs on the shell (endocarp) and hull (exocarp and pericarp) of the fruit at harvest. The infestation and damage by H. halys on almond warrants further research to develop Integrated Pest Management (IPM) strategies for this pest.

Arthropod Fauna Associated to Soybean in Croatia

RNA interference (RNAi) is an homology-dependent gene silencing mechanism that is a feasible and sustainable avenue for the management of hemipteran pests. Commercial implementation of RNAi-based control strategies is impeded by limited knowledge about the mechanism of double-stranded RNA (dsRNA) uptake, the function of core RNAi genes and systemic RNAi mechanisms in hemipteran insects. This review briefly summarizes recent progress in RNAi-based studies aimed to reduce insect populations, viral transmission and insecticide resistance focusing on hemipteran pests. This review explores RNAi-mediated management of hemipteran insects and offers potential solutions, including in silico approaches coupled with laboratory-based toxicity assays to circumvent potential off-target effects against beneficial organisms. We further explore ways to mitigate degradation of dsRNA in the environment and the insect such as stacking and formulation of dsRNA effectors. Finally, we conclude by considering nontransformative RNAi approaches, concatomerization of RNAi sequences and pyramiding RNAi with active constituents to reduce dsRNA production and application cost, and to improve broad-spectrum hemipteran pest control. © 2020 Society of Chemical Industry.

Cotton is a cash crop majorly affected by many hemipteran pests, among them the cotton mealybug, Phenacoccus solenopsis. Cotton mealybug attack has a devastating effect on cotton production and causes huge yield losses. In this study, 25 potential RNA interference (RNAi) target genes were selected from the iBeetle database and a transcriptome data set for P. solenopsis. To assess the effectiveness of the selected target genes, three methods were utilized to deliver double-stranded (ds)RNA (ingestion, artificial diet bioassay and transient gene silencing). dsRNA molecules at different concentrations were fed to insects and insect mortality was recorded for each target gene. Based on the mortality data, three genes, Krüppel homologue-1, ADP-ATP/Translocase and IDGF-1, were selected for further gene expression studies using a reduced concentration of dsRNA (5 μg/ml). Of the three genes, Krüppel homologue-1 showed significantly downregulated expression (by 70.81% and 84.33%) at two different time points (8 and 14 days). An RNAi silencing construct was designed for Krüppel homologue-1 under control of the double enhancer CamV35S promoter in the plant binary vector. Significant downregulation of gene expression, by 66.69% and 81.80%, was found for Krüppel homologue-1 using transient gene silencing at the same time intervals. This work provides the first evidence for targeting the Krüppel homologue-1 gene in a hemipteran pest, P. solenopsis, using RNAi technology through oral delivery and in planta-based transient gene silencing methods. © 2020 Society of Chemical Industry.

Tropical agriculture areas are complex systems for management because they have a high diversity of species (mainly arthropods) interacting among them. The lack of knowledge about the species diversity and ecological interactions promotes the choice of simplistic agriculture practices and with negative impact in species community and environment (e.g. intense pesticide application). Ecological interactions between pests and their natural enemies (predators and parasitoids) are particularly interesting because may help adopting efficient and sustainable control strategies (e.g. conservative biological control). Using molecular markers and sequencing tools it is possible to analyze the predator gut content to identify with precision, which preys were ingested and find out if there are other ecological interactions such as intraguild predation. Thus, the aim of the present study was to evaluate the impact of different maize cropping systems on species richness and abundance, prey/predator interactions of important generalist maize predators. To achieve these objectives, five areas of organic and conventional corn were sampled in the state of São Paulo, with dry pitfall traps and active collection. Richness and abundance were analyzed using all samples. The main prey and predators had their DNA barcodes produced through the amplification of the COI gene. For the detection of predation, specific primers were designed for these most common pests in corn, and PCR reactions were performed with the intestinal contents of predators to detect the presence of pest DNA. Bioassays were done to identify the half-life of prey DNA in the gut of predators. To evaluate the impact of different farming systems on the food web, predators collected in dry pitfall traps and manual collection were used. DNA from the intestinal contents was extracted and then the Amplicon libraries were prepared for metabarcoding, and the sequences edited and compared with the sequences available at the NCBI by bioinformatics. The primers designed for Spodoptera frugiperda and Diabrotica speciose were efficient in prey amplification. It was possible to detect in the field the presence of predation by Coccinellidae and Doru luteipes on S. frugiperda. With metabarcoding it was possible to detect predation events in insects of no economic importance and only one species of agricultural pest. Intraguild predation events were detected mainly from Tachinidae in Harmonia axyridis and among coccinellids. Molecular tools are important to elucidate trophic interactions, allowing us to understand how species interact in the field. In addition, results such as those found here can help in future biological control work and also in integrated pest management.

Using sown groundcovers as trap crops to protect a cash crop is a traditional pest management tool. Pistachio is a major crop in California’s Central Valley, where high summer temperatures and little to no precipitation between May and November lead to summer dry-down of annual groundcover. Hemipteran pests that consist of ‘small bugs’ and ‘large bugs’ are a major contributor to nut damage, especially in organic production. In this 2-year field study, we tested the use of irrigated trap crop mixtures, sown between tree rows, to reduce those hemipteran pests’ abundance or damage. Biweekly beat samples of the tree canopy and sweep samples of the sown groundcovers in trap crop plots and resident weedy vegetation in control plots were taken over two consecutive growing seasons. Arthropod richness and abundance were highest in the groundcover and tree canopy in the trap crop plots. Small and large bug pest populations were higher and lower, respectively, in the tree canopy in trap crop plots, indicating a mixed response of these hemipterans to the presence of the trap crops. Additionally, natural enemy populations were more abundant in the tree canopy in trap crop plots than in control plots. There was no difference in nut damage between plots with and without the trap crop. These findings suggest that populations of hemipteran pests and beneficials can be manipulated successfully with irrigated trap crops, but future studies will need to focus on doing so in a way that decreases hemipteran pistachio damage.

Vegetable production by most farmers in the Philippines is highly dependent on pesticides. Pesticides are commonly applied before pest species are identified and intensity assessed. Current pesticide practice can lead to as many as 19 applications in 45 days per crop of pakchoi. The integration of integrated pest management (IPM) into crop management strategies is prompted by our view that pesticide use is excessive and costly, can lead to reduced pesticide efficacy and to human health problems from consumption of vegetables with pesticide residue. We have therefore, embarked upon a program among vegetable growers to demonstrate that pest identification, monitoring of pest intensity, and judicious use of effective pesticides can be combined into a holistic strategy of crop management. For this purpose a series of IPM training materials was developed. The majority of farmers attending farmer field schools assessed the IPM materials as very useful. Prior to being trained in IPM, farmers used 300 % the amount of insecticide but only 68% of the fungicide amount than researchers who followed IPM guidelines. Use of fungicides increased because training made them aware of the damage caused by pathogens which had previously been ignored. Pesticide residue was detected in 7 of 9 field samples. In two, the amount detected exceeded maximum residue levels (MRL) established by ASEAN for Chlorpyrifos and in one sample the amount exceeded the MRL for Cypermethrin. The results are critically discussed in regard to the implementation of IPM materials.

Simple SummaryThe leaffooted plant bug, Leptoglossus zonatus, is widely distributed in the Western Hemisphere. In California, two lineages (strains) occur. One lineage is known from California, and the second is found in California and Brazil. Although this species has been in California since 1900, it has become a pest in almonds in the last decade. It is possible that a cryptic species or strain has been introduced. This study investigated the distribution of the two lineages (strains) of L. zonatus in the Western Hemisphere. Specimens from the Leptoglossus collection in the national insect collection in Mexico were used to extract DNA and sequence the mitochondrial DNA cytochrome oxidase I gene. These sequences were combined with others in Genbank from California and South America to determine the strain distributions. The first strain occurred in California and Mexico, while the second was widespread from California into South America. When all samples were combined, there was overall low genetic diversity. The small number of genetic types (haplotypes), the range expansion, and the economic pest status of L. zonatus in California, suggest this insect is a potentially invasive insect pest.The leaffooted plant bug, Leptoglossus zonatus (Dallas) (Hemiptera: Coreidae) is polyphagous and widely distributed in the Western Hemisphere. Although it has been recorded in California since around 1900, it has become a more common pest in almonds in the last decade. Other studies have shown that an established insect can become a pest when a new genotype is introduced. This study investigated the distribution of two lineages (strains) of L. zonatus in the Western Hemisphere. Specimens from the Leptoglossus collection in the national insect collection in Mexico were used to extract DNA and sequence the mitochondrial DNA cytochrome oxidase I (mtDNA COI) gene, for use in population genetic and phylogenetic analyses. New sequences from Mexico, Central and South America were combined with those available in GenBank, from California and Brazil. Two lineages (strains) of L. zonatus were uncovered. One lineage occurs in California, Mexico and Ecuador. The second lineage is more widespread and found in California, Mexico, Guatemala, Nicaragua, Bolivia and Brazil. The haplotype number and diversity, and nucleotide diversity, were found for samples from California, Mexico, and Brazil, for the two lineages, and for all 118 sequences combined. All sequences combined produced five haplotypes, and a haplotype diversity of 0.54. California and Brazil had 3 haplotypes each, with one haplotype shared (5 total). Haplotype diversity in California and in Brazil were 0.526 and 0.505, respectively. A haplotype network found that one haplotype was most abundant and widespread. The small number of haplotypes, a range expansion, and economic pest status of L. zonatus in California, all contribute to this insect being a potentially invasive insect pest.

Integrated pest management (IPM) is an educated and systematic effort to use multiple control techniques to reduce pest damage to economically acceptable levels while minimizing negative environmental impacts. Although its benefits are widely acknowledged, IPM is not universally practiced by farmers. Potato farming, which produces one of the most important staple crops in the world, provides a good illustration of the issues surrounding IPM adoption. Potatoes are attacked by a complex of insect pests that can inflict catastrophic crop losses. Potato production has gone through the processes of consolidation and intensification, which are linked to increased pest problems, particularly selection for insecticide-resistant pest populations. While use of insecticides remains the most common method of pest control in potatoes, other techniques, including crop rotation and natural enemies, are also available. In addition, there are effective monitoring techniques for many potato pests. However, reliable economic thresholds are often lacking. Potato ecosystems are complex and diverse; therefore, the knowledge necessary for developing ecologically based pest management is not easily obtained or transferable. Furthermore, potato systems change with the arrival of new pest species and the evolution of existing pests. Modern technological advances, such as remote sensing and molecular biotechnology, are likely to improve potato IPM. However, these tools are not going to solve all problems. IPM is not just about integrating different techniques; it is also about integrating the efforts and concerns of all stakeholders. The collaboration of farmers and scientists in agricultural research is needed to foster the development of IPM systems that are appropriate for grower implementation and thus more likely to be adopted. Additional emphasis also needs to be placed on the fact that not only does IPM decrease degradation of the environment, but it also improves the economic well-being of its practitioners.

The capacity to lay eggs inside healthy fruits rather than on decaying plant matter differentiates insect fruit pests from domestic species. This niche differentiation has been previously proposed to be an adaptation to avoid competition. We hypothesize that pest species will be more strongly affected by competition. We compare the impact of larvae density on fitness traits between Drosophila pests ( Drosophila suzukii (Matsumura, 1931); Zaprionus indianus Gupta, 1970) and domestic species ( Drosophila immigrans Sturtevant, 1921; Drosophila melanogaster Meigen, 1830). We assessed the effect of crowding on adult emergence and development time. Viability decreased gradually with density for D. immigrans and D. suzukii, while for D. melanogaster and Z. indianus it remained high. Development time increased with density; this was stronger on Z. indianus and D. immigrans than on D. suzukii, which had a moderate increase, and D. melanogaster, which did not change. Contrary to expectations, the distinct patterns observed were not related to each species' domestic or pest lifestyle. In fact, patterns consistent with either scramble or contest type of competition were observed on both pest and domestic species, respectively. These findings challenge prior beliefs regarding competition effects among Drosophila pest species and provide information relevant to integrated pest management.