Control Of Agricultural Pests Research Articles

Effect of faba bean nectar on longevity and fecundity of Plutella xylostella and its parasitoid Cotesia vestalis

AbstractIntercropping faba bean with vegetables provides a possibility to promote pest control and better nutrient cycling in sustainable agriculture. Faba bean produces extrafloral nectar which supports parasitoid wasps that play a role in the biological control of pest insects. However, adult lepidopteran pests also benefit from nectar, increasing their lifespan and the number of offspring they produce. Here, a laboratory-based study was conducted to assess the role of faba bean on the components of a Brassica-based host-parasitoid system. We measured how access to faba bean affected the longevity and fecundity of the brassica pest Plutella xylostella and its parasitoid Cotesia vestalis. It was also studied if odors of flowering faba bean disrupt host finding by C. vestalis in Y-tube bioassays and volatile organic compounds were analyzed to explain the olfaction-based choices made by the parasitoids. The longevity of C. vestalis was 6.6 times longer and the number of pupae produced almost 10 times greater when they had access to faba bean. Meanwhile, the longevity of P. xylostella was 3.6 times longer and it laid 4.6 times more eggs when provided access to faba bean. In Y-tube bioassays, C. vestalis females also oriented toward host-related odors of the damaged cabbage more than intact cabbage when odors of faba bean were mixed with both of them. In conclusion, faba bean provided sustenance to both pest insects and their natural enemies that prolonged their lifespans and their reproductive capacity.

Assessment of the Entomopathogenic Potential of Fungal and Bacterial Isolates from Fall Armyworm Cadavers Against Spodoptera frugiperda Caterpillars and the Adult Boll Weevil, Anthonomus grandis.

Increased attention is being focused on the biological control of agricultural pests using microorganisms, owing to their potential as a viable substitute for chemical control methods. Insect cadavers constitute a potential source of entomopathogenic microorganisms. We tested whether bacteria and fungi isolated from Spodoptera frugiperda (JE Smith) cadavers could affect its survival, development, egg-laying pattern, and hatchability, as well as induce mortality in Anthonomus grandis Boheman adults. We isolated the bacteria Enterobacter hormaechei and Serratia marcescens and the fungi Scopulariopsis sp. and Aspergillus nomiae from fall armyworm cadavers and the pest insects were subjected to an artificial diet enriched with bacteria cells or fungal spores to be tested, in the case of S. frugiperda, and only fungal spores in the case of A. grandis. Enterobacter hormaechei and A. nomiae were pathogenic to S. frugiperda, affecting the survival of adults and pupae. The fungus Scopulariopsis sp. does not affect the survival of S. frugiperda caterpillars and pupae; however, due to late action, moths and eggs may be affected. Aspergillus nomiae also increased mortality of A. grandis adults, as well as the development of S. frugiperda in the early stages of exposure to the diet, as indicated by the vertical spore transfer to offspring and low hatchability. Enterobacter hormaechei and A. nomiae are potential biocontrol agents for these pests, and warrant further investigation from a toxicological point of view and subsequently in field tests involving formulations that could improve agricultural sustainability practices.

Baccharis essential oils from the Atlantic Forest as sources of natural pesticides

Substances derived from bioactive plants of the Atlantic Forest can potentially be used for agricultural pest control, with fewer environmental consequences than other measures. Baccharis species present several biological properties, including insecticidal action. The present study aimed to characterize and evaluate the insecticidal activity of the following essential oils (EOs) obtained from native species of the Atlantic Forest: Baccharis articulata (Lam.) Pers., Baccharis calvescens DC., and Baccharis milleflora (Less.) DC. (Asteraceae), the last two of which are endemic to Brazil. EOs were obtained by steam extraction in a vat for 3 h, and the constituents were identified by gas chromatography coupled to mass spectrometry (GC/MS). Insecticidal activity was evaluated against Anticarsia gemmatalis, Sitophilus oryzae, Sitophilus zeamais, and Lucilia cuprina. A total of 7, 16, and 27 compounds were identified in EO samples from B. articulata, B. calvescens, and B. milleflora, respectively. All EOs caused 100 % mortality to A. gemmatalis, and 76.67 %, 98.33 %, and 95 % mortality to L. cuprina using EOs of B. milleflora, B. calvescens, and B. articulata, respectively. Only B. articulata caused mortality greater than 80 % to S. zeamais (83.88 %) and S. oryzae (86.03 %) by fumigation. The present study provides information on the use of EOs from Baccharis species as natural alternative substances to chemical pesticides, contributing to more sustainable production in Brazilian agriculture.

Efficiency of Citrus limon L. Ripe Peel Extract In The Control of Raoiella indica (HIRST, 1924) (Prostigmata: Tenuipalpidae)

Purpose: This study aimed to evaluate the acaricidal potential of the aqueous extract obtained from the ripe peels of Citrus limon on adults of Raoiella indica. Theoretical Reference: R. indica is a phytophagous mite that primarily attacks plants of the Arecaceae family. As it is considered a relatively new pest in Brazil, there are few control methods available, with synthetic chemical control being the primary one. Method: The ripe peels of C. limon were dried and ground into a fine powder, which was used to formulate extract concentrations of 0.00, 1.00, 1.64, 2.70, 4.44, 7.30, and 12.00%. The extracts were sprayed on 12 adult females of R. indica per experimental unit, with 7 repetitions for each concentration. Mortality was assessed at 24, 48, and 72 hours after spraying. Results and Conclusion: The mortality of R. indica increased as the concentrations of the ripe peel extract of C. limon increased, reaching 88% for the highest concentration after 72 hours of application. Research Implications: The aqueous extract of ripe peels of C. limon demonstrated acaricidal efficiency against R. indica under controlled conditions. Originality/Value: This work adds value to the study of alternative methods of agricultural pest control, as a means of promoting more economically and ecologically sustainable management.

Polymorphic Clustering and Approximate Masking Framework for Fine-Grained Insect Image Classification

Insect diversity monitoring is crucial for biological pest control in agriculture and forestry. Modern monitoring of insect species relies heavily on fine-grained image classification models. Fine-grained image classification faces challenges such as small inter-class differences and large intra-class variances, which are even more pronounced in insect scenes where insect species often exhibit significant morphological differences across multiple life stages. To address these challenges, we introduce segmentation and clustering operations into the image classification task and design a novel network model training framework for fine-grained classification of insect images using multi-modality clustering and approximate mask methods, named PCAM-Frame. In the first stage of the framework, we adopt the Polymorphic Clustering Module, and segmentation and clustering operations are employed to distinguish various morphologies of insects at different life stages, allowing the model to differentiate between samples at different life stages during training. The second stage consists of a feature extraction network, called Basenet, which can be any mainstream network that performs well in fine-grained image classification tasks, aiming to provide pre-classification confidence for the next stage. In the third stage, we apply the Approximate Masking Module to mask the common attention regions of the most likely classes and continuously adjust the convergence direction of the model during training using a Deviation Loss function. We apply PCAM-Frame with multiple classification networks as the Basenet in the second stage and conduct extensive experiments on the Insecta dataset of iNaturalist 2017 and IP102 dataset, achieving improvements of 2.2% and 1.4%, respectively. Generalization experiments on other fine-grained image classification datasets such as CUB200-2011 and Stanford Dogs also demonstrate positive effects. These experiments validate the pertinence and effectiveness of our framework PCAM-Frame in fine-grained image classification tasks under complex conditions, particularly in insect scenes.

An Overview of the Mechanisms of Action and Administration Technologies of the Essential Oils Used as Green Insecticides

The need to use environmentally friendly substances in agriculture for pest control has become increasingly urgent in recent years. This was generated by humanity’s awareness of the harmful effects of chemicals with increased persistence, which accumulated in nature and harmed living beings. Essential oils are among the most important biopesticides and could significantly contribute to the expansion of ecological agriculture, replacing traditional methods. However, for judicious use, it is necessary to have a thorough knowledge of the mechanisms by which these oils act on both harmful and useful insects. An important step in transitioning from theory to practice is adapting essential oil application technologies for open fields, overcoming the difficulties created by their high volatility and low remanence, which results in a rapid reduction in the toxic effect. The review proposes an in-depth, up-to-date analysis of the existing literature on these subjects, aiming to provide researchers with some potential future study directions and practitioners with a solid base of information regarding the interaction between insects and essential oils.

Harmony and Sustainability: Traditional Ecological Knowledge Systems of the Kaluppini Indigenous People

The existence of knowledge of local indigenous local knowledge in natural resource management has experienced a shift. This research aims to reveal the forms of wise tought of the natural environment by the Kaluppini indigenous people, and to reveal how the Kaluppini community maintains the ecological knowledge systems. This research used ethnographic methods. It is a qualitative research procedure for describing, analyzing, and interpreting elements of a cultural group such as behavior patterns, beliefs, and language that develop over time. Data analysis techniques are processed. The collected data was analyzed by using Berkes' theory (1980). The research results show that the Kaluppini indigenous people maintain their traditional ecological knowledge from time time. First, traditional institutions which include the role of traditional stakeholders along with the legal system and rules for implementing traditional rituals, play a core role in maintaining harmony between society and the environment. Second, ethical land management in the form of traditional agricultural methods, pest and disease control, crop rotation systems, selection of plant varieties, and efficient irrigation systems support agricultural sustainability. Third, the existence of myths related to nature produces a respectful attitude towards the surrounding natural environment. Finally, the implementation of zoning reflects a wise policy to conserve natural resources while meeting community needs. It is important to recognize that most regions in Indonesia are currently facing serious challenges in the form of the climate crisis, including the phenomenon of long droughts that threaten agricultural activities and daily life. However, the Kaluppini community stands out as a unique example amidst this changing climate.

The impact of resource limitation on the pest-natural enemy ecosystem with anti-predator behavior and fear effect

Research on agricultural pest control data indicates that the actual effectiveness of insecticides may exhibit slight variations, influenced by factors such as the type and quantity of pests. Additionally, the development of resistance by pests, as a result of adaptation to the environment, can impact the precision of pest control strategies. Hence we suggest implementing a nonlinear pulse state-dependent feedback control system, considering resource limitations, to investigate the influence of varying pesticide fatality rates on pest outbreaks. This paper takes into account the fear effect and anti-predator behavior to accurately portray the farmland ecosystem. We assessed the phase set and Poincaré map under the conditions for the existence of order-k (where k=1,2,3\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$k=1,2,3$\\end{document}) periodic solutions and examined their stability behavior. Remarkably, the system exhibited diverse bifurcation phenomena associated with pesticide-related parameters. Furthermore, the system demonstrated a multistability phenomenon involving the coexistence of the order-1 periodic solution and the limit cycle. This suggests that altering control strategies can disturb the initial coexistence status of pests and natural enemies. It also underscores that resource limitations can indeed impact the outbreak patterns and frequencies of pests. In addition to the variability in pesticide fatality rates, the inclusion of natural enemy releases in the nonlinear pulse strategy contributes to the model exhibiting complex dynamic characteristics. All these findings are substantiated by numerical simulations.

The Bombyx mori singed Gene Is Involved in the High-Temperature Resistance of Silkworms.

Temperature is an important factor in the growth, development, survival, and reproduction of organisms. The high-temperature resistance mechanism of insects may be significant for use in the prevention and control of insect pests. The silkworm, Bombyx mori, is an important Lepidoptera model species for studies on pest control in agriculture and forestry. We identified a gene in B. mori, the B. mori singed (Bmsn) gene, which is involved in the high-temperature resistance of silkworms. Sn proteins are highly conserved among species in many taxonomic groups. The overexpression of the Bmsn gene promoted the proliferation of silkworm cells, reduced oxidation, and reduced the accumulation of reactive oxygen species under stress. Interfering with the Bmsn gene had the opposite result. We constructed a transgenic B. mori strain that overexpressed the Bmsn gene. The physiological traits of the transgenic strain were significantly improved, and it had stronger high-temperature resistance. The Bmsn gene is involved in the process by which fat bodies respond to high-temperature stress. These findings provide insights into the mechanism of high-temperature resistance of insects and offer a new perspective on agricultural and forestry pest control.

Bioactivity of Plant Nanoemulsions against Stored-Product Insects (Order Coleoptera): A Review1

Abstract As the risks arising from the use of chemical pesticides increase, researchers are continuously exploring alternatives that are safer for humans and the environment. Among these alternatives is the use of plant extracts; however, plant extracts have various disadvantages, including the instability of their compounds that evaporate with time, thereby reducing their effectiveness. With the development of nanotechnology and its applications, researchers are focused on testing the performance of plant-based nanocomposites for eliminating pests. Numerous issues with agricultural and insect pest control can be addressed by using nanotechnology, including increasing the physical stability, water dispersion, and bioavailability of oil emulsions and coating the desired surface area with small oil droplets. Thus, issues with essential oil application, such as volatility, low water solubility, and oxidation, can be resolved by using nanoformulations. These nanoformulations progressively release active ingredients on site, reducing the toxicity for nontarget species and demonstrating their potential as substitutes for synthetic pesticides in the management of stored-grain pests. Research on nanoemulsions from plant sources and their role in controlling stored-product coleopteran insects was reviewed with emphasis on articles from 2014 through 2023. This review compiles important data for this field of research, providing information for design of future studies.

Genetic differentiation and phylogeography of Erythroneurini (Hemiptera, Cicadellidae, Typhlocybinae) in the southwestern karst area of China.

Erythroneurini is the largest tribe of the microleafhopper subfamily Typhlocybinae. Most prior research on this tribe has focused on traditional classification, phylogeny, and control of agricultural pests, and the phylogeography of the group remains poorly understood. In this study, the mitochondrial genomes of 10 erythroneurine species were sequenced, and sequences of four genes were obtained for 12 geographical populations of Seriana bacilla. The new sequence data were combined with previously available mitochondrial DNA sequence data and analyzed using Bayesian and Maximum-Likelihood-based phylogenetic methods to elucidate relationships among genera and species and estimate divergence times. Seriana was shown to be derived from within Empoascanara. Phylogeographic and population genetic analysis of the endemic Chinese species Seriana bacilla suggest that the species diverged about 54.85 Mya (95% HPD: 20.76-66.23 million years) in the Paleogene period and that population divergence occurred within the last 14 million years. Ancestral area reconstruction indicates that Seriana bacilla may have originated in the central region of Guizhou, and geographical barriers are the main factors affecting gene flow among populations. Ecological niche modeling using the MaxEnt model suggests that the distribution of the species was more restricted in the past but is likely to expand in the future years 2050 and 2070.

The Impact of Neocidol on Hematological Parameters in Swiss Albino Mice

Neocidol, containing Diazinon, stands as a prevalent compound in the fields of plant protection and insect control for public health. Despite its historical prominence, Neocidol, classified as a non-systemic organophosphate, exerts its effects by inhibiting cholinesterase, a pivotal enzyme in nerve transmission. In light of the widespread use of Neocidol in Libya and the absence of local studies, this research endeavors to assess its impact on blood parameters and the biochemistry of female white mice. The study involves prolonged tests wherein a sublethal concentration of 15 µl Neocidol per kg of body weight is introduced through the mice's drinking water. Toxicity assessments reveal noteworthy distinctions in various blood parameters between treated and untreated mice. Treated mice exhibit elevated leukocyte and erythrocyte values, coupled with diminished MCHC and MCV values. While blood chemistry results generally align between the control and treatment groups, an exception is observed in the form of heightened Alk-phosphatase values in treated mice. In summary, despite Neocidol's historical favorability in agricultural and public health pest control, this study underscores emerging criticisms concerning its identified health and environmental implications.

Occurrence of Stenopoda spinulosa Giacchi, 1969 (Hemiptera, Reduviidae, Stenopodainae) in Brazil

The Reduviidae family is economically important, as many species are used in the biological control of agricultural pests. Many species in the Stenopodainae subfamily are endemic to tropical forests, and some smear their front paws with sticky plant-derived resin to help capture prey. The genus Stenopoda Laporte, 1833, has 14 species in Brazil. Stenopoda spinulosa Giacchi, 1969 (Reduviidae: Stenopodainae) has so far only been reported for the State of Rio Grande do Sul. They have wings that serve to protect the second pair of membranous wings and the body against crushing shocks. They are characterized by rigidity close to the notch of the wing and, at the same time, by the membranous region at the tip of the wing in the distal region. Their bite can cause edema, allergies, pain, and inflammation. To collect insects, a sweeping net or entomological net was used in shrubs and grasses. The objective of this study is to report the first occurrence of S. spinulosa in the State of Goiás, Brazil.

Knockdown of MAPK p38-linked genes increases the susceptibility of Chilo suppressalis larvae to various transgenic Bt rice lines

Bacillus thuringiensis (Bt) toxins have provided exceptional control of agricultural insect pests, however, over reliance on the proteins would potentially contribute to the development of field tolerance. Developing new sustainable insect pest control methods that target the mechanisms underlying Bt tolerance can potentially support the Bt control paradigm while also providing insights into basic insect physiology. The MAPK p38 pathway is strongly associated with Bt tolerance in Chilo suppressalis, a major pest of rice. To gain insights into how this pathway impacts tolerance, high-throughput screening of C. suppressalis larval midguts initially identified eight novel target genes. Increased larval sensitivity to the transgenic cry1Ca rice strain T1C-19 was observed following RNA interference-mediated knockdown of four of the genes, Cscnc, Csgcp, Cszfp26 and CsZMYM1. Similar enhanced sensitivity to the TT51 (expressing Cry1Ab/1Ac) and T2A-1 (expressing Cry2Aa) transgenic rice lines occurred when Cszfp26 and CsZMYM1 were knocked down. All four target genes are downstream of the MAPK p38 pathway but do not participate in negative feedback loop of the pathway. These results implicate Cscnc, Csgcp, Cszfp and CsZMYM1 in the C. suppressalis transgenic cry1Ca rice tolerance mechanism regulated by MAPK p38. These findings further enhance our understanding of the MAPK p38-dependent molecular mechanisms underlying Bt tolerance in C. suppressalis and open new avenues of tolerance management to develop.

Effect of agricultural intensification on the genetic diversity of Helicoverpa armigera

AbstractAgricultural intensification affects natural and crop ecosystems, and increases the risk of agricultural pests in agroecosystems. Helicoverpa armigera Hübner (Lepidoptera: Noctuidae) is an important pest that damages a wide range of crops. However, the effect of agricultural intensification on the genetic diversity of this pest is still unclear. In this study, we investigated the effects of the composition and configuration of the landscape on the genetic diversity of the agricultural pest H. armigera based on cytochrome oxidase subunit I (COI) analyses. In total, 10 haplotypes were found in 2016 and 15 haplotypes in 2021 based on COI genes. The haplotype diversity and nucleotide diversity were the highest in the Anqiu (AQ) region during 2016 and in the Bincheng (BC) region during 2021. Haplotype 2 and haplotype 3 (Hap2 and Hap3) were the dominant haplotypes in the H. armigera population. Agricultural intensification had no effect on the genetic diversity of H. armigera between 2016 and 2021. Our study highlights the effect of agricultural intensification on the genetic diversity of H. armigera. Understanding the genetic consequences of agricultural intensification is essential for the green control of agricultural pests and the sustainable development of agriculture.

Bazı entomopatojen nematodların etkinliğinde kuraklığın rolü

Entomopathogenic nematodes (EPNs) are endoparasitic organisms commonly used in the control of agricultural pests. There are several factors that determine the efficacy of EPNs on hosts, with one of the most significant being soil moisture. The aim of this study is to determine the effectiveness of some EPNs on hosts at different doses and under different soil moisture conditions. The study utilized 1 Hybrid Strain and 3 EPN isolates, Heterorhabditis bacteriophora Poinar, 1976 (Rhabditida: Heterorhabditidae) HBH hybrid strain, Steinernema carpocapsae Weiser, 1955 TUR-S4 isolate, and Steinernema feltiae Weiser, 1955 (Rhabditida: Steinernematidae) TUR-S3 and S-Bilecik isolates. These species were applied to Tenebrio molitor L., 1758 (Coleoptera: Tenebrionidae) larvae at 5, 10, and 15 Infective Juveniles (IJs) doses, under 1, 4, 7, 10, and 13% soil moisture conditions. The study was conducted in 2024 at Bursa Uludağ University, Faculty of Agriculture, Department of Plant Protection, Nematology Laboratory. As a result, the highest mortality rates on T. molitor larvae were obtained at 13% soil moisture with 15 IJs, 100% for HBH, 93.33% for TUR-S4, 86.67% for TUR-S3, and 83.33% for S-Bilecik. This study carries important implications for understanding the relationship between EPN efficacy on hosts and soil moisture.

Toxicity of agrochemicals: Impact on environment and human health

Agrochemicals, while essential for increasing agricultural yields and pest control, have unintended consequences. They contaminate soil and water, disrupting ecosystems, reducing biodiversity, and threatening aquatic life. Furthermore, agrochemicals harm non-target organisms, disrupting ecological balance. On the human health front, farmworkers and pesticide applicators face acute poisoning risks, with symptoms ranging from discomfort to severe illness or death. Chronic health effects include links to cancer, neurological disorders, and reproductive problems, raising concerns about food safety and worker well-being. Addressing agrochemical toxicity requires a multifaceted approach. Governments must enforce strict regulations to minimize environmental contamination and ensure safe handling practices. The agricultural industry can adopt sustainable methods like integrated pest management (IPM) and organic farming to reduce reliance on agrochemicals. Innovations such as precision agriculture, biological pest control, nanotechnology, and artificial intelligence for early risk detection are essential. Collaboration among stakeholders is critical for a more sustainable and environmentally friendly agriculture sector, involving regulatory measures like maximum residue limits (MRLs) and sustainable practices like IPM and organic farming. In summary, this review highlights the urgent need to address agrochemical toxicity holistically, balancing agricultural productivity with environmental and health concerns to ensure a sustainable future for agriculture and the planet.

IPM Essentials: Combining Biology, Ecology, and Agriculture for Sustainable Pest Control

Integrated Pest Management (IPM) represents a paradigm shift in pest control, moving away from heavy reliance on chemical pesticides to a more sustainable, environmentally friendly approach. This article explores IPM, an ecosystem based strategy that integrates biological, ecological, and agricultural sciences to achieve longterm pest control in agriculture. IPM emphasizes understanding pest life cycles and their interaction with the environment, utilizing a combination of techniques including biological control, cultural practices, mechanical and physical barriers, and targeted chemical interventions. Regular monitoring and informed decision making form the crux of this approach, focusing on economically viable and environmentally responsible pest control methods. The article highlights various success stories, the challenges faced in implementing IPM, and future directions including the incorporation of precision agriculture technologies and genetic advancements. Overall, IPM emerges as a crucial element in sustainable agriculture, promising to maintain ecological balance while ensuring effective pest management and provides an in depth examination of Integrated Pest Management (IPM), a multifaceted approach to sustainable pest control that synergizes biology, ecology, and agricultural science. IPM represents a paradigm shift from traditional, chemically intensive pest control methods to a more holistic, environmentally conscious framework. The core of IPM lies in understanding the life cycles and ecological interactions of pests, employing a diverse array of strategies including biological control through natural predators, cultural practices like crop rotation, mechanical and physical barriers, and judicious use of chemical pesticides. The article underscores the importance of regular monitoring and decision making based on established thresholds to maintain an effective, economically viable, and ecologically responsible pest management system. Case studies highlighting the successful implementation of IPM in various agricultural settings are discussed, alongside the challenges and prospects of IPM, particularly in the context of climate change and technological advancements. The article concludes that IPM is not only essential for sustainable pest control but also pivotal in ensuring long term agricultural productivity and environmental health.

Identification and RNAi-based function analysis of trehalase family genes in Frankliniella occidentalis (Pergande).

Insects utilize trehalases (TREs) to regulate energy metabolism and chitin biosynthesis, which are essential for their growth, development, and reproduction. TREs can therefore be used as potential targets for future insecticide development. However, the roles of TREs in Frankliniella occidentalis (Pergande), a serious widespread agricultural pest, remain unclear. Three TRE genes were identified in F. occidentalis and cloned, and their functions were then investigated via feeding RNA interference (RNAi) and virus-induced gene silencing (VIGS) assays. The results showed that silencing FoTRE1-1 or FoTRE1-2 significantly decreased expression levels of FoGFAT, FoPGM, FoUAP, and FoCHS, which are members of the chitin biosynthesis pathway. Silencing FoTRE1-1 or FoTRE2 significantly down-regulated FoPFK and FoPK, which are members of the energy metabolism pathway. These changes resulted in 2-fold decreases in glucose and glycogen content, 2-fold increases in trehalose content, and 1.5- to 2.0-fold decreases in chitinase activity. Furthermore, knocking down FoTRE1-1 or FoTRE1-2 resulted in deformed nymphs and pupae as a result of hindered molting. The VIGS assay for the three FoTREs revealed that FoTRE1-1 or FoTRE2 caused shortened ovarioles, and reduced egg-laying and hatching rates. The results suggest that FoTRE1-1 and FoTRE1-2 play important roles in the growth and development of F. occidentalis, while FoTRE1-1 and FoTRE2 are essential for its reproduction. These three genes could be candidate targets for RNAi-based management and control of this destructive agricultural pest. © 2024 Society of Chemical Industry.

Effect of Guanylate Cyclase-22-like on Ovarian Development of Orius nagaii (Hemiptera: Anthocoridae).

This study identified and characterized the gene encoding recep tor-type guanylate cyclase-22-like (GCY-22; OnGCY) from the pirate bug Orius nagaii, an important biological control agent. The full-length cDNA of the GCY of O. nagaii was obtained by rapid amplification of cDNA ends (RACE); it had a total length of 4888 base pairs (bp), of which the open reading frame (ORF) was 3750 bp, encoding a polypeptide of 1249 amino acid residues. The physicochemical properties of OnGCY were predicted and analyzed by using relevant ExPASy software, revealing a molecular formula of C6502H10122N1698O1869S57, molecular weight of ~143,811.57 kDa, isoelectric point of 6.55, and fat index of 90.04. The resulting protein was also shown to have a signal peptide, two transmembrane regions, and a conserved tyrosine kinase (tyrkc). Silencing OnGCY by RNA interference significantly inhibited ovarian development and decreased fertility in female O. nagaii in the treated versus the control group. Additionally, OnGCY silencing significantly decreased the expression levels of other GCY and Vg genes. Thus, these results clarify the structure and biological function of OnGCY, which has an important role in insect fecundity. The results also provide a reference for agricultural pest control and future large-scale breeding of biological control agents.