Search

With the loss of effective chemical controls of crop pests, a move towards biological controls is a way to future‐proof our agricultural system. Floral field margins have shown successes in reducing crop pests, though the effect may not be precise enough to control infestations in commercial crops. Entomopathogenic nematodes (EPNs) may provide a more species‐ and time‐specific control and combining these methods may have synergy.Three in‐field vegetation margins, divided into four plots each (two floral and two grass), were established in March 2022. Three strips of sprouting broccoli were planted parallel in April, May and June. Each strip had a split‐plot design, with eight replicates of four nematode treatments placed alongside each floral/grass plot: Steinernema carpocapsae, S. feltiae and Heterorhabditis bacteriophora and a nematode‐free control.Pest pressure was assessed using adult counts. Assessments of crop yield and crop damage associated specifically with the swede smidge (Contarinia nasturtii) were also made.It was found that utilising a combination of control measures was successful in controlling a wider range of pests, though the success of each control method was highly dependent on the time of crop plantings. Field margins had a significant influence on crop damage associated with the swede midge. The EPN H. bacteriophora was an effective control method for the cabbage stem flea beetle and the swede midge, as well as reducing crop damage and yield loss.Field margins and EPNs combined have an interactive effect on crop yield, highlighting the need for control methods to be tested in combination in future integrated pest management research to accurately understand their effects within an integrated system. [ABSTRACT FROM AUTHOR]

Beauveria bassiana is an entomopathogenic fungus that has been shown to have the potential to control the potato white grub (Premnotrypes vorax), a pest that significantly affects potato production, especially in Ecuador. Therefore, the present study has focused on evaluating the effectiveness of Beauveria bassiana in the control of the potato white grub under laboratory conditions. To this end, neutrosophic statistics have been used to analyze larval mortality, by applying concentrations of and conidia of Beauveria bassiana by spraying and immersion. Among the results, it was determined that treatment at a concentration of 108 conidia per spray has proven to be the best option, with a neutrosophic coding from very effective to extremely effective in mortality in larvae. In conclusion, neutrosophic analysis has shown that Beauveria bassiana is effective in controlling white grub, especially with high concentrations and spraying. [ABSTRACT FROM AUTHOR]

Bioinformatics sequence data mining can reveal hidden microbial symbionts that might normally be filtered and removed as contaminants. Data mining can be helpful to detect Wolbachia, a widespread bacterial endosymbiont in insects and filarial nematodes whose distribution in plant-parasitic nematodes (PPNs) remains underexplored. To date, Wolbachia has only been reported a few PPNs, yet nematode-infecting Wolbachia may have been widespread in the evolutionary history of the phylum based on evidence of horizontal gene transfers, suggesting there may be undiscovered Wolbachia infections in PPNs. The goal of this study was to more broadly sample PPN Wolbachia strains in tylenchid nematodes to enable further comparative genomic analyses that may reveal Wolbachia’s role and identify targets for biocontrol. Published whole-genome shotgun assemblies and their raw sequence data from 33 Meloidogyne spp. assemblies, seven Globodera spp. assemblies, and seven Heterodera spp. assemblies were analyzed to look for Wolbachia. No Wolbachia was found in Meloidogyne spp. and Globodera spp., but among seven genome assemblies for Heterodera spp., an H. schachtii assembly from the Netherlands was found to have a large Wolbachia-like sequence that, when re-assembled from reads, formed a complete, circular genome. Detailed analyses comparing read coverage, GC content, pseudogenes, and phylogenomic patterns clearly demonstrated that the H. schachtii Wolbachia represented a novel strain (hereafter, denoted wHet). Phylogenomic tree construction with PhyloBayes showed wHet was most closely related to another PPN Wolbachia, wTex, while 16S rRNA gene analysis showed it clustered with other Heterodera Wolbachia assembled from sequence databases. Pseudogenes in wHet suggested relatedness to the PPN clade, as did the lack of significantly enriched GO terms compared to PPN Wolbachia strains. It remains unclear whether the lack of Wolbachia in other published H. schachtii isolates represents the true absence of the endosymbiont from some hosts. [ABSTRACT FROM AUTHOR]

ABSTRACT Plants can perceive and respond to external stimuli by activating both direct and indirect defences against herbivores. Soil‐dwelling entomopathogenic nematodes (EPNs), natural enemies of root‐feeding herbivores, carry symbiotic bacteria that grow and reproduce once inside arthropod hosts. We hypothesized that the metabolites produced by EPN‐infected insect cadavers could be perceived by plants, thereby activating plant defences systemically. We tested this hypothesis by adding three EPN‐infected Galleria mellonella cadavers to maize plants and testing plant responses against a major maize pest (Spodoptera frugiperda) and one of its parasitoids (Trichogramma dendrolimi). We found that S. frugiperda females deposited fewer, and caterpillars fed less on maize plants growing near EPN‐infected cadavers than on control plants. Accordingly, EPN‐infected cadavers triggered the systemic accumulation of defence hormones (SA), genes (PR1), and enzymes (SOD, POD, and CAT) in maize leaves. Furthermore, four volatile organic compounds produced by plants exposed to EPN‐infected cadavers deterred S. frugiperda caterpillars and female adults. However, these compounds were more attractive to T. dendrolimi parasitoids. Our study enhances the understanding of the intricate relationships within the above‐ and belowground ecosystems and provides crucial insights for advancing sustainable pest management strategies. [ABSTRACT FROM AUTHOR]

Efficacy of two Indian isolates of entomopathogenic nematodes (EPNs) viz., Heterorhabditis bacteriophora MK256358 and Steinernema feltiae MK256355 were tested in laboratory against the larvae of cabbage butterfly, Pieris brassicae. Larval mortality was found directly proportional to initial inoculum level of infective juveniles (IJs). Susceptibility of larvae varied with respect to their variable size. H. bacteriophora MK256358 @ 25 IJs/larva caused 100% mortality to 3rd instar larvae at 72 h but @ 75 IJs/larva, the same mortality was achieved in 48 h. S. feltiae MK256355 @ 100 IJs/larva caused 100% mortality to 3rd instar larvae of P. brassicae at 48 h. H. bacteriophora MK256358 @ 25 and 100 IJs/larva resulted in 100% mortality to 4th and 5th instar larvae, respectively at 72 h, however S. feltiae MK256355 was unable to cause 100% mortality to either 4th or 5th instar larvae at any inoculum level or time period used in the study. LD50 and LT50 values of H. bacteriophora MK256358 were lower than S. feltiae MK256355 indicating that less nematode dose and time is required to kill 50% pest population. Reproduction capacity of nematode within the host was directly proportional to individual larval size and nematode inoculum level and for H. bacteriophora MK256358, it was higher and statistically significant (P ≤ 0.05) from S. feltiae MK256355. Our experimental findings open new avenues for utilization of EPNs against P. brassicae and set the basis for safe insect pest management programme. [ABSTRACT FROM AUTHOR]

BACKGROUND: Root‐knot nematodes (RKNs), Meloidogyne spp., are one of the most destructive polyphagous plant‐parasitic nematodes. They pose a serious threat to global food security and are difficult to control. Entomopathogenic nematodes (EPNs) show promise in controlling RKNs. However, it remains unclear whether the volatile organic compounds (VOCs) emitted from EPN‐infected cadavers can control RKNs. RESULTS: We investigated the fumigation activity of VOCs released from cadavers infected by five different species of EPNs on RKNs in Petri dishes, and found that VOCs released from Steinernema feltiae (SN strain) and S. carpocapsae (All strain) infected cadavers had a significant lethal effect on second‐stage juveniles (J2s) of Meloidogyne incognita. The VOCs released from the cadavers infected with S. feltiae were analyzed using SPME‐GC/MS. Dimethyl disulfide (DMDS), tetradecane, pentadecane, and butylated hydroxytoluene (BHT), were selected for a validation experiment with pure compounds. The DMDS compound had significant nematicidal activity and repelled J2s. DMDS also inhibited egg hatching and the invasion of tomato roots by J2s. In a pot experiment, the addition of S. feltiae‐infected cadavers and cadavers wrapped with a 400‐mesh nylon net also significantly reduced the population of RKNs in tomato roots after 7 days. The number of root knots and eggs was reduced by 58% and 74.34%, respectively, compared to the control. CONCLUSION: These results suggested that the VOCs emitted by the EPN‐infected cadavers affected various developmental stages of M. incognita and thus have the potential to be used in controlling RKNs through multiple methods. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Enterotoxigenic Escherichia coli (ETEC) is the major bacterial cause of diarrheal diseases in pigs, particularly at young ages, resulting in significant costs to swine farming. The pathogenicity of ETEC is largely dependent on the presence of fimbriae and the ability to produce toxins. Fimbriae are responsible for their initial adhesion to the intestinal epithelial cells, leading to the onset of infection. In particular, the F4 type (K88) fimbriae are often attributed to neonatal infections and have also been associated with post-weaning diarrheal infections. This disease is traditionally prevented or treated with antibiotics, but their use is being severely restricted due to the emergence of resistant bacteria and their impact on human health. Emerging approaches such as aptamers that target the F4-type fimbriae and block the initial ETEC adhesion are a promising alternative. The aim of this study is to assess the effectiveness of two aptamers, Apt31 and Apt37, in controlling ETEC infection in the G. mellonella in vivo model. Initially, the dissociation constant (KD) of each aptamer against ETEC was established using real-time quantitative PCR methodology. Subsequently, different concentrations of the aptamers were injected into Galleria mellonella to study their toxicity. Afterwards, the anti-ETEC potential of Apt31 and Apt37 was assessed in the larvae model. The determined KD was 81.79 nM (95% CI: 31.21-199.4 nM) and 50.71 nM (95% CI: 26.52-96.15 nM) for the Apt31 and Apt37, respectively, showing no statistical difference. No toxicity was observed in G. mellonella following injection with both aptamers at any concentration. However, the administration of Apt31 together with ETEC-F4+ in G. mellonella resulted in a significant improvement of approximately 30% in both larvae survival and health index compared to ETEC-F4+ alone. These findings suggest that aptamers have promising inhibitory effect against ETEC infections and pave the way for additional in vivo studies. [ABSTRACT FROM AUTHOR]

Metarhizium anisopliae (Clavicipitaceae, Hypocreales) is a globally distributed entomopathogenic fungus, which has been largely studied and used in agriculture for its potent entomopathogenicity. Since its taxonomic establishment as a member of Metarhizium, many closely related taxa have been described with highly similar morphology (cryptic species). A holotype specimen of M. anisopliae is not extant, and the ex-neotype strain (CBS 130.71) does not form a monophyletic clade with other strains, up to now, recognized as M. anisopliae sensu stricto. In this study, we have conducted an integrative taxonomic treatment of M. anisopliae sensu lato by including the ex-neotype strain of M. anisopliae, other unknown strains from our collections identified as M. anisopliae s. lat., as well as other known species that have been previously delimited as closely related but distinct to M. anisopliae. By including whole-genome sequencing, morphometric analysis, LC–MS based metabolomics, and virulence assays, we have demonstrated that M. anisopliae s. str. should also include M. lepidiotae (synonym), and that M. anisopliae s. str. differentiates from the other species of the complex by its metabolome and less severe entomopathogenicity. New taxa, namely M. hybridum, M. neoanisopliae and M. parapingshaense spp. nov., are proposed. The novel taxa proposed here have strong phylogenomics support, corroborated by fine-scale differences in the length/width of conidia/phialides, while the metabolomics and virulence data still largely overlap. We have also demonstrated via population genomics data the existence of local clonal lineages, particularly the one corresponding to the persistence of a biocontrol candidate strain that has been used in the field application for three years. This study showcases the utility of combining various data sources for accurate delimitation of species within an important group of fungal biocontrol agents against pest insects. [ABSTRACT FROM AUTHOR]

Background: Entomopathogenic nematodes (EPN) are used as a biological control agent for different insect pests in agriculture. The genera Heterorhabditis and Steinernema are the most used commercially. For an EPN species to be used as a biological controller, it is necessary to know its ecological aspects, including reproductive potential, movement capacity, and mean lethal concentration (LC50). These aspects were evaluated in three EPN strains isolated in Galleria mellonella larvae collected in the Lambayeque-Peru region, to determine if they are promising as biological controllers. The strains of EPN studied are Heterorhabditis sp. (PC9 strain), H. bacteriophora Poinar (PM10 strain), and Steinernema diaprepesi Nguyen y Duncan (SV19 strain). Results: Heterorhabditis sp. (PC9 strain) and H. bacteriophora (PM10 strain) had high production of infective juveniles (IJs): 217.750 and 186.800, respectively, while S. diaprepesi (SV19 strain) only reached 84.150 IJs. The movement capacity of Heterorhabditis sp. (PC9 strain) and H. bacteriophora (PM10 strain) reached a depth of 15 cm to parasitize G. mellonella larvae, while S. diaprepesi (SV19 strain) only reached 10 cm. In decreasing order, the LC50 value of S. diaprepesi (SV19 strain), Heterorhabditis sp. (PC9 strain) and H. bacteriophora (PM10 strain) were: 24.03, 13.74, and 8.19 IJs/ml, respectively. Conclusions: Heterorhabditis sp. PC9 and H. bacteriophora PM10 are promising a biological control agent because they present great production of IJs, great displacement capacity, and high pathogenicity against G. mellonella. Additionally, both strains present a mixed search strategy or seeker-hunter (seeker-browser). [ABSTRACT FROM AUTHOR]

The red palm weevil (Rhynchophorus ferrugineus) is a highly destructive pest, causing severe damage to palm trees and significantly reducing their productivity. This paper aims to develop and analyze a mathematical model that captures the interactions between palm trees, Rhynchophorus ferrugineus, and entomopathogenic nematodes as a means of integrated control. We identify the equilibrium points of the system and perform a stability analysis to assess the system's behavior. Additionally, we design a linear quadratic regulator (LQR) to limit the spread of the red palm weevil within a locally linearized framework. The feedback control law, which is both straightforward and immediately implementable, is employed to avoid the need for complex cost calculations, thus simplifying the solution to the optimal control problem. Numerical simulations demonstrate that the proposed control strategy is effective in reducing the number of infected palm trees. The results indicate that increasing the population of entomopathogenic nematodes can significantly decrease the red palm weevil population, offering a promising approach to mitigating this pest's impact. [ABSTRACT FROM AUTHOR]

Simple Summary: Xenorhabdus is a bacterial genus that symbioses with entomopathogenic nematodes, specifically classified within Steinernema. These nematodes transport the bacteria into target insects, where the bacteria suppress the host's immune responses and induce septicemia. Within the cadaver of the insect, the nematodes reproduce and re-establish their association with the symbiotic bacteria. This study identifies significant variability in insecticidal virulence across different Xenorhabdus species or strains. This variability arises from differences in their growth rates and suppressive activities against host immune functions. Analysis of secondary metabolites revealed the presence of several peptides in the virulent strains. Further analysis of non-ribosomal peptide synthetase genes suggested cyclo Pro-Phe (cPF) as a virulence factor, which suppressed insect immune responses and enhanced the bacterial virulence. Entomopathogenic bacteria, classified into the genus Xenorhabdus, exhibit a dual lifestyle as mutualistic symbionts to Steinernema nematodes and as pathogens to a broad range of insects. Bacterial virulence depends on toxin proteins that induce toxemia and various immunosuppressive secondary metabolites that cause septicemia. Particularly, the immunosuppressive properties of Xenorhabdus bacteria determine the variability of their insecticidal activities. This study explored the role of peptide metabolites in virulence and its variation among six bacterial strains across three species: X. nematophila, X. bovienii, and X. hominickii. Initially, their virulence significantly varied against a susceptible lepidopteran host, Maruca vitrata, but showed less variation against a tolerant coleopteran host, Tenebrio molitor, with high median lethal bacterial doses. In M. vitrata, virulence was strongly correlated with bacterial growth rate and inhibitory activity against phospholipase A2. Secondly, the six strains differed in the compositions of their secreted secondary metabolites, analyzed by GC-MS following ethyl acetate extraction. Notably, there was significant variation in the production of di- or tetra-peptides. Highly virulent strains commonly produced the cyclic Pro-Phe (cPF). Thirdly, the expression of non-ribosomal peptide synthetase (NRPS) genes varied greatly among the strains. NRPS genes were minimally expressed in the tolerant T. molitor and highly expressed in the susceptible M. vitrata. In M. vitrata, specific NRPS genes were markedly expressed in the virulent strains. Finally, cPF demonstrated potent immunosuppressive activity against the cellular and humoral responses of M. vitrata. The addition of cPF significantly enhanced the virulence against the tolerant T. molitor. These findings suggest that immunosuppression is necessary for the pathogenicity of Xenorhabdus bacteria, wherein NRPS products play a critical role in suppressing immune-associated factors in target insects. [ABSTRACT FROM AUTHOR]

Aromia bungii Faldermann (Coleoptera: Cerambycidae) is an emerging invasive pest of economically important Prunus species that is native to China, Mongolia, the Russian Far East, Korea, and Vietnam. It was recently introduced to Japan, Germany, and Italy, where it is spreading and damaging crops and ornamental trees. It exhibits an adaptable lifecycle, a high reproductive output, and the larvae live concealed under the bark of infested trees, which are traits that promote its invasiveness. Detection and monitoring of A. bungii currently rely upon visual identification of infested trees that are usually already damaged, which is inefficient and not target-specific. Current control methods rely primarily upon the labour-intensive physical removal of infested trees. Although native parasitoid natural enemies of A. bungii provide control in Chinese orchards, none are appropriate for classical biological control in invaded areas due to biosafety concerns surrounding their broad host ranges. However, entomopathogenic fungi and nematodes may provide viable options for biological control in invaded ranges. Recent advancements in semiochemical baited traps may provide sustainable, target-specific, and efficacious methods to monitor and control A. bungii. There remains much to learn about the biology and control of A. bungii, and continued advancements in the study of sustainable control tools are needed for the management of this emerging pest. [ABSTRACT FROM AUTHOR]

Cole crops, the most important and attractive vegetables, belonging to the family Cruciferae are widely grown all over the world. In India, their annual production has been reported to be about 191.77 million metric tons, so chips into the economy by a huge amount. Pieris brassicae, one of the dreaded insect pests incur damage to different vegetables to a tune of 40%. To curb this pest damage various synthetic insecticides are applied, albeit showing promising results yet posing drastic negative imprints on non-target organisms, environment and pest resistance. These drawbacks demand a perfect alternative which seals all the glitches created by the chemical insecticides. For this Infective Juveniles (IJs) of Entomopathogenic Nematodes (EPNs) act as perfect biocontrol agents. So, work done in these lines has been reviewed to facilitate students and researchers for advanced research related to entomopathogenic nematodes and P. brassicae. [ABSTRACT FROM AUTHOR]

Diseases and pests are a growing threat to small and large banana farmers and can cause catastrophic losses. Diseases affect all parts of the plant and are caused by fungi, bacteria and viruses. Although their impact is generally less devastating, pests, mainly insects and nematodes, are also significant factors. For better management of these diseases and pests, several technologies and or agroecological practices are often used by small farmers but are not often known or disseminated. Here, we did a meta-analysis combined with a review to describe banana diseases and pests as well as agroecological methods for their management. On the basis of the meta-analysis, 11 main bananas pests and diseases have been identified. Depending on the importance of their management by agroecological methods, Mycosphaerella fijiensis was most studied here (Z-value = 0.48), followed by the nematodes Radopholus similis (Z-value = 0.32) and Helicotylenchus multicinctus (Z-value = 0.32). The insect pests Erionota thrax (Z-value = 0.28), Cosmopolites sordidus (Z-value = 0.23) and Polytus mellerborgi (Z-value = 0.22) were also widely studied. Banana Bunchy Top Disease (BBTD) was moderately studied (Z-value = 0.26). There was a significant positive response of pest and disease to agroecological practices / technologies. Agricultural technologies involving the use of predators to control pests and the use of biopesticides were the most demonstrated in studies. This study made it possible to make a synthesis of the agroecological technologies and practices used to be disseminated for the bananas production by small farmers. [ABSTRACT FROM AUTHOR]

BACKGROUND: β‐N‐acetylhexosaminidases (HEXs) are widely distributed in fungi and involved in cell wall chitin metabolism and utilization of chitin‐containing substrates. However, details of the fungal pathogens‐derived HEXs in the interaction with their hosts remain limited. RESULTS: An insect nutrients‐induced β‐N‐acetylhexosaminidase, BbHex1, was identified from the entomopathogenic fungus Beauveria bassiana, which was involved in cell wall modification and degradation of insect cuticle. BbHex1 was localized to cell wall and secreted, and displayed enzyme activity to degrade the chitinase‐hydrolyzed product (GlcNAc)2. Disruption of BbHex1 resulted in a significant decrease in the level of cell wall chitin in the presence of insect nutrients and during infection of insects, with impaired ability to penetrate insect cuticle, accompanying downregulated cell wall metabolism‐involved and cuticle‐degrading chitinase genes. However, the opposite phenotypes were examined in the gene overexpression strain. Distinctly altered cell wall structures caused by BbHex1 mutation and overexpression led to the easy activation and evasion (respectively) of insect immune response during fungal infection. As a result, BbHex1 contributed to fungal virulence. Bioinformatics analysis revealed that promoters of some co‐expressed chitinase genes with the BbHex1 promoter shared conserved transcription factors Skn7, Msn2 and Ste12, and CreA‐binding motifs, implying co‐regulation of those genes with BbHex1. CONCLUSION: These data support a mechanism that the fungal pathogen specifically expresses BbHex1, which is co‐expressed with chitinases to modify cell wall for evasion of insect immune recognition and to degrade insect cuticle, and contributes to the fungal virulence against insects. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

BACKGROUND: In agricultural pest management, especially in combatting the invasive red imported fire ant (RIFA, Solenopsis invicta), significant challenges emerge as a consequence of the constraints of solely depending on chemical insecticides or entomopathogenic nematodes (EPNs). The utilization of chemical insecticides carries environmental and ecological hazards, whereas EPNs, when applied independently, might not offer the immediate effectiveness necessary for adequate RIFA suppression. Acknowledging these hurdles, our study investigates a synergistic method that integrates EPNs with chemical insecticides, aiming to fulfill the urgent demand for more efficient and environmentally friendly pest control solutions. RESULTS: Our evaluation focused on the interaction between the highly pathogenic Steinernema riobrave 7–12 EPN strain and prevalent insecticides, specifically beta‐cypermethrin and a mixture of bifenthrin and clothianidin, applied at highly diluted recommended concentrations. The findings revealed a notable increase in RIFA mortality rates when EPNs and these insecticides were used together, outperforming the results achieved with each method individually. Remarkably, this enhanced efficacy was especially evident at lower concentrations of the bifenthrin–clothianidin mixture, indicating a valuable approach to minimizing reliance on chemical insecticides in agriculture. Furthermore, the high survival rates of EPNs alongside the tested insecticides indicate their compatibility and potential for sustained use in integrated pest management programs. CONCLUSION: Our research underscores the effectiveness of merging EPNs with chemical insecticides as a powerful and sustainable strategy for RIFA management. This combined approach not only meets the immediate challenges of pest control in agricultural settings, but also supports wider environmental objectives by reducing the dependency on chemical insecticides. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

AbstractLeopard moth Zeuzera multistrigata (Lepidoptera: Cossidae) is a xylophagous insect whose larval stages are cryptic woodborers in apple and many other horticultural and forestry crops. The present study was carried out to test effectiveness of some biocontrol agents along with most effective pesticide against this pest on apple (cv. Royal Delicious) in Himachal Pradesh, India, for three consecutive years by injecting biocontrol agents/chemicals directly into galleries made by pest larvae. Investigations were conducted to observe the effect of Beauveria bassiana, Metarhizium anisopliae, Steinernemma feltiae, Heterorhabditis bacteriophora and azadirachtin along with a synthetic pesticide chlorpyriphos. The application of chlorpyriphos (0.04%) caused a 100%%larval mortality, whereas among the biocontrol agents H. bacteriophora (5000 IJs/gallery) exhibited the highest mortality of 66.7 to 80.0%% during these three years, which was significantly at par with application of azadirachtin (Neem baan) 1500 ppm @ 2 ml/Litre and S. feltiae @ 5000 IJs/gallery. The lowest mortality (33.3%) was observed with B. bassiana (5 g/Litre) for the first two years and with M. anisopliae (5 g/L) in the third year i.e. 40.0%. Application of entomopathogenic nematode H. bacteriophora (5000 IJs/gallery) is proven to be best among all biocontrol agents. [ABSTRACT FROM AUTHOR]

Background: The employment of entomopathogenic microorganisms is a promising approach for ensuring optimal phytosanitary protection in the framework of biological management of insect crop pests. Among these microbes, entomopathogenic soil-borne bacteria are preferred over pesticides because they help successfully in the natural regulation of arthropod populations, as soil has a favorable ecology for the availability and richness of many beneficial bacterial species. In this study, it was focused on the isolation, identification and characterization of entomopathogenic bacteria isolated from cultivated citrus soils and on the evaluation of their insecticidal potential in the laboratory against the mealy plum aphid, Hyalopterus pruni (Geoffroy 1762) (Hemiptera: Aphididae), a polyphagous and major pest attacking and virus-transmitting of several Prunus crops. Results: Isolation results gave 11 bacterial isolates, which were more than 50% effective in selection tests on H. pruni aphids at 1 × 108 CFU/ml. A total of seven isolates generated significant insecticidal potential at different concentrations, and their molecular identification based on 16S rRNA genome sequencing yielded the following results: Lysinibacillus fusiformis (B4), Bacillus thuringiensis (B13), B. thuringiensis (B22), B. thuringiensis (B23), B. thuringiensis (B24), Pseudomonas sp. (P2) and Enterococcus gallinarum (P4). The most pathogenic potential of these strains was for E. gallinarum (P4), which induced 100% H. pruni mortality after 72 h of treatment at the concentration (C3 = 1 × 106 CFU/ml), followed by B. thuringiensis (B23), (B22), (B4), (P2), (B13) and (B24) isolates, which caused 96, 91, 85, 83, 65 and 50% mortality rates, respectively, at the lowest concentration (C4 = 1 × 105 CFU/ml). The LC50 and LT50 values were calculated for the entomopathogenic isolates of (P2), (P4), (B23) and (B24). A lowest LC50 value was 1.08 × 102 CFU/ml for (P4) E. gallinarum after 72 h of treatment, whereas (P2) Pseudomonas sp. presented the shortest LT50 of 33.6 h at concentration (C4 = 1 × 105 CFU/ml). Conclusions: The present study's outcomes have confirmed the existence, abundance, and variety of entomopathogenic bacteria at the soil level in citrus groves. Interestingly, these bacteria could be useful for aphids' population control on a wide scale through the utilization of their toxins and enzymes, even against insect pests of a broad order. [ABSTRACT FROM AUTHOR]

Insect hemocytes eliminate foreign substances from the hemocoel through various immune reactions. Integrins, receptor proteins present on the cell membrane, are formed as a heterodimer from α and β subunits and are known to be involved in various immune reactions. To elucidate the role of integrins in the immunity of the lepidoptera Mythimna separata, genes encoding integrins were screened from the genome, resulting in the identification of eight α and four β integrin genes. The expression levels of the integrin genes did not change in response to the injection of small abiotic beads undergoing phagocytosis in M. separata larvae. However, significant inductions of some integrin gene expressions were observed in hemocytes that formed capsules around large abiotic beads during encapsulation, especially in MysIntα2. Under biotic stimulation, induction of the MysIntα2 was evident after exposures to Gram‐negative bacteria (Escherichia coli) and entomopathogenic nematodes (Steinernema carpocapsae), but not to Gram‐positive bacteria (Micrococcus luteus). Immunostaining analysis revealed that MysIntα2 was specifically localized to hemocytes surrounding the beads during the encapsulation reaction. Furthermore, the spreading and encapsulation abilities of hemocytes were significantly inhibited by incubation with MysIntα2 antibodies. Suppression of MysIntα2 expression in M. separata larvae by injecting double‐stranded RNA also resulted in a decrease in encapsulation activity. Collectively, these results indicate that MysIntα2 plays pivotal roles in the cellular immune response of M. separata, particularly during encapsulation. This likely occurs through the regulation of hemocyte spreading activity, thereby facilitating the formation of multilayered capsules around large invaders. [ABSTRACT FROM AUTHOR]

The non-Mendelian transmission of sex chromosomes during gametogenesis carries significant implications, influencing sex ratios and shaping evolutionary dynamics. Here we focus on known mechanisms that drive non-Mendelian inheritance of X chromosomes during spermatogenesis and their impact on population dynamics in species with different breeding systems. In Drosophila and mice, X-linked drivers targeting Y-bearing sperm for elimination or limiting their fitness, tend to confer unfavourable effects, prompting the evolution of suppressors to mitigate their impact. This leads to a complex ongoing evolutionary arms race to maintain an equal balance of males and females. However, in certain insects and nematodes with XX/X0 sex determination, the preferential production of X-bearing sperm through atypical meiosis yields wild-type populations with highly skewed sex ratios, suggesting non-Mendelian transmission of the X may offer selective advantages in these species. Indeed, models suggest X-meiotic drivers could bolster population size and persistence under certain conditions, challenging the conventional view of their detrimental effects. Furthering our understanding of the diverse mechanisms and evolutionary consequences of non-Mendelian transmission of X chromosomes will provide insights into genetic inheritance, sex determination, and population dynamics, with implications for fundamental research and practical applications. [ABSTRACT FROM AUTHOR]

The Mediterranean Corn Borer (MCB), Sesamia nonagrioides, poses a significant threat to maize crops, necessitating effective pest management strategies. This study investigates the compatibility of two entomopathogenic nematode (EPN) isolates, Steinernema feltiae KV6 and Heterorhabditis bacteriophora EO7, with four registered insecticides for MCB control: deltamethrin, flubendiamide, spinetoram, and betacyfluthrin. The impact of these insecticides on EPN mortality, infectivity, and reproduction was assessed. Results indicate that deltamethrin exhibits the lowest toxicity to EPNs, with mortality rates of 1.3% for S. feltiae and 0.63% for H. bacteriophora at field dose (FD) after 24 h and 4.63% and 1.96%, respectively, after 48 h. In contrast, betacyfluthrin showed higher toxicity, with mortality rates of 38.04% and 14.17% for S. feltiae at 2FD and FD after 48 h. The infectivity assays demonstrated that deltamethrin-treated EPNs caused up to 100% mortality in MCB larvae, while the reproduction capacity varied significantly between the EPN species and insecticides. H. bacteriophora exhibited higher progeny production, especially in the presence of deltamethrin (87,900 IJs/larva). The findings suggest that integrating EPNs with selective insecticides like deltamethrin can enhance pest control efficacy and support sustainable agricultural practices. This study provides valuable insights for developing integrated pest management (IPM) strategies aimed at mitigating MCB infestations in maize while minimizing environmental impacts. [ABSTRACT FROM AUTHOR]

Simple Summary: In recent years, the use of alternative animal models to vertebrates for the study of infectious processes and antimicrobial drug development has become a major challenge in experimentation. Insects, in particular Galleria mellonella, may represent a good model for preclinical studies, as their response to infections allows for the preliminary selection of molecules with biological activity in a potential sepsis event. However, discordant data are often reported in the literature, and this is often due to the different methods implemented in many laboratories. The aim of this work was therefore to develop a standard protocol for infection with a Gram-positive bacterium, as we consider it important to apply these unified methodologies in order to obtain reproducible data. Our results made it possible to define a correct growth curve of Micrococcus luteus and, in parallel, an infection methodology that would provide consistent and repeatable data. We are therefore confident that this work can be a support for preclinical studies on model insects, as a link between the development of new drugs and its availability for patients. The aim of this work was to develop an experimental protocol for the infection of Galleria mellonella with Gram-positive bacteria. Some physiological characteristics of these insects are comparable to those of vertebrates, therefore allowing the replacement of mammals in the preclinical phases of drug development. G. mellonella Linnaeus 1758 (Lepidoptera: Pyralidae) is accepted as an alternative model for the study of infectious diseases. Since data on infection procedures with different bacterial strains are scarce and sometimes conflicting, also due to different and non-uniform protocols, we developed an experimental protocol that would allow for controlled and repeatable infections, using the Gram-positive bacterium GRAS (Generally Regarded As Safe) Micrococcus luteus. After analyzing the morphology and defining the growth rate of M. luteus, doses of between 101 and 106 CFU/larvae were administered to late-stage larvae. The survival rate of the larvae was monitored up to 7 days and the LD50 determined. The bacterial clearance capacity of the larvae after injection with 103 and 105 CFU/larvae was assessed by hemolymph bacterial load analysis. The results made it possible to define the growth curve of M. luteus correlated with the CFU count; based on the LD50 (103.8 CFU/larvae) calculated on the survival of G. mellonella, infections were carried out to evaluate the immune efficiency of the larvae in bacterial clearance. This protocol, standardized on G. mellonella larvae, could provide a functional tool to study the course of bacterial infections. [ABSTRACT FROM AUTHOR]

Simple Summary: The greater wax moth, Galleria mellonella, is a significant pest in apiculture. This investigation explores the individual and combined effects of the ectoparasite Bracon hebetor (B.h.) and the entomopathogenic nematode Steinernema carpocapsae (S.c.) on G. mellonella larvae. We found that control larvae exhibited higher glutathione peroxidase (GPx) and glutathione S-transferase (GST) activities compared to those treated with B.h., S.c., or the B.h. + S.c. combination. Conversely, malondialdehyde (MDA) levels displayed an opposite trend. Superoxide dismutase (SOD) activity was reduced in the B.h. and S.c. groups but significantly higher in the combined treatment. Cytochrome P450 activity increased in response to parasitism by B. hebetor. The Annexin V-FITC assay revealed decreased cell viability in parasitized groups (B.h. 79.4%, S.c. 77.3%, B.h. + S.c. 70.1%) compared to controls. DNA damage analysis demonstrated significant differences between groups, and SEM observations confirmed severe cuticle abnormalities or malformations in G. mellonella larvae. The greater wax moth, Galleria mellonella, is a significant pest in apiculture and a well-established model organism for immunological and ecotoxicological studies. This investigation explores the individual and combined effects of the ectoparasite Bracon hebetor (B.h.) and the entomopathogenic nematode Steinernema carpocapsae (S.c.) on G. mellonella larvae. We evaluated the activity of oxidative stress enzymes, including superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione S-transferase (GST), malondialdehyde (MDA) levels, cytochrome P450 activity, cell viability using Annexin V-FITC, DNA damage via comet assay, and larval morphology through scanning electron microscopy (SEM). Control larvae exhibited higher GPx and GST activities compared to those treated with B.h., S.c., or the B.h. + S.c. combination. Conversely, MDA levels displayed the opposite trend. SOD activity was reduced in the B.h. and S.c. groups but significantly higher in the combined treatment. Cytochrome P450 activity increased in response to parasitism by B. hebetor. The Annexin V-FITC assay revealed decreased cell viability in parasitized groups (B.h. 79.4%, S.c. 77.3%, B.h. + S.c. 70.1%) compared to controls. DNA damage analysis demonstrated significant differences between groups, and SEM observations confirmed severe cuticle abnormalities or malformations in G. mellonella larvae. These findings highlight the complex interactions between B. hebetor, S. carpocapsae, and their host, G. mellonella. Additionally, they illuminate the intricate physiological responses triggered within the host larvae. [ABSTRACT FROM AUTHOR]

Simple Summary: Natural predators such as the chrysopid Chrysoperla lucasina occur in agroecosystems, where they naturally contribute to containing pest populations. Their biological properties can be leveraged by mass rearing in the laboratory and releasing them in the field, where they can express their predatory potential against pest species. To ensure the preservation of these beneficial species, plant protection products should be harmless to them. Accordingly, the use of biopesticides based on microbial entomopathogens, such as the fungus Beauveria bassiana strain ATCC 74040, is promoted as they are generally regarded as safe to non-target species. However, such safety should be demonstrated case by case. In addition, safety should be ensured for both the wild species and those released for biological control. This study involved experiments including laboratory-reared and wild C. lucasina larvae and determined only slight or no effects of B. bassiana on their survival, immature development, adult emergence, and reproductive potential. These findings highlight the compatibility of the predator and this strain of B. bassiana, emphasising the opportunity for their combined use in environmentally friendly pest management strategies. The need to reduce the impact of plant protection products on agroecosystems fosters the use of augmentative biological control involving the release of beneficial species into the field, the employment of entomopathogenic microbials, and the protection of naturally occurring biocontrol agents. This study aimed to investigate the compatibility of the entomopathogenic fungus Beauveria bassiana with the generalist insect predator Chrysoperla lucasina, in comparative experiments involving a laboratory-reared and a wild chrysopid strain. The larvae of the predators were exposed to different concentrations of fungal conidia up to a concentration of 107 conidia/mL by contact and ingestion. The treated insects showed only slight differences in terms of survival and immature development time compared to the untreated control insects. A significant decrease in the proportion of the male adults of C. lucasina that emerged from the laboratory-reared larvae that were exposed to higher concentrations of the fungus suggested a potentially different susceptibility between the sexes. A slightly lower adult emergence rate was observed in the wild strain, while no significant differences were recorded in the adult reproductive performance. These findings indicate that the B. bassiana strain ATCC 74040, at concentrations commonly used in the field, did not pose a significant risk to C. lucasina and can be safely used in combination with this predator for sustainable pest management. [ABSTRACT FROM AUTHOR]

Insect herbivore diet mediates interactions with entomopathogens, yet this is relatively unexplored for microsporidia. Here, we examine a diet‐mediated tri‐trophic interaction between an outbreaking forest defoliator, forest tent caterpillar (FTC) Malacosoma disstria Hübner and Nosema sp. microsporidia.We conducted two experiments where diet quality was manipulated by incorporating lyophilized aspen (Populus tremuloides Michaux) foliage into an artificial diet, which was compared to a standard artificial diet. Diet quantity varied between fully fed and partially starved conditions, simulating an outbreak scenario. Microsporidia infection occurred naturally or was induced via experimental inoculation. We assessed FTC survival, microsporidia infection and load, and sublethal effects of treatments on FTC traits.Plant secondary metabolite concentrations in aspen‐augmented diets varied between experiments. In Experiment 1, the aspen‐augmented diet contained lyophilized aspen foliage with low concentrations of secondary metabolites, which increased FTC survival and reduced microsporidia infection. Diet quality and infection load also interactively influenced adult wing traits in Experiment 1. In Experiment 2, the aspen‐augmented diet contained lyophilized aspen foliage with higher concentrations of secondary metabolites, which negatively affected FTC. No diet‐mediated interactions with microsporidia were observed in Experiment 2.Diet quality (Experiments 1 and 2), diet quantity (Experiment 2) and microsporidia infection (Experiments 1 and 2) directly influenced FTC survival and/or had sublethal effects on FTC that may have cascading effects on population dynamics and dispersal.We demonstrated that diet quality can mediate interactions between FTC and microsporidia, but these interactions depend on the defensive chemistry of the FTC diet. To our knowledge, this is the first study to report diet‐mediated interactions between an outbreaking forest pest and microsporidia and one of only a few studies to examine this tri‐trophic interaction among Lepidoptera. [ABSTRACT FROM AUTHOR]

AbstractCarpophilus hemipterus (L.) (Coleoptera: Nitidulidae), a dried fruit beetle is a major pest on various grains and fruits all over the world and causes significant economic losses. Recently, due to the negative effects of pesticides on the environment and humans, biological control agents such as entomopathogenic nematodes (EPNs) used to control insects are gaining importance. The aim of this study was carried out to determine biocontrol potential of three local entomopathogenic nematode isolates against different stages of dried fruit beetle (larvae, pupae, and adults) under controlled conditions. S. carpocapsae isolate Bakışlı05, H. bacteriophora isolate Z-1 and H. bacteriophora isolate TOK-20 used in experiments. Isolates were applied at four different concentrations i.e. 0, 250, 500, and 1000 IJs/ml at 25 °C. Mortality rates of larvae, pupae, and adults of C. hemipterus were determined four times (24, 48, 72, and 96 h) following inoculation. The highest mortality rate of larvae of C. hemipterus was caused by Heterorhabditis bacteriophora isolate Z-1 with 98.67% mortality followed by H. bacteriophora isolate TOK-20 with 93.85% and then Steinernema carpocapsae isolate Bakışlı05 with 86.67% at the highest concentration (1000 IJs/ml). The highest mortality rate on C. hemipterus pupae was recorded at the highest concentration of S. carpocapsae isolate Bakışlı05, which was 48.00%, followed by H. bacteriophora isolate Z-1 and H. bacteriophora isolate TOK-20, which had mortality rates of 43.33% and 38.00%, respectively. Moreover, the highest adult mortality rate was determined at the maximum concentration of S. carpocapsae (Bakışlı05), with 42.67% among all EPN isolates tested. This study shows that the use of entomopathogenic nematodes (EPN) for the management of dried fruit beetle can be an alternative method to pest control. [ABSTRACT FROM AUTHOR]

Currently, it is widely accepted that the type III secretion system (T3SS) serves as the transport platform for bacterial virulence factors, while flagella act as propulsion motors. However, there remains a noticeable dearth of comparative studies elucidating the functional disparities between these two mechanisms. Entomopathogenic nematode symbiotic bacteria (ENS), including Xenorhabdus and Photorhabdus, are Gram-negative bacteria transported into insect hosts by Steinernema or Heterorhabdus. Flagella are conserved in ENS, but the T3SS is only encoded in Photorhabdus. There are few reports on the function of flagella and the T3SS in ENS, and it is not known what role they play in the infection of ENS. Here, we clarified the function of the T3SS and flagella in ENS infection based on flagellar inactivation in X. stockiae (flhDC deletion), T3SS inactivation in P. luminescens (sctV deletion), and the heterologous synthesis of the T3SS of P. luminescens in X. stockiae. Consistent with the previous results, the swarming movement of the ENS and the formation of biofilms are dominated by the flagella. Both the T3SS and flagella facilitate ENS invasion and colonization within host cells, with minimal impact on secondary metabolite formation and secretion. Unexpectedly, a proteomic analysis reveals a negative feedback loop between the flagella/T3SS assembly and the type VI secretion system (T6SS). RT-PCR testing demonstrates the T3SS's inhibition of flagellar assembly, while flagellin expression promotes T3SS assembly. Furthermore, T3SS expression stimulates ribosome-associated protein expression. [ABSTRACT FROM AUTHOR]

Entomopathogenic nematodes of the genera Steinernema and Heterorhabditis, along with their bacterial symbionts from the genera Xenorhabdus and Photorhabdus, respectively, are important biological control agents against agricultural pests. Rapid progress in the development of genomic tools has catalyzed a transformation of the systematics of these organisms, reshaping our understanding of their phylogenetic and cophlylogenetic relationships. In this review, we discuss the major historical events in the taxonomy and systematics of this group of organisms, highlighting the latest advancements in these fields. Additionally, we synthesize information on nematode–bacteria associations and assess the existing evidence regarding their cophylogenetic relationships. [ABSTRACT FROM AUTHOR]

Biological control of weeds involves deliberate introduction of host‐specific natural enemies into invaded range to reduce the negative impacts of invasive species. Assessing the specificity is a crucial step, as introduction of generalist natural enemies into a new territory may pose risks to the recipient communities. A mechanistic understanding of host use can provide valuable insights for the selection of specialist natural enemies, bolster confidence in non‐target risk assessment and potentially accelerate the host specificity testing process in biological control. We conducted a comprehensive analysis of studies on the genomics of host specialization with a view to examine if genomic signatures can help predict host specificity in insects. Focusing on phytophagous Lepidoptera, Coleoptera and Diptera, we compared chemosensory receptors and enzymes between "specialist" (insects with narrow host range) and "generalist" (insects with wide host range) insects. The availability of genomic data for biological control agents (natural enemies of weeds) is limited thus our analyses utilized data from pest insects and model organisms for which genomic data are available. Our findings revealed that specialists generally exhibit a lower number of chemosensory receptors and enzymes compared with their generalist counterparts. This pattern was more prominent in Coleoptera and Diptera relative to Lepidoptera. This information can be used to reject agents with large gene repertoires to potentially accelerate the risk assessment process. Similarly, confirming smaller gene repertoires in specialists could further strengthen the risk evaluation. Despite the distinctive signatures between specialists and generalists, challenges such as finite genomic data for biological control agents, ad hoc comparisons, and fewer comparative studies among congeners limit our ability to use genomic signatures to predict host specificity. A few studies have empirically compared phylogenetically closely related species, enhancing the resolution and the predictive power of genomics signatures thus suggesting the need for more targeted studies comparing congeneric specialists and generalists. [ABSTRACT FROM AUTHOR]

Simple Summary: Entomopathogenic nematodes and their symbiotic bacteria are widely utilized for biological control. However, whether nematode-derived signals influence the immune response of insects remains unexplored. In this study, we provide comprehensive insight into the interactions among symbiotic bacteria, nematode pheromone ascarosides, and the G. mellonella insect host. Our findings reveal that under the induction of Photorhabdus bacteria, ascarosides enhance the host's immunity response. Specifically, they suppress the intensity of body color change and increase the expression of related-immunity gene expression. Additionally, ascarosides reduce the Photorhabdus cell load and delay G. mellonella larval mortality. These results imply that G. mellonella larvae may employ nematode pheromones to enhance insect immunity in the presence of symbiotic bacteria, thereby enhancing the resistance to invasive bacteria. Insects protect themselves through their immune systems. Entomopathogenic nematodes and their bacterial symbionts are widely used for the biocontrol of economically important pests. Ascarosides are pheromones that regulate nematode behaviors, such as aggregation, avoidance, mating, dispersal, and dauer recovery and formation. However, whether ascarosides influence the immune response of insects remains unexplored. In this study, we co-injected ascarosides and symbiotic Photorhabdus luminescens subsp. kayaii H06 bacteria derived from Heterorhabditis bacteriophora H06 into the last instar larvae of Galleria mellonella. We recorded larval mortality and analyzed the expressions of AMPs, ROS/RNS, and LPSs. Our results revealed a process in which ascarosides, acting as enhancers of the symbiotic bacteria, co-induced G. mellonella immunity by significantly increasing oxidative stress responses and secreting AMPs (gallerimycin, gloverin, and cecropin). This led to a reduction in color intensity and the symbiotic bacteria load, ultimately resulting in delayed host mortality compared to either ascarosides or symbiotic bacteria. These findings demonstrate the cross-kingdom regulation of insects and symbiotic bacteria by nematode pheromones. Furthermore, our results suggest that G. mellonella larvae may employ nematode pheromones secreted by IJs to modulate insect immunity during early infection, particularly in the presence of symbiotic bacteria, for enhancing resistance to invasive bacteria in the hemolymph. [ABSTRACT FROM AUTHOR]

The capsule-associated protein 10 gene (CAP10) is indispensable due to its involvement in pod formation and virulence maintenance in Cryptococcus neoformans. The function of the CAP10 gene in nematode-predatory fungi remains unreported. As a typical nematode-trapping fungus, Dactylellina haptotyla efficiently captures nematodes using adhesive knobs, which has potential applications in the biological control of plant-parasitic nematodes. In this study, we investigated the function of DHXT1 (a CAP10 homologous protein) in D. haptotyla–nematode interactions based on the disruption and overexpression of DHXT1, phenotypic analysis and metabolomic analysis. As a result, it was shown that the disruption of the DHXT1 gene causes a marked decrease in the number of adhesive knobs, and on the contrary, the overexpression of the DHXT1 gene causes a substantial increase in the number of adhesive knobs. Interestingly, the variety of metabolites increased with the disruption of the DHXT1 and decreased with the overexpression of the DHXT1 gene. The results suggest that DHXT1 effects pathogenicity through its involvement in adhesive knobs' formation and metabolite synthesis and serves as a key virulence factor in D. haptotyla. [ABSTRACT FROM AUTHOR]

Summary: The genus Oscheius includes species with different habits and some of them have been shown to kill some insect pests. The occurrence of Oscheius in hay meadow soils from the area recently invaded by the Japanese beetle Popillia japonica in Lombardy, Italy, has been surveyed. Oscheius myriophilus was detected at five out of 18 sites resulting positive to entomopathogenic nematodes (EPN), either alone or together with other genera of EPN, indicating a widespread occurrence. The morphological analysis of the strains retrieved showed that they are morphologically in agreement with those of the type population and with other populations recently described. The phylogenetic analysis supported the sub-grouping of all sequences of O. myriophilus from Lombardy with those present in the databases and a close relationship with O. safricana was observed. The capacity to kill the laboratory host Galleria mellonella was similar to that observed in a previous study related to isolates from P. japonica , although O. myriophilus did not cause significant mortality in laboratory trials with the invasive beetles. The isolates of O. myriophilus from Lombardy were characterised in relation to their infectivity to G. mellonella and response to environmental stress, such as heat tolerance and desiccation. Overall, O. myriophilus appears to be an important component of the EPN community of hay meadow soil in Lombardy and might play a role in the containment of the invasive P. japonica. [ABSTRACT FROM AUTHOR]

Xenorhabdus nematophila is a symbiotic Gammaproteobacterium that produces diverse natural products that facilitate mutualistic and pathogenic interactions in their nematode and insect hosts, respectively. The interplay between X. nematophila secondary metabolism and symbiosis stage is tuned by various global regulators. An example of such a regulator is the LysR-type protein transcription factor LrhA, which regulates amino acid metabolism and is necessary for virulence in insects and normal nematode progeny production. Here, we utilized comparative metabolomics and molecular networking to identify small molecule factors regulated by LrhA and characterized a rare γ-ketoacid (GKA) and two new N-acyl amides, GKA-Arg (1) and GKA-Pro (2) which harbor a γ-keto acyl appendage. A lrhA null mutant produced elevated levels of compound 1 and reduced levels of compound 2 relative to wild type. N-acyl amides 1 and 2 were shown to be selective agonists for the human Gprotein-coupled receptors (GPCRs) C3AR1 and CHRM2, respectively. The CHRM2 agonist 2 deleteriously affected the hatch rate and length of Steinernema nematodes. This work further highlights the utility of exploiting regulators of host-bacteria interactions for the identification of the bioactive small molecule signals that they control. [ABSTRACT FROM AUTHOR]

The common cutworm, Spodoptera litura, is a serious insect pest of many vegetables and crops worldwide. Entomopathogenic nematodes (EPN) have been utilized as biological control agents for controlling various insect pests, including the larvae of S. litura. Many indigenous EPN have been recognized to be more effective in specific field applications. Among the 160 soil samples collected in undisturbed areas of western Thailand, three samples tested positive for EPN. Three indigenous EPN were identified as Steinernema siamkayai namely, EPNKU63, EPNKU70 and EPNKU85, based on ITS and D2/D3 expansion region analysis of the 28s rRNA genes. Additionally, genetic analysis of the symbiotic bacteria using recA rRNA sequences confirmed their identity as Xenorhabdus stockiae namely, PEPNKU63, PEPNKU70 and PEPNKU85. To evaluate their initial biocontrol potential against the 6th instar larvae of Galleria mellonella, virulence assays were conducted. The application of 100 infective juveniles (IJs)/insects resulted in the mortality of 80–100% of G. mellonella larvae after 72 h. When symbiotic bacteria were applied at 1 × 106 cells/insect, they exhibited 63–93% mortality against G. mellonella larvae after 120 h. In further laboratory tests, three S. siamkayai isolates achieved 100% mortality of 3rd instar Spodoptera litura larvae within 72 h, with LC50 values ranging from 29 to 30 IJs/insect. In screenhouse experiments, it was revealed that all S. siamkayai isolates displayed substantial virulence, ranging from 62% to 74%, against 3rd instar S. litura larvae within 72 h. This study demonstrates the biocontrol potential of S. siamkayai in controlling S. litura larvae. [ABSTRACT FROM AUTHOR]

The cross-hybridization of American chestnut (Castanea dentata (Marsh.) Borkh.) with Chinese chestnut (Castanea mollissima Bl.) is a promising strategy for restoring a blight-resistant strain of this keystone species to the Appalachian mountains. To assess the ecological impacts of hybridization on invertebrate communities, we conducted a study across chestnut plots with varying degrees of hybridization (75%, 94%, or 100% American chestnut). Our findings indicate American chestnut hybridization impacted invertebrate communities above- and belowground. Aboveground insect community composition, insect herbivory, gall infestation, and belowground invertebrate diversity were all altered. While some of these differences could be explained by different growth habits or environmental differences, stark differences in Asian chestnut gall wasp infestation (Dryocosmus kuriphilus Yasumatsu.) suggest a genetic component. These results suggest that chestnut hybridization, and particularly expanded restoration efforts using chestnut hybrids, could impact invertebrate communities above- and belowground in addition to pest dynamics. Understanding these effects is crucial for successful chestnut restoration and ecosystem management. [ABSTRACT FROM AUTHOR]

Background: The chickpea Cicer arietinum (Fabaceae) field has suffered significant economic losses due to the presence of cotton bollworm, Helicoverpa armigera Hübner (Lepidoptera: Noctuidae). Attempts to control the larval population through chemical pesticides led to some reduction but also resulted in the development of resistance among the larvae. Consequently, the H. armigera population experienced a rapid resurgence in the field. Given the substantial losses caused by Helicoverpa larvae, there is now a growing interest in adopting eco-friendly methods for management. The application of biocontrol agents has emerged as a promising solution for effectively managing the infestation. Results: In the laboratory experiment, the entomopathogenic nematodes (EPNs) Steinernema pakistanense NNRC-NB.14, S. balochiense NNRC-NB.23, and S. abbasi NNRC-NB.33 were evaluated for their infectivity and mortality effects on mature cotton bollworm at various concentrations. The study demonstrated that the highest mortality rates were achieved at a concentration of 250 infective juveniles (IJs) per larva after 72 h. Steinernema pakistanense and S. balochiense exhibited higher mortality rates (95–98%) compared to S. abbasi (77%) at higher application concentrations. The field trial results reinforced the laboratory findings, demonstrating a significant decrease in H. armigera larval populations when employing EPN strains, particularly NNRC-NB.14 and NNRC-NB.33, compared to NNRC-NB.23. Despite the initial applications showing relatively low mortality percentages, the most effective larval control occurred after the third application of EPNs. The field trials revealed that, following the third spray, mortality percentages significantly increased from the initial range of 20–32% to a more substantial 70–90%. This cumulative impact highlights the importance of multiple applications in achieving optimal pest control. Conclusion: The findings of these studies highlight the promising potential of EPN as an eco-friendly and sustainable method for controlling the cotton bollworm. However, the successful implementation of EPN-based control strategies in agricultural systems requires careful consideration of factors such as nematode species selection, application methods, environmental conditions, and integration with other pest management practices. Further research is needed to optimize the efficacy and practicality of using EPN on a larger scale, addressing issues such as nematode production, formulation, and compatibility with existing farming practice. [ABSTRACT FROM AUTHOR]

AbstractThe box tree moth (BTM), Cydalima perspectalis, and the fall webworm (FWW), Hyphantria cunea are two invasive forest pests in northern Iran. Entomopathogenic nematodes (EPNs) are usually compatible with integrated pest management programs. In this study, the efficacy of five isolates of EPNs was evaluated against the two pests in laboratory and field conditions. LC50 values of Steinernema carpocapsae (IRTabriz), S. feltiae (IRTabriz), S. feltiae (Entonem), Oscheius rugaoensis and Heterorhabditis bacteriophora (IRTabriz) were as follow: 44.8, 66.5, 113.8, 190.7 and 515.9 infective juveniles (IJs) larva−1 on the fifth instar larvae of BTM; and 75.2, 96.6, 131.0, 258.0 and 292.5 IJs larva−1 on fifth instar larvae of FWW, respectively in the laboratory tests 48 h post-treatment at 25 °C and 60% relative humidity. Under field conditions, the foliar applications of S. carpocapsae (IRTabriz), S. feltiae (IRTabriz), and S. feltiae (Entonem) at the rate of 106 IJs L−1 resulted in 36–58% mortality after 48 h against BTM and 15–52% mortality against FWW, respectively. The results demonstrate that EPNs are promising candidates for biocontrol of BTW and FWW. [ABSTRACT FROM AUTHOR]

The greater amberjack is a very important fishery species with high commercial value, and it is distributed worldwide. Transcriptome-based studies on S. dumerili have been limited by an inadequate reference genome and a lack of well-annotated full-length transcripts. In this study, a total of 12 tissues from juvenile and adult fish both sexes were collected for next-generation RNA sequencing (RNA-seq) and full-length isoform sequencing (Iso-seq). For Iso-seq, a total of 163,218, 149,716, and 189,169 high-quality unique transcript sequences were obtained, with an N50 of 5,441, 5,255, and 5,939, from juvenile, adult male and adult female S. dumerili, respectively. We integrated the Iso-seq and RNA-seq data to construct a comprehensive gene annotation and systematically profiled the dynamics of gene expression across the 12 tissues. Our gene models had greater detail and accuracy than those from NCBI and Ensembl, with more precise polyA locations. These resources serve as a foundation for functional genomic studies and provide valuable insights into the molecular mechanisms underlying the development, reproduction and commercial traits of amberjack. [ABSTRACT FROM AUTHOR]

Unravelling the multifaceted and bidirectional interactions between microbiota and host physiology represents a major scientific challenge. Here, we utilise the nematode model, Pristionchus pacificus, coupled to a laboratory-simulated decay process of its insect host, to mimic natural microbiota succession and investigate associated tripartite interactions. Metagenomics reveal that during initial decay stages, the population of vitamin B-producing bacteria diminishes, potentially due to a preferential selection by nematodes. As decay progresses to nutrient-depleted stages, bacteria with smaller genomes producing less nutrients become more prevalent. Lipid utilisation and dauer formation, representing key nematode survival strategies, are influenced by microbiota changes. Additionally, horizontally acquired cellulases extend the nematodes' reproductive phase due to more efficient foraging. Lastly, the expressions of Pristionchus species-specific genes are more responsive to natural microbiota compared to conserved genes, suggesting their importance in the organisms' adaptation to its ecological niche. In summary, we show the importance of microbial successions and their reciprocal interaction with nematodes for insect decay in semi-artificial ecosystems. This study uses decomposing beetle grubs to replicate the natural microbial habitat of a nematode model organism. The approach enables exploration of interactions between nematodes and their microbiota and was used to show the importance of microbial successions and their reciprocal interaction with nematodes for insect decay. [ABSTRACT FROM AUTHOR]

Senegalese sole, Solea senegalensis, is a flatfish of high commercial value in the world. It has been identified as an interesting and promising species for marine commercial aquaculture diversification in Europe for at least four decades and was introduced to China in 2003. Early ontogenesis from embryo to juvenile stages in S. senegalensis was analysed under controlled laboratory conditions to provide morphological information for aquaculture. From 0 to 59 days post hatching (dph), 10–20 larvae were sampled and measured each day (0–17 dph) or every 2–6 days (17–59 dph). Morphological characteristics from the egg to the juvenile stage were described. The eggs were separate and spherical with multiple oil globules. After 3 dph, the yolk sac was completely absorbed, mouth and anus were open, a swim bladder appeared, and larvae began feeding on rotifers (Brachionus plicatilis). The larvae began metamorphosis as the notochord flexed upward and the left eye migrated upward after 10 dph. The left eye migrated to the dorsal midline at 15 dph. At 19 dph, the left eye was translocated to the right‐ocular side, and the juveniles adopted a benthic lifestyle. The swim bladder degenerated, and the juveniles completed metamorphosis at 23 dph. The growth patterns of some parameters (TL, SL, BH, BW) during larval and juvenile development stages were identified. The inflection points, which are slopes of growth changes, were calculated in growth curves. Three inflection points occurring in the growth curves of larvae and juveniles were found to be associated with metamorphosis, weaning, and transitions in feeding habits. The basic information of embryo development and ontogenesis in this study represents a valuable contribution to the S. senegalensis industry, especially in artificial breeding and rearing techniques. [ABSTRACT FROM AUTHOR]

The Guatemalan potato moth (Tecia solanivora) is one of the most destructive pests affecting potatoes in Colombia. Our objective was to evaluate the susceptibility of T. solanivora to a combination of entomopathogenic nematodes and entomopathogenic fungi, to study the interactions of these two agents under laboratory conditions. We evaluated the mortality of fourth instar larvae against 200 Infective Juveniles (IJs) per larva of ten strains of entomopathogenic nematodes, and 104–108 conidia per larva of Beauveria bassiana sensu lato Bb9205 and Metarhizium anisopliae sensu lato Ma9236. We found that Steinernema feltiae SC125 caused a mortality rate of 98.2% with an LC50 of 33 IJs/larva. M. anisopliae sensu lato Ma9236 achieved a mortality rate of 88.8% with an LC50 of 6.9 × 105 conidia/larva. We selected these strains for the interaction tests. We determined that the interaction test results were statistically additive regardless of any difference in application times of the entomopathogens and despite the observation of signs of infection in the hosts from both the nematode and the fungus. Despite not having found synergistic interactions between the evaluated control agents, these laboratory tests suggest a possible strategy of combining entomopathogenic nematode and fungi for biological management of the guatemalan moth T. solanivora in potato crops. [ABSTRACT FROM AUTHOR]

Entomopathogenic nematodes (EPNs) are an important component of integrated pest management (IPM) strategies; understanding their compatibility with other biocontrol options is of crucial importance in promoting their use. In this study, the toxicity of azadirachtin, sulfoxaflor, spindle oil (Mineral oil), and thyme oil was tested on the survival and pathogenicity of Steinernema carpocapsae (Weiser, 1955) (Rhabditida: Steinernematidae), Steinernema bicornutum sp. n. (Rhabditida: Steinernematidae), Heterorhabditis bacteriophora (Poinar, 1976) (Rhabditida: Heterorhabditidae), and Heterorhabditis indica (Poinar, Karunakar & David, 1992) under controlled conditions (25 ± 1 °C, 60 ± 10% RH). The toxicity of aforementioned agrochemicals to EPNs was evaluated in 12-well plates and the infective juveniles (IJs) of each EPN species (6000 IJs/50 µL ddh2O) were exposed to the recommended field concentrations of agrochemicals. In the pathogenicity tests, the agrochemical and IJs solutions (3000 IJs/ml agrochemical) were applied to potato tubers in plastic containers which contained 20 adults of Planococcus citri (Risso, 1813) (Hemiptera: Pseudococcidae). The survival of IJs and P. citri (Adults) was evaluated daily for three consecutive days after treatment. The results revealed that all tested EPN species were quite compatible with tested agrochemicals and showed survival of over 95% after 72 h of exposure to tested agrochemicals. EPNs and spindle oil combination induced the highest mortality of adult P. citri, and all EPN species caused mortalities over 90% at 72 h after treatment, except for S. bicornotum-spindle oil combination. Additive effects were observed in all combinations of EPNs with agrochemicals except for thyme oil. It appears, therefore, that EPNs applied in combination with azadirachtin, sulfoxaflor, and spindle oil have a great potential for successful control of P. citri. However, further studies are still required to determine the antagonistic or otherwise synergistic effects of tested chemicals on EPNs in controlling P. citri under field conditions. [ABSTRACT FROM AUTHOR]

Biopesticides are made up of plant materials that kill insects and a variety of microorganisms that kill insects, such as entomopathogenic fungi, entomopathogenic bacteria, entomopathogenic viruses, and entomopathogenic nematodes. These are used to get rid of agricultural and household insect pests. Several new methods are being developed in the biopesticide sector, and production and marketing of biopesticides are increasing significantly worldwide because of the noteworthy results in integrated pest management. Lots of Bt-genic crops, different types of entomopathogenic bacteria, entomopathogenic viruses, entomopathogenic fungi, and nematode-associated entomopathogenic bacteria are available in the market and are being used in agriculture to protect crops from insect pests and reduce insect pest populations. In the present review, we describe the role of biopesticides, including microbial and plant-derived ones, in insect pest management and the importance of their uses. An updated illustration of the present information on biopesticides and the availability of their commercial products and active substances in plants that can be very helpful in Insect pest management is reported in this review. [ABSTRACT FROM AUTHOR]

Entomopathogenic fungi have been considered potential biological control agents against the fall armyworm Spodoptera frugiperda (J. E. Smith), the world's most important pest of maize. In this study, we evaluated the natural infection, molecular characteristics, and biological activity of Metarhizium rileyi (Farlow) isolated from S. frugiperda larvae of this insect, collected from maize crops in five Mexican locations. Natural infection ranged from 23% to 90% across all locations analyzed. Twenty-four isolates were evaluated on S. frugiperda second instars at a concentration of 1.0 × 108 conidia/mL, causing 70% to 98.7% mortality and 60.5% to 98.7% sporulation. Isolates T9-21, Z30-21, PP48-21, and L8-22 were selected to determine their phylogenetic relationships by β-tubulin gene analysis and to compare median lethal concentration (CL50), median lethal time (LT50), and larval survival. These isolates were grouped into three clades. The T9-21, PP48-21, and J10-22 isolates were closely related (clade A), but phylogenetically distant from Z30-21 (clade B) and L8-22 (clade C) isolates. These genetic differences were not always reflected in their pathogenicity characteristics since no differences were observed among the LC50 values. Furthermore, isolates T9-21, J10-22, and L8-22 were the fastest to kill S. frugiperda larvae, causing lower survival rates. We conclude that native M. rileyi isolates represent an important alternative for the biocontrol of S. frugiperda. [ABSTRACT FROM AUTHOR]

Soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) are central components of the machinery mediating cell membrane fusion and intracellular vesicular trafficking in eukaryotic cells, and have been well-documented to play critical roles in growth, development, and pathogenesis in the filamentous fungal plant pathogens. However, little is known about the contributions of SNAREs to the physiology and biocontrol potential in entomopathogenic filamentous fungi. Here, a genome-wide analysis of SNARE genes was performed taking advantage of the available whole genome sequence of Beauveria bassiana, a classical entomopathogenic fungus. Based on the compared genomic method, 22 genes encoding putative SNAREs were identified from the whole genome of B. bassiana, and were classified into four groups (7 Qa-, 4 Qb-, 6 Qc-, and 5 R-SNAREs) according to the conserved structural features of their encoding proteins. An R-SNARE encoding gene BbSEC22 was further functionally characterized by gene disruption and complementation. The BbSEC22 null mutant showed a fluffy appearance in mycelial growth and an obvious lag in conidial germination. The null mutant also exhibited significantly increased sensitivity to oxidative stress and cell wall perturbing agents and reduced the yield of conidia production by 43.1% compared with the wild-type strain. Moreover, disruption of BbSEC22 caused a significant decrease in conidial virulence to Spodoptera litura larvae. Overall, our results provide an overview of vesicle trafficking in B. bassiana and revealed that BbSec22 was a multifunctional protein associated with mycelial growth, sporulation, conidial germination, stress tolerance, and insecticidal virulence. [ABSTRACT FROM AUTHOR]

The Colorado potato beetle (CPB), Leptinotarsa decemlineata, poses a significant threat to potato crops globally and has developed resistance to numerous insecticides. Entomopathogenic nematodes (EPNs), from the genera Steinernema and Heterorhabditis, are promising biocontrol agents. This study aimed to identify the bacterial symbionts of ten native EPN isolates, evaluate the efficiency of cell free supernatants (CFSs) from their symbiotic bacteria against different developmental stages of CPB, and determine the effect of these CFSs on CPB developmental stages and lifespan. The recA gene region was utilized to determine the symbiotic bacteria of ten local EPNs. CFSs from these bacteria were applied orally and through contact to CPB's various developmental stages (L1/L2, L3/L4 larval stages, and adults). Mortalities, developmental transition times, and lifespans of adults were observed. The CFSs showed significant toxicity to CPB, with higher efficiency against young larvae. The CFSs exhibited cumulatively lethal effects over time, particularly on L1/L2 larval stages. CFSs from X. bovienii exhibited the highest efficacy. In all cases, where larvae received CFSs orally or by contact, they failed to develop into pupae and adults. In contrast, the transition periods of old larvae to pupal and adult stages were comparable to those of the control group. Lifespans of adults differed based on bacterial isolates and application methods. This study shows the potential efficacy of CFSs from Xenorhabdus and Photorhabdus as biocontrol agents against CPB, particularly in its young larval stages. Further research is needed to unravel the mechanisms behind these effects and examine the impact on CPB mating and oviposition behaviors. [ABSTRACT FROM AUTHOR]

Insufficient analysis of carriers and their interaction with biocontrol agents can lead to ineffective formulations. Therefore, it is important to thoroughly study the compatibility and interactions between carriers and biocontrol agents for high-quality biological formulations. The present study aimed to evaluate the effect of four different formulation compositions containing gum katira biogel, vermiculite, and diatomaceous earth on the survival and infectivity of infective juveniles (IJs) of two entomopathogenic nematodes (EPNs) species namely, Steinernema abbasi and Heterorhabditis indica at 25 and 35 °C. The physicochemical analysis of the prepared formulations revealed their slightly acidic nature with pH ranging from 5.65 to 6.10. Rheological studies validated the solid-like behavior of the developed formulations. The highest survival of S. abbasi IJs was observed in the case of gum katira biogel-vermiculite blended composition at both 25 °C (94.2%) and 35 °C (88.4%) after 90 days of storage. Interestingly, gum katira biogel alone sustained maximum survival percentage (63.5%) of H. indica as compared to control (41.5%) after 90 days at 25 °C. The formulation compositions failed to retain alive H. indica IJs at 35 °C even after seven days of storage. Moreover, the gum katira singly or in combination with vermiculite resulted in superior infectivity against Galleria mellonella (4th instar larvae) as compared to the other treatments in case of both the nematode species. The presence of diatomaceous earth in all the compositions irrespective of moisture and EPN species showed a negative impact on the survival and infectivity of IJs after 90 days of storage. Gum katira biogel alone or in combination with vermiculite was favorable to sustaining the survivability and infectivity of test EPN IJs at ambient storage temperatures. These formulants can further be used to develop biocontrol EPN formulations for organic farming and integrated pest management programs. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the effect of biostimulants derived from Streptomyces avermitilis metabolites on entomopathogenic nematodes: Steinernema carpocapsae, Steinernema feltiae, and Heterorhabditis bacteriophora, obtained from the soil of several Miscanthus × giganteus plantations in 2020–2023. The nematodes were isolated, identified, and cultured using live insects (the greater wax moth Galleria mellonella). Three preparations containing biostimulants – Charkor, Stimpo, and Regoplant, were tested for compatibility with entomopathogenic and plant parasitic nematodes. Their effect on nematode survival was evaluated using the Petri dish test. The study showed that the effect of biostimulants on the survival of nematodes depended on the concentration of aversectin contained in the evaluated preparations. Stimpo and Regoplant had an adverse effect on plant parasitic nematodes. The highest G. mellonella mortality was observed at the higher dose of Charkor (0.4%), and the lowest at the lower dose of Regoplant (1.22%). The study showed that the virulence of the nematodes decreased after 48 hours of incubation in Regoplant and Stimpo solutions containing aversectin. The degree of interaction between nematodes depended on the nematode species, trophic preferences, and the concentration of active ingredients in the preparations. This conclusion is crucial for the selection of appropriate types of entomopathogenic nematodes and the application rate of plant parasitic nematodes in the assessment of their short- and long-term spread, persistence, and recycling in field conditions. [ABSTRACT FROM AUTHOR]

This work focused on studying these interactions through laboratory bioassays to characterize the effects of native isolates of entomopathogenic nematodes (EPNs) on the larvae of Spodoptera frugiperda (Smith) at the pathogenic and molecular levels. In addition, through the ingestion of EPNs-treated diet, their non-target effects on larvae of the generalist predator Chrysoperla carnea (Stephens) were also studied. Molecular characterization revealed that the EPN isolates tested corresponded to Oscheius myriophilus (Poinar) and Rhabditis spp. Infection of the S. frugiperda larvae with both EPNs produced high mortality (up to 56.52%) with different results in the rate of death according to median time to death analysis. Similarly, ingestion by the predator mediated by a treated diet triggered lethal effects on the preimaginal parameters of C. carnea. In this study, it was demonstrated that the use of native isolates of EPNs for the control of S. frugiperda is a strategy that can be applied for the management of this insect. Resumen Este trabajo se centró en estudiar estas interacciones mediante bioensayos de laboratorio para caracterizar los efectos de aislamientos nativos de nematodos entomopatógenos (NEPs) sobre larvas de Spodoptera frugiperda (Smith) a nivel patogénico y molecular. Además, a través de la ingestión de dieta tratada con NEPs se estudió su efecto no objetivo sobre larvas del depredador generalista Chrysoperla carnea (Stephens). La caracterización molecular reveló que los aislados de NEPs analizados corresponden a Oscheius myriophilus (Poinar) y Rhabditis spp. La infección de larvas de S. frugiperda con ambos NEPs produjo una alta mortalidad (hasta 56.52%) con resultados diferentes en la velocidad de muerte de acuerdo con el análisis de la mediana del tiempo de mortalidad. De manera similar, la ingestión por parte del depredador mediada por dieta tratada desencadenó efectos letales en parámetros preimaginales de C. carnea. En este estudio, se demostró que el uso de aislamientos nativos de NEPs para el control de S. frugiperda es una estrategia que puede ser aplicada para el manejo del insecto. [ABSTRACT FROM AUTHOR]

Entomopathogenic nematodes (EPNs) are biocontrol agents against various insect pests in the world for their characteristics of infectivity and compatibility with different control agents. Several environmental factors directly affect the EPN populations in the soil, as well as the resistance of certain insect pests to EPN penetration. Under these circumstances, EPNs cannot exhibit high virulence on the targeted insect pest; therefore, they should be applied in combination with some of the other control agents. In this context, the main objective of this review was to summarize the current knowledge on the compatibility of EPNs with various agrochemicals and examine the interactions of EPNs and these agents in combined application against insect pests. This review highlighted firstly the growing research attention worldwide concerning the compatibility of EPNs with other control agents. Then, the compatibility of EPNs with synthetic insecticides of different classes was reviewed. In this regard, also, some special attention has been paid to herbicides, fungicides and nematicidal compounds as possible compatible agents to EPNs. Later on, the current review discussed the importance of EPN application in combination with different insect growth regulators, juvenoids, ecdysteroids and chitin synthesis inhibitors. An overview of agricultural management practices and soil amendments in relation to EPNs was provided including the compatibility of EPNs with organic and inorganic fertilizers. Some attention has been paid to the EPN tolerance and susceptibility to heavy metals and other soil chemical pollutants, and EPNs as good bio-indicators of the environmental pollutants. The last aspect was the compatibility of EPNs with crude plant extracts and isolated phytochemicals. In conclusion, a combination of EPNs with compatible agrochemicals is a promising approach to the pest control strategy. EPNs may be combined with various compatible agrochemicals with additive, or preferably synergistic, effects on pest mortality. For this purpose, also, the exposure period should also be taken into consideration, because the exposure of EPNs to agrochemicals for a prolonged exposure period may turn their interaction to antagonistic and subsequently low control efficiency against the targeted insect due to the reduction of the EPN viability and infectivity. [ABSTRACT FROM AUTHOR]