Search Results (97)

The tomato leafminer Tuta absoluta (Meyrick) is a devastating invasive pest that threatens tomato production worldwide. Reliance on chemical insecticides raises sustainability concerns, highlighting the need for effective biological alternatives. Combining predators with entomopathogenic nematodes (EPNs) represents a promising strategy, yet their interactions remain poorly characterized. Here, we conducted laboratory bioassays to assess the individual and joint effects of the predatory bug Arma chinensis (Fallou) and four EPN species, Steinernema carpocapsae, S. feltiae, S. riobrave, and Heterorhabditis bacteriophora, against T. absoluta larvae. Under these controlled conditions, H. bacteriophora showed the highest compatibility with A. chinensis, exhibiting the lowest virulence against the predator. Female A. chinensis exhibited strong predation on freely exposed second-instar larvae, but efficiency declined markedly against leaf-mining larvae. Heterorhabditis bacteriophora caused consistently high mortality in second instars regardless of protection. Their combined application resulted in additive mortality with significantly reduced LT₅₀ values. We also observed A. chinensis preying on nematode-infected larvae and occasional infection of the predator under confined conditions. These laboratory findings demonstrate additive effects against T. absoluta, providing preliminary evidence for stage-specific integrated biological control strategies. Full article

Alphitobius diaperinus (Panzer) (Coleoptera: Tenebrionidae) is a common pest in poultry farms, causing significant economic damage, spreading easily and quickly. The species is resilient, adaptable, and capable of thriving in a variety of environments, and both larvae and adults can hide in hard-to-reach places; thus, control becomes highly challenging. Moreover, the species has developed resistance to commonly used insecticides, increasing the need to adopt integrated pest management strategies. Hence, this study examined the mortality dynamics of A. diaperinus larvae exposed to the entomopathogenic nematodes (EPNs) Heterorhabditis downesi Stock, Griffin & Burnell 2002 (Rhabditida: Heterorhabditidae) and Steinernema kraussei (Steiner, 1923) (Rhabditida: Steinernematidae) across a range of temperatures, dose rates, and exposure intervals. The patterns of larval mortality closely followed the classical EPN infection timeline: limited mortality during the first hours, a pronounced increase between day 2 and 4, and high cumulative mortality after day 8. Steinernema kraussei produced moderate early mortality, increasing by day 8, across all tested temperatures, reflecting its relatively slower but effective infection progression. In contrast, H. downesi induced higher early mortality at moderate temperatures and stronger dose-dependent responses. Temperature significantly modulated infection in both species, with reduced performance at 35 °C, particularly for H. downesi, although high-dose treatments achieved substantial mortality. The significant temperature × dose × time interactions align with established EPN biology and previous research on both species and, overall, the results confirm that they both possess strong pathogenic potential against A. diaperinus, while their performance characteristics support their suitability as biological control agents for poultry facilities. Full article

Storage insects consist a continuous global threat to food safety. In this study, the efficacy of the entomopathogenic nematodes (EPNs) Steinernema khuongi and Heterorhabditis downesi was evaluated against larvae of Tribolium castaneum, Tribolium confusum, Tenebrio molitor, and Trogoderma granarium in wheat and maize at six concentrations and two exposure intervals. Both EPNs exhibited higher virulence when applied in wheat than in maize. Generally, larval mortalities were higher under H. downesi treatments vs. S. khuongi, both in commodities and exposures. Notably, the tested EPNs caused high mortalities to T. granarium larvae (range, 88.9–92.2%) and T. castaneum larvae (range, 81.1–94.4%), respectively, at 10,000 IJs/mL in wheat vs. mortality ranges 72.2–77.8% and 74.4–87.8% in maize, respectively. In contrast, T. confusum larvae were tolerant to both EPNs. Tenebrio molitor larvae were tolerant to S. khuongi (<34.0% mortality) whereas susceptible to H. downesi (>83.3% mortality) at 10,000 IJs/mL in wheat and maize. These findings highlight the potential of S. khuongi and H. downesi as beneficial organisms against several stored-product insect pests. Full article

Entomopathogenic nematodes (EPNs) are crucial biocontrol agents, yet optimizing the yield and quality of infective juveniles (IJs) during commercial liquid production remains challenging. This study utilized a central composite rotatable design to optimize liquid culture parameters (ascaroside, dimethyl sulfoxide, medium volume, IJ inocula) for Heterorhabditis bacteriophora H06 and Steinernema carpocapsae All. The results demonstrated that improving aeration (inferred from reduced media volume), combined with ascr#11 regulation, synergistically enhanced IJ yield and quality. Under optimized conditions, yields reached 3.35 × 10⁵ IJs/mL for H. bacteriophora H06 and 2.67 × 10⁵ IJs/mL for S. carpocapsae All. Crucially, the IJs from the high-yield flask exhibited significantly superior infectivity (24–26% single-IJ infection rate) compared to solid-culture controls (13–14%). Targeted metabolomics profiling of sugar, energy and fatty acids of H. bacteriophora H06 revealed upregulated tricarboxylic acid (TCA) cycle intermediates (citrate, pyruvate) and the significant accumulation of stress-protectant trehalose and immune-modulating polyunsaturated fatty acids (eicosapentaenoic acid, arachidonic acid). These findings establish a fermentation strategy that simultaneously enhances IJ yield and biological quality by reducing media volume (used as a proxy for improved aeration) and supplementing ascr#11. Furthermore, the distinct metabolic profile enriched in energy, stress, and immune-modulating metabolites identified in H. bacteriophora provides a plausible explanatory framework for the parallel phenotypic improvements observed across both species. Full article

Nematodes in the genus Oscheius (Rhabditidae) have traditionally been regarded as free-living bacteriophagous or necromenic associates of insects. Over the past two decades, however, multiple Oscheius species and isolates have been shown to express facultative pathogenicity toward insects and, in some cases, parasitism of mollusks. This has stimulated interest in Oscheius as a complementary group of biological control agents that may function under conditions limiting classical entomopathogenic nematodes (EPNs) of the genera Steinernema and Heterorhabditis. Here, we synthesize current knowledge on Oscheius taxonomy and diversity, life-history strategies, bacterial associations and virulence mechanisms, evidence for control of insect and mollusk pests, and recent advances in chemo-ecology relevant to host finding. We emphasize that Oscheius represents a continuum of ecological strategies, and we adopt conservative terminology in which “entomopathogenic” is reserved for Oscheius species/isolates that meet operational criteria of insect pathogenicity. Finally, we highlight key barriers to wider implementation—strain variability, bacterial partner instability, non-target and community effects, and production/quality control needs—and propose research priorities for the development of robust, field-reliable Oscheius-based biocontrol. Full article

This study evaluated entomopathogenic nematodes (EPNs) isolated from a cacao agroforestry system in the Peruvian Amazon, focusing on their molecular characterization and efficacy against Spodoptera frugiperda (Lepidoptera: Noctuidae) larvae. Thirteen EPN isolates were obtained from 50 soil samples using the Galleria mellonella baiting technique. Mortality assays revealed significant differences among isolates at 24, 48, and 72 h, with isolates 11N-A4 and 8N-B1 being the most virulent, achieving maximum mortalities of 100% and 96.3% at 72 h, respectively. Median lethal time (LT₅₀) values indicated rapid action of these isolates on G. mellonella larvae, with 33.3 h for 11N-A4 and 32.4 h for 8N-B1. Molecular identification using ITS, D2–D3 (LSU), and COI markers confirmed the isolates as Heterorhabditis sp. (11N-A4) and Heterorhabditis amazonensis (8N-B1). In bioassays with S. frugiperda larvae, both EPNs exhibited dose- and time-dependent mortality. H. amazonensis showed rapid action, reaching 100% mortality at the highest dose (60 IJs/larvae) within 48 h, whereas Heterorhabditis sp. displayed a gradual, sustained increase, attaining 91% mortality at 72 h. Median lethal dose (LD₅₀) and LT₅₀ values reflected the efficiency of both isolates, with Heterorhabditis sp. achieving lower LD₅₀ at later stages and shorter LT₅₀ at low-to-intermediate doses. These findings highlight the potential of Heterorhabditis sp. and H. amazonensis as effective biocontrol agents adapted to local conditions and represent the first report of H. amazonensis in Peru. Further studies under field conditions are required to confirm their suitability for incorporation into integrated pest management strategies in the Peruvian Amazon. Full article

The South American tomato pinworm, Tuta absoluta, is a devastating invasive pest that threatens global tomato production, while entomopathogenic nematodes (EPNs) represent promising biocontrol agents. Because a detailed understanding of the molecular basis of the insect immune response is crucial for uncovering how hosts detect and counteract nematode infection, such knowledge may reveal weaknesses exploitable for improved control strategies. However, the molecular mechanisms governing the immune interaction between this pest and EPNs remain poorly understood This study investigated the biocontrol potential of a native Chinese EPN strain, Heterorhabditis indica CQ7-2, against T. absoluta and delineated the host’s molecular immune responses via a time-course transcriptomic analysis. Bioassays revealed that H. indica CQ7-2 LC₅₀ was 1.35 IJs per larva. Comparative transcriptome profiling of larvae revealed that the EPN infection was associated with transcriptional patterns consistent with immunosuppression. Key genes involved in humoral and cellular immunity were significantly suppressed during the early and middle infection stages. Although a widespread upregulation of immune genes occurred after 18 h post-infection (hpi), it was insufficient to prevent host mortality. These findings demonstrate that the virulence of H. indica CQ7-2 is underpinned by associated with modulation of key immune pathways, leading to an ineffective defense response. This work provides deep insights into the molecular arms race between an invasive pest and a native EPN, supporting CQ7-2 as a promising biocontrol agent and providing a framework for understanding host-EPN interactions. Full article

Berry crops such as strawberry Fragaria × ananassa (Weston), raspberry Rubus idaeus L., blackberry Rubus ulmifolius Schott, 1818, and blueberry Vaccinium myrtillus L. are economically and nutritionally valuable worldwide. However, the intensive use of synthetic pesticides for pest management in these crops has led to ecological imbalance, pest resistance, and negative effects on non-target organisms and human health. The integration of biological control agents into sustainable integrated pest management (IPM) systems represents an alternative. This review compiles and evaluates current advances in the application of baculoviruses (BVs), entomopathogenic fungi (EPFs), nematodes (EPNs), predatory mites (PMs), and parasitoid wasps (PWs) for pest suppression in berry crops. Emphasis was placed on their ecological interactions, host specificity, and compatibility within IPM frameworks. The combined use of micro- and macrobiological control agents effectively reduces key pest populations. However, field efficacy remains influenced by abiotic stressors such as UV radiation, temperature fluctuations, and chemical incompatibility. The integration of native micro- and macrobiological control agents of through conservation biological control (CBC) strategies can enhance sustainability in berry production systems. Future efforts should focus on formulation improvements, adaptive management under field conditions, and synergistic interactions among microbial and arthropod natural enemies. Full article

Entomopathogenic nematodes (EPNs), including Steinernema and Heterorhabditis, are obligate insect parasites widely used in biological pest control. However, their efficacy is often limited by susceptibility to environmental stresses like desiccation. Aquaporins (AQPs), channel proteins facilitating water and solute movement across membranes, are hypothesized to play a key role in the osmotic stress response of EPNs. This study identified and cloned three AQP genes (L596_g7661, L596_g18121, and XLOC_007750) from four strains of Steinernema carpocapsae. Bioinformatic analysis confirmed that these AQPs belong to the aquaglyceroporin subfamily and share high sequence homology across strains. Functional characterization in Xenopus oocytes demonstrated that AQP L596_g7661 facilitates glycerol transport. Expression patterns under osmotic dehydration revealed significant upregulation of L596_g7661 and XLOC_007750 in all strains, while L596_g18121 expression remained unchanged. These findings indicate that specific AQPs are involved in the molecular response of S. carpocapsae to osmotic stress, providing crucial insights for breeding resilient EPN strains and enhancing their field application. Full article

The free-living infective juveniles of entomopathogenic nematodes (EPNs) are critical biological control agents against insect pests. The field efficacy of EPNs is largely determined by their tolerance to low-humidity stress, a trait closely linked to the mobilization of their energy reserves. This study aims to investigate how varying levels of humidity stress influence energy reserve dynamics in two EPNs, Steinernema kraussei 0657L and Heterorhabditis brevicaudis 0641TY, and their relationship with the survival rate and pathogenicity. The results demonstrated that lipids were the predominant energy reserve, followed by proteins and sugars. Notably, neutral lipid constituted approximately 3% of the total lipid content. Among sugars, soluble sugar levels were the highest, followed by glycogen and trehalose. Exposure to low-humidity stress resulted in increased levels of protein, total lipid, glycogen, and trehalose in nematodes. These increases were more pronounced in S. kraussei 0657L, a highly drought-resistant strain, compared to H. brevicaudis 0641TY. Furthermore, the accumulation of protein, total lipid, and trehalose was negatively correlated with survival rate and pathogenicity. However, positive correlations were observed between trehalose and both total lipids and soluble sugars. Furthermore, transcriptome analysis revealed that under low-humidity stress, S. kraussei 0657L exhibited an enrichment of differentially expressed genes (DEGs) involved in glycolysis/gluconeogenesis, fatty acid metabolism, and glycerophospholipid metabolism pathways. This indicates that S. kraussei 0657L regulated energy metabolism to adapt to low-humidity stress. These findings provide insights into the mechanisms underlying drought resistance in EPNs and offer an experimental basis for their application in arid environments. Full article

As a staple food, potato (Solanum tuberosum L.) (Solanaceae) is one of the most produced food crops to ensure food security. The potato tuber moth (PTM), Phthorimaea operculella (Zeller, 1873) (Lepidoptera: Gelechiidae), is a major pest of potato, damaging both the growing and storage processes. In recent years, green pest control strategies have been gaining importance to reduce the adverse effects of chemicals and protect the environment. Entomopathogenic nematodes (EPNs) and their bacterial endosymbionts (Xenorhabdus and Photorhabdus spp.) have been one of the top topics studied in sustainable pest control approaches. In the present study, the two most common EPN species, Steinernema feltiae and Heterorhabditis bacteriophora, and their bacterial associates, Xenorhabdus bovienii and Photorhabdus luminescens subsp. kayaii were evaluated against PTM larvae separately and in combination with spinosad. The survival rates of infective juveniles (IJs) of EPNs were over 92% after 72 h of direct exposure to spinosad. Co-application of EPNs and bioactive compounds (BACs) of endosymbiotic bacteria with spinosad induced synergistic interactions and achieved the maximum mortality (100%) in PTM larvae 48 h post-treatment. Spinosad and BAC combinations were highly efficient in controlling the PTM larvae and provided LT₅₀ values below 23.0 h. Gas chromatography mass spectrometry (GC-MS) analysis identified 29 compounds in total, 20 of which belonged to P. luminescens subsp. kayaii. The results indicate that the integration of EPNs and BACs of endosymbiotic bacteria with spinosad presents a synergistic interaction and enhances pest control efficacy. Full article

Entomopathogenic nematodes (EPNs) are valuable biological control agents and research models in agriculture and ecology. Traditional extraction and rearing methods for EPNs, such as the Baermann funnel and White trap, work well but have limitations in efficiency and practicality. The NEMA Device, constructed from PVC components, was designed to address these limitations by combining extraction and rearing into a single tool with improved portability, scalability, and ease of use. The efficiency of the NEMA Device was evaluated by comparing it to the conventional Baermann funnel extraction method and the White trap method for nematode multiplication. Validation of the instrument was performed using two nematode species, Steinernema khuongi and Heterorhabditis bacteriophora, which vary in size and can be used for pest control. Our results demonstrated that the NEMA Device achieved higher recovery rates of both S. khuongi and H. bacteriophora compared to the Baermann method. Additionally, the production rate of nematodes using the NEMA Device was comparable to that of the White trap method, with no significant difference observed between the two methods. The NEMA Device offers a standardized, cost-effective methodology for the extraction and multiplication of EPNs, enhancing the accessibility and efficiency of studying these agriculturally important nematodes and potentially improving biological control outcomes. Full article

Insect pests cause severe damage and yield losses to many agricultural crops globally. The use of chemical pesticides on agricultural crops is not recommended because of their toxic effects on the environment and consumers. In addition, pesticide toxicity reduces soil fertility, poisons ground waters, and is hazardous to soil biota. Therefore, applications of entomopathogenic nematodes (EPNs) and plant growth-promoting rhizobacteria (PGPR) are an alternative, eco-friendly solution to chemical pesticides and mineral-based fertilizers to enhance plant health and promote sustainable food security. This review focuses on the biological and ecological aspects of these organisms while also highlighting the practical application of molecular communication approaches in developing a novel plant health product. This insight will support this innovative approach that combines PGPR and EPNs for sustainable crop production. Several studies have reported positive interactions between nematodes and bacteria. Although the combined presence of both organisms has been shown to promote plant growth, the molecular interactions between them are still under investigation. Integrating molecular communication studies in the development of a new product could help in understanding their relationships and, in turn, support the combination of these organisms into a single plant health product. Full article

This study investigates the potential of entomopathogenic nematodes (EPNs) as biological control agents by exploring their occurrence and diversity in Amazcala, Querétaro. The aim was to characterise their distribution and evaluate their pathogenicity against insect pests. Soil samples were collected from various agricultural lands, followed by laboratory isolation and the molecular identification of EPN species. Morphological and genetic analyses confirmed the presence of several species with distinct pathogenic profiles. Pathogenicity assays using the larval stages of Galleria mellonella and Tenebrio molitor revealed that Heterorhabditis bacteriophora and Heterorhabditis atacamensis exhibited significant virulence, with Galleria mellonella being more susceptible. Among the 12 recovered EPN isolates, three strains—AMZX05 (Heterorhabditis atacamensis), AMZX10 (Heterorhabditis bacteriophora), and AMZX13 (Heterorhabditis atacamensis)—demonstrated particularly high pathogenic potential. These strains represent promising candidates for biological control and could contribute to sustainable integrated pest management (IPM) strategies. Further research is recommended to optimise their application across diverse agroecosystems. Full article

Cockroaches, particularly the German cockroach (Blattella germanica Linnaeus, Blattodea: Ectobiidae) and the American cockroach (Periplaneta americana (Linnaeus), Blattodea: Blattidae), are major public health pests due to their ability to transmit pathogens and develop resistance to chemical insecticides, including synthetic pyrethroids, which are widely used worldwide. Given the increasing resistance, entomopathogenic nematodes (EPNs) have emerged as a potential biological control alternative. This study evaluates the efficacy of three EPN species, Steinernema carpocapsae (Weiser), S. feltiae (Filipjev), and Heterorhabditis bacteriophora Poinar, against B. germanica and P. americana collected from different regions of Antalya, Türkiye. Laboratory bioassays were conducted under controlled conditions, testing five EPN concentrations (100, 250, 500, 750, and 1000 IJs/mL). The results showed that S. carpocapsae was the most effective, causing mortality rates of 46.7% to 100% in adult German cockroaches and 20% to 66.7% in nymphs, while S. feltiae and H. bacteriophora exhibited lower efficacy. American cockroaches showed higher resistance, with S. carpocapsae achieving a maximum mortality of 33.3% at the highest concentration, whereas S. feltiae and H. bacteriophora had no significant lethal effect. These findings suggest that S. carpocapsae could be a promising biological control agent for B. germanica, particularly in pyrethroid-resistant populations. Full article