Search Results (85)

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

The hazelnut weevil larvae (Curculio dieckmanni) is a major pest of nut weevils, spending part of its life cycle in the soil and causing significant damage to hazelnut crops. Moreover, its concealed feeding behavior complicates effective control with chemical insecticides. The entomopathogenic nematode Steinernema carpocapsae, which efficiently kills weevil larvae, offers a promising biological control agent. To investigate the molecular responses of hazelnut weevil larvae to nematode infection, we employed integrated transcriptomic and proteomic analyses following infection by S. carpocapsae. Our results revealed substantial alterations in gene expression, particularly the upregulation of immune-related transcripts such as antimicrobial peptides (AMPs) and stress-responsive proteins like heat shock protein 70 (HSP70). Furthermore, significant metabolic reprogramming occurred, marked by the downregulation of carbohydrate metabolic pathways and activation of energy conservation mechanisms. Although we observed an overall correlation between mRNA and protein expression levels, notable discrepancies highlighted the critical roles of post-transcriptional and post-translational regulatory processes. Collectively, these findings advance our understanding of the molecular interaction between insect hosts and pathogenic nematodes and contribute valuable knowledge for enhancing the effectiveness of EPN-based pest management strategies. Full article

The tarnished plant bug, Lygus lineolaris Palisot de Beauvois (Hemiptera: Miridae), is an economically important pest of row crops worldwide. Ten isolates of entomopathogenic nematodes (EPNs) (Rhabditida: Steinernematidae and Heterorhabditidae) were evaluated against the third instar nymphal stage of the tarnished plant bug and its generalist predator, the sculpted damsel bug, Nabis roseipennis Reuter (Hemiptera: Nabidae), one of the most abundant and commonly encountered damsel bugs in cotton and soybean agroecoscapes across the Southeastern United States. The objectives of these experiments were to assess the infectivity of entomopathogenic nematodes (EPN) by direct topical exposure against the sculpted damsel bug and tarnished plant bug, whether the predator prey choice is affected by EPN infection, and if feeding on EPN-infected tarnished plant bug (TPB) prey items could result in cross-infection of the predator. Mortality rates at a concentration of 200 infective juveniles (IJs)/mL significantly differed among isolates and insect species, ranging from 30% to 93% for tarnished plant bugs and from 6% to 38% for sculpted damsels, respectively. The third instars of L. lineolaris were more susceptible to the ten nematode isolates than N. roseipennis. Higher pathogenicity on the tarnished plant bug and a low mortality potential make strains HbHP88, HbVS, Sc17c+e, and SfSN the most promising candidates for the biological control of L. lineolaris under lab and greenhouse conditions while preserving beneficial predators of the Southeastern United States. Full article

Dissolved biochar (DBC) can make a significantly impact on soil ecosystems and the associated biota due to its high environmental bioavailability. However, the impact of DBC on the adaptability of entomopathogenic nematodes (EPNs), such as Steinernema feltiae, remains uncertain. This study investigates the impact of DBC on oxidative stress, antioxidant enzyme activity, virulence, and gene expression in EPNs through culture assays and RNA-seq analysis. Results showed that DBC exposure significantly increased the accumulation of reactive oxygen species (ROS) accumulation. The nematodes treated with DBC700 exhibited 64.34% higher ROS levels, while those treated with DBC400 had 51.13% higher levels compared to the control. Superoxide dismutase (SOD) and catalase (CAT) activities were significantly suppressed, with a stronger inhibition observed in the DBC700 group. As revealed by virulence assays, DBC treatment reduced the infectivity of EPNs against Galleria mellonella larvae. Transcriptome analysis revealed that DBC primarily affected oxidative stress response, membrane transport, and longevity regulation pathways. Moreover, DBC400 predominantly inhibited carbohydrate metabolism, whereas DBC700 significantly impacted oxidative metabolism, protein processing, and neuronal signaling pathways, suggesting the presence of distinct metabolic adaptation mechanisms between the two DBCs. Overall, this study suggests that DBC may impair the biocontrol efficacy of S. feltiae through oxidative stress and genetic perturbations, providing new insights into its long-term ecological impacts on soil ecosystems. Full article

The growing reliance on chemical pesticides in agriculture has raised significant concerns about their environmental and health impacts. This study investigates the potential of Indigenous entomopathogenic nematodes (EPNs), specifically Steinernema pakistanense and Heterorhabditis indica, as biological control agents for Leucinodes orbonalis, the brinjal fruit and shoot borer, a major pest in Karachi, Sindh, Pakistan. A comprehensive soil sampling was carried out across 30 locations. Molecular identification via PCR and sequencing confirmed the taxonomic classification of the isolated strains, showing high genetic similarity to known EPN species. The reproductive potential of the isolated strains varied, with Pak.S.SA.22 exhibiting the highest fecundity, averaging 91,944 offspring per larva, indicating strong biocontrol potential. Laboratory bioassays at different concentrations showed that Pak.S.SA.22 achieved 100% mortality of L. orbonalis at a concentration of 200 IJs/mL, confirming its effectiveness. Field trials further validated these findings, demonstrating up to 90% pest control efficacy over multiple application intervals, highlighting the practical applicability of this strain in field conditions. These results advocate for the inclusion of indigenous EPNs in integrated pest management (IPM) programs as a sustainable, environmentally friendly alternative to chemical pesticides, contributing to the promotion of sustainable agricultural practices. Full article

The efficacy of entomopathogenic nematodes (EPNs), Steinernema feltiae and Heterorhabditis bacteriophora, for controlling Frankliniella occidentalis (Thysanoptera: Thripidae, Pergande, 1895) in nectarine orchards, was evaluated, alongside their potential impact on honeybees (Apis mellifera, Hymenoptera: Apidae, Linnaeus, 1785). Field trials revealed that S. feltiae significantly reduced thrips populations and fruit damage compared to the control, while H. bacteriophora showed no significant effect. The reduction in feeding scars on fruits from S. feltiae–treated trees underscores its potential as a sustainable biocontrol agent. However, laboratory bioassays indicated that another EPN, Steinernema carpocapsae, induced delayed mortality in honeybees under high-exposure conditions, pinpointing the need for careful application to minimize risks to pollinators. These findings demonstrate the potential of S. feltiae for integrated pest management (IPM) in nectarine cultivation while emphasizing the importance of species-specific selection and pollinator safety. Future research should focus on optimizing application methods, understanding environmental influences on EPN efficacy, and assessing long-term impacts on pollinator health to ensure sustainable pest management practices. Full article

Lycoriella ingenua (Dufour) is a major pest in mushroom facilities in Serbia and worldwide. The study aimed to determine the virulence (in vitro) and effectiveness (in vivo) of three Serbian native populations of entomopathogenic nematodes (EPNs) Steinernema feltiae (Filipjev), P9, K2, and ZŠT, compared to a commercial population of S. feltiae against L. ingenua, and their impact on mushroom yield. In vitro bioassays showed that seven days after exposure to a series of nematode suspensions (IJ cm⁻²), two of the three native (P9 and K2) populations and the commercial population of S. feltiae caused significant mortality of L₄ instar larvae of L. ingenua. The following LC_50s were estimated: 18.47, 15.77, and 11.48 IJ cm⁻² for P9, K2, and the commercial populations, respectively. These populations were further used for in vivo bioassays, where their IJs were applied as drench treatment twice (at the rate of 75 IJ cm⁻²) during casing time and seven days later. Control of L. ingenua larvae with the commercial population of S. feltiae was 85%, while the effectiveness of the native populations was 70%. The lack of adequate pest control measures emphasizes a need to promote local EPNs as biologically based and ecotoxicologically safe products. Full article

The substrate for button mushroom (Agaricus bisporus) cultivation includes a highly complex microbiome. The aim of the study was to evaluate ecological interactions (synergistic, antagonistic, or additive) between a commercial population of the entomopathogenic nematode Steinernema feltiae (EPN) and beneficial microorganisms, bacterium Bacillus amyloliquefaciens B-241 (BA) or actinobacterium Streptomyces flavovirens A06 (SF). Their relationships were evaluated in efficacy against the pathogenic fungus Trichoderma aggressivum and the fungus gnat Lycoriella ingenua. Moreover, their impact on mushroom yield was estimated. The synergy factor was calculated as the ratio of observed to expected values regarding their efficacy against T. aggressivum/L. ingenua and influence on mushroom production. Additive relationships in efficacy against T. aggressivum were observed between EPN and BA or SF. As for the impact on yield, synergistic interactions were indicated between each beneficial microorganism and EPN. Considering suppression of L. ingenua, a mild antagonistic reaction between EPN and each beneficial microorganism was observed in plots without T. aggressivum and additive in plots inoculated with the pathogenic fungus, although high efficacy was achieved in all combinations (>80%). Tested native strains of both beneficial microorganisms could be combined with the commercial EPN strain for successful biological pest and disease control in mushroom production. Full article

Non-target organisms are not well studied. The objective of this work was to evaluate the effect of seven essential oils, two fixed oils, d-limonene and eugenol on the mortality, behavior and infectivity of entomopathogenic nematodes (ENPs). The oils were diluted at 1% (v/v) in water with Tween^® 80 PS at 0.05% (v/v), and water with Tween^® alone was used as the control treatment. In the mortality test, 2 mL of solution containing 50 µL of the nematode suspension, 20 µL of oil/compounds solution isolated with Tween 80, and 1930 µL of water were placed in plastic containers. After four days, the number of dead juveniles was counted. In the bioassay of the behavior of the EPNs, the frequency of lateral body beats of the infective juveniles in liquid medium was analyzed after exposure to the solutions. In the infectivity test, after contact of the EPNs with oils and essential oil chemical compounds, the juveniles were washed and applied to second-instar Spodoptera eridania larvae. All oils and isolated compounds caused mortality in H. amazonensis and S. rarum, with Ocimum canum and the isolated compound eugenol showing the highest efficacy against H. amazonensis and O. canum, Eucalyptus citriodora, Zingiber officinale, Salvia sclarea and the isolated compound eugenol being the most effective against S. rarum. There was a reduction in the number of lateral beats of H. amazonensis and S. rarum for all treatments, with the exception of Cymbopogon winterianus in H. amazonensis and Annona muricata in S. rarum. The infectivity of H. amazonenis and S. rarum on S. eridania was reduced when exposed to the solutions, with the exception of the isolated compound d-limonene in both species, soursop for H. amazonenis and rosemary for S. rarum, which were classified as non-toxic to the species tested. The results obtained in this study may be useful for the choice of oils and essential oil chemical compounds with potential use in integrated pest management programs. Full article

The tomato leaf miner Phthorimaea (syn. Tuta) absoluta Meyrick (Lepidoptera: Gelechiidae) is invasive in many agricultural regions. Its larvae feed inside leaf mines or tomato fruits and are difficult to reach with plant protection products. In contrast, entomopathogenic nematodes (EPNs) are highly virulent and can search for larvae. The challenge is to formulate EPNs to remain protected on a sprayed leaf surface until they enter the mines. We tested 11 formulations, including 2 oils, 4 gels or thickeners, 2 surfactants, 2 UV protectants, water, and combinations with and without the EPN Steinernema carpocapsae (Weiser) RW14-G-R3a-2 (Rhabditida: Steinernematidae), under non-closed low-humidity conditions. Six tomato leaf experiments with 1000 EPNs sprayed per leaf showed that EPNs in 0.25 to 0.5% canola oil or in 5% alkyl polyglycoside surfactant were the most effective (26 to 37%). Other formulations and an insecticide had less or no effect. Seven other bioassays showed that most formulations did not adversely affect EPN survival or pathogenicity. We assume that formulations of EPNs can be further improved, such as with other flowable gels or combinations, and encourage investment in the development of practical and economic protective sprayable formulations of EPNs against leaf miners to reduce reliance on chemical insecticides. Full article

White grubs possess natural defense mechanisms against entomopathogenic nematodes (EPNs). Hence, EPN isolates that naturally infect white grubs tend to be among the most effective biological control agents of white grubs. We tested the virulence of four EPN isolates recently isolated from infected white grubs in turfgrass areas in central New Jersey, USA against third-instar larvae of Anomala orientalis, Popillia japonica, and Cyclocephala borealis, which are pests of turfgrass and ornamental plants in the northeastern USA. Against A. orientalis and P. japonica larvae, the Steinernema scarabaei Ad and S. scarabaei SL isolates were highly virulent in laboratory tests, whereas S. cubanum HF was less virulent and S. glaseri SH the least virulent. None of the isolates caused high mortality of C. borealis larvae. EPN efficacy in greenhouse tests against A. orientalis followed the same pattern. The original isolate of S. scarabaei, the AMK001 strain, that had been maintained in the laboratory on A. orientalis and P. japonica larvae for 19 years showed the same virulence level against A. orientalis larvae as it did soon after its first isolation and was also as virulent as the fresh S. scarabaei Ad isolate; both isolates were more virulent than S. scarabaei SL. Future tests should determine the ability of these white grub-adapted isolates to provide long-term suppression of white grub populations. Full article

The large pine weevil (Hylobius abietis L.) is a major pest in European and Asian coniferous forests, particularly in managed plantations where clear-felling practices create ideal conditions for its population growth. Traditional management practices involving synthetic insecticides have limited efficacy in terms of reducing pest populations and pose environmental risks. This study evaluated the effectiveness of a wild entomopathogenic fungus (EPF) and the commercial entomopathogenic nematode Steinernema carpocapsae (EPN) as biological control agents (BCAs) against H. abietis in clear-felled spruce plantations in Wales and Scotland. Field trials used a randomised block design with three treatments (EPN full dose, EPF full dose and a combination of EPF+EPN at half doses each) compared to a control. Emergence trapping and destructive sampling were employed to assess treatment efficacy. All treatments significantly reduced weevil emergence, with the mixed treatment showing the greatest impact. Destructive sampling revealed strong associations between treatment type and infection outcomes in H. abietis, with a small but significant relationship between weevil developmental stages and infection types. Importantly, the treatments had no significant impact on the total abundance or taxon richness of non-target invertebrates. These findings suggest that wild EPFs alone and combined with EPNs are effective and environmentally safe alternatives to synthetic insecticides for managing H. abietis populations in managed forests. Full article

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. Full article