Strains Of Entomopathogenic Fungi Research Articles

Efficacy of entomopathogenic fungi against Philaenus spumarius, the vector of Xylella fastidosa.

Xylella fastidiosa is an important causative agent of Olive Quick Decline Syndrome in the Apulia region of Italy. The current study evaluated the bioefficacy of three entomopathogenic fungal strains: Beauveria bassiana SGB7004, Metarhizium robertsii SGB1K, and Akanthomyces lecanii SGB4711 against Philaenus spumarius the main vector of this pathogen, under laboratory conditions. Pathogenicity bioassays were performed by dipping nymphs and adults of P. spumarius in an aqueous suspension of powdered fungal culture (PFC) or conidial suspension (CS) of the three fungal strains. Both B. bassiana SGB7004 and M. robertsii SGB1K affected the viability of nymphs, resulting in more than 80% mortality at 48 h post treatment, while the effect of A. lecanii SGB4711 was not statistically significant. On adults, all three biocontrol strains were effective in a time- and concentration-dependent manner. The PFCs of B. bassiana SGB7004, M. robertsii SGB1K, and A. lecanii SGB4711 at the highest concentration tested (120 mg mL-1) resulted in 97%, 83% and 27% mortality at the trial endpoint (120 h), respectively. Mycelial growth was observed on 38.5%, 37.0% and 61.5% of dead insects treated with B. bassiana SGB7004 (2.3 × 108 CFU mL-1), M. robertsii SGB1K (3.8 × 106 CFU mL-1) and A. lecanii SGB4711 (5.4 × 108 CFU mL-1), respectively. None of the PFCs of the tested strains was pathogenic when injected into nymph spittle. Beauveria bassiana SGB7004 and M. robertsii SGB1K significantly affected the survival of P. spumarius nymphs and adults, while A. lecanii SGB4711 was not effective on nymphs and only slightly effective against adults. © 2024 Society of Chemical Industry.

Entomopathogenic Fungi in Forest Habitats of Ixodes ricinus.

(1) Background: In addition to the microclimate, host availability, and tick microbiota, soil environmental microorganisms can affect tick populations. This study aimed to (1) determine the presence and diversity of entomopathogenic fungi (EF) in forests, where ticks are abundant, and (2) estimate the effectiveness of the isolated EF strains against Ixodes ricinus. (2) Methods: EF were isolated using the trap insect method from soil collected from tick sites. A bioassay was used to estimate the effectiveness of EF against ticks. (3) Results: The presence of EF was found in all tested forest habitat types. A total of 53 strains belonging to the genera Metarhizium, Beauveria, and Isaria were isolated. All the six strains subjected to the bioassay showed potential efficacy against both adult and nymphal stages of I. ricinus; however, the strains differed in their effectiveness. The most effective isolate against I. ricinus was the soil environmental strain of Metarhizium anisopliae. (4) Conclusion: The study indicates that tick habitats can be the source of entomopathogenic fungi, which have a lethal effect on ticks, as demonstrated in preliminary laboratory tests with I. ricinus. However, for practical use, extensive field tests and further research on application methods and long-term effects are necessary to develop effective and sustainable tick management strategies.

Multienzymatic biotransformation of flavokawain B by entomopathogenic filamentous fungi: structural modifications and pharmacological predictions

BackgroundFlavokawain B is one of the naturally occurring chalcones in the kava plant (Piper methysticum). It exhibits anticancer, anti-inflammatory and antimalarial properties. Due to its therapeutic potential, flavokawain B holds promise for the treatment of many diseases. However, due to its poor bioavailability and low aqueous solubility, its application remains limited. The attachment of a sugar unit impacts the stability and solubility of flavonoids and often determines their bioavailability and bioactivity. Biotransformation is an environmentally friendly way to improve the properties of compounds, for example, to increase their hydrophilicity and thus affect their bioavailability. Recent studies proved that entomopathogenic filamentous fungi from the genera Isaria and Beauveria can perform O-methylglycosylation of hydroxyflavonoids or O-demethylation and hydroxylation of selected chalcones and flavones.ResultsIn the present study, we examined the ability of entomopathogenic filamentous fungal strains of Beauveria bassiana, Beauveria caledonica, Isaria farinosa, Isaria fumosorosea, and Isaria tenuipes to transform flavokawain B into its glycosylated derivatives. The main process occurring during the reaction is O-demethylation and/or hydroxylation followed by 4-O-methylglycosylation. The substrate used was characterized by low susceptibility to transformations compared to our previously described transformations of flavones and chalcones in the cultures of the tested strains. However, in the culture of the B. bassiana KCh J1.5 and BBT, Metarhizium robertsii MU4, and I. tenuipes MU35, the expected methylglycosides were obtained with high yields. Cheminformatic analyses indicated altered physicochemical and pharmacokinetic properties in the derivatives compared to flavokawain B. Pharmacological predictions suggested potential anticarcinogenic activity, caspase 3 stimulation, and antileishmanial effects.ConclusionsIn summary, the study provided valuable insights into the enzymatic transformations of flavokawain B by entomopathogenic filamentous fungi, elucidating the structural modifications and predicting potential pharmacological activities of the obtained derivatives. The findings contribute to the understanding of the biocatalytic capabilities of these microbial cultures and the potential therapeutic applications of the modified flavokawain B derivatives.

INTEGRATED PEST MANAGEMENT STRATEGIES USING ENDOPHYTIC ENTOMOPATHOGENIC FUNGI

Insect pests harm crops severely and disperse a wide range of diseases that are transmitted by insects. Chemical pesticides are frequently used to manage them. Due to their constant usage over many years, insect pests have become increasingly resistant to practically all kinds of chemical pesticides, which has increased the demand for alternatives. For effective and environmentally safe insect pest control, insect pathogenic fungi are seen to be a viable alternative to practically all kinds of conventional pesticides. However, the viability of this strategy is being constrained by the sluggish death rate and necessity of large conidial concentrations. The ability of these fungi to regulate insects has previously been examined, but more recent research has focused on their potential to operate as plant endophytes to protect plants from phytopathogens and enhance other elements of agricultural output. The significance of these entomopathogenic fungi as endophytes in the context of biological control is discussed in this article. Finding local strains of entomopathogenic fungi that can colonise endophytes and their possible utility in the management of disease-causing pests are the main goals of our research for this review.

Entomopathogenic fungi against the red palm weevil: Lab and field evidence

Palms are threatened by a major pest, the red palm weevil, Rhynchophorus ferrugineus (Olivier) (Coleoptera: Curculionidae). The damage caused by its infestation is costly, often resulting in the removal of affected trees and the need for additional treatments to halt the pest's spread. The larvae's development and feeding activities within the trunk cause extensive damage to the trees. However, the lack of early infestation signs worsens the spread of the attack. While chemical treatments are effective, they pose issues such as pest resistance, worker health risks, and environmental concerns. Entomopathogenic fungi (EPF) such as Beauveria bassiana, Metarhizium anisopliae, Isaria fumosorosea, and Lecanicillium lecanii, are a promising alternative for managing RPW infestations. This literature review delves into the biology, ecology, and infection process of EPF and RPW, as well as the factors influencing the effectiveness of EPF against R. ferrugineus throughout its life cycle. The review also assesses the various EPF application and delivery methods along with the challenges and risks associated with their field use. It summarizes the results of various studies that tested the ability of EPF to control RPW in the laboratory and in the field, comparing the efficacy of different species and strains of EPF. The review concludes that EPF can significantly reduce RPW populations and damage, particularly when used in conjunction with other control methods like pheromone traps, insecticides, and sanitation. However, it also underscores the need for additional research and development to optimize the use of EPF for R. ferrugineus management and ensure their safety and sustainability.

Effect of Selected Entomopathogenic Fungal Species on Embryonic Development of Ascaris suum (Nematoda).

The aim of the study was to evaluate the potential of using five selected species of entomopathogenic fungi (Beauveria bassiana, B. brongniartii, Conidiobolus coronatus, Isaria fumosorosea, and Metarhizium robertsii) in the bioregulation of the dispersive stages of the parasitic nematode-Ascaris suum. Experimental cultures of each of the selected entomopathogenic fungi, as well as a control culture without fungi, were incubated with A. suum eggs at 26 °C for 28 days. Development of the A. suum eggs was observed using a light microscope on the 7th, 14th, 21st, and 28th days of incubation. The API-ZYM® test was used to determine, semiquantitatively, the activity of 19 hydrolytic enzymes from the entomopathogenic fungi. The cytotoxicity of the fungi was determined using tetrazole salt MTT. It was found that none of the five tested strains of entomopathogenic fungi showed an ovicidal effect, and none of them colonized the A. suum egg shells. However, ovistatic activity was observed mainly until the 14th day of incubation by I. fumosorosea, M. robertsii, and B. bassiana. In the MTT test, M. robertsii showed moderate cytotoxicity, while the other species showed low cytotoxicity. Among the strains tested, I. fumosorosea showed the highest spectrum of hydrolase production (13 out of 19 enzymes gave a positive reaction from 3 to 5; 20-40 nM or more). The absence of morphological changes in the A. suum egg shells suggests that the antagonistic effect of the studied entomopathogenic fungi may be due to their cytotoxicity, associated with the production of secondary metabolites-toxins (M. robertsii) and enzymatic activity (I. fumosorosea).

Development of potential microbial agents with two new entomopathogenic fungal strains to control the red palm weevil Rhynchophorus ferrugineus (Olivier) (Coleoptera: Curculionidae)

BackgroundEntomopathogenic fungi, representing a class of microbial agent, have been widely used in the field of pest management. The objective of this work was to isolate different species of fungi and to evaluate their virulence against the destructive and invasive red palm weevil (RPW), Rhynchophorus ferrugineus (Olivier) (Coleoptera: Curculionidae).ResultsTwo new entomopathogenic fungal strains isolated from dead diseased RPWs were identified as Metarhizium anisopliae ZZ-A1 and Fusarium oxysporum ZZ-L1 using growth characteristics, morphology, and rDNA-ITS sequence amplification. Bioassays showed that M. anisopliae ZZ-A1 strain exhibited significantly higher corrected mortality than F. oxysporum ZZ-L1 strain (90.92 vs. 77.28%) in fourth instar RPW larvae 12 days after treatment with a concentration of 1.0 × 1010 conidia/ml, as well as low median lethal concentration (LC50) and median lethal time (LT50) values.ConclusionsThe results suggest that both fungal isolates can potentially be developed as effective and persistent a microbial agent against this widespread pest, RPW. However, M. anisopliae ZZ-A1 showed relatively higher insecticidal activity than F. oxysporum ZZ-L1.

The effects of Beauveria bassiana infection on the gene expression profiles of Diaphorina citri adults

The Asian citrus psyllid, Diaphorina citri Kuwayama, is a citrus pest worldwide. This pest transmits the pathogens of Huanglongbing, Candidatus Liberibacter asiaticus (CLas), and has led to huge economic losses. The use of chemical pesticides is the first choice for field pest control, while resistance, resurgence, and residue (3R) problems have received widespread attention. Biological control is an optional and effective method for D. citri management and needs to be developed. In this study, eleven entomopathogenic fungi strains were collected, and their morphologies were recorded. After blasting with the ITS sequences, eight strains were identified as Beauveria bassiana, and three strains were Metarhizium anisopliae. The pathogenicity of these fungi on D. citri adults at 1.0 × 107 conidia/mL was tested, with the LT50 ranging from 4.764 to 8.551. The virulence of B. bassiana strain XM-D1 was further evaluated, and the LC50 was 4.93 × 105 conidia/mL. A total of 155 and 894 differentially expressed genes (DEGs) were identified in the samples after 24 and 48 h of XM-D1 infection, respectively. Further analyses found that the pathways of apoptosis, cholesterol metabolism, fatty acid biosynthesis, and vitamin digestion and absorption could be involved in the response of D. citri adults to 48 h of infection, and DEGs encoding chaperone proteins, cuticle protein 12.5, P450s, and lysozymes may play important roles in immune defense. Our preliminary findings enrich the entomopathogenic fungi repository and shed light on the defense mechanism of D. citri in response to B. bassiana infection at the molecular level.

Efficacy of entomopathogenic fungi against three major stored insect pests, Rhyzopertha dominica, Sitophilus zeamais and Trogodermagranarium

The use of biological control agents such as pathogens and natural enemies could be helpful in reducing reliance on synthetic non-selective insecticides and environmental pollution. Entomopathogenic fungi act as pathogens for insect pests and could be a good alternative to insecticides. In the present work, control potential of six native entomopathogenic fungi: Aspergillus nidulans, Aspergillus fumigatus, Cladosporium cladosporioides, Metarhizium flavoviride, Penicillium citrinum and Trichoderma harzianum, was evaluated against three major stored insect pests, Rhyzopertha dominica, Sitophilus zeamais and Trogoderma granarium, under laboratory conditions. Four doses of each fungal isolate viz., 1 × 104, 1 × 106, 1 × 108 and 1 × 1010 conidia/kg wheat grains were evaluated in terms of adult mortality and progeny suppression of subsequent generation. Bioassays were performed in an incubator with 30 °C, 65% relative humidity and without lighting, and the vials were observed after 7, 14, and 21 d post exposure to calculate mortality of introduced adults. The results revealed that insects’ mortality was dose and time dependent. In most of the cases, M. flavoviride caused the highest mortality and progeny suppression of all tested insect species followed by T. harzianum and C. cladosporioides, while the lowest were observed against A. nidulans followed by A. fumigatus and P. citrinum. Overall, R. dominica was the most susceptible species to all fungal isolates followed by S. zeamais and T. granarium. In summary, the data of the present work indicate a significant potential of tested entomopathogenic fungi as biological control agents against R. dominica, S. zeamais and T. granarium. Further studies are recommended to evaluate control potential of these entomopathogenic fungi against stored insect pests under storage environment. Evaluation of more virulent strains of entomopathogenic fungi and their isolates, development of suitable formulation(s), and standardizing mode application will also be the questions for future research.

Synergized toxicity exhibited by indigenous entomopathogenic fungal strains, plant extracts and synthetic insecticides against fall armyworm Spodoptera frugiperda (J.E. Smith) under laboratory and semi-field conditions

Synergized toxicity exhibited by indigenous entomopathogenic fungal strains, plant extracts and synthetic insecticides against fall armyworm Spodoptera frugiperda (J.E. Smith) under laboratory and semi-field conditions

Effects of tomato inoculation with the entomopathogenic fungus Metarhizium brunneum on spider mite resistance and the rhizosphere microbial community.

Entomopathogenic fungi have been well exploited as biocontrol agents that can kill insects through direct contact. However, recent research has shown that they can also play an important role as plant endophytes, stimulating plant growth, and indirectly suppressing pest populations. In this study, we examined the indirect, plant-mediated, effects of a strain of entomopathogenic fungus, Metarhizium brunneum on plant growth and population growth of two-spotted spider mites (Tetranychus urticae) in tomato, using different inoculation methods (seed treatment, soil drenching and a combination of both). Furthermore, we investigated changes in tomato leaf metabolites (sugars and phenolics), and rhizosphere microbial communities in response to M. brunneum inoculation and spider mite feeding. A significant reduction in spider mite population growth was observed in response to M. brunneum inoculation. The reduction was strongest when the inoculum was supplied both as seed treatment and soil drench. This combination treatment also yielded the highest shoot and root biomass in both spider mite-infested and non-infested plants, while spider mite infestation increased shoot but reduced root biomass. Fungal treatments did not consistently affect leaf chlorogenic acid and rutin concentrations, but M. brunneum inoculation via a combination of seed treatment and soil drenching reinforced chlorogenic acid (CGA) induction in response to spider mites and under these conditions the strongest spider mite resistance was observed. However, it is unclear whether the M. brunneum-induced increase in CGA contributed to the observed spider mite resistance, as no general association between CGA levels and spider mite resistance was observed. Spider mite infestation resulted in up to two-fold increase in leaf sucrose concentrations and a three to five-fold increase in glucose and fructose concentrations, but these concentrations were not affected by fungal inoculation. Metarhizium, especially when applied as soil drench, impacted the fungal community composition but not the bacterial community composition which was only affected by the presence of spider mites. Our results suggest that in addition to directly killing spider mites, M. brunneum can indirectly suppress spider mite populations on tomato, although the underlying mechanism has not yet been resolved, and can also affect the composition of the soil microbial community.

Popillia japonica - Italian outbreak management.

Popillia japonica, a priority pest for the EU, was first detected in Northern Italy in 2014. Since its discovery, the outbreak extended over an area of more than 16,000 square kilometers in Northern Italy and Southern Switzerland. In this review, we summarize the state-of-the-art of research conducted in Italy on both the spreading capacity and control measures of P. japonica. Chemical, physical, and biological control measures deployed since its detection are presented, by highlighting their strengths and weaknesses. An in-depth study of the ecosystems invaded by P. japonica disclosed the presence and pathogenicity of natural strains of entomopathogenic fungi and nematodes, some of which have shown to be particularly aggressive towards the larvae of this pest under laboratory conditions. The Plant Health authorities of the Lombardy and Piedmont regions, with the support of several research institutions, played a crucial role in the initial eradication attempt and subsequently in containing the spread of P. japonica. Control measures were performed in the infested area to suppress adult populations of P. japonica by installing several traps (e.g., for mass trapping, for auto-dissemination of the fungus Metarhizium anisopliae, and "attract & kill"). For larval control, the infested fields were treated with commercial strains of the entomopathogenic fungus M. anisopliae and nematode Heterorhabditis bacteriophora. Future studies will aim at integrating phenological and spread models developed with the most effective control measures, within an ecologically sustainable approach.

The infection efficacy of Metarhizium strains (Hypocreales: Clavicipitaceae) against the Queensland fruit fly Bactrocera tryoni (Diptera: Tephritidae).

The Queensland fruit fly (Qfly), Bactrocera tryoni Froggatt, is a devastating pest of Australia's commercial fruit systems. Fruit fly mitigation is heavily centered around the use chemical insecticides, with limited investigation into microbial control alternatives. The wet tropics of northern Queensland is a highly biodiverse ecosystem containing many species of insect pathogenic fungi, but it is unclear whether any of these entomopathogens could contribute to Qfly management programs. In laboratory trials, we investigated the potential for Qfly microbial control by 3 locally sourced strains of entomopathogenic fungi comprising 2 species, Metarhizium guizhouense (Chen and Guo) and Metarhizium lepidiotae (Driver and Milner). Additionally, we evaluated 2 different inoculation methods to derive the most effective way to expose the flies to conidia-either through dry conidia or in a conidial suspension. All 3 strains were successful in causing Qfly mortality. Metarhizium lepidiotae resulted in the highest mean mortality over the trials, while M. guizhouense resulted in the highest mortality in a single replicate. Laboratory experiments revealed exposure through dry conidia to be the most effective method to inoculate the flies. These results suggest that fungal entomopathogens could be a viable pathway to Qfly suppression.

Efficacy of endophytic wild strains of entomopathogenic fungi against the tomato leafminer Tuta absoluta Meyrick) (Lepidoptera: Gelechiidae) in tomato plants

BackgroundTomato (Solanum lycopersicum L.) is a vegetable of great economic value. The tomato leafminer Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) is a serious pest of tomato. Its control is difficult due to the protection of the larvae in the galleries they create its fast resistance development too many active ingredients and due to its many generations per year. Many entomopathogenic fungi (EPF) have been reported as endophytes for various plant pathogens and pests. In this study, the endophyticity of Beauveria bassiana Balsamo (Vuillemin) (Hypocreales: Cordycipitaceae) and Metarhizium anisopliae (Metchnikoff) Sorokin (Hypocreales: Clavicipitaceae) isolated from the soils of Crete against larvae of T. absoluta in tomato plants was examined.ResultsAs a result, the EPF isolates of Crete decreased both the distance of larval travel from the egg to the opening of the gallery and the weight of the T. absoluta larvae, but also colonized the tomato plants. The entomopathogenic fungi were isolated from tomatoes again. Mycelium began to appear 7 days later and had developed completely after 12 days at 25 ± 2 °C and in 95% RH. Interestingly, the period between the hatched egg and the emerged first instar T. absoluta larvae was affected significantly by the different treatments, but not by "repetition" or "plant". Interestingly, the distance was further significantly shortened after treatment with M. anisopliae isolate Crete and B. bassiana isolate Crete and the commercial strain. The development period of T. absoluta larvae varied significantly among the treatments, but not by repetition in time or plant. The treatments caused a significant variation in the weight of T. absoluta pupae. The lowest weight was recorded in the plants colonized by M. anisopliae isolate Crete.ConclusionsThe study demonstrated the ability of the B. bassiana and M. anisopliae from Crete to colonize the tomato plants and the wild strains of Crete affect the distance of larvae. With the presence of endophytic EPF, the period between the hatched egg and the emerged first instar T. absoluta larvae was decreased, as does the weight of the T. absoluta pupae.

Entomopathogenic Action of Wild Fungal Strains against Stored Product Beetle Pests.

There is ample evidence that entomopathogenic fungi can be used as alternative biological control agents for the management of insect pests in storage facilities. As the market demands more environmentally friendly methods and chemical insecticides become increasingly obsolete, more studies are being conducted to evaluate new strains of entomopathogenic fungi for their efficacy in storage facilities. In this context, we tested ten species of fungi isolated from soil, belonging to the genera Cladosporium, Condenascus, Lecanicillium, and Penicillium, for their long-term effects on economically important beetle species. Whole wheat was directly sprayed with a conidial suspension of 108 spores/Ml of each of the tested fungi and then adults of Sitophilus granarius, S. oryzae, S. zeamais, Rhyzopertha dominica, and Trogoderma granarium were placed on the sprayed medium to study the mortality effects. Significantly higher mortality than the control was observed in all treatments. The lowest LT50 (9.164 days) was observed in T. granarium infected with Penicillium goetzii. The isolate with the strongest results was L. dimorphum, which recorded remarkably low LT50 values in S. oryzae (~11 days), R. dominica (~12 days), T. granarium (~10 days), and S. granarius (~13 days). However, for S. zeamais, it was more than 16 days. Our results confirm the existing literature on the efficacy of EPF on storage beetles, suggest the possible virulence of wild untested strains, and also highlight the importance of EPF specificity.

Breeding of entomopathogenic fungi in different substrates

The issue of entomopathogenic fungi’s prodigious rate of reproduction plagues both academic research and clinical practice. Several production technologies and preparations based on them are currently available. These medications appear to be liquid, powdery, dry, and grainy. The selection of nutritional medium and substrates, as well as the identification of ideal breeding conditions, are crucial steps in the manufacturing of pesticide formulations. Making preparations based on fungus is successful when solid nutritional substrates are used. Because in solid nutritional medium, fungus develop more spores. This article presents the results of experiments on the selection of nutrient substrates EMV-71 for the cultivation of strains of P. varioti EMR-57 and B. bassiana, which have been found to be virulent against spider mites and aphids, for use against sucking pests of vegetable crops in greenhouses. Barley grain has been found to be the most effective food substrate for the cultivation of entomopathogenic fungal strains and obtaining large numbers of spores from them.

SUSCEPTIBILITY OF FOUR STORED-PRODUCT INSECT PESTS TO BEAUVERIA BASSIANA AND METARHIZIUM ANISOPLIAE STRAINS

Insect infestations are considered one of the major problems causing enormous economic losses in stored grains. Laboratory bioassays were performed to establish the mortality induced by the commercially available Beauveria bassiana strain ATCC74040 (formulated product: Naturalis®) and by Metarhizium anisopliae strain CIST8 against four stored products pests. Adults of four grain and legume pest species (Cathartus quadricollis, Callosobruchus maculatus, Sitophilus granarius, and Oryzaephilus surinamensis) were exposed in laboratory assays to three different concentrations (103, 105 and 107/mL) of each entomopathogenic fungal strain. For each insect species, fungal strain and concentration, the mortality was recorded daily over a period of 7 days. Mean survival time and final cumulative mortality were determined, and 7-day mortality curves were established. A significant effect of insect species, fungal strain, and conidial concentration was observed on the 7-day mortality curves and the final cumulative mortality. Also, the mean survival time varied significantly with the conidial concentration. In addition, a significant interaction between insect species and fungal strain was recorded for all three assessed parameters. In general, at all tested concentrations, B. bassiana strain ATCC 74040 caused higher mortality than M. anispliae strain CIST8 in all four insect species. Our results suggest that entomopathogenic fungi could be effectively used as part of an integrated pest management program for the control of legumes and grain pests. Key Words: Entomopathogenic fungi, Beauveria bassiana, Metarhizium anisopliae, stored-products pests

Impact of Beauveria bassiana and Metarhizium anisopliae on the Metabolic Interactions between Cucumber (Cucumis sativus L.) and Cucumber Mosaic Virus (CMV)

In natural systems, plant–endophyte interactions are important for reducing abiotic and biotic stresses in plants by producing a variety of metabolites that protect plants from pathogens and herbivores. Biocontrol strategies are increasingly being used as a viable alternative to chemical pesticides. Entomopathogenic fungi (EPF) are one of them, and they have been touted as a successful method for biological pest control in plants. Because EPF strains are sensitive to environmental conditions when sprayed, the recently discovered endophytic behavior of several EPF strains has improved their management. Cucumber mosaic virus (CMV) is one of the most common and serious plant viruses worldwide, infecting over 1200 plant species and being spread by more than 80 aphid species. CMV control is directed towards the use of chemical insecticides to eradicate its insect vectors. Endophytic EPF is currently being studied to control plant virus infection, and antagonistic effects have been reported. Metabolomics is an emerging research field for plant metabolite profiling and is employed to study plant–endophyte interactions. In the present research, metabolomics approaches were conducted to gain information into mechanisms involved in defense against CMV in endophytes Beauveria bassiana and Metarhizium anisopliae (EPF)-treated diseased cucumber plants. In addition, CMV-induced metabolic changes in cucumber plants were investigated. Our analysis indicated large differences in cucumber metabolites due to endophytes application. In total, six hundred and thirty-one metabolites were differentially expressed in endophyte-treated CMV diseased cucumber plants. Regulation of different kinds of amino acids, organic acids, and phenylpropanoids metabolites could provide insight about plant defense mechanism against CMV pathogen. Important metabolites were found to be regulated in diseased cucumber plants due to fungal endophytes treatment that could possibly confer tolerance to CMV disease.

Virulence evaluation of entomopathogenic fungi against Panonychus citri (Acari: Tetranychidae) and its compatibility with acaricides and predatory mites

The citrus red mite, Panonychus citri (McGregor), is one of the most notoriously agricultural pests which can cause severe damage to over 100 species of plants. The species is difficult to control because of its short generation time and high reproductive rate. Owing to the reliance on chemical acaricides in pest management in the field, P. citri has evolved resistance to a number of chemical acaricides over the years. The emergence of pesticide resistant populations of P. citri is a significant concern worldwide. Thus, it is urgent to find alternative ways to keep the pest populations below the economic injury levels based on the IPM strategy. Nowadays, ecologically-sound control strategies have been sought for this pest and many biocontrol agents have been introduced into pest management such as the entomopathogenic fungi (EPF) and predatory insects. In our study, 5 EPF strains designated HL3, Bbzwn9, Bb0601, Bb07, and Bblh were tested for their efficacy against P. citri by spraying conidia suspension in the laboratory. Amongst these, the HL3 strain exhibited the highest pathogenicity against P. citri and was identified as Isaria cateniannulata using ITS sequences. Further bioassays of HL3 strain indicated the LC50 (3.093x104 conidia/mL) at 7 d post inoculation and the LT50 (3.356 d) at a concentration of 1x108 conidia/mL against P. citri. Subsequently, HL3 was evaluated for its compatibility with four commonly used chemical acaricides at their low dosages (gradient dilution of their labeled application rates for P. citri control) and its side effects on the predatory mite, Neoseiulus barkeri. Briefly, HL3 exhibited an ideal compatibility with avermectin compared to other three acaricides, with the lowest inhibition rate of colony growth, sporulation and spore germination in the PDA culture medium containing avermectin. Besides, the fungal strain was harmless to N. barkeri with only 9.167% mortality rate, and no significant impact was recorded on N. barkeri oviposition rates, although HL3 possessed a slightly negative effect on the predatory ability of N. barkeri. The analysis of functional response indicated that compared with the untreated P. citri, the handling time of predator increased on HL3-treated P. citri, while the attack rates decreased with the increase of the time after inoculation. In summary, in combination with avermectin or the natural enemy N. barkeri, HL3 exhibited a potential ability for sustainable control of the mite pest.

FIRST EVIDENCE OF THE TICKICIDE EFFECT OF ENTOMOPATHOGENIC FUNGI ISOLATED FROM MEXICAN CATTLE FARMS AGAINST AMBLYOMMA MIXTUM.

This is the first study to empirically evaluate the mortality of Amblyomma mixtum larvae caused by native entomopathogenic fungi (EPF) from cattle farm soils and the impact of the physicochemical conditions of those soils on the ability of EPF to kill ticks. The efficacy of 25 EPF strains isolated from cattle farms soils in Veracruz, Mexico, against A. mixtum ticks was evaluated using a larval immersion test. Physicochemical analyses of the soils where the EPF were isolated were carried out, and the results were correlated with the obtained mortality. The MaV25 strain showed a mortality of 36.55% (P < 0.05), followed by MaV57 with 27.30%, MaV08 with 26.21%, and MaV31 with 24.32% (P < 0.05). Nitrogen and potassium are nutritional components of soils that seem to be associated with mortality caused by the evaluated fungal strains. This is the first study in Mexico where the effect of EPF against A. mixtum is evaluated and also is the first study in the world that uses native strains from livestock soils against larvae of this tick. It is necessary to determine the virulence characteristics of EPF on A. mixtum to improve knowledge of fungus-tick interactions (Metarhizium anisopliae-A. mixtum).