Fungus Beauveria Bassiana Research Articles

Exploring immune memory traits in the social immunity of a fungus-growing ant.

The immune system is crucial for organisms to defend against pathogens. Likewise, analogous immune features evolved against similar pressures at the superorganism scale. Upregulating hygiene to the same fungus pathogen is one assumption for convergent immune mechanisms in social insects, although more evidence of immune memory features remains to be confirmed. Here, we assess immune memory traits at the colony level in the leaf-cutting ant Atta sexdens. We exposed their fungus cultivar to both homologous and heterologous challenges with the entomopathogenic fungi Metarhizium anisopliae and Beauveria bassiana, as well as the mycoantagonistic fungi Fusarium oxysporum and Trichoderma spirale. By measuring ants' behaviours, we evaluated the capacity of A. sexdens: (i) to enhance their collective hygiene, (ii) speed their hygiene in further infections, (iii) how long this capacity lasts in the colonies and (iv) the degree of specificity to increase hygienic responses. Fungus grooming behaviour was enhanced mostly against entomopathogenic fungi, with a trend of faster reactions during homologous challenges. In general, the capacity to elicit such upregulated actions lasted for up to 30 days, but no longer than 60 days. Overall, colonies exhibited a degree of immune specificity, enhancing hygiene only in response to homologous exposures but decreasing it when infected secondarily with a different fungus, indicating flexible social immunity of A. sexdens after immune challenges.

Discovery and characterization of a novel Lepidoptera‐specific antimicrobial peptide from the fall armyworm, Spodoptera frugiperda (Lepidoptera: Noctuidae)

AbstractAntimicrobial peptides (AMPs) are critical components of innate immunity in diverse organisms, including plants, vertebrates, and insects. This study identified and characterized a novel Lepidoptera‐specific AMP, named lepidoptin, from the invasive pest Spodoptera frugiperda (Lepidoptera: Noctuidae). Lepidoptin is a 116‐amino acid protein containing a signal peptide and a novel β‐sandwich domain that is distinct from previously reported AMPs. Temporal and spatial expression analyses revealed a significant upregulation of the lepidoptin gene in vivo and in cultured SF9 cells in response to pathogens. Molecular docking analysis identified a specific binding cavity. Enzyme‐linked immunosorbent assay and binding assays confirmed that lepidoptin can bind to pathogen‐associated molecular patterns, bacteria, and fungi. Recombinant lepidoptin exhibited potent antibacterial activity by inducing bacterial agglutination, inhibiting bacterial growth, increasing bacterial membrane permeability, and preventing biofilm formation. Lepidoptin also showed antifungal activity against the entomopathogenic fungus Beauveria bassiana by inhibiting spore germination, increasing fungal cell permeability, and increasing reactive oxygen species. Injection of recombinant lepidoptin into S. frugiperda larvae increased survival after B. bassiana infection, whereas knockdown of lepidoptin by RNA interference decreased larval survival. In addition, lepidoptin showed antimicrobial activity against the plant pathogen Fusarium graminearum by inhibiting spore germination and alleviating disease symptoms in wheat seedlings and cherry tomatoes. This study demonstrates the remarkable dual functionality of lepidoptin in enhancing S. frugiperda immunity and controlling plant pathogens, making it a promising candidate for biocontrol strategies in both pest management and plant disease prevention.

Insights into larval development and protein biochemical alterations of Agrotis ipsilon (Hufnagel) (Lepidoptera: Noctuidae) following Beauveria bassiana and Solanum lycopersicum treatments

BackgroundThe polyphagous notorious pest, black cutworm, Agrotis ipsilon (Hufnagel) (Lepidoptera: Noctuidae), cause significant production losses due to its distinctive feeding and hiding behavior, making it particularly challenging to control it with conventional methods. Therefore, sustainable agriculture demands more effective and environmentally safe pest control solutions. This study aimed to investigate the toxicity of two insecticide alternatives, the entomopathogenic fungus (EPF) Beauveria bassiana and Solanum lycopersicum extract (Tomato plant crude extract, TPCE), using two bioassay methods: the poisoned bait method and the leaf dipping method. In addition, the impact of these biological tools on larval development and protein profiles was evaluated.ResultsThe bait application of both tested materials exhibited higher toxicity than the leaf dipping method, as indicated by the toxicity index. The LC50 values for B. bassiana were 1.6 × 10⁸ and 1.8 × 10⁶ conidia ml−1 using the leaf dipping method and poisoned baits method, respectively. For TPCE, the LC50 values were 4.35 and 1.51 mg ml−1 for the same methods, respectively. In addition, sublethal concentrations of both materials altered the larval and pupal durations. B. bassiana significantly reduced the concentration of larval hemolymph protein. A maximum of 12 protein bands in the control sample, with molecular weights (Mw) ranging between 35 and 120 kDa, were detected by sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS–PAGE). In B. bassiana-treated larvae, ten bands were detected with Mw ranging from 35 to 120 kDa. At least seven bands were detected in TPCE-treated larvae, with Mw ranging from 35 to 97 kDa.ConclusionsThe findings of this study can be integrated into management programs for A. ipsilon. In addition, the availability of B. bassiana and TPCE in Egypt and their cost-effectiveness as insecticide alternatives support their use in the management programs of this critical pest. These methods are particularly effective when applied in bait form.Graphical

Computational identification and characterization of chitinase 1 and chitinase 2 from neotropical isolates of Beauveria bassiana.

The fungus Beauveria bassiana is widely used for agronomical applications, mainly in biological control. B. bassiana uses chitinase enzymes to degrade chitin, a major chemical component found in insect exoskeletons and fungal cell walls. However, until recently, genomic information on neotropical isolates, as well as their metabolic and biotechnological potential, has been limited. Eight complete B. bassiana genomes of Neotropical origin and three references were studied to identify chitinase genes and its corresponding proteins, which were curated and characterized using manual curation and computational tools. We conducted a computational study to highlight functional differences and similarities for chitinase proteins in these Neotropical isolates. Eleven chitinase 1 genes were identified, categorized as chitinase 1.1 and chitinase 1.2. Five chitinase 2 genes were identified but presented a higher sequence conservation across all sequences. Interestingly, physicochemical parameters were more similar between chitinase 1.1 and chitinase 2 than between chitinase 1.1 and 1.2. Chitinases 1 and 2 demonstrated variations, especially within chitinase 1, which presented a potential paralog. These differences were observed in their physical parameters. Additionally, CHIT2 completely lacks a signal peptide. This implies that CHIT1 might be associated with infection processes, while CHIT2 could be involved in morphogenesis and cellular growth. Therefore, our work highlights the importance of computational studies on local isolates, providing valuable resources for further experimental validation. Intrinsic changes within local species can significantly impact our understanding of complex pathogen-host interactions and offer practical applications, such as biological control.

Study Of The Effect Of Silver And Zinc Nanoparticles Prepared Biologically By The Fungus Beauveria Bassiana On The Feeding Behavior And The Insect Body Content Of Some Materials And Nutrients In The Periplaneta Americana L.

The study was conducted in the laboratories of the Department of Prevention / College of Agriculture / Tikrit University during the years 2023-2024 to study the effect of the nanomaterial resulting from treating the fungus Beauveria bassiana with a solution of silver nitrate and a solution of zinc oxide as it affected the daily feeding rate of the last-age nymphs of the Periplaneta americana, as this rate was 0.015 g / insect on the second day of treatment with the nanomaterial prepared using silver nitrate, while it was 0.04 for the zinc oxide treatment. While it was 0.07 g / insect for the control treatment, and the nanomaterial affected the two solutions in addition to the control treatment in a fluctuating manner during seven days of feeding. Both silver nitrate and zinc oxide treatments and the control treatment recorded 0.007, 0.05, 0.085 gm/insect on the eighth day of treatment. The treatment also affected the percentage of each of the fats for the concentrations of 0.125, 0.250, 0.500 mg/L and the control treatment if it was 23.8, 23.9, 24 and 23.8 mg) respectively for the silver nitrate treatment, while it was 22.3, 20.6, 19.5, 23.8 for the zinc oxide treatment. While the protein weight was 234.24, 127.64, 35.72, 382.81 mg/g for silver nitrate, while it was 304.37, 43.756, 233.125, 43.75 mg/g for zinc oxide. It also affected the potassium element, as the concentrations were recorded as 0.125, 0.250, 0.500 mg/L and the control treatment was 4.65, 2.36, 0.54, 6.22 mg respectively for silver nitrate and 5.14, 3.21, 0.75 and 6.25 mg respectively for zinc oxide. It also affected the weight of the sodium element, as the concentrations were recorded as 0.125, 0.250, 0.500 mg/L and the control treatment was 2.63, 1.22, 0.46, 3.24 mg respectively for silver nitrate and 2.45, 1.08, 0.42 and 3.34 mg respectively for zinc oxide. It affected the percentage of phosphorus element, as the above concentrations were recorded, 4.32, 2.61, 0.40, 6.13 mg for silver nitrate, while they were 5.12, 3.43, 0.70, 6.24 mg for zinc oxide.

Biosynthesis of Iron Oxide Nanoparticles by Fungi Beauveria Bassiania and Study of their Structural and Optical Properties

Iron oxide nanoparticles were synthesized using a biological approach using the Beauveria bassiana fungus. The synthesized nanoparticles were characterized using X-ray diffraction (XRD), scanning analysis (SEM), and atomic energy microscope (AFM). The iron nanoparticles in an average grain size of ~ 39 nm. The topography and features of the surface show that there are ripples distributed regularly and homogeneously on the surface and that the deposited film is regular. The optical properties of iron oxide were studied using UV/Vis spectroscopy, and it was found that the absorbance gradually decreases as we approach the visible light region, starting from its peak at short wavelengths, where the surface plasmon resonance was recorded, which showed the absorbance at the UV wavelength at (282 nm), and the absorbance is at its maximum at high energies (short wavelengths), then decreases with increasing wavelength to reach its lowest value in the visible region of the spectrum, and for this reason the absorbance decreases with increasing wavelength, where the energy gap value is (2.5 electron volts). The FTIR spectrum showed functional groups have been recorded in a range These results confirm the presence of the fungal extract belonging to the fungus Beauveria bassiana. The vibrations in the phenolic compounds are responsible for the interaction process with the salts of the basic materials used in the preparation

Acaricidal Efficacy of Abamectin against Tetranychus urticae Populations When Combined with Entomopathogenic Fungi

Tetranychus urticae (Acari: Tetranychidae) is a widespread and serious mite pest that infests tomato plants and causes economic losses worldwide. We investigated the acaricidal efficacy of two isolates of entomopathogenic fungi (EPF) Metarhizium robertsii (WG-7) and Beauveria bassiana (WG-12) alone and in combination with abamectin when applied topically to tomato leaf discs in the laboratory against T. urticae. We also evaluated the establishment and proliferation of T. urticae mite life stages on tomato plants in the greenhouse after application of each of the above treatments. The combination of abamectin with each EPF caused 100% mortality in T. urticae immatures after 2 days while each EPF or abamectin alone caused moderate mortality, not exceeding 74.2% 3 days post-exposure. Complete (100%) mortality of adults was observed after 5 days in leaf discs treated with M. robertsii plus abamectin whereas B. bassiana plus abamectin caused 100% mortality after 7 days. The mean number of eggs, emerged immatures, and adults were significantly reduced on both sides of the leaves (i.e., abaxial and adaxial sides) after using the combined application of M. robertsii or B. bassiana plus abamectin, compared to abamectin alone and controls. Our results reveal that the acaricidal efficacy of abamectin combined with either EPF was significantly better in managing the T. urticae life stages than either treatment alone under greenhouse conditions.

Application of Entomopathogenic Fungus Beauveria Bassiana on Shallot Plants Through Soaking the Bulbs and its Effect on the on the Growth of Spodoptera Exigua Larvae

Spodoptera exigua Hubner is a major pest of shallots. This pest attack can cause a decrease in shallot production. The use of entomopathogenic fungus Beauveria bassiana is an environmentally friendly pest control alternative. This study aims to study the development of S. exigua larvae in shallot plants applied with B. bassiana fungus. This study was arranged in a Completely Randomized Design (CRD) with 6 treatments and 5 replications. Five isolates of B. bassiana (BbWS, BbJG, PD114, TD312, PB211) were used in this study. The concentration of B. bassiana suspension used was 108 conidia/ml. B. bassiana was applied to shallots by soaking the bulbs for 15 minutes. The results showed that the mortality of larvae feeding on plants applied with B. bassiana reached 100%. The application of B. bassiana also extended the larval period, reducing the percentage of pupae and adults formed. BbWS and TD312 were isolated and were better at inhibiting the growth of S. exigua larvae

Unlocking the Siderophore Biosynthesis Pathway and Its Biological Functions in the Fungal Insect Pathogen Beauveria bassiana.

Siderophores are small molecule iron chelators. The entomopathogenic fungus Beauveria bassiana produces a plethora of siderophores under iron-limiting conditions. In this study, a siderophore biosynthesis pathway, akin to the general pathway observed in filamentous fungi, was revealed in B. bassiana. Among the siderophore biosynthesis genes (SID), BbSidA was required for the production of most siderophores, and the SidC and SidD biosynthesis gene clusters were indispensable for the production of ferricrocin and fusarinine C, respectively. Biosynthesis genes play various roles in siderophore production, vegetative growth, stress resistance, development, and virulence, in which BbSidA plays the most important role. Accordingly, B. bassiana employs a cocktail of siderophores for iron metabolism, which is essential for fungal physiology and host interactions. This study provides the initial network for the genetic modification of siderophore biosynthesis, which not only aims to improve the efficacy of biocontrol agents but also ensures the efficient production of siderophores.

Evaluation of the In2Care Mosquito Station at low deployment density: a field study to manage Aedes aegypti and Culex quinquefasciatus (Diptera: Culicidae) in North Central Florida.

In the last 2 decades, there has been an increase in the geographic range and frequency of vector-borne diseases. Management of mosquito populations has become challenging due to increasing rates of resistance to existing insecticidal products and formulations. Several alternative tools have emerged to suppress or replace mosquito populations. One of these tools is the In2Care Mosquito Station (In2Care station). This dual-action station contains the insect growth regulator pyriproxyfen which disrupts the development of immatures and the entomopathogenic fungus Beauveria bassiana (B. bassiana) strain GHA which kills exposed adult mosquitoes. The In2Care stations have previously been shown to effectively control Aedes aegypti in field settings at a density of 6 stations/acre rather than the label-recommended 10 stations/acre. To further test the efficacy of low station density deployment, we deployed In2Care stations in the Pleasant Street Historic District of Gainesville, Florida, at a density of 3 stations/acre over a period of 2 years in the presence or absence of ground larvicidal applications. The deployment of stations resulted in no measurable impact on Ae. aegypti and Culex quinquefasciatus adult or immature abundance suggesting that the low-density deployment of In2Care stations is insufficient to reduce Ae. aegypti and Cu. quinquefasciatus abundance within treatment areas.

Safety of the Entomopathogenic Fungus Beauveria bassiana for Wild and Laboratory-Reared Chrysoperla lucasina Strains.

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.

Evaluation of some techniques for drying conidiated rice culture of the entomopathogenic fungus Beauveria bassiana (Bals.) Vuill. with a bioassay evaluating their eligibility

BackgroundProduction of entomopathogenic fungi on a solid substrate, mostly on rice, is preferred by many producers due to its low technological requirements. Drying may be needed after fermentation to preserve the viability of the conidia until use. This study aimed to introduce some uncomplicated drying techniques and study their effectiveness in terms of drying time and extent, as well as their impact on the quantity of conidia produced and their biological activity. Four techniques were studied, i.e., condensing water vapor (by cooling), desiccant (using NaOH), air drying on a net, and air drying on a solid (impermeable) surface.ResultsCondensing water vapor and desiccant techniques were the fastest and most efficient, resulting in the lowest moisture content, ranging between 12 and 13%. While drying on a solid surface was the slowest and resulted in the highest moisture content of 32.98%. All of the dried samples yielded a lower quantity of conidia compared to the fresh samples. Samples of condensing water vapor, desiccant, and net techniques yielded approximately a similar quantity of conidia, ranging between 74 and 71% of the yield of the fresh sample. The solid surface sample yielded the lowest quantity of conidia, representing 63.78% of the fresh sample yield. A bioassay test on the mite, Tetranychus urticae Koch (Acari: Tetranychidae), showed that conidia dried via condensing water vapor and desiccant techniques kept their pathogenicity similar to the fresh sample, while samples dried on a net and solid surface significantly lost part of their pathogenicity.ConclusionThe condensing water vapor and desiccant techniques were the most efficient regarding the time needed, conidia yield, and pathogenicity. Drying on a solid surface was the least effective regarding the same factors.

Improved control of Trialeurodes vaporariorum using mixture combinations of entomopathogenic fungi and the chemical insecticide spiromesifen

Greenhouse whitefly (Trialeurodes vaporariorum) is a major global pest, causing direct damage to plants and transmitting viral plant diseases. Management of T. vaporariorum is problematic because of widespread pesticide resistance, and many greenhouse growers rely on biological control agents to regulate T. vaporariorum populations. However, these are often slow and vary in efficacy, leading to subsequent application of chemical insecticides when pest populations exceed threshold levels. Combining chemical and biological pesticides has great potential but can result in different outcomes, from positive to negative interactions. In this study, we evaluated co-applications of the entomopathogenic fungi (EPF) Beauveria bassiana and Cordyceps farinosa and the chemical insecticide spiromesifen in laboratory bioassays. Complex interactions between the EPFs and insecticide were described using an ecotoxicological mixtures model, the MixTox analysis. Depending on the EPF and chemical concentrations applied, mixtures resulted in additivity, synergism, or antagonism in terms of total whitefly mortality. Combinations of B. bassiana and spiromesifen, compared to single treatments, increased the rate of kill by 5 days. Results indicate the potential for combined applications of EPF and spiromesifen as an effective integrated pest management strategy and demonstrate the applicability of the MixTox model to describe complex mixture interactions.

Microbial agents for the control of ticks Rhipicephalus microplus.

Ticks are ectoparasites responsible for the transmission of various pathogens to vertebrates. They represent one of the major threats to livestock production worldwide due to their impact on the health, production and welfare of livestock destined for human consumption. The development of resistance to the main families of ixodicides used for their control has led to the search for new alternatives, where microbial control is an option. The use of microbial control agents against the tick Rhipicephalus microplus is reviewed in this paper. Bacteria such as Bacillus thuringiensis, Serratia marcescens and Staphylococcus spp. the nematodes Steinernema spp. and Heterorhabditis spp. as well as the fungi Metarhizium anisopliae and Beauveria bassiana are the most studied organisms for use as biological control agents against ticks. Laboratory, stable and field trials with free-living and parasitised ticks have shown that microbial agents can control both susceptible and ixodicide-resistant tick populations. However, multidisciplinary studies using novel tools like genomics, transcriptomics and proteomics should be carried out to understand the virulence factors which microbial agents use to induce pathogenesis and virulence in ticks. In addition, applied research will be carried out with the aim of improving techniques for large-scale application, as well as the improvement of cultivation, storage, formulation and application methods.

Comparative Transcriptomics of the Entomopathogenic Fungus Beauveria bassiana Grown on Aerial Surface and in Liquid Environment.

Beauveria bassiana, the causative agent of arthropod, proliferates in the host hemolymph (liquid environment) and shits to saprotrophic growth on the host cadaver (aerial surface). In this study, we used transcriptomic analysis to compare the gene expression modes between these two growth phases. Of 10,366 total predicted genes in B. bassiana, 10,026 and 9985 genes were expressed in aerial (AM) and submerged (SM) mycelia, respectively, with 9853 genes overlapped. Comparative analysis between two transcriptomes indicated that there were 1041 up-regulated genes in AM library when compared with SM library, and 1995 genes were down-regulated, in particular, there were 7085 genes without significant change in expression between two transcriptomes. Furthermore, of 25 amidase genes (AMD), BbAMD5 has high expression level in both transcriptomes, and its protein product was associated with cell wall in aerial and submerged mycelia. Disruption of BbAMD5 significantly reduced mycelial hydrophobicity, hydrophobin translocation, and conidiation on aerial plate. Functional analysis also indicated that BbAmd5 was involved in B. bassiana blastospore formation in broth, but dispensable for fungal virulence. This study revealed the high similarity in global expression mode between mycelia grown under two cultivation conditions.

1H-NMR-based metabolomics profiling of Beauveria bassiana on different growth media for the determination of its secondary metabolites

The entomopathogenic fungus (EPF) Beauveria bassiana is commercially used as a microbial insecticide against agricultural pests. Some strains of B. bassiana protect crops from pathogens. B. bassiana produces bioactive secondary metabolites (SMs) with potential applications. The present study aims to monitor the growth and behaviour of B. bassiana in different growth media and the effect of different growth media on the production of SMs. The fungal culture was recultivated and then inoculated in broth and agar growth media to perform this study. After 12 days of incubation of B. bassiana in potato dextrose broth (PDB) and a specific medium at temperatures between 28 - 30℃, SMs were extracted from broth cultures using liquid-liquid extraction. To harvest the SMs, the broth media of each culture was extracted using ethyl acetate. After the evaporation of the ethyl acetate using a rotary evaporator, the crude extracts were obtained. The crude extracts were then subjected to 1H-NMR and 2D HSQC analysis using a 600 MHz NMR spectrometer to monitor the presence of different SMs in the crude extracts. The analysis revealed that different types of SMs were produced by B. bassiana under different media and conditions. However, some SMs were detected in the 1H- NMR spectrum of the PDB extract that was completely absent in specific Fingal medium, further confirmed by the 2D HSQC experiment. In conclusion, this study revealed that modifying the media constituents and conditions, such as variable temperatures, could produce different SMs, as predicted by the NMR analysis.

Photoreactivation Activities of Rad5, Rad16A and Rad16B Help Beauveria bassiana to Recover from Solar Ultraviolet Damage.

In budding yeast, Rad5 and Rad7-Rad16 play respective roles in the error-free post-replication repair and nucleotide excision repair of ultraviolet-induced DNA damage; however, their homologs have not yet been studied in non-yeast fungi. In the fungus Beauveria bassiana, a deficiency in the Rad7 homolog, Rad5 ortholog and two Rad16 paralogs (Rad16A/B) instituted an ability to help the insect-pathogenic fungus to recover from solar UVB damage through photoreactivation. The fungal lifecycle-related phenotypes were not altered in the absence of rad5, rad16A or rad16B, while severe defects in growth and conidiation were caused by the double deletion of rad16A and rad16B. Compared with the wild-type and complemented strains, the mutants showed differentially reduced activities regarding the resilience of UVB-impaired conidia at 25 °C through a 12-h incubation in a regime of visible light plus dark (L/D 3:9 h or 5:7 h for photoreactivation) or of full darkness (dark reactivation) mimicking a natural nighttime. The estimates of the median lethal UVB dose LD50 from the dark and L/D treatments revealed greater activities of Rad5 and Rad16B than of Rad16A and additive activities of Rad16A and Rad16B in either NER-dependent dark reactivation or photorepair-dependent photoreactivation. However, their dark reactivation activities were limited to recovering low UVB dose-impaired conidia but were unable to recover conidia impaired by sublethal and lethal UVB doses as did their photoreactivation activities at L/D 3:9 or 5:7, unless the night/dark time was doubled or further prolonged. Therefore, the anti-UV effects of Rad5, Rad16A and Rad16B in B. bassiana depend primarily on photoreactivation and are mechanistically distinct from those for their yeast homologs.

Pathogenicity Efficacy of Entomopathogen Fungus Beauveria bassiana Against In Vitro Rice Stem Borer (Scirpophaga innotata)

White rice stem borer (Scirpophaga innotata) is one of the dangerous pests for rice (Oryzae sativa) because it attacks rice stems that can cause 50% loss of total production. The purpose of this study was to determine the pathogenicity of Entomopathogen Fungus Beauveria bassiana at different conidia dilutions (J), namely J1 (105), J2 (106), J3 (107), J4 (108), and J5 (109). The mortality of S. innotata larvae was tested with the density of B. bassiana of 2.08 × 106 conidia/ml. The effect of B. bassiana on the success transformation of S. innotata larvae to pupae for 14 observation day was also observed at the same B. bassiana density. This research resulted in the optimal pathogenicity of B. bassiana at dilution of 107 (treatment J3) which caused 100% death and 100% successful pupation. The lowest treatment was J5 (109 dilution) with a mortality rate of 50% and a successful pupation of 20%. The results of the probit analysis showed that the fastest average lethal time (LT50) value was found in treatment of 107 (J3) which reached 11.11 h. Keywords: Beauveria bassiana, Pathogenicity, Probit analysis, Scirpophaga innotata.

The fungal protease BbAorsin contributes to growth, conidiation, germination, virulence, and antiphytopathogenic activities in Beauveria bassiana (Hypocreales: Cordycipitaceae)

The fall armyworm, Spodoptera frugiperda (Lepidoptera: Noctuidae), is one of the most destructive agricultural pests. The entomopathogenic fungus Beauveria bassiana (Hypocreales: Clavicipitaceae) is a biopesticide widely used for biocontrol of various pests. Secreted fungal proteases are critical for insect cuticle destruction and successful infection. We have previously shown that the serine protease BbAorsin in B. bassiana has entomopathogenic and antiphytopathogenic activities. However, the contribution of BbAorsin to fungal growth, conidiation, germination, virulence and antiphytopathogenic activities remains unclear. In this study, the deletion (ΔBbAorsin), complementation (Comp), and overexpression (BbAorsinOE) strains of B. bassiana were generated for comparative studies. The results showed that ΔBbAorsin exhibited slower growth, reduced conidiation, lower germination rate, and longer germination time compared to WT and Comp. In contrast, BbAorsinOE showed higher growth rate, increased conidiation, higher germination rate and shorter germination time. Injection of BbAorsinOE showed the highest virulence against S. frugiperda larvae, while injection of ΔBbAorsin showed the lowest virulence. Feeding BbAorsinOE resulted in lower pupation and adult eclosion rates and malformed adults. 16S rRNA sequencing revealed no changes in the gut microbiota after feeding either WT or BbAorsinOE. However, BbAorsinOE caused a disrupted midgut, leakage of gut microbiota into the hemolymph, and upregulation of apoptosis and immunity-related genes. BbAorsin can disrupt the cell wall of the phytopathogen Fusarium graminearum and alleviate symptoms in wheat seedlings and cherry tomatoes infected with F. graminearum. These results highlight the importance of BbAorsin for B. bassiana and its potential as a multifunctional biopesticide.

Biological control potential of two Beauveria bassiana isolates against the stink bugs Nezara viridula L. and Piezodorus guildinii Westwood (Hemiptera: Pentatomidae) in common bean

BackgroundThe stink bugs, Nezara viridula L. and Piezodorus guildinii Westwood (Hemiptera: Pentatomidae) are the most important and widespread species of polyphagous stink bugs in the tropical and subtropical regions of Latin America, which affect the quality and yield of the common bean (Phaseolus vulgaris L.). The use of synthetic chemical insecticides is the major control strategy to manage stink bugs in common beans and alternatives are needed. In this study, mortality and median Lethal Time (LT50) of two Cuban isolates of the entomopathogenic fungus Beauveria bassiana (18 S-O-R and 96 P-O-E), as well as one commercial Cuban isolate (Bb-18), at a concentration of 1 × 108 conidia/ml were evaluated. These evaluations were conducted against both stink bug species using Petri dish bioassays and a semi-field experiment in common beans.ResultsIn Petri dish bioassays, the isolates 18 S-O-R and 96 P-O-E caused 100% mortality of both N. viridula and P. guildinii. This was significantly higher than for isolate Bb-18, which caused 86.3% N. viridula and 81.3% P. guildinii mortality. In the semi-field experiment, when pooling both stink bug species, total mortality after 14 days was 91.3% for 18 S-O-R, 80.0% for 96 P-O-E and 73.8% for Bb-18 isolates. LT50 value for isolate 18 S-O-R tested under laboratory conditions was 6.04 ± 0.18 days for N. viridula and 5.32 ± 0.14 days for P. guildinii at the same concentration of 1 × 108 conidia/ml. LT50 value for isolate 18 S-O-R in semi field was 6.79 ± 0.37 days for N. viridula and 7.71 ± 0.32 days for P. guildinii at 1 × 108 conidia/ml.ConclusionThe study highlights the potential of B. bassiana 18 S-O-R as a promising candidate for control of stink bugs in common bean under tropical conditions as an alternative to conventional chemical insecticides in integrated pest management (IPM) programs. Moving forward, further research should focus on validating the efficacy under diverse field conditions and integrating application methods into practical IPM approaches. Future use of B. bassiana will enhance sustainability and reduce environmental impacts associated with pesticide use.