Bassiana Isolates Research Articles

Isolation, morphological characterization, and screening virulence of Beauveria bassiana and Metarhizium robertsii fungal isolates in Galleria mellonella

Background Entomopathogenic fungi exists naturally in plants as an asymptote and have the potential to reduce the population of insect pests through indirect interactions. This study was conducted to detect and characterize the endophytic fungi Beauveria bassiana and Metarhizium robertsii from the rhizosphere soil of tomato plants and their virulence effect on Galleria melonella. Methods From the rhizosphere soil of 40 tomato fields, three Beauveria bassiana and seven Metarhizium robertsii isolates were isolated using the galleria bait method. All fungi isolate were morphologically characterized by their colony color, shape, and surface texture. Isolates with the highest percentages of germination, conidial yield, and radial growth were selected, and their virulence was evaluated on second instar larvae of Galleria melonella under laboratory conditions. Results In this study, Beauveria bassiana showed white colony color and aseptate hyphae, whereas Metarhizium robertsii showed dark green to light green colony color and septate hyphal structures. Maximum spore production and conidial length were obtained by Beauveria bassiana isolate APPRC-27 with 2.67x107 spores ml-1 and 3.24 µm, respectively. Colony radial growth rates ranged from 1.73 to 3.24 mm day-1. The results revealed that the highest mortality rate of Galleria melonella (100%) was obtained by Metarhizium robertsii isolates K-61 and K-102 at a concentration of 1x108 conidial ml-1 at 7 days post-inoculation. The lowest mortality rate was registered by Metarhizium robertsii isolate RST-11. Conclusions In the present study, isolates that produced the most spores and had the highest germination rates were the most virulent to Galleria mellonella second instar larvae. Therefore, virulent entomopathogenic fungi, Beauveria bassiana and Metarhizium robertsii, are promising bioagents for the control of insect pests.

Entomopatojen fungus, Beauveria bassiana’nın Myzus persicae ve Trialeurodes vaporariorum üzerindeki etkisinin adipokinetik hormon ile arttırılması

The aim of this study was to investigate the effects of the co-application of entomopathogenic fungi (EMFs) and adipokinetic hormone (AKH) on the green peach aphid, Myzus persicae, and the greenhouse whitefly, Trialeurodes vaporariorum. Single and combined applications of two Beauveria bassiana isolates with AKH were tested. The green peach aphid was more susceptible to treatments than the greenhouse whitefly. Mortality rates of 58%, 67%, %95, and 95% were observed for the single and combined applications of BMAUM M6-4 and BMAUM LD 2016, respectively, against M. persicae. The application of these fungi singly and in combination with AKH against T. vaporariorum caused mortality rates of 44%, 68% and 45% and78%, respectively. The protein level measured at 595 nm with the standard, Bovine Serum Albumin (BSA), for M. persicae and T. vaporariorum revealed that the highest level of nutrient mobilization was for the BMAUM M6-4+AKH treatment. The level of carbohydrate (glucose) was slightly higher in the AKH treatments when compared to the control group. The lowest glucose level was measured for the entomopathogenic fungi application, and highest level was determined for the isolates combined with AKH. The mechanism of action of AKH applied with B. bassiana isolates is not fully understood. Therefore, more detailed studies are needed in this area to determine the potential of this promising approach for inclusion in IPM programs for the control of these insect pests.

Potential for the Use of the Entomopathogenic Fungus Beauveria bassiana in the Biological Control of Cryptolestes ferrugineus and Acanthoscelides obtectus

In this study, the effectiveness of different conidial suspensions of the entomopathogenic fungus Beauveria bassiana (Balsamo) on stored product pests Acanthoscelides obtectus (Bean Seed Beetle) (Coleoptera, Chrysomelidae) and Cryptolestes ferrugineus (Rusty Grain Beetle) (Coleoptera, Laemophloeidae) was aimed to be determined. For this purpose, suspensions of B. bassiana isolate at concentrations of 106, 107, and 108 conidia/ml were used, with sterile water as a negative control and a recommended Declare (EC 25 g/l) as a positive control. The application was set up in three replicates, with 10 adults in each replicate, and applied using the spraying method. To calculate the percentage of mortality, Petri dishes were regularly checked every 24 hours from the application, and the numbers of live and dead adults were recorded. According to the obtained data, it was determined that B. bassiana isolate was effective against C. ferrugineus at a rate of 80% and against A. obtectus at a rate of 56.67% after 168 hours. Among the applied suspensions, the most effective suspension was recorded at 108 conidia/ml. As a result, the entomopathogenic fungus B. bassiana (ET 10) isolate used as a biological control agent, is considered a promising biological control agent against the storage pests C. ferrugineus and A. obtectus.

Control of Root-knot Nematodes (Meloidogyne spp.) on Tomato (Lycopersicum esculentum Mill.) using Antagonist Fungi

Nematodes Meloidogyne spp. is the most important phytonematode in the world, especially in agriculture in tropical areas. The level of root damage to tomato plants caused by the nematode Meloidogyne spp. can reach 68.3%. In general, control of plant parasitic nematodes is still carried out using pesticides in the form of insecticides which can also be used as nematicides. Continuous use of chemicals to control nematodes can cause environmental pollution, resurgence and nematode resistance to chemicals. One alternative control is biological. One of the biological agents that can be used to control Meloidogyne nematodes is the endophytic fungus Beauveria bassiana and Trichoderma asperellum. The research aims to obtain the best isolates of endophytic fungi for controlling rootknot nematodes (Meloidogyne spp.). The isolates tested were 2 Beauveria bassiana isolates and 2 Trichoderma asperellum isolates. The results showed that the fungus isolate Beauveria bassiana isolate TD312 had a higher ability to control Meloidogyne spp on tomatoes.

Isolation, morphological characterization, and screening a virulence of Beauveria bassiana and Metarhizium robertsii as bioagents

Background: Entomopathogenic fungi exists naturally in plants as an asymptote and has the potential to reduce the population of insect pests through indirect interactions. This study was conducted to detect and characterize the endophytic fungi Beauveria bassiana and Metarhizium robertsii from the rhizosphere soil of tomato plants and their virulence effect on Galleria melonella. Methods: From the rhizosphere soil of 40 tomato fields, three Beauveria bassiana and seven Metarhizium robertsii isolates were identified using the galleria bait method. All fungi isolates were morphologically characterized by their colony color, shape, and surface texture. Isolates with the highest percentages of germination, conidial yield, and radial growth were selected, and their pathogenicity was evaluated on second instar larvae of Galleria melonella under laboratory conditions. Results: In this study, Beauveria bassiana showed white colony color and aseptate hyphae, whereas Metarhizium robertsii showed dark green to light green colony color and septate hyphal structures. Maximum spore production and conidial length were obtained by Beauveria bassiana isolate APPRC-27 with 2.67x107 spores ml-1 and 3.24 µm, respectively. Colony radial growth rates ranged from 1.73 to 3.24 mm day-1. The results revealed that the highest mortality rate of Galleria melonella (100%) was obtained by Metarhizium robertsii isolates K-61 and K-102 at a concentration of 1x108 conidial ml-1 at 7 days post-inoculation. The lowest mortality rate was registered by Metarhizium robertsii isolate RST-11. Conclusions: In the present study, isolates that produced the most spores and had the highest germination rates were the most virulent to Galleria mellonella second instar larvae. Therefore, virulent entomopathogenic fungi, Beauveria bassiana and Metarhizium robertsii, are promising bioagents for the control of pests.

The effect of two isolates of Beauveria bassiana (Bals.) Vull. on the larvae of confused flour beetle [Tribolium confusum du Val., 1863 (Coleoptera: Tenebrionidae)

The confused flour beetle cause economic losses in stored products, especially in products obtained from wheat. Although using insecticides against storage pests is an effective method, their frequent and continuous use can lead to resistance and toxicity issues in non-target organisms. In this study, the effect of local Beauveria bassiana isolates (BMAUM LD.2016 and BMAUM M6-4) on the 3rd instar larvae of confused flour beetle (Tribolium confusum) was determined under laboratory conditions. As a result of the experiment, both isolates of B. bassiana were found to be more effective on the larvae in the spraying method compared to the dipping method. In the spraying method, mortality rates on the 9th day were 72% in BMAUM LD.2016 isolate, 34% in the dipping method, respectively. Mortality rates of BMAUM M6-4 isolate were recorded as 96% in the spraying method and 8% in the dipping method. In the spraying method, the mortality date (LT50) was determined as 6.09 days for BMAUM LD.2016 isolate and 3.90 days for BMAUM M6-4 isolate. The LT50 value could not be calculated in the dipping method, since the mortality rates were below 50% for both isolates. BMAUM M6-4 isolate caused higher mortality in larvae than BMAUM LD.2016 isolate. As a result, B. bassiana isolates have shown a high level of effectiveness against T. confusum, demonstrating that they can be used as isolates for insect control.

Detection of a PCR‐based mating type for native intraspecific Beauveria bassiana isolates

AbstractThis study developed a PCR‐based mating‐type analysis of 30 intraspecific Beauveria bassiana isolates after ITS phylogenetic analysis. Out of 30 isolates, only 11 B. bassiana isolates, viz., Bb4, Bb5, Bb11, Bb18, Bb19, Bb20, Bb23, Bb25, Bb27, Bb28, and Bb29, exhibited amplification of the mating‐type loci and were thought to be heterothallic. All of these isolates, with the exception of Bb20, had MAT1 mating‐type amplification. All these 11 isolates were clustered together with the MAT1‐ and MAT2‐specific reference strains of B. bassiana in the maximum likelihood phylogenetic analysis of mating‐type genes (IFO 31953 and IFO 31676, respectively). Although the PCR products obtained by the mating‐type assay were short, the phylogenetic trees of the mating‐type genes gave better resolution than that of the ITS region. Understanding the mating type of fungi can clarify the biological species concept and the identification of sex‐related genes in fungi without the presence of teleomorphs. So, combining phylogenetic, developmental, and mating research on each teleomorph specimen has the potential to clarify the systematics of Beauveria species.

Biochemical Basis of Abiotic Stress Tolerance in Native Isolates of <i>Beauveria bassiana</i> (Balsamo) Vuillemin from Kerala

A study on the screening of Beauveria bassiana (Balsamo) Vuillemin native isolates for abiotic stress tolerance was carried out at the Department of Agricultural Entomology, College of Agriculture, Vellanikkara, Thrissur, Kerala during 2019-2023. The growth and biochemical parameters of the three native isolates of B. bassiana (BTL1: OP271760, BTL2: OP290199 and PKDE: OP292066) were studied under different abiotic stress conditions viz., temperature, water stress, acidity and salinity. The results revealed that the highest temperature tolerance (40° C) was displayed by the B. bassiana isolate PKDE. It also survived at high water stress (45% polyethylene glycol), acidic (pH2) and saline (1.5 M) conditions. The analysis of biochemical parameters in stress tolerant isolate revealed that the greatest levels of trehalose (2.033± 0.025, 2.043± 0.006 mg/ min/ g of mycelia), catalase (0.0072± 0.007, 0.0032± 0.003 EU/ min/ mg protein) and peroxidase (0.0602± 0.005, 0.0175± 0.017 EU/ min/ mg tissue weight) were observed after exposure to high temperature and water stress, respectively. This shows that exposure to abioticstress and biochemical parameters are closely related and can be used as determinants for evaluating the potential of biocontrol agents.

Isolation, Identification and Evaluation of the Effects of Native Entomopathogenic Fungi from Côte d'Ivoire on Galleria mellonella.

The fall armyworm, Spodoptera frugiperda (Lepidoptera: Noctuidae), is a polyphagous pest highly damaging to maize and other food crops in Africa, particularly in Côte d'Ivoire. Chemical pesticides not only have often proved to be unsuccessful, but cause adverse effects on the environment and human health; therefore, entomopathogenic fungi could represent an alternative biocontrol solution. Against this background, fungi were isolated from soil samples collected in maize fields in three regions of Côte d'Ivoire, by the methods of soil dilution and baiting with Galleria mellonella. The resulting 86 fungal isolates were phenotypically and genetically identified. The pathogenicity of seven isolates of Metarhizium spp., three isolates of Beauveria bassiana and two isolates of Trichoderma sp. was evaluated on fifth instar larvae (L5) of G. mellonella. Larval mortality rates and the median lethal time (LT50) were determined seven days after inoculation for each of these selected isolates. The median lethal concentration (LC50) was determined for a selection of isolates. Beauveria bassiana isolate A214b was the most effective, causing 100% mortality, with an LT50 of 2.64 days and an LC50 of 1.12 × 104 conidia mL-1. Two other promising isolates, A211 and A214a, belonging to B. bassiana, caused 100% mortality with LT50 values of 3.44 and 4.04 days, respectively. Mortality caused by Metarhizium isolates varied from 65.38% to 100%, with Metarhizium anisopliae isolate T331 causing 100% mortality with an LT50 of 3.08 days at an LC50 of 3.33 × 104 conidia mL-1. Trichoderma sp. isolates were the least pathogenic ones. Beauveria bassiana and Metarhizium isolates showed to be virulent against the model Lepidopteran G. mellonella and will be tested on S. frugiperda.

Isolation, morphological characterization, and screening virulence of Beauveria bassiana and Metarhizium robertsii fungal isolates on Galleria mellonella.

Entomopathogenic fungi exists naturally in plants as an asymptote and have the potential to reduce the population of insect pests through indirect interactions. This study was conducted to detect and characterize the endophytic fungi Beauveria bassiana and Metarhizium robertsii from the rhizosphere soil of tomato plants and their virulence effect on Galleria melonella. From the rhizosphere soil of 40 tomato fields, three Beauveria bassiana and seven Metarhizium robertsii isolates were isolated using the galleria bait method. All fungi isolate were morphologically characterized by their colony color, shape, and surface texture. Isolates with the highest percentages of germination, conidial yield, and radial growth were selected, and their virulence was evaluated on second instar larvae of Galleria melonella under laboratory conditions. In this study, Beauveria bassiana showed white colony color and aseptate hyphae, whereas Metarhizium robertsii showed dark green to light green colony color and septate hyphal structures. Maximum spore production and conidial length were obtained by Beauveria bassiana isolate APPRC-27 with 2.67x10 7 spores ml -1 and 3.24 µm, respectively. Colony radial growth rates ranged from 1.73 to 3.24 mm day -1. The results revealed that the highest mortality rate of Galleria melonella (100%) was obtained by Metarhizium robertsii isolates K-61 and K-102 at a concentration of 1x10 8 conidial ml -1 at 7 days post-inoculation. The lowest mortality rate was registered by Metarhizium robertsii isolate RST-11. In the present study, isolates that produced the most spores and had the highest germination rates were the most virulent to Galleria mellonella second instar larvae. Therefore, virulent entomopathogenic fungi, Beauveria bassiana and Metarhizium robertsii, are promising bioagents for the control of insect pests.

Gül Yaprakbiti, Macrosiphum rosae L. (Hemiptera: Aphididae)’nin potansiyel biyolojik mücadele etmenleri olarak yerel entomopatojen funguslar

The rose aphid, Macrosiphum rosae L. (Hemiptera: Aphididae), is one of the important pests of roses (Rosa spp.) (Rosaceae) in many parts of the world, including Türkiye. In the present study, the pathogenic activity of five indigenous entomopathogenic fungal (EPF) isolates [three isolates of Beauveria bassiana (BbDm-1, BbKm-1, BbMp-1), one isolate of Isaria farinosa (IfGp-1) and one isolate of Purpureocillium lilacinum (PlKa-1)], were tested for their activity against nymphs and adults of M. rosae under laboratory conditions. Spore suspensions of three different concentrations (1 × 107, 1 × 108 and 1 × 109 conidia/ml) obtained from a 10-day old culture of the isolates on PDA (Potato Dextrose Agar) medium were tested by spray application against both nymphs and adults of M. rosae. The mortality rate was dose-dependent and increased with spore concentration of the isolates (P < 0.05). Of the five isolates tested, two B. bassiana isolates, BbDm-1 and BbKm-1, were the most pathogenic and caused mortalities of 100% and 83.3% in nymphs, and 96.7% and 80.0% in adults, respectively, at the highest concentration (1 x 109 conidia/ml), 7 days after treatment. Overall results suggest that these two B. bassiana isolates have the potential to be used in the control of M. rosae.

Isolation, morphological characterization, and screening a virulence of Beauveria bassiana and Metarhizium robertsii as bioagents

Background: Entomopathogenic fungi exists naturally in plants as an asymptote and has the potential to reduce the population of insect pests through indirect interactions. This study was conducted to detect and characterize the endophytic fungi Beauveria bassiana and Metarhizium robertsii from the rhizosphere soil of tomato plants and their virulence effect on Galleria melonella. Methods: From the rhizosphere soil of 40 tomato fields, three Beauveria bassiana and seven Metarhizium robertsii isolates were identified using the galleria bait method. All fungi isolates were morphologically characterized by their colony color, shape, and surface texture. Isolates with the highest percentages of germination, conidial yield, and radial growth were selected, and their pathogenicity was evaluated on second instar larvae of Galleria melonella under laboratory conditions. Results: In this study, Beauveria bassiana showed white colony color and aseptate hyphae, whereas Metarhizium robertsii showed dark green to light green colony color and septate hyphal structures. Maximum spore production and conidial length were obtained by Beauveria bassiana isolate APPRC-27 with 2.67x107 spores ml-1 and 3.24 µm, respectively. Colony radial growth rates ranged from 1.73 to 3.24 mm day-1. The results revealed that the highest mortality rate of Galleria melonella (100%) was obtained by Metarhizium robertsii isolates K-61 and K-102 at a concentration of 1x108 conidial ml-1 at 7 days post-inoculation. The lowest mortality rate was registered by Metarhizium robertsii isolate RST-11. Conclusions: In the present study, isolates that produced the most spores and had the highest germination rates were the most virulent to Galleria mellonella second instar larvae. Therefore, virulent entomopathogenic fungi, Beauveria bassiana and Metarhizium robertsii, are promising bioagents for the control of pests.

Genomic virulence features of Beauveria bassiana as a biocontrol agent for the mountain pine beetle population

BackgroundThe mountain pine beetle, Dendroctonus ponderosae, is an irruptive bark beetle that causes extensive mortality to many pine species within the forests of western North America. Driven by climate change and wildfire suppression, a recent mountain pine beetle (MPB) outbreak has spread across more than 18 million hectares, including areas to the east of the Rocky Mountains that comprise populations and species of pines not previously affected. Despite its impacts, there are few tactics available to control MPB populations. Beauveria bassiana is an entomopathogenic fungus used as a biological agent in agriculture and forestry and has potential as a management tactic for the mountain pine beetle population. This work investigates the phenotypic and genomic variation between B. bassiana strains to identify optimal strains against a specific insect.ResultsUsing comparative genome and transcriptome analyses of eight B. bassiana isolates, we have identified the genetic basis of virulence, which includes oosporein production. Genes unique to the more virulent strains included functions in biosynthesis of mycotoxins, membrane transporters, and transcription factors. Significant differential expression of genes related to virulence, transmembrane transport, and stress response was identified between the different strains, as well as up to nine-fold upregulation of genes involved in the biosynthesis of oosporein. Differential correlation analysis revealed transcription factors that may be involved in regulating oosporein production.ConclusionThis study provides a foundation for the selection and/or engineering of the most effective strain of B. bassiana for the biological control of mountain pine beetle and other insect pests populations.

Genomic Characterization and Functional Description of Beauveria bassiana Isolates from Latin America.

Beauveria bassiana is an entomopathogenic fungus used in agriculture as a biological controller worldwide. Despite being a well-studied organism, there are no genomic studies of B. bassiana isolates from Central American and Caribbean countries. This work characterized the functional potential of eight Neotropical isolates and provided an overview of their genomic characteristics, targeting genes associated with pathogenicity, the production of secondary metabolites, and the identification of CAZYmes as tools for future biotechnological applications. In addition, a comparison between these isolates and reference genomes was performed. Differences were observed according to geographical location and the lineages of the B. bassiana complex to which each isolate belonged.

Seed priming with Beauveria bassiana improves growth and salt stress response in rice

One of the most important abiotic factors that hinder plant development, growth, and production is salt stress. In recent years, there has been a lot of interest in the biological treatment of salt stress in plants using beneficial microbes. The fungal endophyte Beauveria bassiana provides a wide variety of ecosystem services, like suppressing insect pests and pathogens and enhancing plant growth. However, the role of B. bassiana in reducing salt stress in plants has not yet been clarified. This study was undertaken to evaluate the performance of B. bassiana isolate BeauA1 primed rice under salt stress by estimating rice growth, stress parameters, and mitigator characteristics. Primarily, rice seeds were primed with BeauA1 and placed in an agar medium with 120 mM NaCl (≈12 dS m−1 salt solution) to observe the role of BeauA1 in the early establishment of rice seedlings in salt conditions. Seed priming with BeauA1 resulted in an enhancement of rice growth attributes under both control and NaCl stress conditions. In the pot experiment, the BeauA1 primed rice seedlings were planted in soil with different concentrations of salt, viz. 8, 10, and 12 dS m−1. The BeauA1 primed rice plants showed improvement in leaf succulence, leaf area, photosynthetic pigments, and shoot relative water content (RWC), leading to enhanced growth under both salt stress and control conditions. The biochemical study found that BeauA1 considerably increased proline content, total soluble sugars, total carbohydrates, and K+/Na+ in leaves. The antioxidant enzymes catalase (CAT), ascorbate peroxidase (APX), peroxidase (POD), glutathione S-transferase (GST), and nonenzymatic antioxidants phenol and flavonoid were upregulated in BeauA1-primed plants under both control and stressed conditions. Further significant reductions of the lipid peroxidation products malondialdehyde (MDA) and hydrogen peroxide (H2O2) by BeauA1 under salt stress were consistent with higher antioxidant activities in salt stress conditions. Principal component analysis (PCA) further validated BeauA1-primed plants' modulation of growth, antioxidant defense, and reduction of MDA and H2O2 in rice under salt-stress conditions. Our findings indicated that utilizing BeauA1 to reduce salt stress would be a useful strategy to increase rice yield in salt-affected regions.

Antimicrobial Traits of Beauveria bassiana Against Rhizoctonia solani, the Causal Agent of Sheath Blight of Rice Under Field Conditions.

Beauveria bassiana, an entomopathogenic fungus, has recently drawn attention worldwide not only as a potential biocontrol agent against insect pests but also for its other beneficial roles as plant disease antagonist, endophyte, plant growth promoter, and beneficial rhizosphere colonizer. In the present study, 53 native isolates of B. bassiana were screened for antifungal ability against Rhizoctonia solani, the causal agent of sheath blight of rice. Also, the mechanisms underlying such interaction and the responsible antimicrobial traits involved were studied. Following this, potential B. bassiana isolates were assayed against the reduction of sheath blight of rice under field conditions. The results showed that B. bassiana exhibited antagonistic behavior against R. solani with a percent mycelial inhibition recorded maximum of up to 71.15%. Mechanisms behind antagonism were the production of cell-wall-degrading enzymes, mycoparasitism, and the release of secondary metabolites. The study also deciphered several antimicrobial traits and the presence of virulent genes in B. bassiana as a determinant of potential plant disease antagonists. Under field conditions, combined application of the B. bassiana microbial consortium as a seed treatment, seedling root dip, and foliar sprays showed reduced sheath blight disease incidence and severity up to 69.26 and 60.50%, respectively, along with enhanced plant-growth-promoting attributes. This is one of the few studies investigating the antagonistic abilities of the entomopathogenic fungus B. bassiana against phytopathogen R. solani and the underlying mechanisms involved.

Characterization of entomopathogenic fungi from invasive fall armyworm in China and their risk to native pests

AbstractThe role of pathogens in the successful invasion of pests has received increasing attention. Previous hypotheses on parasite‐related invasion mainly focus on the lack of parasites against invasive pests or the introduction of parasites with a higher risk to native pests. Fall armyworm (FAW), Spodoptera frugiperda (J.E. Smith), is a new invasive pest in China. Here, we investigated pathogen infection in eight natural populations of FAW in China, isolated and characterised the pathogens, and then evaluated the infection risk of the pathogens to native pests. The pathogen infection frequencies in FAW were very low (0.32%); only two individuals were found to have typical symptoms of fungal infection, and the fungi were identified as Beauveria bassiana and Metarhizium rileyi. Internal transcribed spacer sequence‐based analysis showed that among 44 B. bassiana isolates worldwide, the SFJS01 isolate was genetically different from only 3 isolates. Among all 13 isolates of M. rileyi from FAW, including the SFGX01 isolate, there was no significant differentiation. Comparison of the mortality caused by B. bassiana SFJS01 or M. rileyi SFGX01 against S. frugiperda, Spodoptera litura, Bemisia tabaci, Laodelphax striatellus and Nilaparvata lugens showed that the new isolates all had the highest virulence to S. frugiperda and the lowest virulence to S. litura, a native pest closely related to FAW. The findings indicated that pathogens isolated from FAW did not pose a high risk to native pests and that they did not play a key role in the successful invasion of the FAW in China.

Biocontrol potential of native isolates of Beauveria bassiana against cotton leafworm Spodoptera litura (Fabricius)

The entomopathogenic fungus (EPF), Beauveria bassiana, is reported as the most potent biological control agent against a wide range of insect families. This study aimed to isolate and characterize the native B. bassiana from various soil habitats in Bangladesh and to evaluate the bio-efficacy of these isolates against an important vegetable insect pest, Spodoptera litura. Seven isolates from Bangladeshi soils were characterized as B. bassiana using genomic analysis. Among the isolates, TGS2.3 showed the highest mortality rate (82%) against the 2nd instar larvae of S. litura at 7 days after treatment (DAT). This isolate was further bioassayed against different stages of S. litura and found that TGS2.3 induced 81, 57, 94, 84, 75, 65, and 57% overall mortality at egg, neonatal 1st, 2nd, 3rd, 4th, and 5th instar larvae, respectively, over 7 DAT. Interestingly, treatment with B. bassiana isolate TGS2.3 resulted in pupal and adult deformities as well as decreased adult emergence of S. litura. Taken together, our results suggest that a native isolate of B. bassiana TGS2.3 is a potential biocontrol agent against the destructive insect pest S. litura. However, further studies are needed to evaluate the bio-efficacy of this promising native isolate in planta and field conditions.

Antifungal activity of local isolates of Beauveria bassiana (Balsamo) Vuillemin against Verticillium dahliae Kleb. causing wilt disease of cotton

BackgroundVerticillium dahliae Kleb. is a soil-borne pathogen with a broad host spectrum and causes yield losses in cotton cultivation worldwide. Beauveria bassiana is an environmentally friendly entomopathogenic fungus (EPF) that has been recognized, used and studied for many years.ResultsAs a control, all local of B. bassiana isolates inhibited mycelial growth of the pathogen at different rates. The highest percentage of inhibition against non-defoliating (PHCVd3 isolate) and defoliating (PHCVd47 isolate) pathotypes was determined in Bb18 (85.3; 81.7%) and Bb1 (82.3; 77.5%) isolates, respectively, when applied 2 days ago. Isolates Bb1 (80.6%) and Bb18 (77.8%) had the highest percentages of inhibition against the PHCVd3 isolate, and Bb18 (75.8%) against isolate PHCVd47, when EPF and pathogen were applied at the same time.ConclusionsBb18 and Bb1 isolates of B. bassiana showed a hope against both pathotypes of wilt disease caused by V. dahliae under in vitro conditions. Especially, B. bassiana was observed to induce higher inhibition rates, when EPF isolates developed in Petri dish 2 days before the pathogen.

Potency of entomopathogen Beauveria bassiana fungus as biofertilizer and biostimulant to increase the plant growth of Cayenne pepper (Capsicum frutescens L.)

This research aimed to determine the Beauveria bassiana entomopathogen fungus as a biofertilizer and biostimulant. The research was conducted at the Biological Control laboratory and Wire House, Universitas Andalas. The potency of B. bassiana produced the IAA hormone was carried out by a This was qualitative research by observing a pink color change in the Salkowsky solution while the potency of B. bassiana to dissolve phosphate by using Pikovskaya medium. The test results on Pikovskaya media showed that all tested isolates had the potential to dissolve phosphate at 7, 10, and 14 days. The largest clear zone area was in the 14 days, found in Bb WS isolates (5.42 mm) followed by TD312 isolates (5.28mm). To test of plant growth in the laboratory was carried out by testing the germination of seeds by blotter test and test on paper. The design used was a non-factorial Completely Randomized. The results showed that the highest percentage of germination was found in TD312 and BbWS isolates. The potency of B. bassiana isolates as growth promoters can be seen from an increase in plant height and the number of chili leaves. All of the results indicated that entomopathogen fungus can be applied as biological fertilizers and biostimulants on cayenne pepper plants.