Entomopathogenic Beauveria Bassiana Research Articles

Foster carers influence brood pathogen resistance in ants.

Social organisms face a high risk of epidemics, and respond to this threat by combining efficient individual and collective defences against pathogens. An intriguing and little studied feature of social animals is that individual pathogen resistance may depend not only on genetic or maternal factors, but also on the social environment during development. Here, we used a cross-fostering experiment to investigate whether the pathogen resistance of individual ant workers was shaped by their own colony of origin or by the colony of origin of their carers. The origin of care-giving workers significantly influenced the ability of newly eclosed cross-fostered Formica selysi workers to resist the fungal entomopathogen Beauveria bassiana. In particular, carers that were more resistant to the fungal entomopathogen reared more resistant workers. This effect occurred in the absence of post-infection social interactions, such as trophallaxis and allogrooming. The colony of origin of eggs significantly influenced the survival of the resulting individuals in both control and pathogen treatments. There was no significant effect of the social organization (i.e. whether colonies contain a single or multiple queens) of the colony of origin of either carers or eggs. Our experiment reveals that social interactions during development play a central role in moulding the resistance of emerging workers.

Plant-mediated effects on entomopathogenic fungi: how the olive tree influences fungal enemies of the olive moth, Prays oleae

The community of entomopathogenic fungi associated with the olive moth Prays oleae is specific for each generation of this insect. The entomopathogen Beauveria bassiana is almost exclusive to the phyllophagous or leaf generation, whereas Paecilomyces formosa mainly occurs in the carpophagous or fruit generation. The main objective of this work was to evaluate olive plant-mediated effects on the development (germination, growth, sporulation and spore viability) of both entomopathogens. While B. bassiana was strongly inhibited by olives, P. formosa development was more restricted by leaves. These inhibitory effects were caused by both volatile and diffusible compounds produced by olives and leaves. Specifically, the effects of two leaf volatile compounds, (Z)-3-hexen-1-ol and (Z)-3-hexenyl acetate were studied. The results suggest that olive plant organs affect entomopathogens by controlling their abundance and function, which may partly explain the occurrence of a fungal species in a specific P. oleae generation.

Growth and sporulation of entomopathogenic Beauveria bassiana, Metarhizium anisopliae, Isaria farinosa and Isaria fumosorosea strains in relation to water activity and temperature interactions

This study examined six strains of Beauveria bassiana s.l. and Isaria farinosa, one strain of Isaria fumosorosea and five strains of Metarhizium anisopliae s.l. to identify the ability for (1) growth and (2) sporulation under interacting environmental factors of water activity (aw) and temperature stress. Growth on Sabouraud Dextrose Agar (SDA; water activity, aw = 0.995) or SDA modified with glycerol to 0.98, 0.96 and 0.94 aw was measured at four different temperatures (25, 30, 35 and 37°C). All M. anisopliae strains grew at 25–35°C and 0.995 aw while only two strains tolerated extreme water stress at 0.94 aw.Three strains of B. bassiana were able to grow at 25–37°C and 0.995 aw. Only one strain of I. farinosa was able to grow at 25–37°C and 0.995 aw. Aw and temperature interactions resulted in different strain-dependent responses, in terms of growth and sporulation. Only one strain of I. farinosa and three of M. anisopliae grew at 0.94 aw and none of the B. bassiana strains tolerated such water stress. At 0.96 and 0.94 aw and 35–37°C, sporulation by all the strains of the three species were significantly affected. Under elevated temperatures and drought stress, very few of these strains of entomopathogenic fungi are able to grow and sporulate. Indeed, the B. bassiana strains were unable to tolerate the extreme conditions examined. Resilience to such abiotic interactions is critical for selecting strains for formulations. Tolerance to water and temperature stress could be good criteria for selection of strains with secondary spread potential for use as part of an integrated pest management system where secondary cycling may be important, especially in sub-tropical and tropical environments.

Screening of liquid media and fermentation of an endophytic Beauveria bassiana strain in a bioreactor.

A novel approach for biological control of insect pests could be the use of the endophytic entomopathogenic Beauveria bassiana isolate ATP-02. For the utilization of the endophyte as a commercial biocontrol agent, the fungus has to be mass-produced. B. bassiana was raised in shake flask cultures to produce high concentrations of total spores (TS), which include blastospores (BS) and submerged conidiospores (SCS). The highest concentration of 1.33×109 TS/mL and the highest yield of 5.32×1010 TS/g sucrose was obtained in the TKI broth with 5% sugar beet molasses which consists of 50% sucrose as a carbon source. In spite of the lower sugar concentration (2.5%) the amount of TS could be increased up to 11-times in contrast to the cultivation with 5% sucrose. The scale-up to a 2 L stirred tank reactor was carried out at 25°C, 200–600 rpm and 1 vvm at pH 5.5. A TS yield of 5.2×1010 TS/g sucrose corresponding to a SCS yield of 0.2×1010 SCS/g sucrose was obtained after 216 h. With regards to the culture medium the cost of 1012 TS amounts to 0.24 €. Plutella xylostella larvae, which were fed with oilseed rape leaves treated with spores from fermentation resulted in 77 ± 5% mortality. Moreover, spores from submerged cultivation were able to colonize oilseed rape leaves via leaf application. This is the first report of fermentation of an endophytic B. bassiana strain in a low-cost culture medium to very high yields of TS.

Enemigos naturales asociados a diaphorina citri kuwayama (hemiptera: psyllidae) en limón persa (citrus latifolia tanaka) en Nayarit, México

Natural enemies associated to Diaphorina citri in the state of Nayarit were identified. The study was carried out in three orchards of Persian lime from May to October 2011. The identified depredator species were Olla v-nigrum, Chilocorus cacti, Cycloneda sanguinea, and Ceraeochrysa sp.; as well as the parasitoid Tamarixia radiata and the entomopathogenic Beauveria bassiana. Nephus sp. Mulsant, 1850 and Pentilia sp. Mulsant, 1850 are new distribution records to Mexico.

Tolerance and Bioaccumulation of Copper by the Entomopathogen Beauveria bassiana (Bals.-Criv.) Vuill. Exposed to Various Copper-Based Fungicides

This work evaluates for the first time the relationships between copper-tolerance, -solubilization and -bioaccumulation in the entomopathogen Beauveria bassiana exposed to Bordeaux mixture, copper oxychloride or copper hydroxide. Bordeaux mixture was highly detrimental to fungus, by inhibiting the growth totally at the recommended dose (RD) and 2×RD. Copper hydroxide and copper oxychloride were found to be less toxic, reducing fungus growth, sporulation and conidial germination in an average of 29%, 30% and 58%, respectively. These two copper forms were the easiest to solubilize, to precipitate and the most accumulated by B. bassiana, suggesting the involvement of all these processes on fungus copper-tolerance.

Establishment of the fungal entomopathogen Beauveria bassiana as a season long endophyte in jute (Corchorus olitorius) and its rapid detection using SCAR marker

An experiment was conducted to introduce the entomopathogen Beauveria bassiana (Balsamo) Vuillemin (Ascomycota: Hypocreales) as an endophyte in jute (Corchorus olitorius), a bast fibre crop through seed treatment. Colonization of root, leaf, stem, capsule, and seed were assessed through plating on selective medium and PCR based detection using B. bassiana specific SCAR markers. Endophytic colonization was detected in all the plants grown from treated seeds, but all the plant parts were not colonized. Colonization was detected in leaves, stems, and green capsules but not in roots and seeds. The endophytic colonization was influenced by both plant part and sampling period. Colonization was greater in leaves (55.87%) compared to stems (12.53%) and capsules (42.44%). The percent colonization was higher in case of 60 days old plants (43.34%) than in 30 days (23.89%) and 120 days (35.39%) old plants. As B. bassiana has already been reported to be pathogenic on jute pests, namely semilooper (Anomis sabulifera) and bihar hairy caterpillar (Spilosoma obliqua), its season long endophytic colonization within jute plant suggests a novel approach of biological control of these pests through seed treatment with the entomopathogen.

Evaluation of entomopathogenic fungi as potential biological control agents of the dengue mosquito, Aedes aegypti (Diptera: Culicidae)

Dengue is a global health concern. Growing insecticide resistance in the primary mosquito vector, Aedes aegypti, limits the effectiveness of vector control, so alternative tools are urgently needed. One approach is the use of biopesticides comprising entomopathogenic fungi, e.g., Beauveria bassiana and Metarhizium anisopliae. These fungi may decrease disease transmission by reducing mosquito vector longevity and also occur worldwide, although many isolates have not been tested for virulence against mosquitoes. Ninety-three isolates of entomopathogenic fungi representing six species (B. bassiana, M. anisopliae, Isaria fumosorosea, I. farinosa, I. flavovirescens, and Lecanicillium spp.) were screened as potential biological control agents of Aedes aegypti. A hierarchical, multi-criteria experimental design was undertaken to find suitable isolates. Initial screening was performed via in vitro assays measuring radial growth and spore persistence, eliminating isolates with poor growth or viability on nutrient-rich substrate. Subsequent measurements of spore persistence revealed that only nine of 30 strains tested had half-lives exceeding 3 weeks. Ten isolates were chosen for in vivo bioassays against adult Ae. aegypti. From these assays, two Australian isolates of B. bassiana, FI-277 and FI-278, appeared to be most promising. Both isolates were shown to be virulent against Ae. aegypti at 20, 26, and 32°C. Spreading spores manually onto substrate was found to be more efficacious than spraying. Ae. aegypti infected by manually-spread spores on cotton substrate were found to have an LT50 of 3.7±0.3 days. These characteristics suggest that FI-277 has promise as a dengue mosquito biocontrol agent, either alone or combined with conventional chemical insecticides.

Efeito de Metarhizium anisopliae (Metsch.) Sorok. e Beauveria bassiana (Bals.) Vuill. Sobre o Ácaro Predador Iphiseiodes zuluagai Denmark & Muma (Acari: Phytoseiidae)

It was aimed at with this work to evaluate the selectivity of the isolated 645 and CG 321, of the fungus entomopathogenic Beauveria bassiana (Bals.) Vuill. and Metarhizium anisopliae (Metsch.) Sorok. respectively, in the concentration of 108 conidia/mL, on recently emerged females of Iphiseiodes zuluagai Denmark & Muma (Acari: Phytoseiidae), originating from of laboratory rearing. The research was developed at the Laboratory of Pathology of Insects of the Rural Federal University of Pernambuco (UFRPE), in Recife, in temperature of 26.5 ± 0.6o C and 78.4 ± 4.2% of UR and fotofase of 12h. The percentage of total mortality provoked by the isolated 645 of B. bassiana was of 35.94% and the confirmed mortality was of 32.81%. Regarding isolated CG 321 of M. anisopliae, the percentage of the total mortality 42.19% and confirmed 35.94%. With base in the obtained results, it can be conclude that both isolated tested 645 and CG 321 showed pathogenic for the mite at laboratory level; however the isolated 645 of B. bassiana showed smaller numeric values of virulence, showing certain selectivity to this mite predator, showed as an alternative for use in programs of biological control.

Colonization of crop plants by fungal entomopathogens and their effects on two insect pests when in planta

Fungal entomopathogens can directly regulate populations of various insects. The entomopathogen Beauveria bassiana can also endophytically colonize various plants. Endophytic colonization by entomopathogens might be more widespread than currently realized and may provide a source of indirect interactions between fungi and insects. We tested whether some common entomopathogens could colonize six crop plants. We also assessed whether the performance of two insects, Aphis gossypii and Chortoicetes terminifera, was affected by entomopathogens in plants. The entomopathogens B. bassiana, Lecanicillium lecanii and Aspergillus parasiticus individually colonized the leaves of all six crop plants when inoculated as conidia. L. lecanii also readily colonized five different cultivars of cotton. When the entomopathogens were present in the soil in which either cotton or wheat seedlings were grown, A. parasiticus was subsequently isolated from the leaves, stem and roots of both plants and B. bassiana from the leaves, stem and root of wheat only, whereas L. lecanii failed to colonize either plant through the soil. Of the three entomopathogens tested, endophytic presence of A. parasiticus reduced growth of cotton, but none reduced growth of wheat. Feeding by A. gossypii on cotton leaves colonized by either B. bassiana or L. lecanii slowed aphid reproduction, and consumption of wheat leaves colonized by either B. bassiana or A. parasiticus slowed the growth of C. terminifera nymphs. The life cycle of at least three entomopathogens potentially includes plants. The presence of entomopathogens as endophytes can influence growth and fecundity of insect herbivores, suggesting a possible role for endophytic entomopathogens in the regulation of insect populations.

Optimization of Solid-State Fermentation for Improved Conidia Production of Beauveria bassiana as a Mycoinsecticide

The production of conidia of entomopathogenic Beauveria bassiana by solid-state fermentation was studied for the development of a biocontrol agent against aphid Myzus persicae. The optimal conditions for conidia production on polished white rice were 40% moisture content, 25°C culture temperature, 2-day-old seeding culture grown in 3% corn meal, 2% rice bran, 2% corn steep powder medium, initial conidia concentration of 107 conidia/g in the wet rice, 10% inoculum size, and use of a polyethylene bag as a container. The polyethylene bag containing inoculated rice was hand-shaken every 12 hr during fermentation. Using optimal conditions, the maximum conidia production obtained was 4.05 g conidia/100 g dry rice after 14 days of cultivation, a rate 2.83 times higher than conidia yield of pre-optimization.

First Record of Entomopathogen Beauveria Bassiana (Bals.-Criv.) Vuill. On Zygogramma Bicolorata Pallister, A Biocontrol Agent of Parthenium Hysterophorus L.

First Record of EntomopathogenBeauveria Bassiana(Bals.-Criv.) Vuill. OnZygogramma BicolorataPallister, A Biocontrol Agent ofParthenium HysterophorusL.Entomopathogenic fungi have great potential as biological control agents against insect pests. So they are being developed worldwide for the control of many pests of agricultural importance. But their effect on non-target insects, such as natural enemies has been a matter of great concern. Recently we came across an entomopathogen infecting a laboratory culture ofZygogramma bicolorata, a potential biocontol agent of noxious weed,Parthenium hysterophorus. The pathogen was isolated from the grubs and beetles and identified asBeauveria bassiana. In the present paper, the entomopathogen,B. bassianais reported and described for the first time from the laboratory culture ofZ. bicolorata.

A new microbial consortia containing entomopathogenic fungus, Beauveria bassiana and plant growth promoting rhizobacteria, Pseudomonas fluorescens for simultaneous management of leafminers and collar rot disease in groundnut

The virulence of 20 isolates of Beauveria bassiana (Balsamo) Vuillemin to larvae of the leafminer, Aproaerema modicella, was tested in the laboratory. Leafminer larvae were sprayed with a standard concentration of 1×108 condia/mL of each B. bassiana isolate. All the B. bassiana isolates tested were pathogenic to A. modicella and the mortality varied between 16.7 and 68.9%. Beauveria bassiana isolate B2 was found to be the most virulent followed by isolate B4 which resulted in 59% mortality. Beauveria isolate B2 was selected for dose–response mortality studies with four different doses (1×102, 1×104, 1×106 and 1×108 conidia/mL). Among the various doses tested, 1×108 conidia/mL produced the highest mortality (70.7%). In addition, morphogenesis of the insect pest in all stages, larval, pupal and adult was greatly affected due to fungal infection. Further, B. bassiana isolate B2 and two Pseudomonas fluorescens strains, TDK1 and Pf1 were tested alone and in combination for suppression of groundnut leafminer and collar rot disease and promotion of plant growth and yield both under glasshouse and field conditions. The mixture of B. bassiana and P. fluorescens strains significantly reduced the leafminer and collar rot disease incidences when applied as talc-based formulation through seed, soil and foliar application under glasshouse and field conditions.

Effects of carbon and nitrogen sources and ratio on the germination, growth and sporulation characteristics of Metarhizium anisopliae and Beauveria bassiana isolates.

The entomopathogenic fungi Metarhizium anisopliae and Beauveria bassiana are ubiquitous and widespread with well documented broad-spectrum myco-pesticidal effects. It has been reported that nutrient source is an integral determinant of growth and virulence of entomopathogenic fungi. Nutrient based studies also impart light towards the identification of most commendable media for laboratory assays as well as selection of the tolerant isolates. With such a perspective, an in-vitro study was undertaken to evaluate conidial germination, mycelial growth and spore yield of fourteen M. anisopliae and seventeen B. bassiana isolates and the effect of different carbon and nitrogen sources on these characteristics were studied. The different isolates showed significant variation with respect to the differing preference for the nutrient sources. From this study it was inferred that isolate UM2 (M. anisoplaie) and AB1 (B. bassiana) exhibited commendable growth potentials on almost all the nutrient sources studied, and were basically more robust isolates and holds high affirmations for commercial usage as biopesticides. Key words: Metarhizium anisopliae, nutrition, germination, growth, sporulation,Beauveria bassiana.

Laboratory Evaluation of Four Fungal Pathogens against the Teak Defoliator, Hyblaea puera (Cramer) (Lepidoptera: Hyblaeidae)

Effect of four entomopathogenic fungi, Beauveria bassiana, B. brongniartii, Paecilomyces fumosoroseus and Metarhizium anisopliae , isolated from different host insects, was tested in the laboratory against the teak defoliator, Hyblaea puera (Cramer) (Lepidoptera: Hyblaeidae) to assess their virulence and efficiency. Five different concentrations, 2x10 6 , 4x10 6 , 6x10 6 , 8x10 6 and 1x10 7 conidia ml -1 were directly and indirectly applied onto third instar larvae of H. puera . All the four fungi tested under both application methods were pathogenic to H. puera with higher efficiency in direct application than indirect application. At 9 days after exposure, the mean per cent mortality obtained was 100, 93.02, 93.02 and 66.74%, respectively, for B. bassiana , B. brongniartii , P. fumosoroseus and M. anisopliae at the highest concentration of 1 x 10 7 conidia ml -1 in direct application. Mortality of the larvae varied according to the concentration of conidia, method of application and fungi. The lowest LC 50 (1.89 x 10 6 conidia ml -1 ) and LT 50 (91.18 hr) values obtained for B. bassiana in direct application showed that B. bassiana was more pathogenic to H. puera than the other three fungi.

Production of Blastospore of Entomopathogenic Beauveria bassiana in a Submerged Batch Culture

The principal objective of this study was to determine the optimal liquid culture conditions in shake flasks for maximal sporulation of Beauveria bassiana. The optimal initial pH for the spore production of B. bassiana using Potato Dextrose Broth was 5.2. The screening in shake flasks of carbon and nitrogen sources resulted in the identification of an optimal medium based on 3% sucrose and 1% casamino acid, with a C : N ratio of 22 : 4. Using this medium, a production level of 5.65 × 107 spores per ml was obtained after 5 days of culture. Using 3% corn meal, 2% corn steep powder, and 2% rice bran, the maximum spore concentration of 8.54 × 108/ml was achieved 8 days after inoculation at 25°C in a rotary shaking incubator operated at 200 rpm. This represents a yield gain of approximately 2.89 times that of pre-optimization.

Compatibility of an entomopathogenic fungus with a predator and a parasitoid in the biological control of greenhouse whitefly

An ongoing debate in biological control consists of whether interference between biological agents can disrupt pest control. This study investigated the outcome of interactions between the entomopathogen Beauveria bassiana with the whitefly predator Dicyphus hesperus and the parasitoid Encarsia formosa, as well as their effect on the control of the greenhouse whitefly Trialeurodes vaporariorum on greenhouse tomato crops. Our objective was to determine whether the generalist B. bassiana would disrupt biological control by interfering with D. hesperus or E. formosa. In experimental greenhouses, whitefly, parasitoid and predator populations were established, and over 27 days, tomato plants were sprayed with three applications of the B. bassiana based product BotaniGard® (5.13×103 conidia/mm2) or water (control). Populations of greenhouse whitefly and biological control organisms were regularly monitored in control and B. bassiana-treated compartments. Overall, 10.6% of all whiteflies in treated compartments were infected, and 0.98% were both infected and parasitized. There were 31.7 and 22.3% fewer immature and adult whiteflies, respectively, on B. bassiana-treated plants relative to controls. Parasitism by E. formosa and predation by D. hesperus occurred at rates of 7.5 and 2.5%, respectively, in B. bassiana-treated compartments, and 5 and 6%, respectively in control compartments. Our study suggests that applications of B. bassiana for short-term biological control of greenhouse whiteflies are compatible with the concurrent use of E. formosa and D. hesperus on greenhouse tomato crops.

Effect of the entomopathogenic fungi on mortality and injury level of western flower thrips, Frankliniella occidentalis

The harmfulness of western flower thrips, Frankliniella occidentalis, including insect mortality and plant injury level after the application of three productive and active strains of the entomopathogenic fungi, Metarhizium anisopliae, Lecanicillium lecanii, and Beauveria bassiana, was estimated. LC50 of the M. anisopliae for second instar larvae was twice that of L. lecanii and 1.7 times higher than that of B. bassiana. The average number of damage zones on leaf surfaces after the application of fungi (5×106 spores per ml) constituted 3.0 ± 0.7, 15.9 ± 4.6, and 22.4 ± 4.3 per leaf, respectively (control 67.0 ± 5.7). The total damage area of the leaves was 2.2 ± 0.4, 5.2 ± 0.9, and 4.5 ± 0.6% (control 13.7 ± 3.0%), respectively. Fungi B. bassiana and L. lecanii showed the same level of insect mortality but the number of damage zones and the total damage areas had significant differences. The most effective fungus was found to be M. anisopliae which provided higher plant protection as measured by the decrease in plant injury.

Insecticidal evaluation of Beauveria bassiana engineered to express a scorpion neurotoxin and a cuticle degrading protease

To improve the insecticidal efficacy of the entomopathogen Beauveria bassiana, the fungus was genetically modified with an insect-specific scorpion neurotoxin AAIT and an insect cuticle degrading protease PR1A from another insect pathogen (Metarhizium anisopliae). The wild-type and the transformants were bioassayed against the larvae of Masson's pine caterpillar Dendrolimus punctatus and the wax moth Galleria mellonella. In comparison to the wild-type strain, engineered isolates took fewer spores to kill 50% of pine caterpillars, 15-fold less for the aaIT single transformant Bb13T and eightfold less for the double transformant Bb13TPR1A, respectively. The median lethal times for Bb13T and Bb13TPR1A were reduced by 40% and 36.7%, respectively against D. punctatus and 24.4% and 20.9%, respectively against G. mellonella. Our data showed that the cotransformation of these two genes produced no synergistic effects on virulence improvement. It is evident from this study that AAIT could be degraded by the protease PR1A when they are expressed together, emphasizing that protein interactions need to be evaluated when working with multiple genes, particularly if they include proteases.

Biosynthesis of the Cyclooligomer Depsipeptide Beauvericin, a Virulence Factor of the Entomopathogenic Fungus Beauveria bassiana

Beauvericin, a cyclohexadepsipeptide ionophore from the entomopathogen Beauveria bassiana, shows antibiotic, antifungal, insecticidal, and cancer cell antiproliferative and antihaptotactic (cell motility inhibitory) activity in vitro. The bbBeas gene encoding the BbBEAS nonribosomal peptide synthetase was isolated from B. bassiana and confirmed to be responsible for beauvericin biosynthesis by targeted disruption. BbBEAS utilizes D-2-hydroxyisovalerate (D-Hiv) and L-phenylalanine (Phe) for the iterative synthesis of a predicted N-methyl-dipeptidol intermediate, and forms the cyclic trimeric ester beauvericin from this intermediate in an unusual recursive process. Heterologous expression of the bbBeas gene in Escherichia coli to produce the 3189 amino acid, 351.9 kDa BbBEAS enzyme provided a strain proficient in beauvericin biosynthesis. Comparative infection assays with a BbBEAS knockout B. bassiana strain against three insect hosts revealed that beauvericin plays a highly significant but not indispensable role in virulence.