Beauveria Bassiana Isolates Research Articles

Pathogenicity of indigenous strains of three entomopathogenic fungi to the sisal weevil, Scyphophorus acupunctatus (Gyllenhal) (Coleoptera: Curculionidae)

Summary The pathogenicity of indigenous isolates of Beauveria bassiana, Metarhizium anisopliae and Isaria fumosorosea was evaluated in the laboratory against larvae and adults of the sisal weevil, Scyphophorus acupunctatus. Inoculation was achieved via immersion of individuals into conidia suspensions of different concentrations. All three fungal species proved high pathogenicity against larvae of the weevil, causing 100% mortality in most of the treatments. Beauveria bassiana caused the highest mortality of the adults (86.67±12%), followed by M. anisopliae (46.67±17.8%) and I. fumosorosea (40±17.5%). Mean survival time also differed significantly among treatments and life stages of the weevil. In total, larvae survived significantly fewer days than adults post infection. Results of the present study indicate the potential of indigenous strains of entomopathogenic fungi as biological control agents against the invasive weevil.

Changes in cellular immune responses of Chilo suppressalis Walker (Lepidoptera: Crambidae) due to pyriproxyfen treatment

Abstract The effects of pyriproxyfen were determined on the cellular immunity and phenoloxidase activity in the 4th instar larvae of Chilo suppressalis Walker. The bioassay results revealed the effective concentrations of: 10L : 18C, 30L : 72C and 50L : 190C μg · ml−1. The sole effect of 18 and 72 μg · ml−1 concentrations at intervals of 1–3 h caused a higher number of total hemocytes in the treated larvae than the control, but the reverse results were observed after 6–24 h. The number of plasmatocytes was lower than that of the control for intervals of 3–24 h but the number of granulocytes was higher than the control after 1–3 h although no significant differences were observed at the other times. In the treated larvae, the activities of phenoloxidase were higher and lower than those of the control after 1–3 h and 6–24 h, respectively. The combined effects of pyriproxyfen and the entomopathogenic fungus, Beauveria bassiana isolate B3 caused higher numbers of total hemocytes, plasmatocytes, and granulocytes in the treated larvae by use of the three concentrations of pyriproxyfen, at intervals of 6 and 12 h. Although the numbers of nodules in the larvae treated with concentrations of 18 μg · ml−1 were higher than those of other treatments, the overall numbers were lower than those of the control. Finally, the activity of phenoloxidase in the treated larvae was higher than that of the control, at intervals of 6 and 12 h post-treatment. Findings of the current study indicate an intervening role of pyriproxyfen in the cellular immunity of C. suppressalis to entomopathogenic objects.

The combined effect of soil‐applied azadirachtin with entomopathogens for integrated management of western flower thrips

AbstractPerformance of soil application of azadirachtin products with entomopathogens was evaluated as single treatments, in multiple combinations and in different concentrations against the soil stages of western flower thrips, Frankliniella occidentalis (Pergande), in French beans Phaseolus vulgaris L. Treatments consisted of NeemAzal‐T solution, neem pellets, Steinernema carpocapsae (Weiser) Nemastar®, isolates of Metarhizium anisopliae (Metschnikoff) Sorokin (IPP 2539 and ICIPE‐69) and Beauveria bassiana (Balsamo) – Naturalis®. All treatments were analysed for the number of emerging adults, while emerged adults in fungi‐based treatments were analysed additionally for the retarded development of mycosis as a possible cause of secondary mortality. Possible interactive effects in combined treatments were analysed using a generalized linear model (GLM) approach, and three levels of dose–response combinations of the selected treatments were further tested. Bioassay results of the single treatments indicated between 43% and 60% reduction in adult emergence with NeemAzal‐T solution thus proving to be the most efficient. However, most cadavers with entomopathogenic fungi (EPF) treatments showed the development of mycosis. Therefore, the reduction in adult emergence attributed to the EPF was altogether >87%. Combined treatments with Steinernema, Metarhizium (ICIPE‐69), NeemAzal‐T and neem pellets resulted in total reduction in adult emergence of 95–97% when late mortality by mycosis was considered. Of the treatment combinations, two showed synergistic, four additive and one an antagonistic response. Combining low concentration of entomopathogenic nematode (EPN) (100 IJ/cm2) with NeemAzal‐T resulted in satisfactory control compared to the operational dose of EPN, while the highest concentration of M. anisopliae (108 conidia) combined with Steinernema showed the best performance with 74% reduction in adult emergence.

Nezara viridula(Hemiptera: Pentatomidae) Cuticle as a Barrier forBeauveria bassianaandPaecilomycessp. Infection

The objective of this study was to evaluate the ability of two Beauveria bassiana isolates and one Paecilomyces sp. isolate to infect Nezara viridula adults under laboratory conditions. The lethal concentrations (LC50) of the Egyptian and exotic Beauveria and Paecilomyces isolates for N. viridula were 323 × 106, 835 × 106 and 281 × 107 conidia/ml, respectively. Although, there was no significant difference observed in the mortality rates of adults exposed to the conidiospores of the fungal isolates, the results demonstrated a concentration-dependent pattern. The conidia showed limited attachment to the insect integument. Interestingly, a positive relationship was observed between the rate of increase in the germination of conidia and that of the exposure time, up to 84–92 % at 48 h post-infection. Furthermore, germination of the isolates on the wings was significantly different. The conidia gave rise to germ tubes at 12 h with bipolar germ tubes and hyphal network at 48 h post-infection. SEM revealed that...

Effectiveness of Beauveria bassiana Native Isolates in the Biological Control of the Med-iterranean Fruit Fly (Ceratitis capitata)

The effectiveness of native entomopathogenic Beauveria bassiana isolates in the biological control of the Mediterranean fruit fly (Ceratitis capitata) was evaluated under laboratory and field condi- tions. Local isolates (P. Bv32, P. Bv39, P. Bv41, P. Bv51, and P. Bv52) of the fungus B. bassiana in- duced higher adult mortalities (77%, 65%, 65%, 65%, and 58%, respectively) than a control against the Mediterranean fruit fly under laboratory conditions. Adult mortality increased by increasing the conidial concentrations. In addition, the lethal time (LT50) for killing adult C. capitata ranged from 3.91 to 5.60 days, and the logged lethal concentration (LC50) ranged from 3.80 to 10.50, de- pending on the isolate. Furthermore, the contact application method induced significantly higher mortality than feeding alone, compared with the control. In addition, spraying peaches with a co- nidial suspension of the isolates P. Bv32 and P. Bv39 significantly reduced infestation by the fruit fly, compared with the control. The isolates grew well at a temperature range of 25˚C - 30˚C; ger- mination of the conidia occurred at 15˚C - 30˚C, and sporulation occurred at 20˚C - 25˚C. High Mediterranean fruit fly mortalities were induced at 15˚C - 30˚C, with significant differences among the isolates. However, the isolates failed to grow, germinate, or sporulate above 35˚C or below 10˚C. Under field conditions, a formula of the bioinsecticide containing the isolate P. Bv32 of B. bassiana significantly reduced peach infestation with Medfly maggots by 25% compared with the control, and by 30% when combined with a low dose of the commercial insecticide Confidor®.

A Study on the Efficiency of Beauveria Bassiana Isolate Inoculation Release for Oryzaephilus surinamensis Control in Date Store Condition

A Study on the Efficiency of Beauveria Bassiana Isolate Inoculation Release for Oryzaephilus surinamensis Control in Date Store Condition

Biodiversity and enzymatic profile of some entomopathogenic fungi

Five fungal isolates belonging to theentomopathogenic fungi where had isolated inBio-insecticide Production Unit, Plant Protection Research Institute , two isolatesof Beauveriabassiana,two isolatesof Lecanicillium antillanum andone of Paecilomyces lilacinus, in addition to one isolate of Rhizopusstolonifer That grows with Lecanicillium antillanum inMycoparasitism relationship.The isolatedfungi wererecovered from Egyptian soil and from larvae of Spodopteralittoralis which found infected in a sugar beet field. Theseisolates were identified by conventional techniques in Mycological Center,Faculty of Science, Assiut University. Among these fungal species L. antillanumis a new record in Egypt. In addition, the activities of proteases, lipases,amylases and L-asparaginase of isolates fungi were recorded. The results showedthat, all isolates were active producers of extracellular hydrolytic enzymes.

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.

A novel approach: Beauveria bassiana granules applied to nursery soil for management of rice water weevils in paddy fields.

Spraying of entomopathogenic fungi formulated as wettable powders and suspension concentrates based on oils or water has been used for the management of crop pests. However, the use of fungal granules to control paddy field pests has not been fully explored. Herein, several Beauveria bassiana isolates (ERL1170, ERL1578 and ERL836) were produced as granules using a millet-based solid culture. The granules were applied to the rice nursery 3 days before transplanting, and their control efficacy against rice water weevils was determined in paddy fields. The solid cultures produced ∼1 × 10(8) conidia g(-1) of millet grains 10 days after the inoculation. The granules were applied to the soil in the rice nursery 3 days before the rice seedlings were transplanted in the paddy fields. Rice in plots with granules of ERL1578 had 17.3% leaf damage (74% control efficacy) 14 days post-application, whereas rice plants in the untreated control had 66.5% damage. Rice plants treated in the nursery with ERL1170 and ERL836 had 52-54% damage. In the rice plots previously treated with ERL1578, the smallest numbers of larvae and adults were observed 38 days post-application. In laboratory conditions, ERL1578-treated larvae turned pink and were covered with mycelial mass. Applications of millet-based B. bassiana granules on rice nursery soil can be an effective and efficient biological control strategy for the management of rice water weevils. This method can be relatively inexpensive and requires less labor than practices involving the spraying of fungi directly on rice in paddy fields.

Differential Expression and Functional Detection of Esterase Isozymes on Isoelectrofocussing Polyacrylamide Gel Electrophoresis from Mexican Beauveria bassiana isolates

The aim of the present study was to analyze the variation of esterase activity as well as the expression patterns of isozymes by isoelectric focusing on polyacrylamide gels (IF-PAGE) and conventional polyacrylamide gel electrophoresis (PAGE). Esterase activity and isoforms were analyzed on total proteins from 9 isolates of Beauveria bassiana, from different hosts and geographic areas from the State of Guerrero, Mexico. Total proteins were separated by IF-PAGE and PAGE, in order to characterize the activity and isoelectric points of the esterase isoforms detected on different isolates. Electrophoretic analysis from 9 isolates of Beauveria bassiana, revealed a polymorphic pattern in terms of esterases activity and the presence of isozymes, showing a total of 10 different isoforms with variations in both the activity and isoelectric point. Each isolate showed between 3-6 different isozymes. Cluster analysis derived from the Jaccards coefficients showed a significant association between the presence-absence of esterase isoforms and the geographical origin of the Beauveria bassiana isolates. We conclude that the use of this methodology for functional detection combined with PAGE and IF-PAGE, can be an excellent tool for biochemical characterization of isolates and further impact evaluation of artificial epizootics derived from Biological control programs.

PCR Based Amplification of Chitinase Gene from Native Isolates of Beauveria Bassiana

Chitinase gene has been widely studied as one of the pest control agents because of its characteristic of degrading chitin. Chitinase is found in insects, nematodes, fungi, some algae and yeast. Beauveria bassiana is an insect pathogenic fungus successfully used as an insect pest control agent worldwide. In the present study, the entomopathogenic fungal isolates, Beauveria were isolated from the soil samples and insect cadavers collected from different places of Tamil Nadu. CTAB method was used for the isolation of DNA from entomopathogenic fungus. The ITS1 (5'-TCCGTAGGTGAACCTGCGG-3') and PN16 (5'-TCCCTTTCAACAATTTCACG-3') primers amplified a fragment of 930bp corresponding to the ITS1 and PN16 regions of the rDNA for the Beauveria isolates examined. Totally, 15 isolates were examined for the amplification of ITS region and all these isolates showed amplified product with size range of 930 bp which showed these isolates were belongs to Beauveria spp. A chitinase gene (1047 bp) was amplified from isolates of B. bassiana genomic DNA by PCR technique using forward primer 523ChitEcoRI (5'-ACATAGGAATTCATGGCTCCTTTTCTTCAAAC-3') and reverse primer 325ChitHindIII (5'-TACCTAACATGAACATTTAAGCTTTT-3'). All the isolates of Beauveria showed amplification at 1047bp. Chitinase has been considered as one of the most important factor for the pathogenicity of B. bassiana to various insect pests.

Effect of culture medium on the production and virulence of submerged spores of Metarhizium anisopliae and Beauveria bassiana against larvae and adults of Aedes aegypti (Diptera: Culicidae)

Three Metarhizium anisopliae and three Beauveria bassiana isolates were cultivated in media containing casamino acids, soybean flour or sunflower seed flour and were shaken for three days. M. anisopliae presented similar yields of around 106 submerged spores/ml without significant differences among them, whereas B. bassiana produced yields of around 108 spores/ml, of which GHA strain produced more submerged spores in the casamino acids medium. The other two strains showed no significant difference in the production of submerged spores in the three media used. Differences in mortality on Aedes aegypti larvae were observed with the submerged spores of Metarhizium depending on isolate and medium used. M. anisopliae 2157 caused significantly higher mortality (40%) when cultivated in casamino acids medium. It presented an LC50 of 8.93 × 105 submerged spores/ml water against mosquito larvae five days after application, whereas it caused 27% mortality in Ae. aegypti adults 10 days after application. In conclusion, fungal nutrition affected virulence of some isolates of M. anisopliae against Ae. aegypti larvae while such an effect was not noted for B. bassiana isolates.

Effect of temperature and humidity on pathogenicity of native Beauveria bassiana isolate against Musca domestica L.

Beauveria bassiana HQ917687 virulence to housefly larvae and adult was assessed at different relative humidity, RH (50, 75, 90, and 100%) and temperature (15, 20, 25, 30, 35, 40, 45°C) conditions at the fungal dose of 10(8)conidia/ml. Depending on the temperature and RH regime tested, difference in mortality rates of housefly adult and larvae were detected. During assay on adult housefly, 100% mortality was achieved at RH, 90 and 100% while the temperature of 30°C showed maximum mortality at all the tested humidity conditions. Lethal time, LT50 was 2.9days at 100% RH. Larval mortality at different humidity conditions varied between 30 and 74%, with maximum mortality at 100% RH and 30°C. Optimum temperature for B. bassiana virulence to housefly larvae was also found to be 30°C. The interaction between temperature and RH revealed significant effect of RH at moderate temperature range (20-35°C), while such an interaction was not observed at extreme temperatures. The results obtained in this study have useful implications in understanding the pathogen behavior under actual field conditions. This in turn may help devising suitable entomopathogen release schedules for maximum fungal infection.

Pathogenicity of Beauveria bassiana isolated from Moroccan Argan forests soil against larvae of Ceratitis capitata (Diptera: Tephritidae) in laboratory conditions

The Mediterranean fruit fly, Ceratitis capitata Wiedemann (Diptera: Tephritidae), is the major tephritid pest in Morocco. This pest survives in Moroccan forests Argania spinosa and continually invades the nearest agricultural areas. Entomopathogenic fungi are an interesting tool for fruit fly control and hold a useful alternative to conventional insecticides. However, primary selection of effective pathogens should be taken in laboratory condition prior to applying them in the field. Here, we used third late instar larvae of C. capitata to investigate the effectiveness of 15 local Beauveria bassiana isolates. Results showed that all isolates were able to infect the larval stage, producing a large mortality rate in puparia ranging from 65 to 95 % and caused significant reduction in adult emergence. The fungal treatments revealed that the mycosis occurred also in adults escaping infection as pupariating larvae. The percentage of mycosed puparia was highest in strain TAM6.2 (95 %) followed by ERS4.16 (90 %), therefore they were the most virulent. Median lethal concentration (LC₅₀) was studied for five isolates at four concentrations ranging from 10⁵ to 10⁸ conidia ml⁻¹. The results showed that the slopes of regression lines for B. bassiana ERS4.16 (slope = 0.386) and TAM6.2 (slope = 0.41) were the most important and had the lowest LC₅₀ values (2.85 × 10³ and 3.16 × 10³ conidia ml⁻¹ respectively). This investigation suggests that the soil of Argan forests contains pathogenic B. bassiana isolates and highlights for the first time their potential as biological control toward C. capitata larval stage in Morocco.

Assessment of entomopathogenic fungi and their extracts against a soil-dwelling pest and soil-borne pathogens of olive

The olive fruit fly Bactrocera oleae (Gmelin) and the olive pathogens Verticillium dahliae, Phytophthora megasperma and Phytophthora inundata are major worldwide limiting factors for olive tree production. Entomopathogenic fungi, such as Metarhizium spp. and Beauveria spp., are suitable for olive fly control by either targeting adults or pupariating larvae and puparia in the soil beneath the tree canopy. Such soil treatments could have an additional impact on other communities of microorganisms present in the soil, such as soil-borne olive pathogens. The present work explores the possible dual biocontrol of both olive pests and diseases with entomopathogenic fungi. Twelve indigenous isolates of Beauveria bassiana, Beauveria pseudobassiana, Beauveria varroae and two isolates of Metarhizium brunneum from olive crops (soil and phylloplane) were evaluated in soil treatments against medfly (Ceratitis capitata Wied.) pre-imaginals. There were significant differences among the isolates in the total percentage of non-viable puparia and the total the puparia and adults showing fungal outgrowth, with percentages ranging from 27.5% to 82.5%, which highlights the potential of soil treatments with entomopathogenic fungi not only to reduce the target pre-imaginals but also the adults emerging from them, therefore contributing to the overall reduction of the next adult generation. The strains EAMa 01/58-Su of M. brunneum and EABb 09/16-Su of B. bassiana were evaluated for antifungal activity against two strains of V. dahliae (V117, V004), one of P. megasperma (PO20), and one of P. inundata (PO47) with one strain of Trichoderma atroviride used as a reference in the antagonism assays. In the dual plate culture assays, T. atroviride caused a 64–79% inhibition of Phytophthora spp. and V. dahliae mycelial growth. Meanwhile, the mycelial growth inhibition rates of M. brunneum and B. bassiana were 42–62% for Phytophthora and 40–57% for V. dahliae, with both entomopathogens causing inhibition halos, supporting the mechanism of antibiosis. Such a mechanism is also supported by the inhibitory activity of the crude extracts of these two M. brunneum and B. bassiana strains against these olive pathogens. Also, after the dialysis of the crude extracts against water in a molecular porous membrane with a cut-off of 3500Da, the antifungal activity was mostly retained (100% inhibition rates) in the dialyzed fractions, indicating that the active compounds were secondary metabolites. Likewise, these dialyzed fractions inhibited the germination of conidia (96–100%) and microesclerotia (58–96%) of V. dahliae and propagules of P. megasperma (38–100%). These results indicate that entomopathogenic fungi have the potential for dual biocontrol of olive soil pests and diseases.

Effectiveness of Beauveria bassiana sensu lato strains for biological control against Rhipicephalus (Boophilus) microplus (Acari: Ixodidae) in China

Owing to the need to combat the spread of acaricide-resistant ticks, the development of long-term biological control has become a hot topic for tick control. In this study, we investigated the pathogenicity of three Beauveria bassiana isolates on the engorged female Rhipicephalus (Boophilus) microplus ticks using different conidial concentrations. The results showed that B. bassiana B.bAT17 was highly pathogenic against engorged R. (B.) microplus females, resulting in lethal time (LT50 and LT90) of 7.14 and 9.33days at a concentration of 109conidia/ml. R. (B.) microplus females treated with B. bassiana B.bAT17 significantly reduced the amount of ovipositioning; and most ticks died before they could begin to oviposit. Proteases and chitinases were analyzed in order to establish a screening method for identification of high virulent strains. This study has confirmed the significant pathogenic effect of entomopathogenic fungi against engorged R. (B.) microplus females in China, and further studies on the efficiency of the fungus against ticks in the field are required.

Dependence of the viability and virulence of siberian isolates of the entomopathogenic fungus Beauveria bassiana (Bals-Griv.) Vuill. on the period of their storage at positive temperatures

A study of Siberian isolates of Beauveria bassiana (Bals-Griv.) Vuill. has shown the dependence of their viability and virulence on the storage period and temperature. The isolates remain viable and virulent for a longer period (up to 3 years) when they are stored at a low positive temperature (+8°C) than when stored at room temperature (+18°C). According to our correlation analysis, when stored at room temperature, the virulence of the studied isolates towards the test insects depends on the storage period (57–72%) and, to a lesser extent (28–43%), on other unaccounted factors.

Immunoliogical Responses of Hyphantria Cunea (Drury) (Lepidoptera: Arctiidae) to Entomopathogenic Fungi, Beauveria Bassiana (Bals.-Criy) and Isaria Farinosae (Holmsk.) Fr.

Abstract Five morphological types of hemocytes were recognized in hemolymph of the 4th instar larvae of Hyphantria cunea (Drury). These hemocytes were: prohemocytes, plasmotocytes, granulocytes, oenocytoids, and spherulocytes. Tests were done on the effects of four isolates of the entomopathogenic fungus Beauveria bassiana (Bals.-Criy) (Fashand, spt-22, Ir-K-40 and 566), one isolate of Isaria farinosae (Holmsk.) Fr. (1872c), and latex-beads on the cellular immune defense mechanism and Phenoloxidase (PO) activity of H. cunea. Observation showed that plasmatocytes and granulocytes engulfed fungal pathogens by phagocytosis. The most phagocytosis occurred 30 and 60 min after injection but nodulation occurred in 3 and 6 hours, in all treatments. The total hemocyte count (THC) and granulocyte, and plasmotocyte numbers increased after the injection of spores. Phenoloxidase activity was determined in the presence of L-DOPA (L-3,4-dihydroxyphenylalanine), as a substrate in intervals, after injection of fungal spores, and latex beads. These studies demonstrated that B. bassiana is a promising candidate for biological control of H. cunea.

Nutritional optimization of a native Beauveria bassiana isolate (HQ917687) pathogenic to housefly, Musca domestica L.

A new Beauveria bassiana isolate, showing high activity against Musca domestica L. (Diptera: Muscidae) adults (mortality-100.0%), larvae (mortality-72.3%) and pupae (Infection in emerged flies-96.7%) was used. The isolate was subjected to a combinational approach towards selection of process parameters for its growth optimization. Initial screening of several carbon and nitrogen sources revealed glucose and NaNO3 as the most suitable source for optimal biomass and spore production. Further, optimization through Placket-Burman and a 2(5) full factorial central composite design revealed highly significant effect of glucose and pH. The optimum composition for maximum biomass yield was (g/l): glucose 28; NaNO3 2.43; KH2PO4 1.32; MgSO4 0.60; and pH 7.00. Glucose concentration showed almost linear relationship with biomass yield, indicating its significant contribution in medium composition for fungal growth. Highly significant interactions were observed between glucose and pH, followed by glucose and NaNO3 concentration.

Laboratory evaluation of virulence of Chinese Beauveria bassiana and Metarhizium anisopliae isolates to engorged female Rhipicephalus (Boophilus) microplus ticks

Rhipicephalus (Boophilus) microplus, an important ectoparasite that can transmit Babesia and Anaplasma, has caused inestimable economic losses around the world. Traditionally, acaricides are used for the control of ticks. However, drawbacks of chemical control, such as resistance, environmental pollution, and traces in food promote alternative strategies to pesticides. Microbial control is one option to reduce tick populations. In this study, we investigated the pathogenicity of thirteen Beauveria bassiana isolates and seven Metarhizium anisopliae isolates to the engorged female R. (B.) microplus ticks using different conidial concentrations of 107, 108 and 109conidiamL–1. Fourteen days after treatment, three B. bassiana isolates (B.bAT01, B.bAT03, B.bAT13) and one M. anisopliae isolate (M.aAT04) resulted in 100% mortality of engorged female ticks with conidial concentrations of 108 and 109conidiamL–1. Isolates of B.bAT01, B.bAT03, B.bAT13 and M.aAT04 at all conidial concentrations could reduce the reproductive efficiency index (REI) of R. (B.) microplus ticks.