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Everton K K Fernandes - One of the best experts on this subject based on the ideXlab platform.
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an intensive search for promising fungal biological control agents of ticks particularly rhipicephalus microplus
Veterinary Parasitology, 2011Co-Authors: Isabele Da Costa Angelo, Thiago C. Bahiense, Drauzio E. N. Rangel, Donald W. Roberts, Everton K K Fernandes, Aurea Maria Lage De Moraes, Vânia Rita Elias Pinheiro BittencourtAbstract:Abstract Entomopathogenic fungi have been investigated worldwide as promising biological control agents of the cattle tick Rhipicephalus microplus. The current study evaluates the virulence of several fungal isolates to R. microplus larva in the laboratory as part of an effort to identify isolates with promise for effective biocontrol of R. microplus in the field. Sixty fungal isolates, encompassing 5 Beauveria spp. and 1 Engyodontium albus (=Beauveria alba), were included in this study. In addition to bioassays, the isolates were characterized morphologically and investigated as to their potential for conidial mass production. These findings were correlated with previous reports on the same fungal isolates of their natural UV-B tolerance ( Fernandes et al., 2007 ), thermotolerance and cold activity ( Fernandes et al., 2008 ), and genotypes ( Fernandes et al., 2009 ). R. microplus larvae obtained from artificially infested calves were less susceptible to Beauveria bassiana infection than ticks acquired from naturally infested cattle from a different location. Isolates CG 464, CG 500 and CG 206 were among the most virulent Beauveria isolates tested in this study. All fungal isolates presented morphological features consistent with their species descriptions. Of the 53 B. bassiana isolates, five (CG 481, CG 484, CG 206, CG 235 and CG 487) had characteristics that qualified them as promising candidates for biological control agents of R. microplus, viz., mean LC50 between 107 and 108 conidia ml−1; produced 5000 conidia or more on 60 mm2 surface area of PDAY medium; and, in comparison to untreated (control) conidia, had the best conidial tolerances to UV-B (7.04 kJ m−2) and heat (45 °C, 2 h) of 50% or higher, and conidial cold (5 °C, 15 d) activity (mycelial growth) higher than 60%. The current study of 60 Beauveria spp. isolates, therefore, singles out a few (five) with high potential for controlling ticks under field conditions.
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ctc medium a novel dodine free selective medium for isolating entomopathogenic fungi especially metarhizium acridum from soil
Biological Control, 2010Co-Authors: Everton K K Fernandes, Chad A Keyser, Nelson R Foster, Drauzio E. N. Rangel, Donald W. RobertsAbstract:The selective media most commonly used for isolating hyphomycetous species of entomopathogenic fungi from non-sterile substrates rely on N-dodecylguanidine monoacetate (dodine) as the selective fungicide. Although these media are effective for isolating many species of Metarhizium and Beauveria from soil, they are inefficient media for isolation of an important Metarhizium species, Metarhizium acridum, from non-sterile soil. Our current study was directed to formulating a dodine-free selective medium that is efficient for isolating naturally occurring Beauveria spp. and Metarhizium spp., especially M. acridum, from soil. The selective medium (designated CTC medium) consists of potato dextrose agar plus yeast extract (PDAY) supplemented with chloramphenicol, thiabendazole and cycloheximide. In comparisons with selective media previously reported in the literature, the CTC medium afforded colonies that were larger and had both earlier and more abundant conidiation of entomopathogenic fungi, features which greatly facilitated identification of the emerging entomopathogenic fungi. In addition to efficient re-isolation of M. acridum, this medium also is an effective tool for selective isolation of Metarhizium brunneum, Metarhizium robertsii, Beauveria bassiana and Beauveria brongniartii from non-sterile field-collected soil samples inoculated (spiked) with fresh conidia in the laboratory.
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variability in tolerance to uv b radiation among Beauveria spp isolates
Journal of Invertebrate Pathology, 2007Co-Authors: Everton K K Fernandes, Vânia Rita Elias Pinheiro Bittencourt, Drauzio E. N. Rangel, Aurea Maria Lage De Moraes, Donald W. RobertsAbstract:Abstract Solar radiation, particularly the UV-B component, negatively affects survival of entomopathogenic fungi in the field. In an effort to identify Beauveria spp. isolates with promise for use in biological control settings with high insolation, we examined 53 Beauveria bassiana isolates, 7 isolates of 4 other Beauveria spp. and Engyodontium albus (= Beauveria alba ). The origins of these fungi varied widely as to host/substrate and country, but approximately 30% of these isolates were B . bassiana from ticks in Brazil. A preliminary trial with three B. bassiana isolates (Bb 19, CG 310 and CG 481) at several UV-B dosages indicated that 2 h of weighted UV-B irradiance at 978 mW m −2 (providing a total dose of 7.04 kJ m −2 ) allowed separation of isolates into low, medium or high UV-B tolerance. This dose, therefore, was selected as a single dose to compare UV-B tolerances of all 60 Beauveria spp. isolates. There was high variability in tolerance to UV-B radiation among the B. bassiana isolates, ranging from virtually zero tolerance (e.g., Bb 03) to almost 80% tolerance (e.g., CG 228). In addition, surviving B. bassiana conidia demonstrated delayed germination; and this is likely to reduce virulence. Conidia of the other species were markedly more sensitive to UV-B, with E. albus (UFPE 3138) being the least UV-B tolerant. Among B. bassiana isolates originating from 0° to 22° latitudes, those from lower latitudes demonstrated statistically significant greater UV-B tolerances than those isolates from higher latitudes. Isolates from above 22°, however, were unaffected by latitude of origin. A similar analysis based on host type did not indicate a correlation between original host and UV-B tolerance. The identification in this study of several B. bassiana isolates with relatively high UV-B tolerance will guide the selection of isolates for future arthropod microbial control experiments.
Samuel Nibouche - One of the best experts on this subject based on the ideXlab platform.
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Description and phylogenetic placement of #Beauveria hoplocheli# sp. nov. used in the biological control of the sugarcane white grub, #Hoplochelus marginalis#, on Reunion Island
Mycologia, 2015Co-Authors: Isabelle Robene-soustrade, Tarryn Goble, Emmanuel Jouen, Didier Pastou, Magali Payet-hoarau, Daphne Linderme, Pierre Lefeuvre, Cédric Calmes, Bernard Reynaud, Samuel NiboucheAbstract:On Reunion Island successful biological control of the sugarcane white grub Hoplochelus marginalis Fairmaire (Coleoptera: Melolonthidae) has been conducted for decades with strains from the entomopathogenic fungal genus Beauveria (Ascomycota: Hypocreales). A study based on morphological characters combined with a multisequence phylogenetic analysis of genes that encode the translation elongation factor 1-alpha (TEF1), RNA polymerase II largest subunit (RPB1), RNA polymerase II second largest subunit (RPB2) and the Bloc nuc intergenic region was carried out on Beauveria strains isolated on Reunion and Madagascar from H. marginalis. This study revealed that these strains, previously identified as Beauveria brongniartii, did not match that species and are closely related to but still distinct from B. malawiensis strains. Therefore we describe the Reunion Island fungus as the new species B. hoplocheli. (Résumé d'auteur)
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Beauveria brongniartii on white grubs attacking sugarcane in South Africa.
Journal of Invertebrate Pathology, 2012Co-Authors: Tarryn Goble, Laurent Costet, Isabelle Robène, Samuel Nibouche, R.s. Rutherford, Desmond Conlong, Martin HillAbstract:Beauveria brongniartii (Saccardo) Petch fungal infections were observed on the melolonthid Hypopholis sommeri Burmeister (Coleoptera: Scarabaeidae) at two sites (Harden Heights and Canema) in the sugarcane producing area of the northern KwaZulu-Natal Midlands of South Africa. To initially identify the disease-causing fungus, 17 different fluorescently-labelled microsatellite PCR primers were used to target 78 isolates of Beauveria spp. DNA. Microsatellite data resolved two distinct clusters of Beauveria isolates which represented the Beauveria bassiana s.s. (Balsamo) Vuillemin (17 isolates) and B. brongniartii (60 isolates) species groups. These groupings were supported by two gene regions, the nuclear ribosomal Internal Transcribed Spacer (ITS) and the nuclear Bloc gene of which 23 exemplar Beauveria isolates were represented and sequenced. When microsatellite data were analysed, 26 haplotypes among 58 isolates of B. brongniartii were distinguished. Relatively low levels of genetic diversity were detected in B. brongniartii and isolates were shown to be closely related. No genetic differentiation was observed between the Harden Heights and Canema populations; they thus may be considered one, structured and fragmented population over a distance of 5.5 km. Historically high levels of gene flow from swarming H. sommeri beetles is the proposed mechanism for this observed lack of genetic differentiation between populations. Microsatellite analyses also showed that B. brongniartii conidia were being cycled from arboreal forest to subterranean sugarcane habitats and vice versa in the environment by H. sommeri life stages. This is the first record of this species of fungus infecting H. sommeri larvae and adults in South Africa.
Donald W. Roberts - One of the best experts on this subject based on the ideXlab platform.
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an intensive search for promising fungal biological control agents of ticks particularly rhipicephalus microplus
Veterinary Parasitology, 2011Co-Authors: Isabele Da Costa Angelo, Thiago C. Bahiense, Drauzio E. N. Rangel, Donald W. Roberts, Everton K K Fernandes, Aurea Maria Lage De Moraes, Vânia Rita Elias Pinheiro BittencourtAbstract:Abstract Entomopathogenic fungi have been investigated worldwide as promising biological control agents of the cattle tick Rhipicephalus microplus. The current study evaluates the virulence of several fungal isolates to R. microplus larva in the laboratory as part of an effort to identify isolates with promise for effective biocontrol of R. microplus in the field. Sixty fungal isolates, encompassing 5 Beauveria spp. and 1 Engyodontium albus (=Beauveria alba), were included in this study. In addition to bioassays, the isolates were characterized morphologically and investigated as to their potential for conidial mass production. These findings were correlated with previous reports on the same fungal isolates of their natural UV-B tolerance ( Fernandes et al., 2007 ), thermotolerance and cold activity ( Fernandes et al., 2008 ), and genotypes ( Fernandes et al., 2009 ). R. microplus larvae obtained from artificially infested calves were less susceptible to Beauveria bassiana infection than ticks acquired from naturally infested cattle from a different location. Isolates CG 464, CG 500 and CG 206 were among the most virulent Beauveria isolates tested in this study. All fungal isolates presented morphological features consistent with their species descriptions. Of the 53 B. bassiana isolates, five (CG 481, CG 484, CG 206, CG 235 and CG 487) had characteristics that qualified them as promising candidates for biological control agents of R. microplus, viz., mean LC50 between 107 and 108 conidia ml−1; produced 5000 conidia or more on 60 mm2 surface area of PDAY medium; and, in comparison to untreated (control) conidia, had the best conidial tolerances to UV-B (7.04 kJ m−2) and heat (45 °C, 2 h) of 50% or higher, and conidial cold (5 °C, 15 d) activity (mycelial growth) higher than 60%. The current study of 60 Beauveria spp. isolates, therefore, singles out a few (five) with high potential for controlling ticks under field conditions.
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ctc medium a novel dodine free selective medium for isolating entomopathogenic fungi especially metarhizium acridum from soil
Biological Control, 2010Co-Authors: Everton K K Fernandes, Chad A Keyser, Nelson R Foster, Drauzio E. N. Rangel, Donald W. RobertsAbstract:The selective media most commonly used for isolating hyphomycetous species of entomopathogenic fungi from non-sterile substrates rely on N-dodecylguanidine monoacetate (dodine) as the selective fungicide. Although these media are effective for isolating many species of Metarhizium and Beauveria from soil, they are inefficient media for isolation of an important Metarhizium species, Metarhizium acridum, from non-sterile soil. Our current study was directed to formulating a dodine-free selective medium that is efficient for isolating naturally occurring Beauveria spp. and Metarhizium spp., especially M. acridum, from soil. The selective medium (designated CTC medium) consists of potato dextrose agar plus yeast extract (PDAY) supplemented with chloramphenicol, thiabendazole and cycloheximide. In comparisons with selective media previously reported in the literature, the CTC medium afforded colonies that were larger and had both earlier and more abundant conidiation of entomopathogenic fungi, features which greatly facilitated identification of the emerging entomopathogenic fungi. In addition to efficient re-isolation of M. acridum, this medium also is an effective tool for selective isolation of Metarhizium brunneum, Metarhizium robertsii, Beauveria bassiana and Beauveria brongniartii from non-sterile field-collected soil samples inoculated (spiked) with fresh conidia in the laboratory.
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variability in tolerance to uv b radiation among Beauveria spp isolates
Journal of Invertebrate Pathology, 2007Co-Authors: Everton K K Fernandes, Vânia Rita Elias Pinheiro Bittencourt, Drauzio E. N. Rangel, Aurea Maria Lage De Moraes, Donald W. RobertsAbstract:Abstract Solar radiation, particularly the UV-B component, negatively affects survival of entomopathogenic fungi in the field. In an effort to identify Beauveria spp. isolates with promise for use in biological control settings with high insolation, we examined 53 Beauveria bassiana isolates, 7 isolates of 4 other Beauveria spp. and Engyodontium albus (= Beauveria alba ). The origins of these fungi varied widely as to host/substrate and country, but approximately 30% of these isolates were B . bassiana from ticks in Brazil. A preliminary trial with three B. bassiana isolates (Bb 19, CG 310 and CG 481) at several UV-B dosages indicated that 2 h of weighted UV-B irradiance at 978 mW m −2 (providing a total dose of 7.04 kJ m −2 ) allowed separation of isolates into low, medium or high UV-B tolerance. This dose, therefore, was selected as a single dose to compare UV-B tolerances of all 60 Beauveria spp. isolates. There was high variability in tolerance to UV-B radiation among the B. bassiana isolates, ranging from virtually zero tolerance (e.g., Bb 03) to almost 80% tolerance (e.g., CG 228). In addition, surviving B. bassiana conidia demonstrated delayed germination; and this is likely to reduce virulence. Conidia of the other species were markedly more sensitive to UV-B, with E. albus (UFPE 3138) being the least UV-B tolerant. Among B. bassiana isolates originating from 0° to 22° latitudes, those from lower latitudes demonstrated statistically significant greater UV-B tolerances than those isolates from higher latitudes. Isolates from above 22°, however, were unaffected by latitude of origin. A similar analysis based on host type did not indicate a correlation between original host and UV-B tolerance. The identification in this study of several B. bassiana isolates with relatively high UV-B tolerance will guide the selection of isolates for future arthropod microbial control experiments.
Vânia Rita Elias Pinheiro Bittencourt - One of the best experts on this subject based on the ideXlab platform.
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an intensive search for promising fungal biological control agents of ticks particularly rhipicephalus microplus
Veterinary Parasitology, 2011Co-Authors: Isabele Da Costa Angelo, Thiago C. Bahiense, Drauzio E. N. Rangel, Donald W. Roberts, Everton K K Fernandes, Aurea Maria Lage De Moraes, Vânia Rita Elias Pinheiro BittencourtAbstract:Abstract Entomopathogenic fungi have been investigated worldwide as promising biological control agents of the cattle tick Rhipicephalus microplus. The current study evaluates the virulence of several fungal isolates to R. microplus larva in the laboratory as part of an effort to identify isolates with promise for effective biocontrol of R. microplus in the field. Sixty fungal isolates, encompassing 5 Beauveria spp. and 1 Engyodontium albus (=Beauveria alba), were included in this study. In addition to bioassays, the isolates were characterized morphologically and investigated as to their potential for conidial mass production. These findings were correlated with previous reports on the same fungal isolates of their natural UV-B tolerance ( Fernandes et al., 2007 ), thermotolerance and cold activity ( Fernandes et al., 2008 ), and genotypes ( Fernandes et al., 2009 ). R. microplus larvae obtained from artificially infested calves were less susceptible to Beauveria bassiana infection than ticks acquired from naturally infested cattle from a different location. Isolates CG 464, CG 500 and CG 206 were among the most virulent Beauveria isolates tested in this study. All fungal isolates presented morphological features consistent with their species descriptions. Of the 53 B. bassiana isolates, five (CG 481, CG 484, CG 206, CG 235 and CG 487) had characteristics that qualified them as promising candidates for biological control agents of R. microplus, viz., mean LC50 between 107 and 108 conidia ml−1; produced 5000 conidia or more on 60 mm2 surface area of PDAY medium; and, in comparison to untreated (control) conidia, had the best conidial tolerances to UV-B (7.04 kJ m−2) and heat (45 °C, 2 h) of 50% or higher, and conidial cold (5 °C, 15 d) activity (mycelial growth) higher than 60%. The current study of 60 Beauveria spp. isolates, therefore, singles out a few (five) with high potential for controlling ticks under field conditions.
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variability in tolerance to uv b radiation among Beauveria spp isolates
Journal of Invertebrate Pathology, 2007Co-Authors: Everton K K Fernandes, Vânia Rita Elias Pinheiro Bittencourt, Drauzio E. N. Rangel, Aurea Maria Lage De Moraes, Donald W. RobertsAbstract:Abstract Solar radiation, particularly the UV-B component, negatively affects survival of entomopathogenic fungi in the field. In an effort to identify Beauveria spp. isolates with promise for use in biological control settings with high insolation, we examined 53 Beauveria bassiana isolates, 7 isolates of 4 other Beauveria spp. and Engyodontium albus (= Beauveria alba ). The origins of these fungi varied widely as to host/substrate and country, but approximately 30% of these isolates were B . bassiana from ticks in Brazil. A preliminary trial with three B. bassiana isolates (Bb 19, CG 310 and CG 481) at several UV-B dosages indicated that 2 h of weighted UV-B irradiance at 978 mW m −2 (providing a total dose of 7.04 kJ m −2 ) allowed separation of isolates into low, medium or high UV-B tolerance. This dose, therefore, was selected as a single dose to compare UV-B tolerances of all 60 Beauveria spp. isolates. There was high variability in tolerance to UV-B radiation among the B. bassiana isolates, ranging from virtually zero tolerance (e.g., Bb 03) to almost 80% tolerance (e.g., CG 228). In addition, surviving B. bassiana conidia demonstrated delayed germination; and this is likely to reduce virulence. Conidia of the other species were markedly more sensitive to UV-B, with E. albus (UFPE 3138) being the least UV-B tolerant. Among B. bassiana isolates originating from 0° to 22° latitudes, those from lower latitudes demonstrated statistically significant greater UV-B tolerances than those isolates from higher latitudes. Isolates from above 22°, however, were unaffected by latitude of origin. A similar analysis based on host type did not indicate a correlation between original host and UV-B tolerance. The identification in this study of several B. bassiana isolates with relatively high UV-B tolerance will guide the selection of isolates for future arthropod microbial control experiments.
Tarryn Goble - One of the best experts on this subject based on the ideXlab platform.
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Description and phylogenetic placement of #Beauveria hoplocheli# sp. nov. used in the biological control of the sugarcane white grub, #Hoplochelus marginalis#, on Reunion Island
Mycologia, 2015Co-Authors: Isabelle Robene-soustrade, Tarryn Goble, Emmanuel Jouen, Didier Pastou, Magali Payet-hoarau, Daphne Linderme, Pierre Lefeuvre, Cédric Calmes, Bernard Reynaud, Samuel NiboucheAbstract:On Reunion Island successful biological control of the sugarcane white grub Hoplochelus marginalis Fairmaire (Coleoptera: Melolonthidae) has been conducted for decades with strains from the entomopathogenic fungal genus Beauveria (Ascomycota: Hypocreales). A study based on morphological characters combined with a multisequence phylogenetic analysis of genes that encode the translation elongation factor 1-alpha (TEF1), RNA polymerase II largest subunit (RPB1), RNA polymerase II second largest subunit (RPB2) and the Bloc nuc intergenic region was carried out on Beauveria strains isolated on Reunion and Madagascar from H. marginalis. This study revealed that these strains, previously identified as Beauveria brongniartii, did not match that species and are closely related to but still distinct from B. malawiensis strains. Therefore we describe the Reunion Island fungus as the new species B. hoplocheli. (Résumé d'auteur)
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Beauveria brongniartii on white grubs attacking sugarcane in South Africa.
Journal of Invertebrate Pathology, 2012Co-Authors: Tarryn Goble, Laurent Costet, Isabelle Robène, Samuel Nibouche, R.s. Rutherford, Desmond Conlong, Martin HillAbstract:Beauveria brongniartii (Saccardo) Petch fungal infections were observed on the melolonthid Hypopholis sommeri Burmeister (Coleoptera: Scarabaeidae) at two sites (Harden Heights and Canema) in the sugarcane producing area of the northern KwaZulu-Natal Midlands of South Africa. To initially identify the disease-causing fungus, 17 different fluorescently-labelled microsatellite PCR primers were used to target 78 isolates of Beauveria spp. DNA. Microsatellite data resolved two distinct clusters of Beauveria isolates which represented the Beauveria bassiana s.s. (Balsamo) Vuillemin (17 isolates) and B. brongniartii (60 isolates) species groups. These groupings were supported by two gene regions, the nuclear ribosomal Internal Transcribed Spacer (ITS) and the nuclear Bloc gene of which 23 exemplar Beauveria isolates were represented and sequenced. When microsatellite data were analysed, 26 haplotypes among 58 isolates of B. brongniartii were distinguished. Relatively low levels of genetic diversity were detected in B. brongniartii and isolates were shown to be closely related. No genetic differentiation was observed between the Harden Heights and Canema populations; they thus may be considered one, structured and fragmented population over a distance of 5.5 km. Historically high levels of gene flow from swarming H. sommeri beetles is the proposed mechanism for this observed lack of genetic differentiation between populations. Microsatellite analyses also showed that B. brongniartii conidia were being cycled from arboreal forest to subterranean sugarcane habitats and vice versa in the environment by H. sommeri life stages. This is the first record of this species of fungus infecting H. sommeri larvae and adults in South Africa.