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Jurg Enkerli - One of the best experts on this subject based on the ideXlab platform.

  • effects of biological and chemical insect control agents on fungal community structures in soil microcosms
    Applied Soil Ecology, 2009
    Co-Authors: Kaspar Schwarzenbach, Jurg Enkerli, Franco Widmer
    Abstract:

    In several European countries the entomopathogenic fungus Beauveria brongniartii is used for specifically controlling the European cockchafer, Melolontha Melolontha, a pest in grassland and orchards. This biological control agent (BCA) is applied to soil, where it specifically infects the soil dwelling larvae of M. Melolontha. Application of a fungal BCA to soil may potentially affect indigenous soil fungal populations. Therefore, it was the objective of this study to assess and compare such potential effects of the BCA to those of a carbofuran-based chemical control agent (CCA). The experimental system consisted of six soil microcosm treatments with and without larvae of M. Melolontha and included BCA- and CCA-treatments. Microcosms were maintained under controlled conditions for 91 days and were sampled three times. Untreated larvae survived until the end of the experiment, whereas all treated larvae died within 28 days. Cultivation-independent quantification of B. brongniartii in soil was based on quantitative real-time PCR analysis of a specific simple-sequence-repeat marker and significantly correlated with cultivation-dependent quantification. Fungal ribosomal internal spacer analysis (RISA) revealed strongest and most significant changes in soil fungal communities for treatments that contained larvae that had died from either control agent. The BCA alone revealed much smaller and transient effects, while effects of the CCA were also small but significantly increased at the end of the experiment. The results revealed that either control strategy induced relatively small effects on soil fungal communities and that molecular genetic tools may be efficiently applied for monitoring and effect assessment of fungal BCAs.

  • development of 16 microsatellite markers for the european cockchafer Melolontha Melolontha
    Molecular Ecology Resources, 2008
    Co-Authors: Jurg Enkerli, Alexandra Gisler
    Abstract:

    : Sixteen polymorphic microsatellite markers were isolated from the European cockchafer, Melolontha Melolontha L., based on enriched genomic libraries. Allelic variability was assessed in a collection of 30 individuals obtained from a field in eastern Switzerland. The number of detected alleles ranged from three to 13 with a mean of 6.69 and average observed and expected heterozygosities were 0.52 and 0.66, respectively. The 16 highly polymorphic microsatellite markers represent a powerful molecular tool, which will allow for detailed population genetic analyses on this important pest insect.

  • long term field persistence of beauveria brongniartii strains applied as biocontrol agents against european cockchafer larvae in switzerland
    Biological Control, 2004
    Co-Authors: Jurg Enkerli, Franco Widmer, Siegfried Keller
    Abstract:

    In field tests between 1985 and 1992, various sites which were infested with Melolontha Melolontha were treated with the biocontrol fungus Beauveria brongniartii. The fungus was applied either as blastospores or as commercially available fungus colonized barley kernels (FCBK). In 1998/1999, soil samples were collected from the test sites and B. brongniartii isolates recovered and maintained in a culture collection. Isolates from this collection were subjected to genetic analyses by use of specific microsatellite markers. The applied B. brongniartii strains were detected at all test sites up to 14 years after their application. At some sites, the B. brongniartii populations consisted of the applied strains exclusively, whereas at other sites, indigenous populations or isolates that may have arisen from mutations or interactions among the applied strains and indigenous isolates were present in addition to the applied strains. The results suggested that applied B. brongniartii strains and indigenous B. brongniartii populations could coexist in the same habitat. Demonstration of long-term persistence of the applied B. brongniartii strains in the fields supported the success of this approach for the biological control of M. Melolontha.

  • strain specific microsatellite markers in the entomopathogenic fungus beauveria brongniartii
    Fungal Biology, 2001
    Co-Authors: Jurg Enkerli, Franco Widmer, C Gessler, Siegfried Keller
    Abstract:

    We have identified ten microsatellite markers in the entomopathogenic fungus Beauveria brongniartii from three genomic libraries enriched for (AAG) n -, (TG) n -, or (TC) n -repeats. The levels of polymorphism of the identified microsatellite loci were assessed in a collection of Beauveria strains originating from different countries, areas, and host insects. Two geographically separated Swiss populations of B. brongniartii originating from European cockchafer ( Melolontha Melolontha ) were also analysed. Microsatellites containing (AAG) n -repeats generally displayed high levels of polymorphism, whereas microsatellites containing either (TG) n - or (TC) n -repeats displayed lower levels of polymorphism. Cluster analysis revealed that strains isolated from M. Melolontha larvae, and two strains isolated from Melolontha hippocastani or Amphimallon solstitiale larvae, formed one cluster which was separated from strains isolated from adult M. Melolontha and other adult insects. A high degree of biodiversity was detected among B. brongniartii strains of the two separated Swiss populations. Distinct haplotypes were identified in 29 of 35 B. brongniartii strains from population A and in 12 of 28 B. brongniartii strains from population B. The high discrimination power of the identified microsatellites makes them a valuable tool, suited for the characterization and identification of B. brongniartii strains used as biocontrol agents. In addition, they may be applied to monitor biological control strains of B. brongniartii in the field and possibly to investigate their interactions with indigenous B. brongniartii isolates.

Monika Hilker - One of the best experts on this subject based on the ideXlab platform.

  • Sensing the Underground – Ultrastructure and Function of Sensory Organs in Root-Feeding Melolontha Melolontha (Coleoptera: Scarabaeinae) Larvae
    2016
    Co-Authors: Elisabeth J. Eilers, Monika Hilker, Giovanni Talarico, Bill S. Hansson, Andreas Reinecke
    Abstract:

    Introduction: Below ground orientation in insects relies mainly on olfaction and taste. The economic impact of plant root feeding scarab beetle larvae gave rise to numerous phylogenetic and ecological studies. Detailed knowledge of the sensory capacities of these larvae is nevertheless lacking. Here, we present an atlas of the sensory organs on larval head appendages of Melolontha Melolontha. Our ultrastructural and electrophysiological investigations allow annotation of functions to various sensory structures

  • Hypothesized function, abundance external morphology and dendritic structure (ODS: outer dendritic segment, TB: tubular body) of sensilla on antennae (A) and maxillary (M) and labial palps (L) in Melolontha Melolontha larvae.
    2012
    Co-Authors: Elisabeth J. Eilers, Monika Hilker, Giovanni Talarico, Bill S. Hansson, Andreas Reinecke
    Abstract:

    Hypothesized function, abundance external morphology and dendritic structure (ODS: outer dendritic segment, TB: tubular body) of sensilla on antennae (A) and maxillary (M) and labial palps (L) in Melolontha Melolontha larvae.

  • pre copulatory isolation in sympatric Melolontha species coleoptera scarabaeidae
    Agricultural and Forest Entomology, 2006
    Co-Authors: Andreas Reinecke, Joachim Ruther, Monika Hilker
    Abstract:

    1 The two most abundant cockchafer species in Europe, the forest cockchafer Melolontha hippocastani Fabr. and the European cockchafer Melolontha Melolontha L., tend to form calamitous mass breedings with casual reports on sympatric and simultaneous occurrence. 2 Both species are known to use feeding-induced green leaf volatiles (GLV) as primary attractants (sexual kairomones) for mate finding. The attractiveness of GLV is enhanced by the sex pheromones 1,4-benzoquinone in M. hippocastani and toluquinone in M. Melolontha. Phenol attracts males from both species. All three compounds are present in females of both species. 3 In the present study, it is confirmed that only male M. Melolontha perform the typical swarming flight at dusk, as has already been shown for M. hippocastani. Furthermore, whether swarming Melolontha males were cross-attracted to heterospecific females, and whether males could discriminate olfactorily between conspecific and heterospecific females, was tested in the field. 4 Males of both species preferred females when given the choice between females and males of the other species. However, they preferred conspecific females when females from both species were offered simultaneously. 5 The results suggest that species-specific pheromone blends contribute to precopulatory reproductive isolation in sympatric populations of M. Melolontha and M. hippocastani, but are not mutually exclusive or indispensable prerequisites for mate finding as in other insects.

  • optimized trap lure for male Melolontha cockchafers
    Journal of Applied Entomology, 2006
    Co-Authors: Andreas Reinecke, Joachim Ruther, Christoph J Mayer, Monika Hilker
    Abstract:

    : Melolontha cockchafer males search for mates using green leaf volatiles (GLV), released by host plants after female feeding. Thus, the feeding-induced plant volatiles act as sexual kairomones. Males of both Melontha hippocastani and Melontha Melolontha are strongly attracted by the GLV (Z)-3-hexen-1-ol (Z-3-ol). Sex pheromones enhance the attractiveness of Z-3-ol and have been identified as toluquinone (TQ) in M. Melolontha, and 1,4-benzoquinone (BQ) in M. hippocastani. Additionally, phenol acts as a male attractant in both species. From the perspective of potential application, we investigated by field experiments with volatile-baited traps the ways of enhancing the number of captured males by the use of specific binary or ternary blends of Z-3-ol with phenol, and TQ or BQ respectively. The data show that in both species binary lures containing Z-3-ol combined with TQ or BQ at a ratio of 10 : 1 are the most potent male attractants.

  • electrophysiological and behavioural responses of Melolontha Melolontha to saturated and unsaturated aliphatic alcohols
    Entomologia Experimentalis Et Applicata, 2005
    Co-Authors: Andreas Reinecke, Joachim Ruther, Monika Hilker
    Abstract:

    Male Melolontha cockchafers are known to use green leaf volatiles induced by female feeding on host plants for their mate location. Earlier studies of the response of the European cockchafer, Melolontha Melolontha L. (Coleoptera: Scarabaeidae), to different green leaf aldehydes, alcohols, and acetates revealed that only green leaf alcohols were attractive to males in the field. Females were not attracted at all by these volatiles. Here, we present a study that aimed to elucidate the structure-activity relationships of aliphatic alcohols. Both behavioural and physiological responses were studied in male and female M. Melolontha by field tests and electroantennography. The compounds tested were saturated aliphatic alcohols with chain lengths between five and eight carbon atoms. Furthermore, the cockchafer's response to six-carbon alcohols with (E)-2-, (E)-3-, (Z)-2-, (Z)-3-, and (Z)-4-configurated double bonds was tested. All compounds elicited dose-dependent responses on the antennae of both sexes. In general, males showed a stronger normalized EAG response to the stimuli than females. However, only the naturally occurring six-carbon alcohols, i.e., 1-hexanol (E )-2-, (Z)-3, and (E)-3-hexen-1-ol were attractive to M. Melolontha males in the field. Females were not attracted to any of the tested compounds, confirming previous results on the olfactory orientation of Melolontha cockchafers.

Andreas Reinecke - One of the best experts on this subject based on the ideXlab platform.

  • Sensing the Underground – Ultrastructure and Function of Sensory Organs in Root-Feeding Melolontha Melolontha (Coleoptera: Scarabaeinae) Larvae
    2016
    Co-Authors: Elisabeth J. Eilers, Monika Hilker, Giovanni Talarico, Bill S. Hansson, Andreas Reinecke
    Abstract:

    Introduction: Below ground orientation in insects relies mainly on olfaction and taste. The economic impact of plant root feeding scarab beetle larvae gave rise to numerous phylogenetic and ecological studies. Detailed knowledge of the sensory capacities of these larvae is nevertheless lacking. Here, we present an atlas of the sensory organs on larval head appendages of Melolontha Melolontha. Our ultrastructural and electrophysiological investigations allow annotation of functions to various sensory structures

  • Hypothesized function, abundance external morphology and dendritic structure (ODS: outer dendritic segment, TB: tubular body) of sensilla on antennae (A) and maxillary (M) and labial palps (L) in Melolontha Melolontha larvae.
    2012
    Co-Authors: Elisabeth J. Eilers, Monika Hilker, Giovanni Talarico, Bill S. Hansson, Andreas Reinecke
    Abstract:

    Hypothesized function, abundance external morphology and dendritic structure (ODS: outer dendritic segment, TB: tubular body) of sensilla on antennae (A) and maxillary (M) and labial palps (L) in Melolontha Melolontha larvae.

  • pre copulatory isolation in sympatric Melolontha species coleoptera scarabaeidae
    Agricultural and Forest Entomology, 2006
    Co-Authors: Andreas Reinecke, Joachim Ruther, Monika Hilker
    Abstract:

    1 The two most abundant cockchafer species in Europe, the forest cockchafer Melolontha hippocastani Fabr. and the European cockchafer Melolontha Melolontha L., tend to form calamitous mass breedings with casual reports on sympatric and simultaneous occurrence. 2 Both species are known to use feeding-induced green leaf volatiles (GLV) as primary attractants (sexual kairomones) for mate finding. The attractiveness of GLV is enhanced by the sex pheromones 1,4-benzoquinone in M. hippocastani and toluquinone in M. Melolontha. Phenol attracts males from both species. All three compounds are present in females of both species. 3 In the present study, it is confirmed that only male M. Melolontha perform the typical swarming flight at dusk, as has already been shown for M. hippocastani. Furthermore, whether swarming Melolontha males were cross-attracted to heterospecific females, and whether males could discriminate olfactorily between conspecific and heterospecific females, was tested in the field. 4 Males of both species preferred females when given the choice between females and males of the other species. However, they preferred conspecific females when females from both species were offered simultaneously. 5 The results suggest that species-specific pheromone blends contribute to precopulatory reproductive isolation in sympatric populations of M. Melolontha and M. hippocastani, but are not mutually exclusive or indispensable prerequisites for mate finding as in other insects.

  • optimized trap lure for male Melolontha cockchafers
    Journal of Applied Entomology, 2006
    Co-Authors: Andreas Reinecke, Joachim Ruther, Christoph J Mayer, Monika Hilker
    Abstract:

    : Melolontha cockchafer males search for mates using green leaf volatiles (GLV), released by host plants after female feeding. Thus, the feeding-induced plant volatiles act as sexual kairomones. Males of both Melontha hippocastani and Melontha Melolontha are strongly attracted by the GLV (Z)-3-hexen-1-ol (Z-3-ol). Sex pheromones enhance the attractiveness of Z-3-ol and have been identified as toluquinone (TQ) in M. Melolontha, and 1,4-benzoquinone (BQ) in M. hippocastani. Additionally, phenol acts as a male attractant in both species. From the perspective of potential application, we investigated by field experiments with volatile-baited traps the ways of enhancing the number of captured males by the use of specific binary or ternary blends of Z-3-ol with phenol, and TQ or BQ respectively. The data show that in both species binary lures containing Z-3-ol combined with TQ or BQ at a ratio of 10 : 1 are the most potent male attractants.

  • electrophysiological and behavioural responses of Melolontha Melolontha to saturated and unsaturated aliphatic alcohols
    Entomologia Experimentalis Et Applicata, 2005
    Co-Authors: Andreas Reinecke, Joachim Ruther, Monika Hilker
    Abstract:

    Male Melolontha cockchafers are known to use green leaf volatiles induced by female feeding on host plants for their mate location. Earlier studies of the response of the European cockchafer, Melolontha Melolontha L. (Coleoptera: Scarabaeidae), to different green leaf aldehydes, alcohols, and acetates revealed that only green leaf alcohols were attractive to males in the field. Females were not attracted at all by these volatiles. Here, we present a study that aimed to elucidate the structure-activity relationships of aliphatic alcohols. Both behavioural and physiological responses were studied in male and female M. Melolontha by field tests and electroantennography. The compounds tested were saturated aliphatic alcohols with chain lengths between five and eight carbon atoms. Furthermore, the cockchafer's response to six-carbon alcohols with (E)-2-, (E)-3-, (Z)-2-, (Z)-3-, and (Z)-4-configurated double bonds was tested. All compounds elicited dose-dependent responses on the antennae of both sexes. In general, males showed a stronger normalized EAG response to the stimuli than females. However, only the naturally occurring six-carbon alcohols, i.e., 1-hexanol (E )-2-, (Z)-3, and (E)-3-hexen-1-ol were attractive to M. Melolontha males in the field. Females were not attracted to any of the tested compounds, confirming previous results on the olfactory orientation of Melolontha cockchafers.

Siegfried Keller - One of the best experts on this subject based on the ideXlab platform.

  • long term field persistence of beauveria brongniartii strains applied as biocontrol agents against european cockchafer larvae in switzerland
    Biological Control, 2004
    Co-Authors: Jurg Enkerli, Franco Widmer, Siegfried Keller
    Abstract:

    In field tests between 1985 and 1992, various sites which were infested with Melolontha Melolontha were treated with the biocontrol fungus Beauveria brongniartii. The fungus was applied either as blastospores or as commercially available fungus colonized barley kernels (FCBK). In 1998/1999, soil samples were collected from the test sites and B. brongniartii isolates recovered and maintained in a culture collection. Isolates from this collection were subjected to genetic analyses by use of specific microsatellite markers. The applied B. brongniartii strains were detected at all test sites up to 14 years after their application. At some sites, the B. brongniartii populations consisted of the applied strains exclusively, whereas at other sites, indigenous populations or isolates that may have arisen from mutations or interactions among the applied strains and indigenous isolates were present in addition to the applied strains. The results suggested that applied B. brongniartii strains and indigenous B. brongniartii populations could coexist in the same habitat. Demonstration of long-term persistence of the applied B. brongniartii strains in the fields supported the success of this approach for the biological control of M. Melolontha.

  • distribution of insect pathogenic soil fungi in switzerland with special reference to beauveria brongniartii and metharhizium anisopliae
    Biocontrol, 2003
    Co-Authors: Siegfried Keller, Philip Kessler, Christian Schweizer
    Abstract:

    Between 1998 and 2000 soil samples from 82fields in north, east, central and south westof Switzerland were analysed for presence ofinsect pathogenic soil fungi using a selectivemedium and the Galleria bait method. Thedetection rates with either method were verysimilar. 96% of the fields distributed overall examined regions contained Metarhiziumanisopliae. The presence of Beauveriabrongniartii was limited to sites colonised byits host, Melolontha Melolontha. It wasalso present at a site where M.Melolontha disappeared about 40 years ago. Onthe other hand, B. brongniartii was notfound in four fields containing M.Melolontha populations. Beauveriabassiana, Paecilomyces fumosoroseus and Conidiobolus sp. were other entomopathogenicfungi isolated during this survey. Differencesin the presence of M. anisopliae betweenarable fields and adjacent meadows as well asbetween orchards and meadows are discussed.

  • strain specific microsatellite markers in the entomopathogenic fungus beauveria brongniartii
    Fungal Biology, 2001
    Co-Authors: Jurg Enkerli, Franco Widmer, C Gessler, Siegfried Keller
    Abstract:

    We have identified ten microsatellite markers in the entomopathogenic fungus Beauveria brongniartii from three genomic libraries enriched for (AAG) n -, (TG) n -, or (TC) n -repeats. The levels of polymorphism of the identified microsatellite loci were assessed in a collection of Beauveria strains originating from different countries, areas, and host insects. Two geographically separated Swiss populations of B. brongniartii originating from European cockchafer ( Melolontha Melolontha ) were also analysed. Microsatellites containing (AAG) n -repeats generally displayed high levels of polymorphism, whereas microsatellites containing either (TG) n - or (TC) n -repeats displayed lower levels of polymorphism. Cluster analysis revealed that strains isolated from M. Melolontha larvae, and two strains isolated from Melolontha hippocastani or Amphimallon solstitiale larvae, formed one cluster which was separated from strains isolated from adult M. Melolontha and other adult insects. A high degree of biodiversity was detected among B. brongniartii strains of the two separated Swiss populations. Distinct haplotypes were identified in 29 of 35 B. brongniartii strains from population A and in 12 of 28 B. brongniartii strains from population B. The high discrimination power of the identified microsatellites makes them a valuable tool, suited for the characterization and identification of B. brongniartii strains used as biocontrol agents. In addition, they may be applied to monitor biological control strains of B. brongniartii in the field and possibly to investigate their interactions with indigenous B. brongniartii isolates.

  • differential susceptibility of two Melolontha populations to infections by the fungus beauveria brongniartii
    Biocontrol Science and Technology, 1999
    Co-Authors: Siegfried Keller, Christian Schweizer, Paresh Shah
    Abstract:

    The susceptibility of second-instar larvae of the European cockchafer, Melolontha Melolontha L., originating from two different geographical locations was investigated with eight isolates of the insect pathogenic fungus Beauveria brongniartii (Sacc.) Petch. 77-94% of larvae from northern Italy (Auer, South Tyrolia) succumbed to mycosis with an average survival time (AST) of 22.9-40.1 days. Infections in larvae from south-western Switzerland (Bramois, Valais) were 28-72% and the ASTs varied between 34.7-56.4 days. Differences in susceptibility between the two host populations may be explained by the historical ages of the two populations and the presence of B. brongniartii resulting in a coevolution of tolerance between the host and pathogen. The Italian population is occasionally infected by B. brongniartii; in comparison, the Swiss population has existed for at least 50 years and regular infections by the pathogen are observed. Coevolution between B. brongniartii and M. Melolontha from Switzerland may ex...

Zihni Demirbag - One of the best experts on this subject based on the ideXlab platform.

  • Isolation and characterization of entomopathogenic fungi from hazelnut-growing region of Turkey
    BioControl, 2010
    Co-Authors: Ali Sevim, Richard A. Humber, Ismail Demir, Monica Höfte, Zihni Demirbag
    Abstract:

    Although Turkey is the first among all hazelnut-producing countries, yield per unit area of this crop is low in comparison to other countries, mainly because many insect species seriously damage hazelnut trees and their fruit. To find effective and safe biocontrol agents, we conducted a survey study to isolate entomopathogenic fungi from the hazelnut-growing region of Turkey and characterized the isolated strains in detail. In addition, we determined the effectiveness of seven selected strains from this region against Melolontha Melolontha (Coleoptera: Scarabaeidae) which is one of the most serious pests of hazelnut. In 2006 and 2007, 301 soil samples were collected randomly and analyzed for presence of entomopathogenic fungi using the Galleria bait method. Entomopathogenic fungi were found to occur in 20.59% of the soil samples studied. Based on morphology, ITS sequence and partial sequencing of the 18S (SSU rDNA) and EF1-α genes, the isolates were identified as Metarhizium anisopliae var. anisopliae , Metarhizium sp., Beauveria bassiana , Beauveria cf. bassiana , Isaria fumosorosea and Evlachovaea sp. Metarhizium anisopliae var. anisopliae was isolated from 34 sites and was the most frequent and abundant entomopathogenic species recovered. All the isolates tested were pathogenic to M . Melolontha . M . anisopliae var. anisopliae KTU-27 and Evlachovaea sp. KTU-36 produced the highest insecticidal activity (86.6%) within 15 days after inoculation. Our results suggest that entomopathogenic fungi could be good biocontrol agents against M . Melolontha , and are discussed with respect to ecology of fungi in relation to habitat in order to evaluate biocontrol potential of these isolates. This is the first study of the distribution of entomopathogenic fungi in the hazelnut-growing region of Turkey and of their pathogenicities against M . Melolontha .

  • Identification and pathogenicity of bacteria from European shot-hole borer,Xyleborus dispar Fabricius (Coleoptera: Scolytidae)
    Annals of Microbiology, 2008
    Co-Authors: Kazim Sezen, Hatice Kati, Remziye Nalcacioĝlu, Hacer Muratoĝlu, Zihni Demirbag
    Abstract:

    In this study, we have isolated and identified 5 bacterial isolates from European shot-hole borer, Xyleborus dispar (Coleoptera: Scolytidae), an important pest of hazelnut. After various morphological, physiological, biochemical and molecular characteristics were determined in detail, bacterial isolates were identified as Pseudomonas fluorescens (Xd1), Bacillus megaterium (Xd2), Bacillus thuringiensis (Xd3), Pseudomonas rhizosphaerae (Xd4) and Pantoea cedenensis (Xd5). Especially, the B. thuringiensis strain was identified in more detail as Bacillus thuringiensis subsp. tenebrionis (H8ab). The insecticidal activities were determined against the larvae of Agelastica alni L. (Col.: Chrysomelidae), Amphimallon solstitiale L. (Col.: Scarabaeidae), Leptinotarsa decemlineata (Say) (Col.: Chrysomelidae), and Melolontha Melolontha L. (Col.: Scarabaeidae) larvae at 1.8×10^9 CFU/ml dose, within five days. The highest insecticidal activities are 100, 100, 80 and 100% for Bacillus thuringiensis subsp. tenebrionis (Xd3) on A. alni, A. solstitiale, L. decemlineata , and M. Melolontha larvae, respectively. Our results indicate that especially B. thuringiensis subsp. tenebrionis (Xd3) may be valuable as a microbial control agent for coleopteran pests, respectively.

  • identification and pathogenicity of entomopathogenic bacteria from common cockchafer Melolontha Melolontha coleoptera scarabaeidae
    New Zealand Journal of Crop and Horticultural Science, 2007
    Co-Authors: Kazim Sezen, Y. Demir, Zihni Demirbag
    Abstract:

    Abstract Melolontha Melolontha larvae are susceptible to several pathogens indigenous to the area in which these insects occur in Turkey. We isolated and identified seven bacterial strains from M. Melolontha and evaluated their pathogenic activity during three hazelnut seasons from 2002 to 2004 on larvae of M. Melolontha. Using various morphological, physiological, and biochemical characteristics in detail, bacterial isolates were identified as Pseudomonas sp., Bacillus thuringiensis, Pseudomonas sp., Enterobacter sp., B. sphaericus, Acinetobacter sp., and B. weihenstephanensis. The insecticidal activity of isolates at 1.8 × 109 bacteria/ml dose, within 10 days on the larvae of M. Melolontha are 40% for Pseudomonas sp., 80% for Bacillus thuringiensis, 50% for Pseudomonas sp., 20% for Enterobacter sp., 60% for B. sphaericus, and 80% for B. weihenstephanensis. We also purified crystals from B. thuringiensis and B. sphaericus and tested the insecticidal activity on the larvae of M. Melolontha. In crystal pro...

  • characterization of a highly pathogenic bacillus thuringiensis strain isolated from common cockchafer Melolontha Melolontha
    Folia Microbiologica, 2007
    Co-Authors: Hatice Kati, Kazim Sezen, Zihni Demirbag
    Abstract:

    A bacterial isolate (Mm2) ofMelolontha Melolontha was identified and characterized. Based on various morphological, physiological, biochemical and molecular characteristics, it was identified asBacillus thuringiensis subsp.tenebrionis. This isolate was compared to the reference strains by electron microscopy, SDS-PAGE analysis, plasmid pattern,cry gene content and insecticidal activity. Cells of the isolate harbored flat square inclusions containing a protein component of ≈65 kDa. After trypsin digestion of solubilized crystals, SDS-PAGE resolved a unique proteinase-resistant peptide of ≈50 kDa. Plasmid pattern showed similar bands to those of the reference strain, PCR analysis showed that the isolate hascry3 gene. Toxicity tests (against 5 coleopteran species) showed 80 % insecticidal activity against the larvae ofM. Melolontha. The isolate Mm2 may be valuable as biological control agent forM. Melolontha and other coleopteran insects.

  • a new isolate of Melolontha Melolontha entomopoxvirus in turkey morphology infectivity and prevalence in the field
    Applied Entomology and Zoology, 2006
    Co-Authors: Kazim Sezen, Zihni Demirbag
    Abstract:

    A virus infection caused by Melolontha Melolontha L. (Coleoptera: Scarabaeidae) entomopoxvirus (MmEPV) was recorded in 0.87% of 1,260 larvae collected in 2001-2002 in Trabzon, Turkey. The diseased larvae had dark brown or black and white spots, compared to the normal white-cream colour of healthy larvae. MmEPV infections reduced the larval life span from 6 mo to 15±5 d (Mean±S.D.). Based on light and electron microscopic observations, the average length of the spheroids was 5.45±2.34 μm (Mean±S.D.) and the average width was 2.89±1.13 μm (Mean±S.D.) (n=50). The presence of a virus was also demonstrated in a DNA-DNA hybridization assay. The bioassays carried out to determine the infectivity of MmEPV proved its effectiveness against the third-instar larvae of the M. Melolontha. The highest insecticidal activity determined in the M. Melolontha larvae was 93.3% at the concentration of 7.5×10 6 spheroids/ml. Our results suggest that a Turkish isolate of MmEPV is promising for biological control of the M. Melolontha larvae.