The six-toothed bark beetle, Ips sexdentatus, is one of the most abundant scolytid species of the central and southern European countries. It mostly feeds on Pinus sp., whereas during population ...outbreaks it can also attack Picea sp. In spite of its broad distribution, its phylogeography has never been studied before. To do that, we employed an mtDNA marker on 489 individuals that covered most of its native range in Europe. Geographic distribution of the 86 haplotypes showed that at least three glacial refugia have played a significant role in shaping the currently observed pattern of genetic divergence in Europe, without excluding the contribution of minor refugial areas that acted in a similar manner. The revealed shallow structure can be considered an artifact of factors that reduced intraspecific diversity, at the same time favoring gene flow. As such, biological traits of the species itself (flying ability and host preference) and even human-mediated transport of wood seem to be the most prevailing and probable reasons that gave rise to the observed pattern.
Occurrence of pathogens in four important forest pest insect species, Ips typographus, Ips sexdentatus, Hylobius abietis and Hylobius pinastri, from Austria, Poland and France was investigated in ...2006-2008. Insects were collected from 46 sampling sites. In total 5,634 living adult beetles were dissected. Some dead adults and some very few dead larvae were inspected for fungal infection. Eight pathogen species (Ips typographus entomopoxvirus, Gregarina typographi, Mattesia sp., Chytridiopsis typographi, Unikaryon montanum, Beauveria bassiana, Beauveria caledonica and Isaria farinosa) were found in I. typographus from the three countries. Four pathogen species were found in I. sexdentatus from Austria and France (Gregarina cf. typographi, Metschnikowia cf. typographi, B. bassiana and B. caledonica). Five pathogen species were found in H. abietis from Austria and Poland and two in H. pinastri from Poland. Some of the pathogen species were found for the first time in one of the three countries or are reported for the first time in one of the investigated beetle species.
Results of studies on diversity of arthropod-pathogenic fungi in selected habitats in Austria and Poland carried out in the years 2006-2007 and 2009-2010 are discussed. In total 47 species of ...entomopathogenic fungi were found as pathogens of different arthropods in Austria. Twenty six entomophthoralean species from different insects and one species from mites were identified and 16 of them are recorded as new to Austria. From among 21 species of anamorphic Hypocreales (Ascomycota) affecting arthropods in Austria, 13 species so far have not been known from this country. In total 51 species of fungi affecting different arthropods in Poland were recorded, among them 28 species of Entomophthorales and 23 anamorphic Hypocreales (Ascomycota) were separated. The most frequent species of the entomopathogenic fungi both in agricultural and afforested areas in Austria were the common and usually worldwide distributed cordycipitaceous anamorphs Beauveria bassiana, Isaria fumosorosea and in areas of this study less numerous I. farinosa. The most frequent pathogens occurring in mite communities on plants and in wood infested by insects were Hirsutella species. Several entomophthoralean species developed epizootics that caused high reduction in host populations of different arthropods in both countries. Especially interesting is the first record of mycoses (up to 60% mortality), caused by Zoophthora spp. on Phyllobius beetles in a mixed forest near Białowieża. During our joint research, we found the first time in Poland and Europe, the presence of the fungus Furia cf. shandongensis on earwigs and Hirsutella entomophila on Ips typographus adults in forest habitats. From the feeding sites of the latter bark beetle and other subcortical species in oak bark (mostly Dryocoetes villosus) and D. alni in black alder over a dozen of various Lecanicillium strains - including few of the features not allowing to classify them to any of so far known species – were isolated both from the scolytids and from accompanying them mites, but these materials have now been successively elaborated. From the commonly occurring in these materials acaropathogenic species Hirsutella cf. brownorum, H. minnesotensis, H. nodulosa and H. rostrata, the two latter infected also adult bark beetles, whereas from the larvae and pupae some supposed nematophagous anamorphs were isolated, among them Harposporium janus and Haptocillium sp.
The aim of this study was to compare the species composition and the intensity of entomopathogenic fungi occurrence in the soil from mid-field woodlots and adjacent small farmlands. The study ...material consisted of soil samples taken from a mid-field woodlot and an adjacent small-scale arable field in three different localities in the vicinity of Siedlce. Entomopathogenic fungi were isolated from soil using two methods: the insect bait method and the selective medium. The comparative study showed that the soil from mid-field woodlots was characterized by a richer species composition of entomopathogenic fungi than of adjacent arable fields. A total of six fungal species representing the anamorphs of Hypocreales (Ascomycota) were isolated from the soil collected from mid-field woodlots: B. bassiana, B. brongniartii, M. anisopliae, M. flavoviride, I. farinosa and I. fumosorosea. The presence of only three species was reported in the farmland soil: B. bassiana, M. anisopliae and I. fumosorosea. This fact confirms the important role of semi-natural habitats as a source of biodiversity of entomopathogenic fungi in agricultural landscape. It was found that entomopathogenic fungi together formed more colony-forming units in the soil from arable fields than that of neighbouring mid-field woodlots. B. bassiana was the species of fungus which infected more bait insect larvae and formed significantly more colony-forming units (CFU) in the soil from mid-field woodlots than that of farmland in the localities studied, whereas the trend was the opposite in the case of I. fumosorosea and M. anisopliae. Given the presence of entomopathogenic fungi in the farmland soil in the three test places together, it was found that I. fumosorosea was dominant in the soil from the two arable fields, where this fungus infected more G. mellenella larvae and formed significantly more CFUs than the other species of fungi. M. anisopliae was the second most frequently isolated farmland species.
The occurrence, species diversity and some aspects of taxonomical affinity and host selectivity of acaropathogenic fungi associated with phytophagous, saprotrophic and predacious mites in Poland and ...other European countries were investigated on wild and cultivated plants, in insect feeding sites under the bark and in decayed wood. From among 33 species of fungi affecting mites only five species of Entomophthorales were separated and the most numerous were Neozygites floridana mostly on Tetranychus urticae, N. abacaridis on a few eriophyid species, and Conidiobolus coronatus attacking gamasid mites most frequently of the genus Dendrolaelaps. The most frequent mite pathogens occurring in mite communities on plants and in wood infested by insects were of the genus Hirsutella. Until now 13 of their form-species have been recognized in these habitats, but only H. kirchneri, H. necatrix and H. thompsonii (including its variety synnematosa) can be treated as exclusive oligophagous pathogens of phytophagous mites, though their potential host range seems to embrace only selected eriophyid or tarsonemid mites. Taxonomical differentiation of fungal strains was based on close morphological observations and molecular analysis of ITS region sequences. Two new species of acaropathogenic fungi were described in these studies. Hirsutella danubiensis sp. nov. was found in the tetranychid T. urticae, whereas H. vandergeesti sp. nov. affected phytoseiid mites of the genera Amblyseius, Neoseiulus, Seiulus and Typhlodromus, and the tarsonemid Tarsonemus lacustris.
Microsporidia are intracellular eukaryotic parasites of animals, characterized by unusual morphological and genetic features. They can be divided in three main groups, the classical microsporidians ...presenting all the features of the phylum and two putative primitive groups, the chytridiopsids and metchnikovellids. Microsporidia originated from microsporidia-like organisms belonging to a lineage of chytrid-like endoparasites basal or sister to the Fungi. Genetic and genomic data are available for all members, except chytridiopsids. Herein, we filled this gap by obtaining the rDNA sequence (SSU-ITS-partial LSU) of
Chytridiopsis typographi
(Chytridiopsida), a parasite of bark beetles. Our rDNA molecular phylogenies indicate that
Chytridiopsis
branches earlier than metchnikovellids, commonly thought ancestral, forming the more basal lineage of the Microsporidia. Furthermore, our structural analyses showed that only classical microsporidians present 16S-like SSU rRNA and 5.8S/LSU rRNA gene fusion, whereas the standard eukaryote rRNA gene structure, although slightly reduced, is still preserved in the primitive microsporidians, including 18S-like SSU rRNA with conserved core helices, and ITS2-like separating 5.8S from LSU. Overall, our results are consistent with the scenario of an evolution from microsporidia-like rozellids to microsporidians, however suggesting for metchnikovellids a derived position, probably related to marine transition and adaptation to hyperparasitism. The genetic and genomic data of additional members of Chytridiopsida and Rozellomycota will be of great value, not only to resolve phylogenetic relationships but also to improve our understanding of the evolution of these fascinating organisms.
In this study, the isolation frequency and density of infectious units of entomopathogenic fungi (EPF) in soils from orchards in different farming systems were determined. Soil samples were collected ...from the fallow and sward strips of apple orchards under various production regimes, including organic, conventional, and integrated pest management (IPM). There were no significant differences for EPF density in organic and conventional orchards, but there were substantial differences between sward strips and fallows, depending on the farming system. The density of soilborne EPF from organic orchards was significantly higher in the fallow than the sward strip. The density of soilborne EPF from the herbicide-treated fallow was significantly lower samples from the sward strip in conventional production. The density of soilborne EPF in the orchards using an IPM program was higher in the herbicide-treated fallow than in the sward strip. Among the four isolated species of entomopathogenic fungi, Metarhizium anisopliae (sensu lato) was the most abundant.
After the successful conclusion of the Joint Meeting of IUFRO’s 7.03.05 & 7.03.10 working parties and given the exciting and novel studies that have been presented in the framework of this meeting, ...we decided to present some of these studies in the current Special Issue of Forests. To make this issue more appealing and interesting to everyone in the field of Forest Protection, studies that cover a wide range of topics were selected, ranging from ecology and phylogeography to forest management and protection. More importantly, as these studies refer to pests and pathogens from different parts of the world, it is expected that the knowledge gained can be further used in the protection of natural environment worldwide.
Background and purpose The pine shoot beetles Tomicus piniperda and Tomicus minor are secondary tree pests attacking weakened Pinus sylvestris and Pinus nigra. Outbreaks occasionally occur, causing ...considerable economic damage. The microsporidian pathogen Canningia tomici infects T. piniperda as its principal host. Bioassays were used to study the infectivity of C. tomici to both beetle species, as well as vertical transmission, and effects on survival and fecundity. Materials and methods Field collected beetles from several locations in Austria (Lower Austria, Burgenland and Styria), Finland (Hyytiälä), Poland (Sękocin), the Czech Republic (Stará Boleslav), and Croatia (Korenica) (3410 T. piniperda, 413 T. minor) were dissected and evaluated for the presence of C. tomici. Uninfected beetles for infection experiments were only collected from the Austrian sites.Canningia tomici spores were extracted from the infected organs of T. piniperda by dissection and host tissue grinding. The number of spores suspended in water was counted in a hemocytometer. Infection experiments began with T. piniperda and T. minor as soon as parental beetles were available in the field in spring, or filial beetles were emerging from infested log sections in the laboratory. To test the effect of maturation feeding on infection success, filial beetles of both species were either inoculated immediately after emergence from a log section, or were allowed to feed on P. sylvestris twigs for several days first. Filial beetles were kept in Petri dishes containing P. sylvestris twigs at 8°C and long-day conditions (16L:8D) during the maturation feeding period. Afterwards, they were removed from the twigs, starved for 24 hours, and then inoculated with a 1-µl spore suspension or water. All beetles checked daily until death, dissected and inspected for the presence of C. tomici spores. All data were analyzed with the software program. Frequency data sets were compared using Chi-square analysis. Multiple comparisons were controlled for Type I errors using the Bonferroni method. The datasets of multiple dependent scale variables were analysed using the LM multivariate procedure, testing the effects of the following factors: year, temperature, inoculation, successful infection, maturation feeding, and sexResultsThe overall prevalence of C. tomici in T. piniperda was 1.9%, with significantly more female T. piniperda infected. No infections were observed in T. minor. After feeding spore suspensions to parental and filial T. piniperda and T. minor, between 0% and 67% of the beetles were successfully infected, regardless of the incubation temperature or the beetles’ sex. The beetles’ survival time was significantly influenced by the incubation temperature and the successful infection; in filial beetles the maturation feeding period was also an important factor. A lower incubation temperature and a successful infection caused both species and generations to survive longer.Conclusion We conclude that when C. tomici infects the reproductive organs of its hosts, this extends the host's lifespan, leading to better reproduction, transmission, and survival of the pathogen in host populations. This is also reflected by higher infection rates of T. piniperda in Finland and Poland, as compared to Austria.
The Western Corn Rootworm D. virgifera virgifera Le Conte (Coleoptera: Chrysomelidae), a serious pest of maize, has been recently introduced into Europe. Several approaches for its control are ...presently under investigation including microbial agents. In order to get information on the role of naturally occurring pathogens in the regulation of Diabrotica populations, we started an investigation in established populations in Hungary, Romania, Serbia, Austria, and Italy in 2005 and 2006. In infested maize fields in Hungary, plants and their root systems were grubbed out and larvae and pupae were collected. Adult D. v. virgifera were collected in Hungary, Austria, Romania, Serbia and Italy. Additionally, the occurrence of entomopathogenic fungi in soils of maize fields was determined using Galleria mellonella and Tenebrio molitor larvae as bait insects. The density of entomopathogenic fungi was obtained by plating soil suspension on selective medium. Metarhizium anisopliae and Beauveria spp. infections were found in 1.4% of field collected larvae, 0.2% of field collected pupae and 0.05% of field collected adults. Whereas natural infections of D. v. virgifera were rarely found, a high density of insect pathogenic fungi was recorded in Hungarian soils. M. anisopliae could be detected in every maize field either using the “bait method” or a “selective medium” method. This is the first report of a natural occurrence of entomoparasitic nematodes (Heterorhabditis sp., Steinernema sp.) in Diabrotica v. virgifera in Europe.
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