200 research outputs found
Microbial biopesticides for integrated crop management : an assessment of environmental and regulatory sustainability
Herbivorous insects and mites, plant diseases and weeds are major impediments to the production of food crops and are increasingly difficult to control with conventional chemicals. This paper focuses on microbial control agents with an emphasis on augmentation. There are marked differences in the availability of products in different countries which can be explained in terms of differences in their regulatory systems. Regulatory failure arises from the application of an inappropriate synthetic pesticides model. An understanding of regulatory innovation is necessary to overcome these problems. Two attempts at remedying regulatory failure in the UK and the Netherlands are assessed. Scientific advances can feed directly into the regulatory process and foster regulatory innovation
Global distribution of two fungal pathogens threatening endangered sea turtles
This work was supported by grants of Ministerio de Ciencia e Innovación, Spain (CGL2009-10032, CGL2012-32934). J.M.S.R was supported by PhD fellowship of the CSIC (JAEPre 0901804). The Natural Environment Research Council and the Biotechnology and Biological Sciences Research Council supported P.V.W. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Thanks Machalilla National Park in Ecuador, Pacuare Nature Reserve in Costa Rica, Foundations Natura 2000 in Cape Verde and Equilibrio Azul in Ecuador, Dr. Jesus Muñoz, Dr. Ian Bell, Dr. Juan Patiño for help and technical support during samplingPeer reviewedPublisher PD
Phylogenetic and morphotaxonomic revision of Ramichloridium and allied genera
The phylogeny of the genera Periconiella, Ramichloridium,
Rhinocladiella and Veronaea was explored by means of partial
sequences of the 28S (LSU) rRNA gene and the ITS region (ITS1, 5.8S rDNA and
ITS2). Based on the LSU sequence data, ramichloridium-like species segregate
into eight distinct clusters. These include the Capnodiales
(Mycosphaerellaceae and Teratosphaeriaceae), the
Chaetothyriales (Herpotrichiellaceae), the Pleosporales, and
five ascomycete clades with uncertain affinities. The type species of
Ramichloridium, R. apiculatum, together with R. musae,
R. biverticillatum, R. cerophilum, R. verrucosum, R. pini, and three new
species isolated from Strelitzia, Musa and forest soil,
respectively, reside in the Capnodiales clade. The human-pathogenic
species R. mackenziei and R. basitonum, together with R.
fasciculatum and R. anceps, cluster with Rhinocladiella
(type species: Rh. atrovirens, Herpotrichiellaceae,
Chaetothyriales), and are allocated to this genus. Veronaea
botryosa, the type species of the genus Veronaea, also resides
in the Chaetothyriales clade, whereas Veronaea simplex
clusters as a sister taxon to the Venturiaceae (Pleosporales), and is
placed in a new genus, Veronaeopsis. Ramichloridium
obovoideum clusters with Carpoligna pleurothecii (anamorph:
Pleurothecium sp., Chaetosphaeriales), and a new combination
is proposed in Pleurothecium. Other ramichloridium-like clades
include R. subulatum and R. epichloës (incertae sedis,
Sordariomycetes), for which a new genus, Radulidium is
erected. Ramichloridium schulzeri and its varieties are placed in a
new genus, Myrmecridium (incertae sedis, Sordariomycetes).
The genus Pseudovirgaria (incertae sedis) is introduced to
accommodate ramichloridium-like isolates occurring on various species of rust
fungi. A veronaea-like isolate from Bertia moriformis with
phylogenetic affinity to the Annulatascaceae (Sordariomycetidae) is
placed in a new genus, Rhodoveronaea. Besides
Ramichloridium, Periconiella is also polyphyletic.
Thysanorea is introduced to accommodate Periconiella papuana
(Herpotrichiellaceae), which is unrelated to the type species, P.
velutina (Mycosphaerellaceae)
Opportunistic, human-pathogenic species in the Herpotrichiellaceae are phenotypically similar to saprobic or phytopathogenic species in the Venturiaceae
Although morphologically similar, species of Cladophialophora
(Herpotrichiellaceae) were shown to be phylogenetically distinct from
Pseudocladosporium (Venturiaceae), which was revealed to be
synonymous with the older genus, Fusicladium. Other than being
associated with human disorders, species of Cladophialophora were
found to also be phytopathogenic, or to occur as saprobes on organic material,
or in water, fruit juices, or sports drinks, along with species of
Exophiala. Caproventuria and Metacoleroa were
confirmed to be synonyms of Venturia, which has Fusicladium
(= Pseudocladosporium) anamorphs. Apiosporina, based on
A. collinsii, clustered basal to the Venturia clade, and
appears to represent a further synonym. Several species with a
pseudocladosporium-like morphology in vitro represent a sister clade
to the Venturia clade, and are unrelated to Polyscytalum.
These taxa are newly described in Fusicladium, which is
morphologically close to Anungitea, a heterogeneous genus with
unknown phylogenetic affinity. In contrast to the
Herpotrichiellaceae, which were shown to produce numerous
synanamorphs in culture, species of the Venturiaceae were
morphologically and phylogenetically more uniform. Several new species and new
combinations were introduced in Cladophialophora, Cyphellophora
(Herpotrichiellaceae), Exophiala, Fusicladium, Venturia
(Venturiaceae), and Cylindrosympodium (incertae
sedis)
Phylogeny of rock-inhabiting fungi related to Dothideomycetes
The class Dothideomycetes (along with Eurotiomycetes)
includes numerous rock-inhabiting fungi (RIF), a group of ascomycetes that
tolerates surprisingly well harsh conditions prevailing on rock surfaces.
Despite their convergent morphology and physiology, RIF are phylogenetically
highly diverse in Dothideomycetes. However, the positions of main
groups of RIF in this class remain unclear due to the lack of a strong
phylogenetic framework. Moreover, connections between rock-dwelling habit and
other lifestyles found in Dothideomycetes such as plant pathogens,
saprobes and lichen-forming fungi are still unexplored. Based on multigene
phylogenetic analyses, we report that RIF belong to Capnodiales
(particularly to the family Teratosphaeriaceae s.l.),
Dothideales, Pleosporales, and Myriangiales, as
well as some uncharacterised groups with affinities to
Dothideomycetes. Moreover, one lineage consisting exclusively of RIF
proved to be closely related to Arthoniomycetes, the sister class of
Dothideomycetes. The broad phylogenetic amplitude of RIF in
Dothideomycetes suggests that total species richness in this class
remains underestimated. Composition of some RIF-rich lineages suggests that
rock surfaces are reservoirs for plant-associated fungi or saprobes, although
other data also agree with rocks as a primary substrate for ancient fungal
lineages. According to the current sampling, long distance dispersal seems to
be common for RIF. Dothideomycetes lineages comprising lichens also
include RIF, suggesting a possible link between rock-dwelling habit and
lichenisation
Optical Light Curves of the Type Ia Supernovae 1990N and 1991T
We present UBVRI light curves for the bright Type Ia supernovae SN 1990N in
NGC 4639 and SN 1991T in NGC 4527 based on photometry gathered in the course of
the Calan/Tololo supernova program. Both objects have well-sampled light curves
starting several days before maximum light and spanning well through the
exponential tail. These data supercede the preliminary photometry published by
Leibundgut et al (1991) and Phillips et al (1992). The host galaxies for these
supernovae have (or will have) accurate distances based on the Cepheid
period-luminosity relationship. The photometric data in this paper provide
template curves for the study of general population of Type Ia supernova and
accurate photometric indices needed for the Cepheid-supernova distance scale.Comment: AAS LaTeX, 30 pages, 10 figures, to appear in the Jan 1998
Astronomical Journal. Figs 1 and 2 (finding charts) not include
The Evolution of Invasiveness in Garden Ants
It is unclear why some species become successful invaders whilst others fail, and whether invasive success depends on pre-adaptations already present in the native range or on characters evolving de-novo after introduction. Ants are among the worst invasive pests, with Lasius neglectus and its rapid spread through Europe and Asia as the most recent example of a pest ant that may become a global problem. Here, we present the first integrated study on behavior, morphology, population genetics, chemical recognition and parasite load of L. neglectus and its non-invasive sister species L. turcicus. We find that L. neglectus expresses the same supercolonial syndrome as other invasive ants, a social system that is characterized by mating without dispersal and large networks of cooperating nests rather than smaller mutually hostile colonies. We conclude that the invasive success of L. neglectus relies on a combination of parasite-release following introduction and pre-adaptations in mating system, body-size, queen number and recognition efficiency that evolved long before introduction. Our results challenge the notion that supercolonial organization is an inevitable consequence of low genetic variation for chemical recognition cues in small invasive founder populations. We infer that low variation and limited volatility in cuticular hydrocarbon profiles already existed in the native range in combination with low dispersal and a highly viscous population structure. Human transport to relatively disturbed urban areas thus became the decisive factor to induce parasite release, a well established general promoter of invasiveness in non-social animals and plants, but understudied in invasive social insects
- …