Invasions by nonnative insect species can massively disrupt ecological processes, often leading to serious economic impacts. Previous work has identified propagule pressure as important driver of the trend of increasing numbers of insect invasions worldwide. In the present article, we propose an alternative hypothesis-that insect invasions are being driven by the proliferation of nonnative plants, which create niches for insect specialists and facilitate their establishment outside their native ranges where their hosts are planted or are invasive. We synthesize mechanisms by which plant invasions facilitate insect invasions, macroecological patterns supporting the tight link between plant and insect invasions, and case studies of plant invasions having facilitated subsequent insect establishment. This body of evidence indicates that plant invasions are a major driver of insect invasions. Consequently, the benefits of limiting the spread of nonnative plants include averting the proliferation of nonnative insects and their spillover onto native plant species.

• Klíčová slova
• empty niche, enemy release, facilitation, human-mediated dispersal, introduction pathways,
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

Trees growing outside their native geographic ranges often exhibit exceptional growth and survival due in part to the lack of co-evolved natural enemies that may limit their spread and suppress population growth. While most non-native trees tend to accumulate natural enemies over time, it remains uncertain which host and insect characteristics affect these novel associations and whether novel associations follow patterns of assembly similar to those of native hosts. Here, we used a dataset of insect-host tree associations in Europe to model which native insect species are paired with which native tree species, and then tested the model on its ability to predict which native insects are paired with which non-native trees. We show that native and non-native tree species closely related to known hosts are more likely to be hosts themselves, but that native host geographic range size, insect feeding guild, and sampling effort similarly affect insect associations. Our model had a strong ability to predict which insect species utilize non-native trees as hosts, but evolutionarily isolated tree species posed the greatest challenge to the model. These results demonstrate that insect-host associations can be reliably predicted, regardless of whether insect and host trees have co-evolved, and provide a framework for predicting future pest threats using a select number of easily attainable tree and insect characteristics.

• Klíčová slova
• evolutionary isolation, geographic ranges, insect–tree associations, invasive species, native trees, novel interactions, phylogeny,
• Publikační typ
• časopisecké články MeSH

The international plant trade results in the accidental movement of invasive pests and pathogens, and has contributed significantly to recent range expansion of pathogens including Dothistroma septosporum. Seeds are usually thought to present a lower biosecurity risk than plants, but the importation of Pinus contorta seeds from North America to Britain in the mid-1900s, and similarities between British and Canadian D. septosporum populations suggests seeds could be a pathway. Dothistroma septosporum has not been isolated from seeds, but inadequately cleaned seed material could contain infected needle fragments. This case study investigated whether cone kilning, and wet and dry heat treatments could reduce D. septosporum transmission without damaging seed viability. Pinus needles infected with D. septosporum were incubated alongside cones undergoing three commercial seed extraction processes. Additional needles were exposed to temperatures ranging from 10 to 67 °C dry heat for up to 48 h, or incubated in water heated to between 20 and 60 °C for up to one hour. Pinus sylvestris seeds were exposed to 60 and 65 dry heat °C for 48 h, and further seed samples incubated in water heated to between 20 and 60 °C for up to one hour. Dothistroma septosporum survived the three kilning processes and while seeds were not damaged by dry heat exceeding 63.5 °C, at this temperature no D. septosporum survived. Wet heat treatments resulted in less than 10% pathogen survival following incubation at 40 °C, while at this temperature the seeds suffered no significant impacts, even when submerged for one hour. Thus, commercial seed kilning could allow D. septosporum transmission, but elevated wet and dry heat treatments could be applied to seed stock to minimise pathogen risk without significantly damaging seed viability.

• Klíčová slova
• Dothistroma needle blight, biosecurity, invasive forest pathogens, phytosanitary, plant disease, seed quality,
• Publikační typ
• časopisecké články MeSH

European forests are threatened by increasing numbers of invasive pests and pathogens. Over the past century, Lecanosticta acicola, a foliar pathogen predominantly of Pinus spp., has expanded its range globally, and is increasing in impact. Lecanosticta acicola causes brown spot needle blight, resulting in premature defoliation, reduced growth, and mortality in some hosts. Originating from southern regions of North American, it devastated forests in the USA's southern states in the early twentieth century, and in 1942 was discovered in Spain. Derived from Euphresco project 'Brownspotrisk,' this study aimed to establish the current distribution of Lecanosticta species, and assess the risks of L. acicola to European forests. Pathogen reports from the literature, and new/ unpublished survey data were combined into an open-access geo-database (http://www.portalofforestpathology.com), and used to visualise the pathogen's range, infer its climatic tolerance, and update its host range. Lecanosticta species have now been recorded in 44 countries, mostly in the northern hemisphere. The type species, L. acicola, has increased its range in recent years, and is present in 24 out of the 26 European countries where data were available. Other species of Lecanosticta are largely restricted to Mexico and Central America, and recently Colombia. The geo-database records demonstrate that L. acicola tolerates a wide range of climates across the northern hemisphere, and indicate its potential to colonise Pinus spp. forests across large swathes of the Europe. Preliminary analyses suggest L. acicola could affect 62% of global Pinus species area by the end of this century, under climate change predictions. Although its host range appears slightly narrower than the similar Dothistroma species, Lecanosticta species were recorded on 70 host taxa, mostly Pinus spp., but including, Cedrus and Picea spp. Twenty-three, including species of critical ecological, environmental and economic significance in Europe, are highly susceptible to L. acicola, suffering heavy defoliation and sometimes mortality. Variation in apparent susceptibility between reports could reflect variation between regions in the hosts' genetic make-up, but could also reflect the significant variation in L. acicola populations and lineages found across Europe. This study served to highlight significant gaps in our understanding of the pathogen's behaviour. Lecanosticta acicola has recently been downgraded from an A1 quarantine pest to a regulated non quarantine pathogen, and is now widely distributed across Europe. With a need to consider disease management, this study also explored global BSNB strategies, and used Case Studies to summarise the tactics employed to date in Europe.

• Klíčová slova
• Brown spot needle blight, Climate change, Emerging and invasive pathogens, Forest conservation, Forest health protection, Forest management, Mycosphaerella dearnessii, Pinus,
• Publikační typ
• časopisecké články MeSH

Invasive, exotic plant pathogens pose a major threat to native and agricultural ecosystems. Phytophthora × cambivora is an invasive, destructive pathogen of forest and fruit trees causing severe damage worldwide to chestnuts (Castanea), apricots, peaches, plums, almonds and cherries (Prunus), apples (Malus), oaks (Quercus), and beech (Fagus). It was one of the first damaging invasive Phytophthora species to be introduced to Europe and North America, although its origin is unknown. We determined its population genetic history in Europe, North and South America, Australia and East Asia (mainly Japan) using genotyping-by-sequencing. Populations in Europe and Australia appear clonal, those in North America are highly clonal yet show some degree of sexual reproduction, and those in East Asia are partially sexual. Two clonal lineages, each of opposite mating type, and a hybrid lineage derived from these two lineages, dominated the populations in Europe and were predominantly found on fagaceous forest hosts (Castanea, Quercus, Fagus). Isolates from fruit trees (Prunus and Malus) belonged to a separate lineage found in Australia, North America, Europe and East Asia, indicating the disease on fruit trees could be caused by a distinct lineage of P. × cambivora, which may potentially be a separate sister species and has likely been moved with live plants. The highest genetic diversity was found in Japan, suggesting that East Asia is the centre of origin of the pathogen. Further surveys in unsampled, temperate regions of East Asia are needed to more precisely identify the location and range of the centre of diversity.

• Klíčová slova
• Hybridization, Invasive pathogen, Polyploidy, Population genetics,
• Publikační typ
• časopisecké články MeSH

UNLABELLED: Lecanosticta acicola causes brown spot needle blight (BSNB) of Pinus species. The pathogen occurs mostly in the Northern Hemisphere but has also been reported in Central America and Colombia. BSNB can lead to stunted growth and tree mortality, and has resulted in severe damage to pine plantations in the past. There have been increasingly frequent new reports of this pathogen in Europe and in North America during the course of the past 10 years. This is despite the fact that quarantine practices and eradication protocols are in place to prevent its spread. TAXONOMY: Kingdom Fungi; Phylum Ascomycota; Subphylum Pezizomycotina; Class Dothideomycetes; Subclass Dothideomycetidae; Order Capniodales; Family Mycosphaerellaceae; Genus Lecanosticta. HOST RANGE AND DISTRIBUTION: Lecanosticta spp. occur on various Pinus species and are found in North America, Central America, South America (Colombia), Europe as well as Asia. DISEASE SYMPTOMS: Small yellow irregular spots appear on the infected pine needles that become brown over time. They can be surrounded by a yellow halo. These characteristic brown spots develop to form narrow brown bands that result in needle death from the tips down to the point of infection. Needles are prematurely shed, leaving bare branches with tufts of new needles at the branch tips. Infection is usually most severe in the lower parts of the trees and progresses upwards into the canopies. USEFUL WEBSITES: The EPPO global database providing information on L. acicola (https://gd.eppo.int/taxon/SCIRAC) Reference genome of L. acicola available on GenBank (https://www.ncbi.nlm.nih.gov/genome/?term=Lecanosticta+acicola) JGI Gold Genome database information sheet of L. acicola sequenced genome (https://gold.jgi.doe.gov/organism?xml:id=Go0047147).

• Klíčová slova
• Lecanosticta acicola, Mycosphaerella dearnessii, Lecanosticta species, Pinus spp, brown spot needle blight, pine pathogen,
• MeSH
• Ascomycota patogenita   MeSH
• borovice mikrobiologie   MeSH
• lesy MeSH
• nemoci rostlin mikrobiologie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Fungi under the order Ophiostomatales (Ascomycota) are known to associate with various species of bark beetles (Coleoptera: Curculionidae: Scolytinae). In addition this group of fungi contains many taxa that can impart blue-stain on sapwood and some are important tree pathogens. A recent survey that focussed on the diversity of the Ophiostomatales in the forest ecosystems of the Czech Republic and Poland uncovered four putative new species. Phylogenetic analyses of four gene regions (ITS1-5.8S-ITS2 region, ß-tubulin, calmodulin, and translation elongation factor 1-α) indicated that these four species are members of the genus Ophiostoma. All four newly described species can be distinguished from each other and from closely related species based on DNA sequence comparisons, morphological characters, growth rates, and their insect associations. Based on this study four new taxa can be circumscribed and the following names are provided: Ophiostoma pityokteinis sp. nov., Ophiostoma rufum sp. nov., Ophiostoma solheimii sp. nov., and Ophiostoma taphrorychi sp. nov. O. rufum sp. nov. is a member of the Ophiostoma piceae species complex, while O. pityokteinis sp. nov. resides in a discrete lineage within Ophiostoma s. stricto. O. taphrorychi sp. nov. together with O. distortum formed a well-supported clade in Ophiostoma s. stricto close to O. pityokteinis sp. nov. O. solheimii sp. nov. groups within a currently undefined lineage A, which also includes Ophiostoma grandicarpum and Ophiostoma microsporum. This study highlights the need for more intensive surveys that should include additional countries of Central Europe, insect vectors and host tree species in order to elucidate Ophiostoma species diversity in this region.

• Klíčová slova
• 4 New taxa, Conifers, Hardwoods, Ophiostoma piceae species complex,
• MeSH
• cévnaté rostliny parazitologie   MeSH
• dřevo parazitologie   MeSH
• elongační faktor 1 genetika   MeSH
• fylogeneze * MeSH
• kalmodulin genetika   MeSH
• mezerníky ribozomální DNA genetika   MeSH
• mykologické určovací techniky MeSH
• nosatcovití růst a vývoj   mikrobiologie   MeSH
• Ophiostoma klasifikace   genetika   izolace a purifikace   fyziologie   MeSH
• RNA ribozomální 5.8S genetika   MeSH
• sekvenční analýza DNA MeSH
• tubulin genetika   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Česká republika MeSH
• Polsko MeSH
• Názvy látek
• elongační faktor 1 MeSH
• kalmodulin MeSH
• mezerníky ribozomální DNA MeSH
• RNA ribozomální 5.8S MeSH
• tubulin MeSH