Adults of the large pine weevil (Hylobius abietis) cause serious damage to coniferous seedlings and are among the most important forest pests in Europe. Seedling protection by chemicals is gradually ...being restricted or banned for environmental reasons, and non-chemical alternatives are therefore needed. In this 3-year study, we compared the following five treatments for protecting Norway spruce seedlings against H. abietis in the Central European mountains where the weevil is especially abundant: alpha-cypermethrin sprays (the only chemical treatment); coating with sprayed glue (Vermifix); wax coating with C and F types (Norsk Wax); and physical protection with collars. The same block design was set up at a clear-cut site and at a nursery site to compare seedling mortality and wax quality under "wild conditions" with pests and under "ideal conditions" without pests. Repeated application of alpha-cypermethrin was the most effective and least expensive method to protect seedlings against H. abietis. Among the four non-chemical methods, repeated application of glue was the most effective. Because collars were moderately effective but not cost-effective, we do not recommend the use of collars. Wax was inexpensive and environmentally safe but protected seedlings for only 1 year; the newer F type of wax performed better than the C type of wax, and perhaps the F type can be improved. In general we found that seedlings at sites with high numbers of H. abietis require protection for at least 3 years. We conclude by providing an overview of all methods currently available for managing H. abietis in forests.
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The black timber bark beetle Xylosandrus germanus (Blandford) is an invasive ambrosia beetle that originates from Southeast Asia and has become successfully established within Europe and North ...America. Herein, we provide a review of the spread and distribution of this tree and timber pest species across Europe, before and after 2000, along with a review of its habitat preferences. Since the spread of X. germanus across Europe has accelerated rapidly post-2000, emphasis is placed on this period. X. germanus was first recorded in Germany in 1951 and since then in 21 other European countries along with Russia. Ethanol-baited traps were deployed in oak, beech, and spruce forest ecosystems in the Western Carpathians, Central Europe, Slovakia, to characterize the distribution and habitat preferences of this non-native ambrosia beetle. Captures of X. germanus within Slovakia have been rising rapidly since its first record in 2010, and now this species dominates captures of ambrosia beetles. X. germanus has spread throughout Slovakia from south-southwest to north-northeast over a period of 5–10 years, and has also spread vertically into higher altitudes within the country. While living but weakened trees in Europe and North America are attacked by X. germanus, the greatest negative impact within Slovakia is attacks on recently felled logs of oak, beech and spruce trees, which provide high quality timber/lumber. We suggest that the recent rapid spread of X. germanus in Central Europe is being facilitated by environmental changes, specifically global warming, and the increasing frequency of timber trade. Recommendations for the management of X. germanus in forest ecosystems are proposed and discussed, including early detection, monitoring, sanitary measures, etc.
Species within the group of winter moths (Geometridae) are important oak defoliators in European forests. Adults of these species emerge either in late autumn (‘autumn species’) or in early spring ...(‘spring species’), and caterpillars of both ‘autumn’ and ‘spring’ species appear in spring. The abundance of adults assessed by regular monitoring allows the prediction of the defoliation intensity in trees by caterpillars in the following spring. ‘Autumn species’ (mostly a single one, Operophtera brumata) are monitored by forestry practices as pests, whereas ‘spring species’ are often not paid any attention. We hypothesised that ‘spring species’ could also have an important share in caterpillar assemblages in oak forests. We aimed to study the proportions between ‘autumn’ and ‘spring’ species in adult and larval stages. In a xeric thermophilous oak forest in southern Slovakia, Central Europe, we collected adult moths using sticky bands set up on trunks of Quercus pubescens during the winter of 2014–2015 and caterpillars from other trees belonging to the same oak species over the following spring. We also captured caterpillars from several oak species in various areas and over different years in Slovakia and Bulgaria, and we compiled relevant literature data. ‘Spring species’ recorded from a unique forest as adults during winter and as caterpillars in the following spring were significantly more abundant than ‘autumn species.’ Moreover, ‘spring species’ from Slovakian forests, regardless of the locality, the oak species and the year of sampling, reached high proportions, mostly over 50% of individuals in caterpillar assemblages. The ‘spring species’ Agriopis leucophaearia was the most abundant, followed by the ‘autumn species’ Operophtera brumata. ‘Spring species’ accounted for more than 50% of individuals in caterpillar assemblages in the Balkan Peninsula (Bulgaria) concerning one case, and they were of little importance in northern Greece. We recommend monitoring all winter moth adults (‘autumn’ and ‘spring’ species together) continuously in forestry practices, using sticky bands on oak trees from late autumn to early spring.
In recent years, the oak lace bug, Corythucha arcuata, has emerged as a significant threat to European oak forests. This species, native to North America, has in the last two decades rapidly extended ...its range in Europe, raising concerns about its potential impact on the continent's invaluable oak populations. To address this growing concern, we conducted an extensive study to assess the distribution, colonization patterns, and potential ecological niche of the oak lace bug in Europe.
We gathered 1792 unique presence coordinates from 21 Eurasian countries, utilizing diverse sources such as research observations, citizen science initiatives, GBIF database, and social media reports. To delineate the realized niche and future distribution, we employed an ensemble species distribution modelling (SDM) framework. Two future greenhouse gas scenarios (RCP 4.5 and RCP 8.5) were considered across three-time intervals (2021–2040, 2061–2080, and 2081–2100) to project and evaluate the species' potential distribution in the future.
Our analysis revealed that significant hotspots rich in host species occurrence for this invasive insect remain uninvaded so far, even within its suitable habitat. Furthermore, the native ranges of Turkey oak (Quercus cerris L.) and Hungarian oak (Quercus frainetto L.) species offer entirely suitable environments for the oak lace bug. In contrast, the pedunculate oak and sessile oak distribution ranges currently show only 40 % and 50 % suitability for colonization, respectively. However, our predictive models indicate a significant transformation in the habitat suitability of the oak lace bug, with suitability for these two oak species increasing by up to 90 %. This shift underlines an evolving landscape where the oak lace bug may exploit more of its available habitats than initially expected. It emphasises the pressing need for proactive measures to manage and stop its expanding presence, which may lead to a harmful impact on the oak population across the European landscape.
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•Oak lace bug occurrence data compiled from 21 countries.•Realized niche and potential distribution was projected using an SDM ensemble model.•The invasive species has not yet colonized all suitable areas.•By 2100, >80 % of oak species distributions could be colonized.
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The large pine weevil (Hylobius abietis) is an important pest of freshly planted coniferous trees. Feeding damage to conifer seedlings can be prevented by protecting the seedlings (mechanically or ...chemically), or by reducing H. abietis abundance. The entomopathogenic fungus Beauveria bassiana has promise for H. abietis control. To test the effects of the B. bassiana-colonized carriers (25 mm in diameter and colonized by strain AMEP20) on H. abietis adults that move into forest clearances, we performed several experiments. These included an experiment in Petri dishes under laboratory conditions, an experiment in cages with Norway spruce seedlings under semi-natural conditions, and a field experiment. Infection by B. bassiana and mortality of H. abietis was confirmed in all three experiments. The total mortality rate in all Petri dishes with B. bassiana carriers after 14 days was 74% (80% with fresh carriers; 68% with carriers that had been treated with UV light; 82% for carriers that had been frozen; 45% for adults that were exposed to carriers for only 24 h; and 95% for carriers that had been stored at 4 °C for 2 months). The mortality of H. abietis adults was affected by the absence/presence of carriers in the cages with spruce plants. The number of dead adults after 4 weeks of treatment in forest clearing were higher in plots with carriers than in the control plot. Mortality was highest for adults trapped in the plot with carriers on trap barks (58%), followed by the plot with carriers and an attractant (48%), and followed by the plots with carriers without an attractant (35%).
The results suggest that carriers colonized by the entomopathogenic fungus B. bassiana could be suitable for reducing H. abietis abundance in forests. The results indicated that H. abietis adults may be infected by B. bassiana after only a short exposure to carriers. The B. bassiana-colonized carrier is ready-to-use, i.e., it could be immediately produced and applied.
•A patent application (PCT/SK2020/050007, International filling date: July 9, 2020) for the B. bassiana-colonized carrier.•The carrier is colonized by the most virulent strain of B. bassiana (strain AMEP20) against the large pine weevil found in a previous study.•The carrier is a ready-to-use, i.e., it can be immediately used for production and application.•Infection by fungus and mortality of H. abietis after contact with carrier was confirmed under laboratory, semi-natural, and field conditions.
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Abstract Resistance of horse chestnut Aesculus hippocastanum ‘Mertelík’ to Cameraria ohridella was proven in the trial under semi-field conditions. Seedlings of vulnerable and resistant trees were ...grown together in rearing cages and were exposed to the strong attack from C. ohridella larvae. Significant differences in leaflet injuries were observed between susceptible and insect-resistant trees. Variety ‘Mertelík’ showed almost none or very small damages compared to high defoliation level in case of standard trees. The results confirmed that this resistant clone could be suitable for use under field conditions.
In June 2018, the presence of one adult specimen and one egg cluster of the North-American oak lace bug Corythucha arcuata were recorded near the village of Mužla, close to the Danube River, in ...southern Slovakia. They were found on leaves of Quercus cerris growing in a mixed stand. In August 2018, other specimens (nymphs and adults) were observed on Quercus robur leaves, near Čičarovce, in eastern Slovakia. This is the first record of C. arcuata in our country. The oak lace bug probably reached us while invading from Hungary, where heavy infestation is reported from several parts of the country.
The capability of a non-native species to withstand adverse weather is indicative of its establishment in a novel area. An unusually cold winter of 2016/2017 that occurred in the West Carpathians of ...Slovakia and other regions within Europe provided an opportunity to indirectly assess survival of the invasive ambrosia beetle
(Coleoptera: Curculionidae, Scolytinae). We compared trap captures of this species in the year preceding and succeeding the respective cold winter. Ethanol-baited traps were deployed in 24 oak dominated forest stands within the southern and central area from April to August 2016, and again from April to August 2017 to encompass the seasonal flight activity of
and to get acquainted with temporal changes in the abundance of this species in these two distant areas. Dispersing
were recorded in all surveyed stands before and after the aforementioned cold winter. Their total seasonal trap captures were lower in the southern area following low winter temperatures, but remained similar in the central area. Our results suggest that
can withstand adverse winter weather in oak dominated forests of the West Carpathians within altitudes of 171 and 450 m asl. It is likely that minimum winter temperatures will not reduce the establishment or further spread of this successful invader in forests in Central Europe.
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Abstract Coniferous forests in Europe have a considerable number of pests that attack trees of all ages from youngest up to oldest ones. One of them is the large pine weevil Hylobius abietis . This ...species is widespread in Europe and occurs from warm southern areas (Spain) up to northern countries (Sweden, Finland). Larvae of this species do not cause damage, they help in the decomposition process of stumps and roots. Adults are harmful as they consume bark of young coniferous seedlings, above all of spruce and pine. One adult can consume on average 75 mm 2 of bark per day. Individuals can live up to 4 years, and during their lives they can damage and kill several tens of coniferous seedlings. Traditional chemical protection of seedlings against this pest is and will gradually be more and more restricted or forbidden. In this review, we describe this method as well as all other alternative methods including biological protection. We estimate that H. abietis causes annual damages in Europe of almost 120 million € and damages several tens of thousands of hectares of young forest stands.
The North American oak lace bug feeds on leaves of ‘white oaks” in its native range. In Europe, it was first discovered in northern Italy in 2000. In recent years, it has subsequently spread rapidly ...and population outbreaks have been observed in several European countries. In the present study, we summarize the steps of its expansion.
To predict its potential host range, we checked 48 oak species in 20 sentinel gardens in seven countries between 2013 and 2018.
In total, 27 oak species were recorded as suitable hosts; 13 of them are globally new ones, 23 out of the 29 in section Quercus (∼ white oaks, an intrageneric taxonomic unit within genus Quercus), including Asian oaks, native to Japan, Korea and China, and four out of five in section Cerris (another intrageneric unit of the same genus), were accepted as hosts. None of the species in section Lobatae (red oaks) or in the Ilex group was accepted.
Host records were also collected in forest stands of 10 countries. We found 11 oak species that were infested. Outbreak populations were most commonly found on Quercus robur, Quercus frainetto, Quercus petraea and Quercus cerris, comprising widespread and outstandingly important oaks species in Europe.
Based on our findings, we conclude that suitable hosts for oak lace bug are present in most of Europe and Asia. This means that a lack of hosts will likely not restrict further range expansion.
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