Search

This study investigated the relationship between genetic and morphological evidence in a species complex of haplodiploid, near-inbred ambrosia beetles, which are also vectors of an invasive tree pathogen: Xyleborus ferrugineus, Xyleborus bispinatus, and Xyleborus impressus. The unorthodox genetic system may blur species boundaries and challenges the applicability of standard species concepts. Haplo-diploid scolytine systematics is rife with contentious species delimitation, but species limits have rarely been tested empirically. To test the congruence of morphology, genetics, and geography in species identity, we analyzed 16 morphological characters and two DNA barcodes (COI mtDNA and CAD DNA sequences) in samples from across Florida. Morphological characters used to distinguish species corresponded with phylogenetic relationships in the majority of individuals. The maximum intraspecific divergence for the COI barcoding region was up to 19%, among the largest reported for animals. The phylogenetic and morphological analyses suggest that the three species are valid, but the astonishing intraspecific genetic diversity suggests either additional cryptic species or pseudogenes. [ABSTRACT FROM AUTHOR]

Simple Summary: In our study, we explored ways to effectively trap invasive ambrosia beetles, which pose significant threats to trees and forests. We focused on comparing two types of bait—pure ethanol and denatured ethanol—to attract these pests in different environments like tree nurseries and orchards. We found that traps using pure ethanol captured more Xylosandrus germanus beetles compared to those with denatured ethanol. Our findings suggest that using pure ethanol could be more effective for monitoring certain ambrosia beetle species. This research contributes to better pest management strategies, helping protect trees from invasive pests, ultimately benefiting society by safeguarding ecosystems and agricultural productivity. Ambrosia beetles, particularly invasive species within the tribe Xyleborini, such as Xylosandrus germanus (Blandford, 1894), pose significant threats to various ecosystems and managed habitats worldwide. Monitoring these invaders is vital for effective pest management, typically accomplished through ethanol-baited traps. We compared trap efficacy using denatured ethanol versus absolute ethanol in orchards, tree nurseries, and lumber yards in northeastern Ohio, USA, finding that absolute ethanol traps captured significantly more X. germanus. Analysis revealed acetone, ethanol, and methyl isobutyl ketone in the denatured ethanol, likely impacting trap efficacy. Our study underscores the importance of using pure denatured ethanol without acetone for effective monitoring, especially for X. germanus. Exotic xyleborines dominated trap captures across various habitats, emphasizing the need for tailored pest management strategies. Further research is warranted to explore the chemical ecology of ambrosia beetles and the influence of ethanol impurities on trap effectiveness. [ABSTRACT FROM AUTHOR]

A new species, Tricosa sokanovskiisp. n. (Coleoptera, Curculionidae: Scolytinae), is described from the south of the Russian Far East based on the material from the neighbourhood of Vladivostok. [ABSTRACT FROM AUTHOR]

Bark and ambrosia beetles are commonly found in forest ecosystems, and their fungal symbionts act as plant pathogens. Accurate information on the presence and population levels of bark and ambrosia beetles is becoming an increasingly crucial to protect the forest ecosystem. This study compared multiple-funnel and bottle traps to monitor the bark and ambrosia beetles in two types of mahogany forest. Multiple-funnel and bottle traps were made from transparent polyethylene terephthalate bottles and baited with 95% ethanol. Two different mahogany forest management (monoculture and polyculture with coffee plants) were used in this study. A total of 2,367 bark and ambrosia beetle specimens were trapped in this study. This research recorded ten genera of Scolytinae and one Platypodinae genus. Xyleborus spp., X. crassiusculus, and P. cavipennis are three predominated ambrosia beetles collected in mahogany monoculture and polyculture. Euplatypus parallelus was identified as a representative of Platypodinae. Results showed that multiple-funnel traps baited with ethanol are effective to catch individuals and several species of bark and ambrosia beetles in mahogany forests. The choice of multiple-funnel or bottle traps is an important consideration in trap-based programs for monitoring or detecting invasive species in forest ecosystems.

Ambrosia beetles, particularly invasive species within the tribe Xyleborini, such as Xylosandrus germanus (Blandford, 1894), pose significant threats to various ecosystems and managed habitats worldwide. Monitoring these invaders is vital for effective pest management, typically accomplished through ethanol-baited traps. We compared trap efficacy using denatured ethanol versus absolute ethanol in orchards, tree nurseries, and lumber yards in northeastern Ohio, USA, finding that absolute ethanol traps captured significantly more X. germanus. Analysis revealed acetone, ethanol, and methyl isobutyl ketone in the denatured ethanol, likely impacting trap efficacy. Our study underscores the importance of using pure denatured ethanol without acetone for effective monitoring, especially for X. germanus. Exotic xyleborines dominated trap captures across various habitats, emphasizing the need for tailored pest management strategies. Further research is warranted to explore the chemical ecology of ambrosia beetles and the influence of ethanol impurities on trap effectiveness.

Xylosandrus spp. ambrosia beetles (Coleoptera: Curculionidae: Scolytinae) are important wood-boring pests of nursery trees weakened by abiotic and biotic stressors. Acibenzolar- S -methyl (ASM), a plant defense elicitor, was tested for inhibiting Xylosandrus spp. tunneling (i.e. attacks) into flood-stressed flowering dogwoods (Cornus florida L. (Cornales: Cornaceae)). Container-grown dogwoods were treated with ASM substrate drench + flooding, ASM foliar spray + flooding, ASM drench + no flooding, ASM foliar + no flooding, no ASM + flooding, or no ASM + no flooding at 3 days before flood stress in a completely randomized design under field conditions. Trees were flooded for 14 days and then drained and watered as needed. Attacks were counted every 2 days for 28 days. Plant tissue samples were collected at 7 and 14 days after flooding to determine ethanol content using solid-phase microextraction–gas chromatography–mass spectrometry. Trees were dissected to determine gallery formation and depth, fungal colonization, and the presence of eggs, larvae, and adults. The highest number of Xylosandrus beetle species attacks were recorded from plants exposed to no ASM + flooding, but attacks were reduced in ASM treated trees (drench or foliar) + flooding. Trees treated with drenches had fewer attacks than foliar sprays. Plants assigned to no flood had the fewest beetle attacks. Moreover, ASM reduced Xylosandrus spp. gallery formation and depth, fungal colonization, and presence of eggs, larvae, and adults. All flooded trees produced ethanol. In conclusion, ASM induced a plant defense response to Xylosandrus spp. tunneling in dogwoods under flood stress conditions. [ABSTRACT FROM AUTHOR]

The ecologically and culturally vital tree species, ʻōhiʻa lehua (Metrosideros polymorpha), is threatened by the fungal pathogens Ceratocystis lukuohia and Ceratocystis huliohia, the causal agents of the disease complex called Rapid ʻŌhiʻa Death (ROD). Four invasive ambrosia beetle (Coleoptera: Curculionidae: Scolytinae) species in the Xyleborini tribe colonize ROD Ceratocystis‐infested 'ōhiʻa and produce inoculum through their frass; however, the potential for direct transmission of the ROD fungi by these beetles was unknown. We fulfilled Leach's rules to support insect transmission of ROD by documenting the visitation of these ambrosia beetles to healthy 'ōhiʻa trees, culturing C. lukuohia and C. huliohia from the ROD‐associated beetles using three different collection methods at multiple study sites, and challenging healthy ʻōhiʻa seedlings with beetles that were exposed to both C. lukuohia and C. huliohia cultures. We documented all four invasive ROD‐associated ambrosia beetle species including Xyleborinus saxesenii, Xyleborus affinis, Xyleborus ferrugineus, and Xyleborus perforans to regularly visit healthy ʻōhiʻa trees on sticky traps. Viable Ceratocystis propagules were isolated from all species, and C. lukuohia was most commonly isolated of the two ROD‐causing fungi. Consistently across all collection techniques, ROD Ceratocystis spp. were detected on just under 3% of all assayed beetles, with the highest detection rate from X. affinis. All four beetle species were capable of directly transmitting both pathogens to healthy ʻōhiʻa seedlings with a high rate of transfer. Ceratocystis spp. are highly virulent pathogens in trees, and a single inoculation can result in tree death, therefore any direct transmission is a cause for concern. After meeting the criteria of Leach's rules, we propose that Xi. saxesenii, X. affinis, X. ferrugineus, and X. perforans are vectors of C. lukuohia and C. huliohia, particularly in areas of high ROD pressure and tree stress. [ABSTRACT FROM AUTHOR]

BACKGROUND: Exotic ambrosia beetles are emerging widespread pests of several wild and managed trees and shrubs. Xylosandrus compactus (Eichhoff) is one of the most invasive species causing damage to a broad range of host plants. Little information is available on its control, including the impact of insecticides. Bioassays were conducted to evaluate the potential of four bioinsecticides and seven synthetic insecticides in controlling X. compactus. Beetle mortality and sublethal effects on tunneling, cultivation of the mutualist fungus and reproduction were assessed. RESULTS: Concentration–mortality curves were determined for all tested insecticides. Lambda‐cyhalothrin was the most toxic insecticide, showing the lowest estimated 90% and 50% lethal concentrations (LC90 and LC50), followed by deltamethrin and thiamethoxam. Acetamiprid caused the highest levels of mortality and brood size reduction under extended laboratory conditions. Moreover, acetamiprid, thiamethoxam and lambda‐cyhalothrin caused the greatest mortality and, together with deltamethrin, strongly affected progeny occurrence inside infested galleries and beetle brood size. Among the bioinsecticides, pyrethrins significantly affected beetle survival under laboratory conditions, but not brood size in extended laboratory bioassays. Some of the tested insecticides had significant lethal and sublethal effects only when beetles were exposed to fresher residues, highlighting differences in toxicity persistence. CONCLUSION: This study provides first baseline toxicity data for synthetic insecticides and bioinsecticides with different modes of action and origin toward X. compactus, and the first evidence that several insecticides can cause multiple sublethal effects on this pest. These findings can help in building suitable integrated pest management packages against this pest. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Many wood-boring insects use aggregation pheromones during mass colonization of host trees. Bark beetles (Curculionidae: Scolytinae) are a model system, but much less is known about the role of semiochemicals during host selection by ambrosia beetles. As an ecological clade within the bark beetles, ambrosia beetles are obligately dependent on fungal mutualists for their sole source of nutrition. Mass colonization of trees growing in horticultural settings by exotic ambrosia beetles can occur, but aggregation cues have remained enigmatic. To elucidate this mechanism, we first characterized the fungal associates of the exotic, massaggregating ambrosia beetle Xylosandrus germanus in Southern Germany. Still-air olfactometer bioassays documented the attraction of X. germanus to its primary nutritional mutualist Ambrosiella grosmanniae and to a lesser extent another common fungal isolate (Acremonium sp.). During two-choice bioassays, X. germanus was preferentially attracted to branch sections (i.e., bolts) that were either pre-colonized by conspecifics or pre-inoculated with A. grosmanniae. Subsequent analyses identified microbial volatile organic compounds (MVOCs) that could potentially function as aggregation pheromones for X. germanus. To our knowledge, this is the first evidence for fungal volatiles as attractive cues during host selection by X. germanus. Adaptive benefits of responding to fungal cues associated with an infestation of conspecifics could be a function of locating a suitable substrate for cultivating fungal symbionts and/or increasing the likelihood of mating opportunities with the flightless males. However, this requires solutions for evolutionary conflict arising due to potential mixing of vertically transmitted and horizontally acquired symbiont strains, which are discussed. [ABSTRACT FROM AUTHOR]

A new species, Tricosa uniseriata sp. nov., is described here. A list of Tricosa species found in Thailand with distributions and an updated key to Tricosa are also provided. [ABSTRACT FROM AUTHOR]

The European shot-hole borer Anisandrus dispar (Fabricius) (Coleoptera Curculionidae Scolytinae) is a well-known ambrosia beetle living on shrubs and several ornamental and fruiting trees where it can cause heavy damages. Like other harmful xyleborine species, A. dispar can represent a potential threat outside its native region. Molecular diagnostic tools can lead to accurate identification of xylophagous species hidden in wooden matrix in phytosanitary surveys at entry points. A molecular assay based on qPCR TaqMan™ Probes was developed for the identification of A. dispar from different matrices. To setup and perform the test, DNA extraction was carried out from adults, larvae, and artificial samples of wood chips from oak healthy plants whose lysates were contaminated with a known amount of DNA of A. dispar adults. The assay has proven inclusive for A. dispar, and exclusive towards the non-target organisms, showing 100% analytical specificity. The limit of detection was 0.32 pg µL-1 for the samples of insect adult DNA of A. dispar, and at 0.8 pg µL-1 for the samples containing lysates of Quercus spp. and 0.1 ng µL-1 of A. dispar adult DNA. Repeatability and reproducibility showed low values independently from the matrix used for DNA extraction, confirming the possible use in diagnostics of biological samples even if not directly related to the presence of A. dispar developmental stages. The presented approach may be adjusted and applied for phytosanitary purposes to other quarantine pests and rapidly detect possible infestations in vegetal matrices globally traded. [ABSTRACT FROM AUTHOR]

Anisandrus maiche (Stark) (Coleoptera: Curculionidae: Scolytinae) is a non‐native ambrosia beetle recently detected in northwestern Indiana. There is a critical need for advanced methods to detect and manage this potentially destructive beetle. Identifying semiochemicals that function as attractants or repellents can inform management practices to protect high‐value plantings of hardwood trees.We evaluated the extent to which (S)‐(−)‐verbenone, (E)‐(±)‐conophthorin and ethanol influence trap capture of A. maiche using two trap types and heights. We also investigated the effect of ethanol release rate on trap capture.Traps baited with ethanol alone captured the most beetles, while traps baited with (S)‐(−)‐verbenone or (E)‐(±)‐conophthorin alone captured few A. maiche, and each compound decreased capture when paired with ethanol lures.There was no difference in mean capture of A. maiche between trap types across treatments, and the height of ethanol‐baited traps did not influence the capture rate suggesting this species is widely distributed throughout the canopy.Our results suggest that (S)‐(−)‐verbenone and (E)‐(±)‐conophthorin are effective repellents for A. maiche and a release rate of at least 3 g/day of ethanol enhances trap to capture. [ABSTRACT FROM AUTHOR]

Ambrosia beetles from the tribe Xyleborini are part of nearly all forest ecosystems. Because of their small size, haplodiploid mating structure, and protected lives inside the sapwood of woody plants, they have a unique ability to expand into new regions via inadvertent human transport. A small number of invasive xyleborines cause significant damage to forests, lumber concerns, and agricultural systems. Most ambrosia pests damage or kill trees by the accumulation of beetle attacks, one is known to cause tree death through the introduction of pathogenic fungus into susceptible Lauraceae trees. The relationships between ambrosia fungi and their beetle vectors range from mutualistic symbiosis to facultative association, but most remain unstudied. Unresolved taxonomies, convergent morphologies, and the difficulty of sampling ambrosia fungi over their entire global ranges make comprehensive surveys of ambrosia fungi difficult to achieve. Ambrosia fungi from Europe and North America are moderately well documented, however, we have yet to sufficiently document those from Africa, Asia, Australia, and South America. Worldwide cooperation to improve and standardize scientific study of the ambrosia symbioses is needed to better understand these impactful organisms. [ABSTRACT FROM AUTHOR]

There are over two million hectares of Acacia plantations in Vietnam and loss from infestations of ambrosia beetles is of increasing concern. In this study, we first determined the key taxa and the extent of damage, and then identified effective trap and lure combinations for trapping adult beetles, and finally quantified the seasonality of flight of Euwallacea for informing pest management decisions. Based on analysis of the mitochondrial cytochrome c oxidase subunit I gene, the greatest threats were confirmed as Euwallacea fornicatus and E. similis (Coleoptera: Curculionidae), which are native to Southeast Asia but known as invasive species in South Africa and elsewhere. The damage incidence of Euwallacea ranged from 16.7% to 34.9% in Acacia plantations throughout Vietnam. There were no significant differences in the numbers of beetles captured between the three trap types (plastic bottles, funnels and panels). Ethanol and quercivorol were more effective as lures than cubeb oil, α-pinene or a distilled water control. Trapping from June 2020 to May 2021 revealed a bimodal frequency of E. fornicatus and E. similis in A. mangium and Acacia hybrid plantations, with captures peaking in April (spring) and October (autumn). These findings can be applied to develop early detection and trapping control programmes for Euwallacea in Acacia plantations in Vietnam and elsewhere. [ABSTRACT FROM AUTHOR]

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 Xylosandrus germanus (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 X. germanus and to get acquainted with temporal changes in the abundance of this species in these two distant areas. Dispersing X. germanus 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 X. germanus 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.

The black stem borer Xylosandrus germanus (Blandford, 1894) (Coleoptera: Curculionidae: Scolytinae) is a species native to Eastern Asia that has invaded 24 countries worldwide, including 21 European countries, the USA, Canada and New Zealand. On the Iberian Peninsula it was recorded for the first time in traps placed in the Basque Country (Northern Spain) in 2003, but its host plants were unknown. In the present work, three populations of X. germanus are recorded in the east of Spain in Girona, Tarragona and Valencia provinces (Automomous Community of Catalonia, and Valencia, respectively). Specimens were collected in traps and on host plants, showing a wider distribution range now including the east and north‐east of the Iberian Peninsula. Infested carob trees (Ceratonia siliqua) were found in agricultural and urban green areas in Tarragona. Ceratonia siliqua is therefore reported here as a new host of X. germanus. [ABSTRACT FROM AUTHOR]

Mediterranean Basin forest ecosystems are recurrently affected by wildfires. The occurrence of insect pests following fire may be a critical factor affecting tree survival and forest recovery. Although ambrosia beetles are viewed with increasing concern, information about the host selection and colonization behavior of these beetles in Mediterranean broadleaf forests is very scarce and inexistent in areas affected by wildfires. After a forest fire in Portugal, we selected 841 burned and unburned cork oak trees and assessed the presence and intensity of ambrosia beetle attacks, as well as other tree characteristics, and used generalized linear models to investigate the factors driving host selection. In contrast with burned oaks, where beetle attacks were frequent, the unburned trees were little affected. Attacks in the burned forest were more frequent in larger trees that suffered higher fire severity, in trees being exploited for cork (but with thicker bark), and in trees that were closer to the unburned area. A contagious effect to neighboring unburned trees was not observed, and cork harvesting in subsequent years following fire also did not increase the probability of beetle attacks. These results help us to understand the risk of ambrosia beetle attacks and improve forest management in cork oak forests. [ABSTRACT FROM AUTHOR]

We describe four new ambrosia beetle species of the tribe Xyleborini, Cyclorhipidion beaveri Lin & Smith sp. nov., Cyclorhipidion cognatoi Lin & Smith sp. nov., Cyclorhipidion hsuae Lin & Smith sp. nov., and Cyclorhipidion wui Lin & Smith sp. nov., which complete their lifecycle on the host plant Castanopsis cuspidata var. carlesii (Hemsl.) Yamazaki (Fagaceae). Five newly recorded species, Anisandrus ursulus (Eggers, 1923), Arixyleborus minor (Eggers, 1940), Coptodryas mus (Eggers, 1930), Cyclorhipidion japonicum (Nobuchi, 1981), and Xyleborinus octiesdentatus (Murayama, 1931) are reported in Taiwan for the first time. We provide brief diagnoses, photographic images and biological information for each species in Taiwan. [ABSTRACT FROM AUTHOR]

Ambrosia beetles from the scolytine tribe Xyleborini (Curculionidae) are important to the decomposition of woody plant material on every continent except Antarctica. These insects farm fungi on the walls of tunnels they build inside recently dead trees and rely on the fungi for nutrition during all stages of their lives. Such ambrosia fungi rely on the beetles to provide appropriate substrates and environmental conditions for growth. A small minority of xyleborine ambrosia beetle–fungal partnerships cause significant damage to healthy trees. The xyleborine beetle Coptoborus ochromactonus vectors a Fusarium (Hypocreales) fungus that is lethal to balsa (Ochroma pyramidale (Malvaceae)) trees in Ecuador. Although this pathogenic fungus and its associated beetle are not known to be established in the United States, several other non-native ambrosia beetle species are vectors of destructive plant diseases in this country. This fact and the acceleration of trade between South America and the United States demonstrate the importance of understanding fungal plant pathogens before they escape their native ranges. Here we identify the fungi accompanying Coptoborus ambrosia beetles collected in Ecuador. Classification based ribosomal internal transcribed spacer 1 (ITS) sequences revealed the most prevalent fungi associated with Coptoborus are Fusarium sp. and Graphium sp. (Microascales: Microascaceae), which have been confirmed as ambrosia fungi for xyleborine ambrosia beetles, and Clonostsachys sp. (Hypocreales), which is a diverse genus found abundantly in soils and associated with plants. Phylogenetic analyses of the Fusarium strains based on ITS, translation elongation factor (EF1-α), and two subunits of the DNA-directed RNA polymerase II (RPB1 and RPB2) identified them as Fusarium sp. AF-9 in the Ambrosia Fusarium Clade (AFC). This Fusarium species was previously associated with a few xyleborine ambrosia beetles, most notably the species complex Euwallacea fornicatus (Eichhoff 1868) (Curculionidae: Scolytinae: Xyleborini). Examination of ITS and EF1-α sequences showed a close affinity between the Graphium isolated from Coptoborus spp. and other xyleborine-associated Graphium as well as the soil fungus Graphium basitruncatum. This characterization of ambrosia fungi through DNA sequencing confirms the identity of a putative plant pathogen spread by Coptoborus beetles and expands the documented range of Fusarium and Graphium ambrosia fungi. [ABSTRACT FROM AUTHOR]

Ambrosia beetles are among the most damaging forest pests. They are frequently moved intercontinentally and are therefore subject to quarantines. The objective of the current research was to determine whether two commercially produced lures for Trypodendron species also attract central European ambrosia beetles. In 2018, Theysohn® traps were deployed in an oak forest that also contained hornbeam and linden trees. Five pair of traps was baited with the standard synthetic pheromone lures, Trypowit® or Lineatin Kombi®. The 201 adults of ambrosia bark beetles that were trapped were identified to eight species, which represents almost the entire spectrum of oak ambrosia scolytids in the region. Trypodendron domesticum, Xyleborinus saxesenii, and Xyleborus monographus were the most abundant species and exhibited a slight preference for the lure with a higher content of alcohols (Lineatin Kombi®). Both lures attracted T. lineatum because both contain lineatin. The number of beetles trapped was low probably because food sources (damaged or wilting oaks) were rare and because the forest was surrounded by agricultural land and therefore isolated from other oak forests.

A catalogue of the fauna of Korean Xyleborine species is provided with information on the Korean records, local and world distribution and taxonomy. The following seven new species and 11 newly recorded species are added to the Korean fauna: Cyclorhipidion laciniosum Park & Smith sp. nov., Cyclorhipidion triste Park & Smith sp. nov., Microperus molestus Park & Smith sp. nov., Xyleborinus kwangreungensis Park & Smith sp. nov., Xyleborus singhi Park & Smith sp. nov., Xylosandrus dentipennis Park & Smith sp. nov., Xylosandrus trunculus Park & Smith sp. nov., Cyclorhipidion fukiense (Eggers), Cyclorhipidion japonicum (Nobuchi), Cyclorhipidion laetum (Niisima), Diuncus haberkorni (Eggers), Dryoxylon onoharaense (Murayama), Euwallacea interjectus (Blandford), Microperus quercicola (Eggers), Xyleborus glabratus Eichhoff, Xyleborus muticus Blandford, Xyleborus ohtoensis Nobuchi, and Xylosandrus compactus (Eichhoff). Two new combinations, Euwallacea praevius (Blandford) comb. nov. and Dryocoetes longipilus (Eggers) comb. nov. (both from Xyleborus), are given. The record of Euwallacea minutus is removed from the Korean fauna.

Mediterranean Basin forest ecosystems are recurrently affected by wildfires. The occurrence of insect pests following fire may be a critical factor affecting tree survival and forest recovery. Although ambrosia beetles are viewed with increasing concern, information about the host selection and colonization behavior of these beetles in Mediterranean broadleaf forests is very scarce and inexistent in areas affected by wildfires. After a forest fire in Portugal, we selected 841 burned and unburned cork oak trees and assessed the presence and intensity of ambrosia beetle attacks, as well as other tree characteristics, and used generalized linear models to investigate the factors driving host selection. In contrast with burned oaks, where beetle attacks were frequent, the unburned trees were little affected. Attacks in the burned forest were more frequent in larger trees that suffered higher fire severity, in trees being exploited for cork (but with thicker bark), and in trees that were closer to the unburned area. A contagious effect to neighboring unburned trees was not observed, and cork harvesting in subsequent years following fire also did not increase the probability of beetle attacks. These results help us to understand the risk of ambrosia beetle attacks and improve forest management in cork oak forests.

We provide an overview of both traditional and innovative control tools for management of three Xylosandrus ambrosia beetles (Coleoptera: Curculionidae: Scolytinae), invasive species with a history of damage in forests, nurseries, orchards and urban areas. Xylosandrus compactus, X. crassiusculus and X. germanus are native to Asia, and currently established in several countries around the globe. Adult females bore galleries into the plant xylem inoculating mutualistic ambrosia fungi that serve as food source for the developing progeny. Tunneling activity results in chewed wood extrusion from entry holes, sap outflow, foliage wilting followed by canopy dieback, and branch and trunk necrosis. Maintaining plant health by reducing physiological stress is the first recommendation for long-term control. Baited traps, ethanol-treated bolts, trap logs and trap trees of selected species can be used to monitor Xylosandrus species. Conventional pest control methods are mostly ineffective against Xylosandrus beetles because of the pests' broad host range and rapid spread. Due to challenges with conventional control, more innovative control approaches are being tested, such as the optimization of the push–pull strategy based on specific attractant and repellent combinations, or the use of insecticide-treated netting. Biological control based on the release of entomopathogenic and mycoparasitic fungi, as well as the use of antagonistic bacteria, has yielded promising results. However, these technologies still require validation in real field conditions. Overall, we suggest that management efforts should primarily focus on reducing plant stress and potentially be combined with a multi-faceted approach for controlling Xylosandrus damage. [ABSTRACT FROM AUTHOR]

Ambrosia beetles are small wood inhabiting members of the Curculionidae that have evolved obligate symbioses with fungi. The fungal symbionts concentrate nutrients from within infested trees into a usable form for their beetle partners, which then utilize the fungi as their primary source of nutrition. Ambrosia beetle species associate with one or more primary symbiotic fungal species, but they also vector auxiliary symbionts, which may provide the beetle with developmental or ecological advantages. In this study we isolated and identified ophiostomatalean fungi associated with ambrosia beetles occurring in a native forest area in South Africa. Using a modified Bambara beetle trap, living ambrosia beetle specimens were collected and their fungal symbionts isolated. Four beetle species, three Scolytinae and one Bostrichidae, were collected. Five species of ophiostomatalean fungi were isolated from the beetles and were identified using both morphological characters and DNA sequence data. One of these species, Raffaelea sulphurea, was recorded from South Africa for the first time and two novel species were described as Ceratocystiopsis lunata sp. nov. and Raffaelea promiscua sp. nov. [ABSTRACT FROM AUTHOR]

Copyright of Silva Lusitana is the property of Unidade de Investigacao de Silvicultura e Productos Florestais and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Ambrosia beetles are among the most damaging forest pests. They are frequently moved intercontinentally and are therefore subject to quarantines. The objective of the current research was to determine whether two commercially produced lures for Trypodendron species also attract central European ambrosia beetles. In 2018, Theysohn® traps were deployed in an oak forest that also contained hornbeam and linden trees. Five pair of traps was baited with the standard synthetic pheromone lures, Trypowit® or Lineatin Kombi®. The 201 adults of ambrosia bark beetles that were trapped were identified to eight species, which represents almost the entire spectrum of oak ambrosia scolytids in the region. Trypodendron domesticum, Xyleborinus saxeseni, and Xyleborus monographus were the most abundant species and exhibited a slight preference for the lure with a higher content of alcohols (Lineatin Kombi®). Both lures attracted T. lineatum because both contain lineatin. The number of beetles trapped was low probably because food sources (damaged or wilting oaks) were rare and because the forest was surrounded by agricultural land and therefore isolated from other oak forests. [ABSTRACT FROM AUTHOR]

A sampling survey for scolytine bark beetles undertaken in Pēpē'ōpae Bog, part of The Nature Conservancy's Kamakou Preserve on the Hawaiian island of Moloka'i, revealed the presence there of two native species of the xyleborine genus Xyleborus Eichhoff not previously known from the island: X. obliquus Sharp, 1885, and X. vulcanus Perkins, 1900. We report these new records in detail, discussing their significance to our understanding of the distribution of Hawaiian bark beetles, list all known native species from Moloka'i together with their known host plants, and provide photographs of the newly recorded beetles, together with a locality map. [ABSTRACT FROM AUTHOR]

We present a reassessment of the diversity of bark and ambrosia beetles in Cuba. For the first time in decades, an official Cuban-American binational collaboration allowed us to re-visit all known entomology collections in Cuba, and collect in the field. There are at least 94 species of scolytine beetles in Cuba. We report a new species, Xylosandrus aurinegro Gomez & Hulcr (Coleoptera: Curculionidae), and 7 new species records, including the first genus record for Dryocoetoides Hopkins and Tricolus Blandford (both Coleoptera: Curculionidae) for the island. In terms of species with potential concern to the USA, we corroborate a subspecies of Ips calligraphus Wood & Bright (Coleoptera: Curculionidae) that acts as a pine pest in Cuba and is not yet present in North America. [ABSTRACT FROM AUTHOR]

Eucalypts are among the most widely planted forest trees in the world, and outside their native Australian range, the main arthropod pests are sap‐sucking insects, defoliators, gall‐making insects and xylophagous beetles. We report on a new association between a polyphagous wood‐boring beetle and Tasmanian blue gum (Eucalyptus globulus Labill.) in Central Portugal. Unidentified wood‐boring insects were found attacking two three‐year‐old E. globulus trees showing signs of decline among otherwise healthy trees in a commercial plantation, in June 2018. Declining trees presented dead twigs and branches, and recently developed epicormic sprouts evident on the trunks. Insects emerging from logs were identified as Ambrosiodmus rubricollis (Eichhoff), a species native to eastern and southern Asia, with the taxonomic identification validated by molecular analysis. To our knowledge, this is the first record of A. rubricollis associated with a eucalypt species worldwide. It is not clear whether the beetles played any significant role on the decline of the trees, but Ambrosiodmus may be potential pests for several tree and shrub species in Europe, as these beetles can transport pathogenic fungi. [ABSTRACT FROM AUTHOR]

The ambrosia beetle Xyleborus volvulus Fabricius has been reported as a potential vector of the plant pathogen Raffaelea lauricola T.C. Harr., Fraedrich & Aghayeva that is affecting avocado orchards in South Florida. In this study, we examined its life cycle, process of gallery formation, gallery structure, and fungal associates by rearing one generation on avocado sawdust medium under control conditions. The adult foundress excavated a vertical tunnel that constituted the main gallery with a length of 2.5 cm, followed by the construction of up to six secondary galleries with a total length of 4.4 cm. The time period for one generation (egg to adult) was 28 days. Teneral males emerged 3 days after the emergence of the first females. The F1 generation did not significantly contribute to gallery expansion. Four species of Raffaelea and nine yeast species were recovered from galleries and beetles. Raffaelea arxii and Candida berthetii were the most frequent symbionts recovered from new adults and galleries. Candida berthetii dominated during the early stages of the gallery development, whereas R. arxii was most frequent in later stages. Other Raffaelea species were inconsistently isolated from galleries, which suggests a strong association between Xyleborus volvulus and both R. arxii and C. berthetii. These results suggest that R. arxii is the primary nutritional symbiont of X. volvulus and that yeast species may be pioneer colonizers that assist with the growth of fungal symbionts. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Economic Entomology is the property of Oxford University Press / USA and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Thousands of species of ambrosia beetles excavate tunnels in wood to farm fungi. They maintain associations with particular lineages of fungi, but the phylogenetic extent and mechanisms of fidelity are unknown. We test the hypothesis that selectivity of their mycangium enforces fidelity at coarse phylogenetic scales, while permitting promiscuity among closely related fungal mutualists. We confirm a single evolutionary origin of the Xylosandrus complex--a group of several xyleborine genera that farm fungi in the genus Ambrosiella. Multi-level co-phylogenetic analysis revealed frequent symbiont switching within major Ambrosiella clades, but not between clades. The loss of the mycangium in Diuncus, a genus of evolutionary cheaters, was commensurate with the loss of fidelity to fungal clades, supporting the hypothesis that the mycangium reinforces fidelity. Finally, in vivo experiments tracked symbiotic compatibility throughout the symbiotic life cycle of Xylosandrus compactus and demonstrated that closely related Ambrosiella symbionts are interchangeable, but the probability of fungal uptake in the mycangium was significantly lower in more phylogenetically distant species of symbionts. Symbiont loads in experimental subjects were similar to wild-caught beetles. We conclude that partner choice in ambrosia beetles is achieved in the mycangium, and co-phylogenetic inferences can be used to predict the likelihood of specific symbiont switches. [ABSTRACT FROM AUTHOR]

Abstract: Cnestus mutilatus (Blandford, 1894) and Microperus quercicola (Eggers, 1926) are recorded in Russia for the first time. These beetles were collected near the city of Partizansk (Primorsky krai) on native tree species by E.A. Yakushkin in 2017. Along with these ambrosia beetles, we recorded Xylosandrus germanus (Blandford, 1894), which recently emerged in the region, and Cyclorhipidion pelliculosum (Eichhoff, 1878), Xyleborus seriatus Blandford, 1894, and Anisandrus maiche (Kurentsov, 1941), which are known from the Far East of Russia. Since all these Xyleborini beetles are known to be polyphagous, can produce males by parthenogenesis, and are easily transported with wood, their potential for invasion in the European part of Russia is high. Photographs and ink drawing of ambrosia beetles are given. [ABSTRACT FROM AUTHOR]

Like other members of the tribe Xyleborini, Xyleborus bispinatus Eichhoff can cause economic damage in the Neotropics. X. bispinatus has been found to acquire the laurel wilt pathogen Raffaelea lauricola (T. C. Harr., Fraedrich & Aghayeva) when breeding in a host affected by the pathogen. Its role as a potential vector of R. lauricola is under investigation. The main objective of this study was to evaluate three artificial media, containing sawdust of avocado (Persea americana Mill.) and silkbay (Persea humilis Nash.), for rearing X. bispinatus under laboratory conditions. In addition, the media were inoculated with R. lauricola to evaluate its effect on the biology of X. bispinatus. There was a significant interaction between sawdust species and R. lauricola for all media. Two of the media supported the prolific reproduction of X. bispinatus, but the avocado-based medium was generally more effective than the silkbay-based medium, regardless whether or not it was inoculated with R. lauricola. R. lauricola had a neutral or positive effect on beetle reproduction. The pathogen was frequently recovered from beetle galleries, but only from a few individuals which were reared on inoculated media, and showed limited colonization of the beetle's mycangia. Two media with lower water content were most effective for rearing X. bispinatus. [ABSTRACT FROM AUTHOR]

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.

Ambrosiella species in the latest definition are tightly associated with ambrosia beetles in genera Anisandrus , Cnestus , and Xylosandrus within the tribe Xyleborini characterized by a mesothoracic mycangium. Eccoptopterus and Hadrodemius are another two xyleborine genera possessing mesothoracic mycangium, but their symbiotic fungi are unknown. A survey of Ambrosiella s.s. in Taiwan revealed five species, including one new species, A . catenulata , and indicated that members of Eccoptopterus and Hadrodemius are also associated with Ambrosiella s.s. It corroborates a previous hypothesis that Ambrosiella s.s. species are exclusively associated with ambrosia beetles having mesothoracic mycangium. The association appears asymmetrical: a single Ambrosiella species can be carried by multiple species of beetles, while each beetle species associates with only one Ambrosiella species. Descriptions and illustrations of species obtained in this study are provided. Identification is based on morphological and molecular analyses. [ABSTRACT FROM AUTHOR]

Genera of ambrosia beetles in the tribe Xyleborini with large, mesonotal mycangia host unique fungal symbionts in the genus Ambrosiella. The symbiont of a recent invasive to the USA from Asia, Anisandrus maiche Stark, had not been previously characterized. We found the mycangium anatomy of An. maiche collected in Ohio to be similar to that of Anisandrus dispar and consistently isolated a novel fungus, Ambrosiella cleistominuta sp. nov., from An. maiche mycangia and galleries. The fungus was distinguished from other named Ambrosiella by morphological characters and DNA sequences (ITS rDNA and tef-1α). The mycangial symbionts of ambrosia beetles had been assumed to be strictly asexual, but A. cleistominuta produces cleistothecious ascomata with ascospores in beetle galleries and in culture. In contrast to ascomata of other Ceratocystidaceae, the relatively small ascomata of A. cleistominuta are neckless and without ostioles. The ascospores are relatively large, and single-ascospore colonies produced ascomata and ascospores in culture, showing that A. cleistominuta is homothallic. [ABSTRACT FROM AUTHOR]